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  • Metal‐induced polymer framework membrane with high performance for CO2 separation
    AlChE J. (IF 3.326) Pub Date : 2018-10-18
    Zhihua Qiao; Menglong Sheng; Jixiao Wang; Song Zhao; Zhi Wang

    In this study, a novel porous material, that is, metal‐induced polymer framework‐1 (MPF‐1) was synthesized using Zn(NO3)2·6H2O and a high‐molecular weight PVAmacid. MPF‐1 has two structural advantages that help to create CO2 separation membranes with simple fabrication procedure and high performance. First, MPF‐1 is a high‐molecular weight polymer with certain flexibility, and thus having good membrane‐forming ability. Second, MPF‐1 has small and uniform distributed pores, and contains amine groups those can react with CO2 molecules reversibly. Therefore, CO2 molecules can preferentially adsorb on pore walls of MPF‐1 and transport across the pores by monomolecular surface diffusion, while most of N2, CH4, or H2 molecules are excluded out the pores. The MPF‐1 was employed to fabricate a microporous membrane by coating the MPF‐1 dispersions on a polysulfone ultrafiltration membrane. CO2 permeance and selectivity of the membrane keep almost unchanged with the feed pressure increasing from 0.11 to 1.0 MPa. © 2018 American Institute of Chemical Engineers AIChE J, 2018

    更新日期:2018-10-19
  • Prediction of diffusive transport through polymer films from characteristics of the pore geometry
    AlChE J. (IF 3.326) Pub Date : 2018-10-18
    Sandra Barman; Holger Rootzén; David Bolin

    Diffusive transport through porous materials is to a large extent determined by the microstructure of the material. To design materials with controlled transport properties, it is hence important to connect properties of the pore geometry to diffusive transport rates. Different kinds of microstructures from a stochastic model are generated and multiplicative regression is used to find relationships between geometric measures of the microstructures and numerically simulated diffusive transport. The main results are that the geodesic tortuosity explains a large part of the transport variation, and that the standard deviations we introduce further improves prediction. It was found that it is best to compute the tortuosity using the whole pore space, instead of using only the inlet, as is commonly done. The effects of calculating the measures using small samples of the pore structure were investigated, and a method for minimizing errors resulting from boundary effects was proposed. © 2018 American Institute of Chemical Engineers AIChE J, 2018

    更新日期:2018-10-19
  • Adaptive evolution of Clostridium butyricum and scale‐Up for high‐Concentration 1,3‐propanediol production
    AlChE J. (IF 3.326) Pub Date : 2018-10-18
    Ai‐Hui Zhang; Xiao‐Yan Zhuang; Kai‐Nan Chen; Shi‐Yang Huang; Chao‐Zhen Xu; Bai‐Shan Fang

    In order to obtain the excellent 1,3‐propanediol (1,3‐PDO) producer from wild‐type Clostridium butyricum, adaptive evolution was carried out to select the strain for fast growth. The most significant change was that fermentation time decreased from 36 h to 20 h after adaptive evolution. Thus, it led to the corresponding volumetric productivity of 1,3‐PDO increasing from 0.97 to 2.14 (g/L·h−1) which increased by 114%. Adaptive evolution was also applied to butyric acid tolerant strain selected based on the fast‐growing one through a simple equipment. 1,3‐PDO concentration increased from 40.28 to 66.23 g/L through fed‐batch fermentation by butyric acid tolerant strain compared with the fast‐growing one. In addition, the endpoint strain was successfully and steadily used in the 50‐L scale fermentation. Thus, adaptive evolution is an excellent strategy which can help us select the fast‐growing strain and reduce the negative effect from substrate and metabolite inhibition. © 2018 American Institute of Chemical Engineers AIChE J, 2018

    更新日期:2018-10-19
  • Designing amino‐based ionic liquids for improved carbon capture: One amine binds two CO2
    AlChE J. (IF 3.326) Pub Date : 2018-10-18
    Xiao Y. Luo; Xiao Y. Lv; Gui L. Shi; Qin Meng; Hao R. Li; Cong M. Wang

    Generally, amine group captures CO2 according to 2:1 or 1:1 stoichiometry. Here, we report a kind of improved carbon capture using amino‐functionalized ionic liquids (ILs) through 1:2 stoichiometry. A serial of amino‐functionalized ILs various with basicity and steric hindrance of anion were designed, prepared, and applied in CO2 capture. Through a combination of absorption experiment, quantum chemical calculation, spectroscopic investigation and calorimetric method, the results indicated that one amine group could bind two CO2 through proton transfer (PT) process and intramolecular hydrogen bond formation, which leading to enhanced capacity that breaks through equimolar. The basicity and steric hindrance of anion play a significant role in promoting amine group to capture two CO2. [P66614]2[Asp] with dual anion was further designed and synthesized to promote PT process, which showed high capacity of 1.96 mol/mol IL at 30°C and 1 atm as well as excellent reversibility. © 2018 American Institute of Chemical Engineers AIChE J, 2018

    更新日期:2018-10-19
  • Gas–liquid mass transfer and bubble size distribution in a multi‐Cyclone separator
    AlChE J. (IF 3.326) Pub Date : 2018-10-18
    Xiao Xu; Hao Lu; Yundong Qian; Bohan Zhang; Hualin Wang; Honglai Liu; Qiang Yang

    This article discusses the use of a multi‐cyclone separator, which is a simplified form of a degassing hydrocyclone, in the separation of sweeping nitrogen bubbles and dissolved oxygen from water. The motion of the nitrogen bubbles and mass transfer of dissolved oxygen is discussed. It was observed that the Sauter mean diameter and gas volume in the swirling flow region as well as the total gas holdup increased as the volumetric ratio of gas to liquid flow increased. Almost all bubbles were found to exit through the gas outlet, indicating optimum performance of the bubble‐separation process. The multi‐cyclone separator was found to achieve good performance for the mass transfer of oxygen from water to nitrogen. This work is important in predicting the destination of bubbles and dissolved gas in swirling flow. © 2018 American Institute of Chemical Engineers AIChE J, 2018

    更新日期:2018-10-19
  • D2O Labeling to measure active biosynthesis of natural products in medicinal plants
    AlChE J. (IF 3.326) Pub Date : 2018-10-17
    Ryan S. Nett; Xin Guan; Kevin Smith; Ann Marie Faust; Elizabeth S. Sattely; Curt R. Fischer

    Plant natural products have served as a prominent source of medicines throughout human history and are still used today as clinically approved pharmaceuticals. However, many medicinal plants that produce useful compounds are slow growing or recalcitrant to cultivation, making it difficult to investigate the underlying genetic/enzymatic machinery responsible for biosynthesis. To better understand the metabolism of bioactive natural products in slow‐growing medicinal plants, we used D2O labeling and LC–MS‐based metabolomics to explore the biosynthesis of medically relevant alkaloids in three plant species. Our results provide evidence for sites of active biosynthesis for these alkaloids and demonstrate that D2O labeling can be used as a general method to determine sites of active secondary metabolism over relatively short‐timescales. We anticipate that these results will facilitate discovery of complete metabolic pathways for plant natural products of medicinal importance, especially for approaches that rely upon transcriptomics and knowledge of active metabolism to identify biosynthetic enzymes. © 2018 American Institute of Chemical Engineers AIChE J, 2018

    更新日期:2018-10-18
  • Insight on the bacterial ecology in membrane bioreactor: operational conditions effect over dominant ecological players
    AlChE J. (IF 3.326) Pub Date : 2018-10-17
    Alejandro Rodriguez‐Sanchez; Gustavo Calero‐Diaz; Jaime Martin‐Pascual; Cristina Lopez‐Lopez; Juan Carlos Torres; Jose Manuel Poyatos

    A bench‐scale bioreactor was operated under two different technologies of membrane bioreactor and hybrid moving bed bioreactor‐membrane bioreactor at hydraulic retention time 6‐16 h, sludge retention time 6‐24 d and mixed liquor suspended solids 3400‐7800 mg L‐1. Analyses of their bacterial community structures showed marked differences between the two technologies for global communities but not for dominant phylotypes, and the domination of different bacterial phylotypes for the different operational conditions. Tetrasphaera genus was ubiquitous (1.1‐19.2% relative abundance) in both bioprocesses. Fodinibacter (0.04‐7.75%) was found to positively correlate with other dominant phylotypes, highlighting the relevance of Intrasporangiaceae family in membrane‐based technologies. Oligotypes distribution of dominant phylotypes showed that certain strains were favored at all operational conditions. Linkage with operational conditions determined that the presence/absence of carriers deeply impacted the relative abundance of dominant phylotypes. The results are relevant to discern the effect of operational conditions over bacterial communities in membrane‐based technologies.

    更新日期:2018-10-17
  • The A2aR C‐terminus provides improved total and active expression yields for adenosine receptor chimeras
    AlChE J. (IF 3.326) Pub Date : 2018-10-15
    Abhinav R. Jain; Steven H. Stradley; Anne S. Robinson

    Heterologous expression of many G‐protein coupled receptors (GPCRs) is a major bottleneck in drug discovery efforts for therapeutic development of the receptor. The goal of this study was to utilize domains from a well‐trafficked GPCR to aid in improving the trafficking of a related receptor. The adenosine A2a receptor (A2aR) shows exceptional expression and trafficking to the plasma membrane in yeast; however, this is not the case for other adenosine receptors. A2aR has a longer C‐terminus than the other adenosine receptors, which may contribute to its exceptional trafficking to the plasma membrane. To test the possibility to improve trafficking of the adenosine A1 receptor (A1R), chimeric receptors containing the seven transmembrane domains of A1R and the full‐length or truncated A2aR C‐terminus were constructed. The chimeric receptor showed improved localization to the plasma membrane and was capable of binding radioligand with native A1R affinity. Functionally active A1R receptor variants were produced at a theoretical yield of 95 pmol/mg total membrane protein, estimated using radioligand binding data, which are greater than three‐fold higher than previously reported yields from other heterologous expression systems, and should facilitate biophysical characterization and drug discovery efforts. © 2018 American Institute of Chemical Engineers AIChE J, 2018

    更新日期:2018-10-16
  • Pattern recognition in chemical process flowsheets
    AlChE J. (IF 3.326) Pub Date : 2018-10-15
    Tong Zhang; Nikolaos V. Sahinidis; Jeffrey J. Siirola

    By recognizing similarities in flowsheets, engineers can understand ways in which to improve the design and efficiency of chemical processes. However, there is no prior literature on how to compare flowsheets and mine them for common patterns. To fill this gap, we propose the first systematic methodology to mine patterns in chemical process flowsheets. The proposed methodology consists of three major steps, each of which has a polynomial time complexity. We apply our methodology to several case studies that involve comparisons of up to 18 different flowsheets. The patterns identified by our methodology are consistent with engineering practice and heuristic rules in the process synthesis literature.

    更新日期:2018-10-16
  • Modeling of dynamic systems with a variable number of phases in liquid‐liquid equilibria
    AlChE J. (IF 3.326) Pub Date : 2018-10-15
    Tobias Ploch; Moll Glass; Andreas M. Bremen; Ralf Hannemann‐Tamàs; Alexander Mitsos

    Modeling of dynamic systems with a variable number of phases is still a challenge, especially for multiple liquid phases. A common approach from literature derives first‐order Karush‐Kuhn‐Tucker (KKT) conditions of the Gibbs free energy minimization and relaxes these if a phase does not exist. It aims at enabling dynamic simulation in all phase regimes of systems in vapor‐liquid equilibrium (VLE) by following a non‐physical continuous solution. In this work, we demonstrate that this continuous solution is not always possible in liquid‐liquid equilibrium (LLE) problems. The demonstration is done both theoretically and for illustrative examples. In order to overcome the demonstrated issues, we review the use of negative flash approach that allows negative molar amounts of non‐existing phases and propose a hybrid continuous formulation that explicitly assigns phase variables in the single‐phase regime and solves flash equations otherwise. Various dynamic case studies demonstrate the applicability and limitations of all three approaches.

    更新日期:2018-10-16
  • A Dead Time Compensation Approach for Multi‐Rate Observer Design with Large Measurement Delays
    AlChE J. (IF 3.326) Pub Date : 2018-10-15
    Chen Ling; Costas Kravaris

    In our previous work, we developed a multi‐rate observer design method in linear systems with asynchronous sampling based on a Luenberger observer design coupled with inter‐sample predictors. In this article, the problem of multi‐rate multi‐delay observer design is addressed where both asynchronous sampling and possible measurement delays are accounted for. The proposed observer adopts an available multi‐rate observer design in the time interval between two consecutive delayed measurements. A dead time compensation approach is developed to compensate for the effect of delay and update past estimates when a delayed measurement arrives. The stability and robustness properties of the multi‐rate observer will be preserved under nonconstant, arbitrarily large measurement delays. A mathematical example and a gas‐phase polyethylene reactor example demonstrate good performance of the proposed observer in the presence of nonuniform sampling and nonconstant measurement delays.

    更新日期:2018-10-16
  • Modeling the Phase Equilibria of Asymmetric Hydrocarbon Mixtures Using Molecular Simulation and Equations of State
    AlChE J. (IF 3.326) Pub Date : 2018-10-15
    Ilias K. Nikolaidis; Ali Poursaeidesfahani; Zsolt Csaszar; Mahinder Ramdin; Thijs J.H. Vlugt; Ioannis G. Economou; Othonas A. Moultos

    Monte Carlo simulation (MC) is combined with equations of state (EoS) to develop a methodology for the calculation of the vapor – liquid equilibrium (VLE) of multicomponent hydrocarbon mixtures with high asymmetry. MC simulations are used for the calculation of the VLE of binary methane mixtures with long n‐alkanes, for a wide range of temperatures and pressures, to obtain sufficient VLE data for the consistent fitting of binary interaction parameters (BIPs) for the EoS. The Soave‐Redlich‐Kwong (SRK), Peng‐Robinson (PR) and PC‐SAFT EoS are considered. The ability of each EoS to correlate the VLE data is assessed and the selected ones are used to predict the VLE of multicomponent gas condensate mixtures. MC simulations proved to be very accurate in predicting the VLE in all conditions and mixtures considered. The BIPs regressed from the simulation dataset lead to equally accurate modeling results for multicomponent mixtures, compared to those regressed from experimental data.

    更新日期:2018-10-16
  • Deep Learning For Pyrolysis Reactor Monitoring: From Thermal Imaging Towards Smart Monitoring System
    AlChE J. (IF 3.326) Pub Date : 2018-10-15
    W. Zhu; Y. Ma; Y. Zhan; M.G. Benton; J.A. Romagnoli

    Monitoring the operation of a pyrolysis reactor is always challenging due to the extremely high operating temperature (over 800°C) in the fired furnace. To improve current monitoring capability, a monitoring framework is proposed that builds upon thermal photography to provide a detailed view inside the fired furnace. Based on the infrared images generated from the temperature data provided by cameras, a deep learning approach is introduced to automatically identify tube regions from the raw images. The pixel‐wise tube segmentation network is named Res50‐UNet, which combines the popular ResNet‐50 and U‐Net architectures. By this approach, the precise temperature and shape on pyrolysis tubes are monitored. The control limits are eventually drawn by the adaptive k‐nearest neighbor (AkNN) method to raise alarms for faults. Through testing over real plant data, the framework assists process operators by providing in‐depth operating information of the reactor and fault diagnosis.

    更新日期:2018-10-16
  • The effect of divalent cations on the thermostability of type II polyketide synthase acyl carrier proteins
    AlChE J. (IF 3.326) Pub Date : 2018-10-15
    Marco A. Rivas; Valentine C. Courouble; Miranda C. Baker; David L. Cookmeyer; Kristen E. Fiore; Alexander J. Frost; Kerilyn N. Godbe; Michael R. Jordan; Emily N. Krasnow; Aurelio Mollo; Stephen T. Ridings; Keisuke Sawada; Kavita D. Shroff; Bradley Studnitzer; Grace A. R. Thiele; Ashley C. Sisto; Saadia Nawal; Adam R. Huff; Robert Fairman; Karl A. Johnson; Joris Beld; Bashkim Kokona; Louise K. Charkoudian

    The successful engineering of biosynthetic pathways hinges on understanding the factors that influence acyl carrier protein (ACP) stability and function. The stability and structure of ACPs can be influenced by the presence of divalent cations, but how this relates to primary sequence remains poorly understood. As part of a course‐based undergraduate research experience, we investigated the thermostability of type II polyketide synthase (PKS) ACPs. We observed an approximate 40 °C range in the thermostability among the 14 ACPs studied, as well as an increase in stability (5–26 °C) of the ACPs in the presence of divalent cations. Distribution of charges in the helix II‐loop–helix III region was found to impact the enthalpy of denaturation. Taken together, our results reveal clues as to how the sequence of type II PKS ACPs relates to their structural stability, information that can be used to study how ACP sequence relates to function. © 2018 American Institute of Chemical Engineers AIChE J, 2018

    更新日期:2018-10-15
  • Pore network modeling of catalyst deactivation by coking, from single site to particle, during propane dehydrogenation
    AlChE J. (IF 3.326) Pub Date : 2018-10-15
    Guanghua Ye; Haizhi Wang; Xuezhi Duan; Zhijun Sui; Xinggui Zhou; Marc‐Olivier Coppens; Weikang Yuan

    A versatile pore network model is used to study deactivation by coking in a single catalyst particle. This approach allows to gain detailed insights into the progression of deactivation from active site, to pore, and to particle—providing valuable information for catalyst design. The model is applied to investigate deactivation by coking during propane dehydrogenation in a Pt‐Sn/Al2O3 catalyst particle. We find that the deactivation process can be separated into two stages when there exist severe diffusion limitation and pore blockage, and the toxicity of coke formed in the later stage is much stronger than of coke formed in the early stage. The reaction temperature and composition change the coking rate and apparent reaction rate, informed by the kinetics, but, remarkably, they do not change the capacity for a catalyst particle to accommodate coke. Conversely, the pore network structure significantly affects the capacity to contain coke. © 2018 The Authors. AIChE Journal published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers. AIChE J, 2018

    更新日期:2018-10-15
  • Air Drying with Ionic Liquids
    AlChE J. (IF 3.326) Pub Date : 2018-10-14
    Gangqiang Yu; Xiaohui Sui; Zhigang Lei; Chengna Dai; Biaohua Chen

    Ionic liquids (ILs) are employed for air drying for the first time. The experimental gas–liquid equilibrium of N2/O2 + [EMIM][BF4] and N2/O2 + [EMIM][BF4] + H2O systems under a broad temperature range are measured. The new modified UNIFAC‐Lei model is successfully extended to predict the N2/O2‐IL‐H2O system based on extensive phase equilibrium data. The air drying experiment using [EMIM][BF4] as an absorbent is conducted, confirming that this new technology is effective and efficient.

    更新日期:2018-10-15
  • Glyceraldehyde 3‐phosphate dehydrogenase modulates nonoxidative pentose phosphate pathway to provide anabolic precursors in hypoxic tumor cells
    AlChE J. (IF 3.326) Pub Date : 2018-10-13
    Woo S. Ahn; Wentao Dong; Zhe Zhang; Jason R. Cantor; David M. Sabatini; Othon Iliopoulos; Gregory Stephanopoulos

    Cancer cells exhibit enhanced lactate production to satisfy biosynthetic adenosine triphosphate requirements and also supply ribose 5‐phosphate (R5P) and nicotinamide adenine dinucleotide phosphate via the pentose phosphate pathway (PPP). Yet, little is known about the mechanism by which glycolytic flux is diverted to PPP to fulfill the increased demand for anabolic precursors and reducing equivalents. Here we show, using a 13C‐labeling methodology quantifying glycolysis and the PPP metabolism, that hypoxic cancer cells not only increase net glycolytic flux but also activate the exchange fluxes catalyzed by aldolase and transaldolase. The increased carbon exchange in the upward direction promotes the supplementation of R5P through the nonoxidative PPP and essentially controls the anaplerosis of upper glycolytic metabolites consumed for biosynthesis. This cascade of events is regulated by glyceraldehyde 3‐phosphate dehydrogenase which plays a critical role in diverting metabolites for the synthesis of nucleotide precursors and thus acts as a limiting enzyme under hypoxia. © 2018 American Institute of Chemical Engineers AIChE J, 2018

    更新日期:2018-10-14
  • Bioreactor scale‐down studies of suspended plant cell cultures
    AlChE J. (IF 3.326) Pub Date : 2018-10-13
    Caleb K. ‐L. Cheung; Noppol Leksawasdi; Pauline M. Doran

    The effect of dissolved oxygen fluctuations on suspended plant cells was investigated using a scale‐down stirred bioreactor system to simulate the heterogeneous conditions found in large‐scale vessels. Transgenic Nicotiana tabacum cells expressing IgG1 antibody and Thalictrum minus cells producing berberine were subjected to gas switching cycles based on a stochastic model of log‐normal circulation time distributions. Because pumping severely damaged the cells, the scale‐down approach was restricted to a single‐vessel system. Dissolved oxygen oscillations of amplitude about ±5% air saturation were achieved in the N. tabacum cultures; however, most simulations produced highly damped fluctuations due to oxygen transfer limitations and no significant effect on the cultures was observed. In contrast, berberine production by T. minus cells was reduced when fluctuations of ±10–15% air saturation were superimposed on mean dissolved oxygen tensions of 25 and 35% air saturation. This work demonstrates that dissolved oxygen gradients such as those found in large‐scale mixing vessels can be detrimental to plant cell cultures even when sufficient average dissolved oxygen levels are provided. © 2018 American Institute of Chemical Engineers AIChE J, 2018

    更新日期:2018-10-14
  • Application of Chemical Reaction Engineering Principles to ‘Body‐on‐a‐Chip' Systems
    AlChE J. (IF 3.326) Pub Date : 2018-10-12
    Jong Hwan Sung; Ying I. Wang; Jung Hun Kim; Jong Min Lee; Michael L. Shuler

    The combination of cell culture models with microscale technology has fostered emergence of in vitro cell‐based microphysiological models, also known as organ‐on‐a‐chip systems. Body‐on‐a‐chip systems, which are multi‐organ systems on a chip to mimic physiological relations, enable recapitulation of organ‐organ interactions and potentially whole‐body response to drugs, as well as serve as models of diseases. Chemical reaction engineering principles can be applied to understanding complex reactions inside the cell or human body, which can be treated as a multi‐reactor system. These systems use physiologically‐based pharmacokinetic (PBPK) models to guide the development of microscale systems of the body where organs or tissues are represented by living cells or tissues, and integrated into body‐on‐a‐chip systems. Here, we provide a brief overview on the concept of chemical reaction engineering and how its principles can be applied to understanding and predicting the behavior of body‐on‐a‐chip systems.

    更新日期:2018-10-14
  • Dynamical reduction of linearized metabolic networks through quasi steady state approximation
    AlChE J. (IF 3.326) Pub Date : 2018-10-12
    Claudia López Zazueta; Olivier Bernard; Jean‐Luc Gouzé

    Metabolic modeling has gained accuracy in the last decades, but the resulting models are of high dimension and difficult to use for control purpose. Here we propose a mathematical approach to reduce high dimensional linearized metabolic models, which relies on time scale separation and the quasi steady state assumption. Contrary to the flux balance analysis assumption that the whole system reaches an equilibrium, our reduced model depends on a small system of differential equations which represents the slow variables dynamics. Moreover, we prove that the concentration of metabolites in quasi steady state is one order of magnitude lower than the concentration of metabolites with slow dynamics (under some flux conditions). Also, we propose a minimization strategy to estimate the reduced system parameters. The reduction of a toy network with the method presented here is compared with other approaches. Finally, our reduction technique is applied to an autotrophic microalgae metabolic network. © 2018 American Institute of Chemical Engineers AIChE J, 2018

    更新日期:2018-10-12
  • A Tribute to Professor Jay Bailey: A Pioneer in Biochemical Engineering
    AlChE J. (IF 3.326) Pub Date : 2018-10-12
    Chaitan Khosla; Douglas S. Clark; Wilfred Chen

    This article, and this issue of the AIChE Journal, is a tribute to Professor James (Jay) E. Bailey who, as an intellectual leader of biochemical engineering, has had a profound impact on chemical engineering. Over his 30‐year career, Bailey pioneered many new approaches that have become cornerstones of modern metabolic engineering, enzyme engineering, and cell culture engineering. We highlight some of these seminal contributions as well as his legacy as a research mentor.

    更新日期:2018-10-12
  • Solvent‐Free Route for Metal‐Organic Framework Membranes Growth aiming for Efficient Gas Separation
    AlChE J. (IF 3.326) Pub Date : 2018-10-12
    Jiamin Hou; Xilu Hong; Sheng Zhou; Yanying Wei; Haihui Wang

    Industrial applications of membranes based on metal‐organic frameworks (MOFs) are challenged by their complex fabrication procedures and poor processability, despite their huge potential for efficient gas separation. Especially, the consumption of a large amount of toxic, expensive solvent and harsh operation by conventional solvothermal growth also make it less attractive for industrial production. Herein, a solvent‐free method is proposed to fabricate continuous defect‐free MOF membranes on commercial porous stainless steel substrates, where the metal precursors are electrodeposited on the support followed by a heat treatment with the ligand powder via solid state reaction without using any solvent. This strategy is proven to be applicable for various MOF membranes and it is expected to be a facile, cheap and environmental friendly way for future large‐scale production.

    更新日期:2018-10-12
  • Advancing in Vitro – in Vivo Toxicity Correlations via High‐Throughput Three‐Dimensional Primary Hepatocyte Culture
    AlChE J. (IF 3.326) Pub Date : 2018-10-12
    Dylan M. Bruckner; Jeannette J. Connerney; Jonathan S. Dordick

    Predicting drug‐induced hepatotoxicity remains a critical, yet elusive, goal in drug safety studies and pharmaceutical development. This difficulty is, in part, a result of the often‐weak relationship between in vitro and animal toxicity models. To address this weakness, we have employed a high‐throughput, three‐dimensional cell culture platform containing two cell types to screen a library of 26 small molecule drugs of various mechanisms of action and modes of toxicity. Correlations of in vitro toxicity to in vivo murine toxicity are substantially improved with primary human hepatocytes vs. a human hepatocyte cell line, HepG2. At a murine LD50 (lethal dose for 50% of population) cutoff of 300 mg/kg, the calculated predictivity for primary human hepatocytes is 76%, as compared to a calculated predictivity for HepG2 cells of 54%. These results demonstrate that primary human hepatocytes may be highly predictive of in vivo outcomes, and the use of the 3D chip platform enables substantial reduction in the number of hepatocytes required for in vitro toxicology studies.

    更新日期:2018-10-12
  • Quantitative Proteomic Analysis of Lactobacillus delbrueckii ssp. lactis Biofilms
    AlChE J. (IF 3.326) Pub Date : 2018-10-12
    Jeremy F. Chignell; Christin Schlegel; Roland Ulber; Kenneth F. Reardon

    Lactic acid is a valuable organic acid that can be produced by fermentation of renewable sugar. Lactate productivity can be increased by retaining cells within the reactor, enabling continuous operation with higher cell concentrations. Biofilms are an inexpensive cell immobilization method. While much is known about the differences in physiology and metabolism of pathogenic biofilms, biofilms relevant to industrial processes are less characterized. The goal of this study was to identify metabolic features of biofilm metabolism Lactobacillus delbrueckii ssp. lactis using quantitative proteomics. Compounds in biofilm samples negatively affected LC‐MS/MS performance, indicating the importance of sample precipitation. Among other differences, proteins associated with metabolic processes such as fatty acid biosynthesis and metal oxidation were more abundant in biofilm cells, as were proteins associated with stress. This is the first proteomic study of a Lactobacillus species in biofilms with relevance to industrial biotechnology.

    更新日期:2018-10-12
  • A Twin‐Column Recycling Chromatography with Solvent Gradient for Reinforcing the Isolation of Minor Impurities
    AlChE J. (IF 3.326) Pub Date : 2018-10-12
    Wei Feng; Yang Zhengwei; Zhao Yingxian; Wang Qiang

    A twin‐column recycling chromatography with solvent gradient was developed to isolate the minor impurities in the drugs. Two columns were connected through two six‐port valves, and the solute band was diverted from one column into another by switching the valves. During the circulation of the solute band, a modifier was constantly added to the middle between the two columns so that the eluotropic strength of the downstream liquid was reduced. Thereby, the front of the band moved slower than the tail, bringing about a band compression effect to offset the band broadening so as to improve the separation and enhance the concentration of fraction without reducing the feeding amount. Such modified scheme was successfully used to purify a proprietary intermediate, displaying great advantages over the conventional scheme without solvent gradient in terms of recovery and fraction concentration.

    更新日期:2018-10-12
  • Kinetic Modeling of Methanol to Olefins Process over SAPO‐34 Catalyst Based on the Dual‐Cycle Reaction Mechanism
    AlChE J. (IF 3.326) Pub Date : 2018-10-10
    Xiaoshuai Yuan; Hua Li; Mao Ye; Zhongmin Liu

    A kinetic model for methanol to olefins (MTO) process over SAPO‐34 catalyst was established based on the dual‐cycle reaction mechanism. Simplifications were made by assuming olefins‐based cycle as virtual species S, and aromatics‐based cycle as R, where the former mainly accounts for the production of higher olefins, while the latter for lower olefins. Transformation of S to R was considered with the participation of methanol and olefins. Meanwhile, a phenomenological deactivation model was developed to account for the deactivation process. With the proposed model, the evolution of methanol conversion and product selectivity with time on stream could be predicted, and key reaction characteristics, such as the autocatalytic nature of the reaction, could also be captured due to its mechanism‐based nature. Further simulations of MTO reactors at different scales validated the robustness and applicability of the current model in MTO process development and optimization.

    更新日期:2018-10-11
  • Random Loose Packing of Small Particles with Liquid Cohesion
    AlChE J. (IF 3.326) Pub Date : 2018-10-10
    Hongsheng Chen; Wenwei Liu; Shuiqing Li

    Random packing of wet grains is numerically investigated using a multiscale discrete element method. The cohesion between wet grains is evaluated by the Weber number, with which the macroscopic and microscopic properties of wet packing are compared with those of dry systems. The effect of capillary force on wet packing partially resembles that of van der Waals force on the dry adhesive packing, because both packing fraction (φ) and coordination number (Z) of wet packing decrease with increasing surface tension, following a Boltzmann‐like exponential decay that leads to a metastable state with φ ≈0.37 and Z≈3.8. The decay processes of wet grains, however, are much faster than that of dry ones due to the additional viscous dissipation. Moreover, in the cases of strong cohesion, the relationship between Z and φ can be well interpreted by the Edwards' ensemble theory, while those with weak cohesion follow an exponential formula instead.

    更新日期:2018-10-11
  • An analytical method of estimating diffusion coefficients of gases in liquids from pressure decay tests
    AlChE J. (IF 3.326) Pub Date : 2018-10-09
    Zehao Yang; Steven Bryant; Mingzhe Dong; Hassan Hassanzadeh

    We present an exact solution of quasi‐equilibrium model, based on pressure decay technique, to measure diffusion coefficient. The results of the quasi‐equilibrium model are compared with the traditional equilibrium model and it was found that the latter is only a special case of former one. We provide new approximate solution to estimate diffusion coefficient that is more convenient to use, compared with the previously reported approaches. It also reveals that our solution is capable of taking into account greater portion of the collected pressure decay test data and is more accurate. Based on the developed solution, estimation approaches, including linear method and exponential method, are presented and applied to analyze synthetic and experimental pressure‐decay data. The quasi‐equilibrium model is also compared with the traditional equilibrium model. The results reveal that analysis of the test data using equilibrium model may introduce large error in estimation of diffusion coefficient. © 2018 American Institute of Chemical Engineers AIChE J, 2018

    更新日期:2018-10-10
  • Identifying optimal thermodynamic paths in Work and Heat Exchange Network Synthesis
    AlChE J. (IF 3.326) Pub Date : 2018-10-09
    Haoshui Yu; Chao Fu; Matias Vikse; Chang He; Truls Gundersen

    The Process Synthesis problem referred to as Work and Heat Exchange Networks (WHENs) is an extension of the classical HENs problem considering only temperature and heat. In WHENs, additional properties are pressure and work, and strong interactions exist between temperature, pressure, work and heat. The actual sequence of heating, cooling, compression and expansion for pressure changing streams will affect the shape of the Composite and Grand Composite Curves, the Pinch point, and the thermal utility demands. Even stream identities (hot or cold) will sometimes change. The identification of the optimal thermodynamic path from supply to target state for pressure changing streams becomes a primary and fundamental task in WHENs. An MINLP model has been developed based on an extension of the Duran‐Grossmann model (that can handle variable temperatures) to also consider changing stream identities. Three reformulations of the extended Duran‐Grossmann model have been developed and tested for two examples.

    更新日期:2018-10-09
  • A Novel Hollow Fiber Membrane‐assisted Antisolvent Crystallization for Enhanced Mass Transfer Process Control
    AlChE J. (IF 3.326) Pub Date : 2018-10-09
    Linghan Tuo; Xuehua Ruan; Wu Xiao; Xiangcun Li; Gaohong He; Xiaobin Jiang

    Herein, a novel hollow fiber membrane‐assisted antisolvent crystallization (MAAC) was proposed to enhance the mass transfer control over the antisolvent crystallization. A polyethersulfone membrane module was introduced as the key device for antisolvent transfer and solution mixing. An antisolvent liquid film layer was formed on the membrane surface and mixed with the solution. The liquid film also prevented the membrane from directly contacting with crystallization solution. By controlling both the shell side flow velocity and the antisolvent transfer, the antisolvent permeation rate achieved sensitive, stable and accurate control during long‐term and repeated utilization. The interfacial mass transfer rate of MAAC was 0.66 mg·cm‐2·s‐1, which was only 1/50 that of conventional droplet antisolvent crystallization. MAAC also provided crystal products with better morphologies and narrower size distributions than the conventional process. The stable performances of MAAC in terms of its accurate antisolvent mass transfer and antifouling capabilities were also highlighted.

    更新日期:2018-10-09
  • Modeling hydrodynamic cavitation in venturi: influence of venturi configuration on inception and extent of cavitation
    AlChE J. (IF 3.326) Pub Date : 2018-10-05
    Alister Simpson; Vivek V. Ranade

    Hydrodynamic cavitation (HC) is useful for intensifying a wide variety of industrial applications including biofuel production, emulsion preparation, and wastewater treatment. Venturi is one of the most widely used devices for HC. Despite the wide spread use, the role and interactions among various design and operating parameters on generated cavitation is not yet adequately understood. This article presents results of computational investigation into the cavitation characteristics of different venturi designs over a range of operating conditions. Influence of the key geometric parameters such as the length of venturi throat and diffuser angle on the inception and extent of cavitation is discussed quantitatively. Formulation and solution of multiphase computational fluid dynamics (CFD) models are presented. Appropriate turbulence and cavitation models are selected and solved using a commercial CFD code. Care was taken to eliminate the influence of numerical parameters like mesh density, discretization scheme, and convergence criteria. The computational model was validated by comparing simulated results with three published data sets. The simulated results in terms of velocity and pressure gradients, vapor volume fractions and turbulence quantities, and so on, are critically analyzed and discussed. Diffuser angle was found to have a significant influence on cavitation inception and evolution. The length of the venturi throat has relatively less impact on cavitation inception and evolution compared to the diffuser angle. The models and simulated flow field were used to simulate detailed time–pressure histories for individual vapor cavities, including turbulent fluctuations. This in turn can be used to simulate cavity collapse and overall performance of HC device as a reactor. The presented results offer useful guidance to the designer of HC devices, identifying key operating and design parameters that can be manipulated to achieve the desired level of cavitational activity. The presented approach and results also offer a useful means to compare and to evaluate different designs of cavitation devices and operating parameters. © 2018 American Institute of Chemical Engineers AIChE J, 2018

    更新日期:2018-10-06
  • Inventory Policies and Safety Stock Optimization for Supply Chain Planning
    AlChE J. (IF 3.326) Pub Date : 2018-10-05
    Braulio Brunaud; Jose M. Laínez‐Aguirre; Jose M. Pinto; Ignacio E. Grossmann

    In this paper, traditional supply chain planning models are extended to simultaneously optimize inventory policies. The inventory policies considered are the (r,Q) and (s,S) policies. In the (r,Q) inventory policy and order for Q units is placed every time the inventory level reaches level r, while in the s,S policy the inventory is reviewed in predefined intervals. If the inventory is found to be below level s, an order is placed to bring the level back to level S. Additionally, to address demand uncertainty four safety stock formulations are presented: 1) proportional to throughput, 2) proportional to throughput with risk‐pooling effect, 3) explicit risk‐pooling, and 4) guaranteed service time. The models proposed allow simultaneous optimization of safety stock, reserve and base stock levels in tandem with material flows in supply chain planning. The formulations are evaluated using simulation.

    更新日期:2018-10-06
  • Synergistic Bimetallic Ru‐Pt Catalysts for the Low‐temperature Aqueous Phase Reforming of Ethanol
    AlChE J. (IF 3.326) Pub Date : 2018-10-05
    Zheng Zhao; Lu Zhang; Qiaohua Tan; Feifei Yang; Jimmy Faria; Daniel Resasco

    Aqueous Phase Reforming (APR) of ethanol has been studied over a series of Ru and Pt catalysts supported on carbon and titania, with different metal loadings and particle sizes. We propose that, on both metals, ethanol is first dehydrogenated to acetaldehyde, which subsequently undergoes C‐C cleavage followed by different paths, depending on the catalyst used. For instance, while monometallic Pt has high selectivity towards H2 via dehydrogenation, it has a low efficiency for C‐C cleavage, lowering the overall H2 yield. Large Ru particles produce CH4 through methanation, which is undesirable since it consumes H2. Small Ru particles have lower activity but higher selectivity towards H2 rather than CH4. On these small particles, CO blocks low‐coordination sites, inhibiting methanation. The combination of the two metals in bimetallic Ru‐Pt catalysts results in improved performance, benefiting from the desirable properties of each Ru and Pt, without the negative effects of either.

    更新日期:2018-10-06
  • Particle Dynamics in Sheared Particulate Suspensions
    AlChE J. (IF 3.326) Pub Date : 2018-10-05
    Anatoliy Strybulevych; Tomohisa Norisuye; Matthew Hasselfield; John H Page

    We report measurements of particle dynamics of neutrally buoyant suspensions of non‐Brownian glass beads in a Couette cell using Dynamic Sound Scattering. The dynamics were studied under steady shear flow across the entire gap between the stator and rotor for shear rates from 0.26 to 6.59 s‐1 and particle concentrations from 20% to 50%, thereby enabling a comprehensive investigation of the dynamics to be carried out. The average particle velocity profile varies linearly with depth inside the cell for all shear rates and concentrations. The fluctuations in the particle velocities are large, indicating that the particles are not confined to streamlines but continue to fluctuate substantially during steady flow. Our data indicate that the fluctuations are anisotropic. The components of the velocity fluctuations (granular temperature) parallel to the flow and in the vertical direction are much larger than in the radial direction. The fluctuation anisotropy decreases as the concentration increases.

    更新日期:2018-10-06
  • Length‐Dependent DNA Degradation Kinetic Model: Decay Compensation in DNA Tracer Concentration Measurements
    AlChE J. (IF 3.326) Pub Date : 2018-10-05
    Gediminas Mikutis; Lucius Schmid; Wendelin J. Stark; Robert N. Grass

    DNA is often used as a tracer in both environmental fluid flow characterization and in material tracking to avoid counterfeiting and ensure transparency in product value chains. The main drawback of DNA as a tracer is its limited stability, making quantitative analysis difficult. Here we study length‐dependent DNA decay at elevated temperatures and under sunlight by quantitative PCR and show that the stability of randomly generated DNA sequences is inversely proportional to the sequence length. By quantifying the remaining DNA length distribution, we present a method to determine the extent of decay and to account for it. We propose a correction factor based on the ratio of measured concentrations of two different length sequences. Multiplying the measured DNA concentration by this length‐dependent correction factor enables precise DNA tracer quantification, even if the DNA molecules have undergone more than 100‐fold degradation.

    更新日期:2018-10-06
  • Microwave‐Induced Polar/Nonpolar Mixture Separation Performance in a Film Evaporation Process
    AlChE J. (IF 3.326) Pub Date : 2018-10-05
    Hong Li; Jiahui Liu; Xingang Li; Xin Gao

    Selective microwave heating and irradiation reportedly have a significant impact on the relative volatility of polar/nonpolar mixtures. However, the use of this feature for a separation process has not yet been reported. In this paper, a microwave‐induced film evaporation process based on a non‐equilibrium process was developed to separate polar/nonpolar mixtures. The influencing mechanism of microwaves on the separation of a polar/nonpolar system was studied by comparing the experimental results in the presence/absence of microwave irradiation. The influences of several operating parameters, such as the initial composition, temperature, residence time, and microwave power density, were explored. The results clearly demonstrate that microwave irradiation can improve the polar component vaporization and shift the vapor phase composition. The results also indicate that the differences in the dielectric properties play a significant role in the effect of microwave irradiation on a film evaporation separation process.

    更新日期:2018-10-06
  • Multi‐Model Sensor Fault Detection and Data Reconciliation: A Case Study with Glucose Concentration Sensors for Diabetes
    AlChE J. (IF 3.326) Pub Date : 2018-10-05
    Jianyuan Feng; Iman Hajizadeh; Xia Yu; Mudassir Rashid; Sediqeh Samadi; Mert Sevil; Nicole Hobbs; Rachel Brandt; Caterina Lazaro; Zacharie Maloney; Elizabeth Littlejohn; Laurie Quinn; Ali Cinar

    Erroneous information from sensors affect process monitoring and control. An algorithm with multiple model identification methods will improve the sensitivity and accuracy of sensor fault detection and data reconciliation (SFD&DR;). A novel SFD&DR; algorithm with four types of models including outlier robust Kalman filter, locally weighted partial least squares, predictor‐based subspace identification, and approximate linear dependency‐based kernel recursive least squares is proposed. The residuals are further analyzed by artificial neural networks and a voting algorithm. The performance of the SFD&DR; algorithm is illustrated by clinical data from artificial pancreas experiments with people with diabetes. The glucose‐insulin metabolism has time‐varying parameters and nonlinearities, providing a challenging system for fault detection and data reconciliation. Data from 17 clinical experiments collected over 896 hours were analyzed; the results indicate that the proposed SFD&DR; algorithm is capable of detecting and diagnosing sensor faults and reconciling the erroneous sensor signals with better model‐estimated values.

    更新日期:2018-10-06
  • Rapid CO2 capture from ambient air by sorbent‐containing porous electrospun fibers made with the solvothermal polymer additive removal technique
    AlChE J. (IF 3.326) Pub Date : 2018-10-04
    Mitchell Armstrong; Xiaoyang Shi; Bohan Shan; Klaus Lackner; Bin Mu

    Direct air capture (DAC) of CO2 is an emerging technology in the battle against climate change. Many sorbent materials and different technologies such as moisture swing sorption have been explored for this application. However, developing efficient scaffolds to adopt promising sorbents with fast kinetics is challenging, and very limited effort has been reported to address this critical issue. In this work, the availability and kinetic uptake of CO2 in sorbents embedded in various matrices are studied. Three scaffolds including a commercially available industrial film containing ion‐exchange resin (IER), IER particles embedded in dense electrospun fibers, and IER particles embedded in porous electrospun fibers are compared, in which a solvothermal polymer additive removal technique is used to create porosity in porous fibers. A frequency response technique is developed to measure the uptake capacity, sorbent availability, and kinetic uptake rate. The porous fiber has 90% IER availability, while the dense fibers have 50% particle accessibility. The sorption half time for both electrospun fiber samples is 10 ± 3 min. Our experimental results demonstrate that electrospinning polymer/sorbent composites is a promising technology to facilitate the handleability of sorbent particles and to improve the sorption kinetics, in which the IER embedded in porous electrospun fibers shows the highest cycle capacity with an uptake rate of 1.4 mol CO2 per gram‐hour. © 2018 American Institute of Chemical Engineers AIChE J, 2018

    更新日期:2018-10-05
  • Multiphase isenthalpic flash: General approach and its adaptation to thermal recovery of heavy oil
    AlChE J. (IF 3.326) Pub Date : 2018-10-04
    Duncan Paterson; Wei Yan; Michael L. Michelsen; Erling H. Stenby

    Isenthalpic flash is a basic equilibrium calculation in process simulation. The recent interest in isenthalpic multiphase flash is mainly caused by the need for simulating thermal recovery of heavy oil. We present here systematic solutions to multiphase isenthalpic flash with full thermodynamics (such as EoS models) or with correlations for K‐factors, and discuss how to tailor the general methods to systems encountered in thermal recovery of heavy oil. First, for the general situation with full thermodynamics we recommend a solution strategy which uses Newton's method for rapid convergence in the majority of cases and Q‐function maximization to safeguard convergence when Newton's method fails. The solution procedure is a generalization of Michelsen's state function based two‐phase flash to multiple phases. The general solution does not need special considerations for the components in the system and is not limited to the selected thermodynamic models and the number of phases. For thermal recovery processes where gas, oil, and aqueous phases are typically involved, the stability analysis and initialization steps are tailored to improve the efficiency. Second, as it is quite common in thermal reservoir simulators to describe phase equilibrium and heat properties with temperature‐dependent K‐factors and separate correlations for heat capacities, we propose a formulation as an extension of the ideal solution isothermal flash formulation to solve such problems. It uses a Newton–Raphson procedure to converge in the majority of cases and a nested loop procedure with the outer loop for a temperature search as a fallback approach for convergence. If the correlations for K‐factors and for heat capacities are thermodynamically consistent, the outer loop can be treated as a maximization. Finally, we present systematic tests of the proposed algorithms using examples with full thermodynamics or K‐factor based thermodynamics. The algorithms prove robust and efficient even in challenging cases including a narrow‐boiling system, a degenerate system, and a four‐phase system. The additional computational cost relative to the corresponding isothermal flash is modest and would be suitable for the purpose of thermal reservoir simulation. © 2018 American Institute of Chemical Engineers AIChE J, 2018

    更新日期:2018-10-05
  • Experimental analysis of a photoreactor packed with Pd‐BiVO4‐Coated glass beads
    AlChE J. (IF 3.326) Pub Date : 2018-10-04
    Xiangchao Meng; Zisheng Zhang

    A photoreactor packed with glass beads coated by palladium nanoparticles‐modified BiVO4 was tested and analyzed in phenol degradation under UV–Visible light. The photocatalytic activity of Pd‐BiVO4 under visible light is higher than TiO2 under UV light, as we previously reported. In this work, we try to use the Pd‐BiVO4 in a large scale by coating the glass beads with it, a potentially industrial‐scale use. For comparison, a flat‐plate reactor and a slurry reactor were also examined. The photocatalytic activity of Pd‐BiVO4 in phenol degradation was found to be higher than that of TiO2 in all systems (slurry, flat‐plate, and packed beads reactor [PBR]). Furthermore, PBR exhibited higher energy efficiency compared to the flat‐plate reactor in phenol oxidation. The superior performance of this reactor is due primarily to the highly exposed catalyst surface area, high mass transfer coefficient, and effective delivery of both photons and reactants to the catalyst surfaces. © 2018 American Institute of Chemical Engineers AIChE J, 2018

    更新日期:2018-10-05
  • Run‐to‐run control of PECVD systems: Application to a multiscale three‐dimensional CFD model of silicon thin film deposition
    AlChE J. (IF 3.326) Pub Date : 2018-10-04
    Marquis Crose; Weiqi Zhang; Anh Tran; Panagiotis D. Christofides

    Deposition of amorphous silicon thin films via plasma‐enhanced chemical vapor deposition (PECVD) and batch‐to‐batch operation under run‐to‐run control of the associated chambered reactor are presented in this work using a recently developed multiscale, three‐dimensional in space, computational fluid dynamics model. Macroscopic reactor scale behaviors are linked to the microscopic growth of amorphous silicon thin films using a dynamic boundary which is updated at each time step of the transient in‐batch simulations. This novel workflow is distributed across 64 parallel computation nodes in order to reduce the significant computational demands of batch‐to‐batch operation and to allow for the application and evaluation in both radial and azimuthal directions across the wafer of a benchmark, run‐to‐run based control strategy. Using 10 successive batch deposition cycles, the exponentially weighted moving average algorithm, an industrial standard, is demonstrated to drive all wafer regions to within 1% of the desired thickness set‐point in both radial and azimuthal directions across the wafer surface. This is the first demonstration of run‐to‐run control in reducing azimuthal film nonuniformity. Additionally, thin film uniformity is shown to be improved for poorly optimized PECVD geometries by manipulating the substrate temperature alone, without the need for re‐tooling of the equipment. © 2018 American Institute of Chemical Engineers AIChE J, 2018

    更新日期:2018-10-05
  • Estimation of mass‐based composition in powder mixtures using Extended Iterative Optimization Technology (EIOT)
    AlChE J. (IF 3.326) Pub Date : 2018-10-03
    Zhenqi Shi; James Hermiller; Salvador García Muñoz

    The Extended Iterative Optimization Technology (EIOT) method is proposed as an extension to Muteki's [I&ECR; 2013;52(35):12258–12268] Iterative Optimization Technology to address deviations from Beer–Lambert's law in powders. The new method estimates the apparent spectrum for the pure species, rather than using the measured spectrum and augments Beer–Lambert's law with a bilinear term to capture the signature and strength of the nonchemical interferences. The proposed method has exhibited acceptable performance in spite of using a lean data set to estimate its parameters. The method provides robust and coherent estimates within the physical boundaries of the system and exhibits robustness to instrument transfer. The lean effort needed to build the EIOT method positions it as an attractive option in early stages of pharmaceutical drug product development. Its robustness to distinguish chemical from nonchemical signals implies a potential to lower the total cost of ownership for an EIOT‐based solution in manufacturing. © 2018 American Institute of Chemical Engineers AIChE J, 2018

    更新日期:2018-10-04
  • Biomass‐degrading enzymes are catabolite repressed in anaerobic gut fungi
    AlChE J. (IF 3.326) Pub Date : 2018-10-02
    John K. Henske; Sean P. Gilmore; Charles H. Haitjema; Kevin V. Solomon; Michelle A. O'Malley

    Anaerobic fungi are among the most active plant‐degrading microbes in nature. Increased insight into the mechanisms and environmental cues that regulate fungal hydrolysis would better inform bioprocessing strategies to depolymerize lignocellulose. Here, we compare the response of three strains of anaerobic fungi (Piromyces finnis, Anaeromyces robustus, and Neocallimastix californiae) to catabolite regulation by simple carbohydrates. Anaerobic fungi exhibited high enzymatic activity against crystalline cellulose, which was repressed upon incubation with free sugars. Cellulolytic degradation was also inhibited when fungi were exposed to sugars they did not metabolize, suggesting a general mode of catabolite repression. RNA‐Seq experiments in the presence of excess glucose confirmed repression of carbohydrate active enzymes during sugar uptake, and offer a path towards unmasking the function of co‐regulated genes that could be involved in biomass degradation. Overall, these results suggest that sugar‐rich hydrolysates tune the behavior of anaerobic fungi by dampening production of their biomass‐degrading enzymes. © 2018 American Institute of Chemical Engineers AIChE J, 2018

    更新日期:2018-10-03
  • Optimization of microstructure and geometry of hydrophobic ceramic membrane for SO2 absorption from ship exhaust
    AlChE J. (IF 3.326) Pub Date : 2018-10-02
    Minghui Qiu; Xiangli Kong; Kaiyun Fu; Shixian Han; Xingyin Gao; Xianfu Chen; Yiqun Fan

    Membrane gas absorption (MGA) is of great interest for SO2 capture from ship exhaust, as it has high separation efficiency and, more importantly, is comprised of a separator that can be flexibly installed and operated on ships. Here, we report a class of hydrophobic tubular asymmetric ceramic membranes for SO2 absorption. To find the membranes with reasonable microstructure and geometry, we used a numerical 2D model to simulate SO2 absorption process and verified the model by comparing its results with experimental data. Simulations showed that most of the SO2 mass transfer resistance existed in membrane phase, indicating that the optimization of membrane parameters, rather than operational conditions, should be the primary consideration to enhance the overall SO2 mass transfer performance. Furthermore, simulations indicated that the SO2 separation performance depended negligibly on membrane pore sizes, but can be significantly improved by optimizing the thickness and inner diameter of membrane tubes. © 2018 American Institute of Chemical Engineers AIChE J, 2018

    更新日期:2018-10-02
  • Modeling of fouling in cross‐flow microfiltration of suspensions
    AlChE J. (IF 3.326) Pub Date : 2018-10-02
    Nopphon Weeranoppanant; Levy I. Amar; Evelyn Tong; Monica Faria; Michael I. Hill; Edward F. Leonard

    Cross‐flow filtration of fine suspensions through microsieves occurs in microprocessing. The interaction of particles with surfaces in microenvironments has been extensively studied, but predominantly in monolayers and not with an eye to microfiltration. Here, we introduce a microfiltration model that pertains to particles that might be seen as fine in a macroscopic environment, but are large enough to intrude significantly into the shear layer of a microchannel. Thus, particle accumulation upon the sieve couples the steady‐state filtrate flux and the suspension flow through the microchannel that feeds the sieve. We envision and create a stable, stationary multilayer of particles whose thickness is shear‐limited and we identify and verify the structure and parameters that limit steady filtration in this environment. At first, a packed bed of particles forms, growing into and regulated by the micro channel's shear flow. A critical shear stress is shown to determine the thickness of the bed, seen as a stationary and stable multilayer of particles through which filtration may occur. As the bed thickens, at the expense of channel area for suspension flow, surface shear stress increases until no further particle adherence is possible. We built a simple example using hard noninteracting polymer microspheres and conducted cross‐flow filtration experiments over Aquamarijn™ microsieves (uniform pore size of 0.8 μm). We observed a steady cake‐layer thickness and because of the simple geometry afforded by uniform spheres, we could approximate the force balance, cake resistance, and filtration rate from first principles. The good fit of our data to the proposed mechanism lays a firm basis for the semiquantitative analysis of the behavior of more complex suspensions. © 2018 American Institute of Chemical Engineers AIChE J, 2018

    更新日期:2018-10-02
  • RNAseq‐based transcriptome assembly of Clostridium acetobutylicum for functional genome annotation and discovery
    AlChE J. (IF 3.326) Pub Date : 2018-10-02
    Matthew T. Ralston; Eleftherios T. Papoutsakis

    Accurate genome annotations are essential in modern biology and biotechnology, yet they are still largely based on genome sequencing and comparative analyses. We show that the Clostridium acetobutylicum genome annotation can be markedly improved by integrating bioinformatic predictions with RNA sequencing (RNAseq) data. Samples were acquired under butanol, butyrate, and unstressed treatments across various growth conditions. Analysis of an initial assembly revealed errors due to background signals and limitations of assembly algorithms. Hurdles for RNAseq transcriptome mapping include optimizing library complexity and sequencing depth, yet most studies report low sequencing depth and ignore the effect of ribosomal RNA abundance. An integrative analysis was developed to combine motif predictions, single‐nucleotide resolution sequencing depth, and library complexity to resolve difficulties in assembly curation. This minimized false positive error and determined gene boundaries, in some cases, to the exact base‐pair of prior studies. This is the first strand‐specific transcriptome assembly in a Clostridium organism. © 2018 American Institute of Chemical Engineers AIChE J, 2018

    更新日期:2018-10-02
  • An interfacial curvature distribution model and phase inversion
    AlChE J. (IF 3.326) Pub Date : 2017-10-06
    A. Vikhansky

    The state of the two‐phase system is described by the interfacial curvature distribution. A phenomenological closure model is proposed for the exact (unclosed) equations. Parameters of the model are related to the existing correlations for drop size in stirred flows. If water is dispersed in oil, the curvature has a uni‐modal distribution with a positive mode. When a control parameter, e.g., water volume fraction is increasing, the distribution becomes bi‐modal with both negative and positive values. After a while, the phase inversion occurs, and the distribution becomes uni‐modal with a negative mode. Going in the other direction the phase inversion happens at lower volume fraction of water, i.e., there is an ambivalent region, where both phases might be in the dispersed state. The model implies, that even if the conditions for phase inversion are met, there might be a significant delay before the new morphology is established. This article is protected by copyright. All rights reserved.

    更新日期:2018-10-01
  • Retraction
    AlChE J. (IF 3.326) Pub Date : 2017-09-01

    Modeling and Prediction of Protein Solubility Using the Second Osmotic Virial Coefficient by Marcel Herhut, Christoph Brandenbusch, Gabriele Sadowski,

    更新日期:2018-10-01
  • Hollow monocrystalline silicalite‐1 hybrid membranes for efficient pervaporative desulfurization
    AlChE J. (IF 3.326) Pub Date : 2018-09-29
    Fusheng Pan; Weidong Li; Ye Zhang; Jie Sun; Meidi Wang; Hong Wu; Zhongyi Jiang; Ligang Lin; Baoyi Wang; Xingzhong Cao; Peng Zhang

    Hollow monocrystalline silicalite‐1 (HMS) nanoparticles were successfully synthesized and firstly incorporated into poly(ether‐block‐amide) (Pebax) to prepare hybrid membranes. The uniformly dispersed HMS in Pebax matrix interrupt the crystalline region and optimize the free volume property. The micropores on the HMS shell enhance the selectivity because of sieving effect, whereas the inner cavity benefits the rapid diffusion of penetrant and elevates the flux. When the content of HMS (200 nm) is 20 wt %, the hybrid membrane possesses a permeation flux of 20.63 kg/(m2 h) and an enrichment factor of 6.11 (82% and 23% higher than that of Pebax membrane, respectively), which surpass the upper bound of the state‐of‐the‐art reported polymeric membranes. Moreover, the hybrid membranes display the remarkable antiswelling and long‐term operation stability. This is a step forward in fabricating the hybrid membranes with superior separation performance by incorporating porous fillers with hollow structure. © 2018 American Institute of Chemical Engineers AIChE J, 2018

    更新日期:2018-09-29
  • Impact of a Hybrid Bitumen Extraction Process on Mined Oil Sands Tailings Behavior
    AlChE J. (IF 3.326) Pub Date : 2018-09-28
    Feng Lin; Yuming Xu

    Hybrid bitumen extraction (HBE) at ambient conditions has potential, as an alternative to the commercially used modified Clark hot water extraction (CHWE) for mined oil sands. In this work, the dewatering behaviors of tailings suspensions generated on a pilot scale from standard CHWE and from HBE are studied. Using a centrifuge‐based technique, sediment height at a given centrifugal acceleration is measured as a function of time, as is equilibrium consolidation height versus acceleration. By fitting the measurements to a consolidation model, compressive yield stress data is obtained. Settling of tailings suspensions under earth's gravitation are also observed for comparison. Results demonstrate that the suspensions from the pilot HBE process settle faster than those from standard aqueous process at a given acceleration. The data also suggest that the suspensions from the pilot HBE are more compressible, as indicated by higher final compressed solids weight fraction for a given yield stress.

    更新日期:2018-09-28
  • Subsystem decomposition of process networks for simultaneous distributed state estimation and control
    AlChE J. (IF 3.326) Pub Date : 2018-09-28
    Xunyuan Yin; Jinfeng Liu

    An appropriate subsystem configuration is a prerequisite for a successful distributed control/state estimation design. Existing subsystem decomposition methods are not designed to handle simultaneous distributed estimation and control. In this article, we address the problem of subsystem decomposition of general nonlinear process networks for simultaneous distributed state estimation and distributed control based on community structure detection. A systematic procedure based on modularity is proposed. A fast folding algorithm which approximately maximizes the modularity is used in the proposed procedure to find candidate subsystem configurations. Two chemical process examples of different complexities are used to illustrate the effectiveness and applicability of the proposed approach.

    更新日期:2018-09-28
  • Consequences of Inclined and Dual Jet Impingement in Stagnant Liquid and Stratified Layers
    AlChE J. (IF 3.326) Pub Date : 2018-09-26
    Abhinav Jain; Vatsal Sanjay; Arup Kumar Das

    Different configurations of bubble entrainment have been explored inside a liquid pool resulting from the impact of plunging jets. Impingement of an inclined jet and the subsequent asymmetries are studied in present effort. The aberrations from the symmetric case have been realized in the genesis of the entrainment, including the formation and collapse of the annular cavity developed immediately after the impact. Furthermore, the three‐dimensional association of bubble population has been found to be skewed in the direction of inertia of liquid jets. The density of bubbles along a particular azimuthal plane has been tracked to quantify the intensity of entrainment in case of jet–jet interaction at different configurations. Toward the end, impingement of different fluid jets on a stratified kerosene–water layer is illustrated and complex interfacial shapes are described as an assemblage of emulsions, encapsulations, and liquid fingers. © 2018 American Institute of Chemical Engineers AIChE J, 00: 1–13, 2018

    更新日期:2018-09-27
  • Control of viscous fingering and mixing in miscible displacements with time‐dependent rates
    AlChE J. (IF 3.326) Pub Date : 2018-09-26
    Qingwang Yuan; Xiang Zhou; Jinjie Wang; Fanhua Zeng; Kelvin D. Knorr; Muhammad Imran

    In miscible displacements encountered in enhanced oil recovery processes, the unfavorable viscosity contrast between injected solvent and oil usually leads to viscous fingering (VF), a hydrodynamic instability which may result in a lower sweep efficiency and oil recovery. This phenomenon can be observed in a wide range of flows in subsurface porous media. This study examined a simple cyclic time‐dependent displacement rate and its effects on the onset and longer development of VF. It is found that such varying displacement rate can either stabilize or destabilize VF, depending on the cycle period, amplitude, and displacement scenarios. The most important mechanism is that such time‐dependent rate can effectively change the competition between convection (destabilizing effect) and dispersion (stabilizing effect). This is different from the widely used constant injection rate where the flow instability is actually determined by the Peclet number and mobility contrast for a given scenario. This study therefore provided a new aspect to control VF, either enhance or reduce, with low additional costs. It is therefore both scientifically and practically important for a wide range of flows in subsurface porous media. © 2017 American Institute of Chemical Engineers AIChE J, 00: 000–000, 2018

    更新日期:2018-09-27
  • Mass transfer around bubbles, drops, and particles in uniaxial and biaxial nonlinear extensional flows
    AlChE J. (IF 3.326) Pub Date : 2018-09-26
    Moshe Favelukis

    Mass transfer around spherical bubbles, drops, and solid particles in uniaxial and biaxial nonlinear extensional creeping flows at large Peclet numbers is the subject of this theoretical report. The fluid mechanics problem is governed by the viscosity ratio (λ) and the nonlinear intensity of the flow (E). The flow outside such bodies reveals a different picture than the linear case (E = 0) such as separating surfaces or closed circulations. There is a range: −1.04 < E < 0 (bubbles and drops) and −0.490 < E < 0 (particles) where the mass transfer rate is lower than the linear case. Outside these ranges, the mass transfer rate is higher than the linear case and in general it increases as |E| increases. Same mass transfer rates are expected in uniaxial and biaxial flows, except in the presence of external closed circulations where the biaxial flow overcomes the uniaxial flow. © 2018 American Institute of Chemical Engineers AIChE J, 2018

    更新日期:2018-09-27
  • CFD study and experimental validation of multiphase packed bed hydrodynamics in the context of Rolling Sea conditions
    AlChE J. (IF 3.326) Pub Date : 2018-09-26
    Amir Motamed Dashliborun; Faïçal Larachi

    The necessity for a validated computational fluid dynamics (CFD)‐based model to deepen our understanding about the complex hydrodynamics of gas–liquid flows in oscillating porous media has driven this experimental and simulation work. A transient three‐dimensional Euler–Euler porous media CFD model using moving reference frame and sliding mesh techniques was applied to elucidate the dynamic features of gas–liquid flows of cocurrent downflow packed beds subject to tilts and oscillations reminiscent of sea conditions. Incorporation of capillary and mechanical dispersion forces besides interphase momentum exchange terms in the CFD model to achieve reliable predictions was evaluated with respect to experimental data acquired by capacitance wire‐mesh sensors and differential pressure transmitter. In the light of the validated CFD model, a detailed sensitivity analysis was performed to address the interrelations between hydrodynamic parameters, influence of fluid properties and packing size on the model predictions, and additional contribution of column oscillations on multiphase dynamics. © 2018 American Institute of Chemical Engineers AIChE J, 2018

    更新日期:2018-09-27
  • A Model for Drop and Bubble Breakup Frequency Based on Turbulence Spectra
    AlChE J. (IF 3.326) Pub Date : 2018-09-25
    Benjamin Lalanne; Olivier Masbernat; Frédéric Risso

    In this article, a new Eulerian model for breakup frequency of drops induced by inertial stress in homogeneous isotropic turbulence is developed for moderately viscous fluids, accounting for the finite response time of drops to deform. The dynamics of drop shape in a turbulent flow is described by a linear damped oscillator forced by the instantaneous turbulent fluctuations at the drop scale. The criterion for breakup is based on a maximum value of drop deformation, in contrast with the usual critical Weber criterion. The breakup frequency is then modeled as a function of the power spectrum of Weber number (or velocity square), based on the theory of oscillators forced by a random signal, which can be related to classical statistical quantities, such as dissipation rate and velocity variance. Moreover, the effect of viscosities of both phases is included in the breakup frequency model without resorting to any additional parameter. © 2018 American Institute of Chemical Engineers AIChE J, 00: 000–000, 2018

    更新日期:2018-09-26
  • Associating lattice cluster theory and application to modeling oleic acid + formic acid + formoxystearic acid
    AlChE J. (IF 3.326) Pub Date : 2018-09-24
    Agnes Froscher; Kai Langenbach; Erik von Harbou; Hans Hasse

    In this work, the Associating Lattice Cluster Theory (ALCT) is developed. It is especially useful for describing mixtures of oligomers of varying architecture. As the influence of the structure is predicted, it can also be applied in cases in which pure component data is lacking. ALCT is used here for the calculation of liquid‐liquid equilibria (LLE) in the system oleic acid (OA) + formic acid (FA) + formoxystearic acid (FSA) that is interesting for biopolymer production. Experi‐mental studies of LLE in that system were carried out at 296 K, 313 K, and 333 K. Ternary mixtures were prepared from the educts OA and FA using heterogeneous acidic catalysis. Quantitative NMR spectroscopy was applied for the analysis. For the educt system, also the excess enthalpy was studied by isothermal titration calorimetry. The prediction of the ternary LLE by ALCT succeeds.

    更新日期:2018-09-25
  • Intensification of liquid–liquid two‐phase mass transfer in a capillary microreactor system
    AlChE J. (IF 3.326) Pub Date : 2018-09-23
    Guangxiao Li; Xin Pu; Minjing Shang; Li Zha; Yuanhai Su

    A convenient strategy to intensify the liquid–liquid mass transfer performance in a capillary microreactor system was developed by narrowing the inlet channel of T‐micromixer or adding baffles into the capillary. Various geometrical parameters such as the inlet mode and diameter of the modified T‐micromixer, the number of baffles and interval distance between baffles in the modified capillary were investigated to elaborate the mass transfer intensification mechanism. The liquid–liquid two‐phase flow patterns in new capillary microreactors were captured by a high‐speed camera. Moreover, pressure drops and specific energy dissipation of these modified microreactor systems were studied and a new parameter indicating the ratio of the mass transfer coefficient to the energy dissipation was proposed. This work highlights the modified capillary microreactor systems with embedding baffle units for achieving high mass transfer rates with its advantages over other types of reactors or microreactors considering specific energy dissipation and effective energy utilization efficiency. © 2018 American Institute of Chemical Engineers AIChE J, 2018

    更新日期:2018-09-25
  • Computational and Experimental Studies of Flexible Fiber Flows in a Normal‐Stress‐Fixed Shear Cell
    AlChE J. (IF 3.326) Pub Date : 2018-09-22
    Y. Guo; K. Buettner; V. Lane; C. Wassgren; W. Ketterhagen; B. Hancock; J. Curtis

    Flow properties of flexible fibers are poorly understood compared to those of rigid particles. In this study, a Schulze ring shear tester is used to measure the flow properties of fibers made of cut fishing wire and cut rubber cord, which have different levels of flexibility. For a comprehensive study, the discrete element method is employed to simulate flexible fiber flows. The simulations are validated by comparing with the experimental measurements. Studies show that an increase in fiber bending modulus leads to a reduction in the deformation and solid volume fraction, but it has no effect on the shear stress with the same normal stress. An increase in fiber‐fiber friction coefficient, below a critical value of 0.8, can augment the angle of internal friction. The contact stiffness, contact damping coefficient, and bond damping coefficient only have limited impact on the shear flow behavior in the ranges considered. © 2018 American Institute of Chemical Engineers AIChE J, 00: 000–000, 2018

    更新日期:2018-09-25
  • Online Monitoring of the Degree of Fill in a Rotating Full‐Flight Screw of a Corotating Twin‐Screw Extruder
    AlChE J. (IF 3.326) Pub Date : 2018-09-22
    Kentaro Taki; Takemasa Sugiyama; Masatoshi Ohara; Sho Umemoto; Shin‐ichiro Tanifuji; Jun‐ichi Murata; Isao Tsujimura; Shin‐ichi Kihara

    It is essential to understand the extent of partial filling of the flight screw, the degree of fill, which is an operational variable of the twin‐screw extruder (TSE). This article reports the first attempt to measure, in situ, the degree of fill in a rotating full‐flight screw using a specialized light‐section method for a TSE. The thickness of the resin sticking to the pushing side decreased with increasing rotational speed. The degree of fill is inversely proportional to the rotational speed and proportional to the feed rate. This result agreed well with the results suggested by the conventional analysis of flow in the TSEs. The fast Fourier transformation of the degree of fill time series indicated that the period of fluctuation correlated with the screw speed rather than the feed rate or throughput. © 2018 American Institute of Chemical Engineers AIChE J, 00: 000–000, 2018

    更新日期:2018-09-25
Some contents have been Reproduced with permission of the American Chemical Society.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
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