02292nas a2200253 4500008004100000022001400041245009200055210006900147260010600216300001400322490000700336520136000343653001901703653000801722653001301730653002601743653002501769100002401794700002301818700002201841700002701863700002901890856011901919 2007 eng d a0009-250900aModeling of bubble column slurry reactor for reductive alkylation of p-phenylenediamine0 aModeling of bubble column slurry reactor for reductive alkylatio aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcDEC a7290-73040 v623 a

A bubble column slurry reactor (BCSR) model has been developed for the reductive alkylation of p-phenylenediamine (PPDA) with methyl ethyl ketone (MEK) to N, N'-di-secondary-alkyl-p-phenylenediamine (Di-amine). This particular reaction system is commercially relevant and involves a combination of parallel and consecutive reactions comprising equilibrium non-catalytic (homogeneous) and catalytic (heterogeneous) steps. The proposed model is based on the `mixing cell approach'. In this work the mixing cell approach has been extended by including a liquid backflow stream from all but the bottommost mixing cell. The model incorporates the contributions of gas-liquid and liquid-solid mass transfer, heat effects, and complex multistep reaction kinetics. CFD model is used to estimate the extent of backflow among mixing cells and its dependence on operating parameters. The effect of gas and liquid velocities, catalyst loading, inlet PPDA concentration, and temperature on the conversion, selectivity, global rate of hydrogenation, and temperature rise is discussed. The comparison of the current approach with the traditional mixing cell model is discussed. The BCSR model presented here will be useful to provide guidelines for designing and improving overall performance of bubble column reactors. (C) 2007 Elsevier Ltd. All rights reserved.

10abubble columns10aCFD10akinetics10aMathematical modeling10aReductive alkylation1 aChaudhari, Amit, S.1 aRampure, Mohan, R.1 aRanade, Vivek, V.1 aJaganathan, Rengaswamy1 aChaudhari, Raghunath, V. uhttps://library.ncl.res.in/content/modeling-bubble-column-slurry-reactor-reductive-alkylation-p-phenylenediamine-001740nas a2200265 4500008004100000020002200041022001400063245011200077210006900189260019400258300001200452490000900464520062700473653002401100653002601124653005201150100002501202700002801227700002201255700002701277700001501304700001201319700001101331856013201342 2010 eng d a978-0-7354-0854-8 a0094-243X00aMathematical modeling and simulation of bubble column reactor for aerial liquid phase cyclohexane oxidation0 aMathematical modeling and simulation of bubble column reactor fo a2 Huntington Quadrangle, STE 1no1, Melville, NY 11747-4501 USAbNatl Inst Technol Durgapur; SERC, Dept Sci & Technol; Caledonian Coll Engn; BRNS, Dept Atom Energy; DRDO, Minist DefencecOCT a151-1590 v12983 a

Cyclohexane oxidation is an important but complex commercial reaction, wherein the desired product, K-A oil appears as an intermediates of the reaction sequence. A mathematical model has been developed for the bubble column reactor operating under isothermal conditions. The mass and energy model equations consisted of stiff ODEs. The model was applied to describe the behavior of bubble column reactor for aerial liquid phase cyclohexane oxidation. Effect of initial substrate concentration, catalyst loading and temperature was studied and discussed in detail. Conclusions were presented at the end of the study.

10aK-A Oil Selectivity10aMathematical modeling10asubstrate conversion and product yield analysis1 aUpkare, Makarand, M.1 aRajurkar, Kalpendra, B.1 aGupta, Pankaj, R.1 aJaganathan, Rengaswamy1 aParuya, S.1 aKar, S.1 aRoy, S uhttps://library.ncl.res.in/content/mathematical-modeling-and-simulation-bubble-column-reactor-aerial-liquid-phase-cyclohexane-002834nas a2200241 4500008004100000022001400041245007600055210006900131260010600200300001200306490000800318520195600326653002202282653002602304653002402330653002602354653001902380653002702399100002602426700001702452700001802469856010502487 2016 eng d a0045-793000aTwo-layer spin coating flow of newtonian liquids: a computational study0 aTwolayer spin coating flow of newtonian liquids a computational  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcJUN a180-1890 v1313 a

Spin coating is the most commonly used method in industries to form coating films of desired thickness and functionality. In case of two-layer spin coating process, stratified layers of two immiscible liquids are deposited onto the substrate simultaneously, which spread and thin to form two-layer coating film of finite thickness. Questions concerning the effect of surface/interfacial tension on uniformity of these films and contact line evolution are relevant and need thorough investigation. Therefore, an axisymmetric model governing the flow of two-layer spin coating process is developed here. Liquids used for the study are assumed to be Newtonian and fully wetting. The contact line singularity is resolved using a precursor layer model and the governing equations are simplified using lubrication approximation. A Galerkin finite-element method (G/FEM) based scheme is developed to solve the resulting fourth order non-linear PDEs. Simulation results reveal that the fluid properties like ratio of the viscosity of upper layer fluid to lower layer and ratio of the upper gas-liquid surface tension to inner liquid-liquid interfacial tension have profound impact on the time evolution of the film profile, contact radius and shape of the capillary ridges. It is observed that a uniform two-layer film surrounded by thin single layer film is formed when the viscosity ratio is small. On the contrary, when viscosity ratio is large, a thin two-layer film surrounded by bulky capillary ridges is formed. Similarly, the results also show that sharpness of capillary ridge increases with decrease in the surface tension ratio. Further, it is found that increase in the precursor layer thickness increases the spreading rate, thereby making the film more uniform. Finally, the uniformity of the final two-layer film does not get affected by the initial volume of fluid present in the upper layer. (C) 2016 Elsevier Ltd. All rights reserved.

10aAxisymmetric flow10aMathematical modeling10aMulti-layer coating10aPrecursor layer model10aThin-film flow10aTwo-layer spin coating1 aSahoo, Subhadarshinee1 aArora, Akash1 aDoshi, Pankaj uhttps://library.ncl.res.in/content/two-layer-spin-coating-flow-newtonian-liquids-computational-study02524nas a2200217 4500008004100000022001400041245016000055210006900215260000800284300000900292490000700301520172900308653001102037653002402048653002102072653000902093653002602102100002702128700002102155856013002176 2020 eng d a0148-605500aRheological quantification of the extent of dissolution of ultrahigh molecular weight polyethylene in melt-compounded blends with high density polyethylene0 aRheological quantification of the extent of dissolution of ultra cJAN a1-120 v643 a

Melt compounding of ultrahigh molecular weight polyethylene (UHMWPE) with high density polyethylene (HDPE) promises to be an alternative route to prepare bimodal polyethylene grades. However, complete dissolution of UHMWPE in HDPE cannot be guaranteed during melt compounding. Indeed, in an earlier work [K. Chaudhuri et al., Polym. Eng. Sci. 59, 821-829 (2019)], it was shown that a fully entangled UHMWPE did not mix well with commercial HDPE. However, a disentangled UHMWPE (dPE) could be melt-mixed in the same HDPE as evidenced qualitatively by rheological measurements. The present work is focused on quantifying the extent of dissolution of dPE in HDPE. The proposed method involves fitting rheological models for linear viscoelasticity of entangled bimodal blends of polydisperse polymers to dynamic oscillatory shear data and extracting information on the extent of dissolved species. The time-dependent diffusion model of des Cloizeaux is used along with the theory of double reptation (DR) to describe the dynamics of polydisperse homopolymers and also to extract the molecular weight distribution of the UHMWPE sample. A quadratic mixing rule, consistent with the DR model, is used to describe the dynamics of bimodal blends. Melt-mixed dPE/HDPE blends were prepared and characterized for their linear viscoelastic response by frequency sweep tests. The blends showed complex behavior with multiple crossover points, especially for the higher content of dPE. The bimodal model was then fit to the experimental frequency sweep data to determine the only unknown parameter, namely, the extent of dissolved dPE. It was found that a considerable fraction of dPE is dissolved in HDPE during melt compounding.

10ablends10aDisentangled UHMWPE10adouble reptation10aHDPE10aMathematical modeling1 aChaudhuri, Krishnaroop1 aLele, Ashish, K. uhttps://library.ncl.res.in/content/rheological-quantification-extent-dissolution-ultrahigh-molecular-weight-polyethylene-melt02210nas a2200265 4500008004100000022001400041245011100055210006900166260000800235300001400243490000700257520132700264653001501591653003001606653002601636653001401662653001501676100002601691700002001717700002501737700001801762700001901780700001701799856012801816 2022 eng d a0268-257500aMechanistic modeling of continuous capture step purification of biosimilar monoclonal antibody therapeutic0 aMechanistic modeling of continuous capture step purification of  cSEP a2404-24190 v973 a

{BACKGROUND Continuous multicolumn Protein A chromatography offers various advantages for capture stage purification of monoclonal antibody therapeutics, like higher productivity and resin capacity utilization, lower buffer consumption, small footprint, etc. Due to the complexity of the continuous process, experimental optimization is time-consuming and cost-intensive. This investigation proposes a hybrid process development approach integrating experimental and mechanistic modeling for time- and cost-effective development and optimization of continuous Protein A affinity chromatography. RESULTS Productivity and capacity utilization of the continuous CaptureSMB process under varying operating conditions were predicted using the Chromatography Analysis and Design Toolkit (CADET) framework and validated with experimental results. Effects of critical process parameters like feed concentration (c(0)), loading breakthrough (s) and residence time (RT) on productivity and capacity utilization were evaluated. Model predictions were validated using the experimental results proving the reliability and feasibility of the modeling approach. At 15.00 +/- 0.20 mg mL(-1) feed model mAb concentration, the model-based approach predicted the best performance giving 27.56 g L-1 h(-1) productivity (RT = 2 min

10aCaptureSMB10acontinuous chromatography10aMathematical modeling10aProtein A10asimulation1 aDeulgaonkar, Prashant1 aBhambure, Rahul1 aPrasad, Bhaskarjyoti1 aMishra, Ashok1 aTiwari, Sanjay1 aMody, Rustom uhttps://library.ncl.res.in/content/mechanistic-modeling-continuous-capture-step-purification-biosimilar-monoclonal-antibody