Charge Transfer Variability in Misfit Layer Compounds: Comparison of SnS-SnS2 and LaS-TaS2

The present paper compares and discusses two selected misfit (layer) compounds exemplarily, namely SnS-SnS₂ and LaS-TaS₂. We have employed a density-functional theory-based approach to calculate structural, energetic, and electronic properties of these structures. We have put emphasis on the difference between single layers, combined double-layer systems and periodically stacked bulk structures. Especially the varying magnitudes of charge transfer between the sublayers were studied. We demonstrate how the chemical constitution of the sublayers affects the interlayer interactions: these may be a weak non-bonding van-der-Waals dominated interlayer interaction as in SnS-SnS₂ and many other layered structures or a strong interaction related to a remarkable charge transfer between the layers as in LaS-TaS₂.     

Interleukin‐4‐Clicked Surfaces Drive M2 Macrophage Polarization

Driving macrophage (M?) polarization into the M2 phenotype provides potential against inflammatory diseases. Interleukin‐4 (IL‐4) promotes polarization into the M2‐M? phenotype, but its systemic use is constrained by dose‐limiting toxicity. Consequently, we developed IL‐4‐decorated surfaces aiming at sustained and localized activity. IL‐4 muteins were generated by genetic code expansion; Lys42 was replaced by unnatural amino acids (uAAs). Both muteins showed cell‐stimulation ability and binding affinity to IL4Rα similar to those of wt‐IL‐4. Copper‐catalyzed (CuAAC) and copper‐free strain‐promoted (SPAAC) 1,3‐dipolar azide–alkyne cycloadditions were used to site‐selectively anchor IL‐4 to agarose surfaces. These surfaces had sustained IL‐4 activity, as demonstrated by TF‐1 cell proliferation and M2, but not M1, polarization of M‐CSF‐generated human M?. The approach provides a blueprint for the engineering of cytokine‐activated surfaces profiled for sustained and spatially controlled activity.     

Multilevel surrogate modeling of an amine scrubbing process for CO2capture

Surrogate models provide a powerful method for simplifying calculations within complex simulations. While surrogate models are broadly applied within chemical engineering, little research exists investigating the level of surrogacy's impact on a simplified process model. In this work, artificial neural networks (ANN) and Kriging models are used as surrogate models at the process, process unit, and thermodynamic levels for a CO₂ amine scrubbing process. The surrogated models are evaluated against an Aspen Plus simulation for accuracy, convergence behavior, computational cost, and ability to extrapolate. The thermodynamic and process unit models can better handle discontinuous, non-smooth behavior, and convergence issues in the surrogated truth model, but poor conditioning in the final system of equations results in a lower accuracy and convergence rate than the process level surrogate. Beyond model accuracy, availability of diverse data, intended re-usability, and the desired outputs must be considered when selecting a level of abstraction.     

Designing oligomeric ethylene terephtalate building blocks by chemical recycling of polyethylene terephtalate

The intelligent recycling of plastics waste is a major concern. Because of the widespread use of polyethylene terephtalate, considerable amounts of PET waste are generated that are ideally re‐introduced into the material cycle by generating second generation products without loss of materials performance. Chemical recycling methods are often expensive and entail environmentally hazardous by‐products. Established mechanical methods generally provide materials of reduced quality, leading to products of lower quality. These drawbacks can be avoided by the development of new recycling methods that provide materials of high quality in every step of the production cycle. In the present work, oligomeric ethylene terephthalate with defined degrees of polymerization and defined molecular weight is produced by melt‐mixing PET with different quantities of adipic acid as an alternative pathway of recycling PET with respect to conventional methods, offering ecofriendly and economical aspects. Additionally, block‐copolyesters of defined block length are designed from the oligomeric products. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39786.     

Komplexkatalyse mit Technetiumverbindungen: Hydroformylierung mit Technetiumcarbonyl-Katalysatoren

Complex Catalysis with Technetium Compounds. Hydroformylation with Technetiumcarbonyl Catalysts The hydroformylation reaction of cyclohexene ( 1 ), propene ( 2 ) and 1-octene ( 3 ) was studied using Tc₂(CO)₁₀ and Tc(CO)₁₀/P(n-C₄H₉)₃, resp., as catalysts in solution. For comparison experiments have also been made with Mn₂(CO)₁₀, Mn₂(CO)₁₀/P(n-C₄H₉)₃ and Re₂(CO)₁₀/P(n-C₄H₉)₃ as catalysts for the hydroformylation of 1 . There is always a competition between hydrogenation and hydroformylation. Tc₂(CO)₁₀/P(n-C₄H₉)₃ gave the best results in activity and selectivity within the subgroup VII complexes studied, but is a rather poor catalyst compared with the cobalt or rhodium compounds.     

Dynamic optimization for gas blending in pipeline networks with gas interchangeability control

The increasing penetration of unconventional gas and liquefied natural gas poses an operational challenge on existing regional gas networks for gas quality problems. A new dynamic model for natural gas pipeline network with multiple supplies is presented with a special emphasis on gas interchangeability control. Wobbe index serves as gas interchangeability indicator and is calculated by equations derived from rigorous composition-based partial differential equations. Disjunctive formulation is applied to represent different modes of gas blending due to gas reversal, and the disjunctive model is then reformulated as a nonsmooth model with min/max and absolute value functions, which is solved by a gradient-based nonlinear program solver after smooth approximation. Moreover, a heuristic algorithm is proposed to tune the penalty parameters in order to focus on different penalty terms while keeping the model well-conditioned. The developed model and strategy are first tested with a small pipeline network model and then extended to a large model. The results show that the model can effectively manage gas interchangeability issues in pipeline networks within reasonable CPU time.     

Comparison of Canola and Soy Flour with Added Isocyanate as Wood Adhesives

Canola is widely grown in the northern latitudes for its vegetable oil, generating large quantities of residual, low value canola flour used as animal feed. The common wood adhesive poly(diphenylmethylene diisocyanate) (pMDI) should react with the wide variety of functional groups in proteins. Therefore, it would seem that canola flour with added pMDI could be an effective adhesive. Two main questions are addressed in this study: How do the wood adhesive properties of canola flour compare to the better-studied soy flour? How well do proteins, which contain an abundance of functional groups, cure with the very reactive pMDI? These questions were addressed using the small-scale adhesive strength test ASTM D-7998, with various adhesive formulations and bonding conditions for canola flour plus pMDI compared to soy adhesives. The more challenging wet cohesive bond strength was emphasized because the dry strengths were usually very good. Generally, soy adhesives were better than canola ones, as was the polyamidoamine-epichlorohydrin cross-linker compared to pMDI, but these generalizations can be altered by the conditions selected. Three-ply plywood tests supported the small-scale test results.     

Advanced trust region optimization strategies for glass box/black box models

We present an improved trust region filter (TRF) method for optimization of combined glass box/black box systems. Glass box systems refer to models that are easily expressed in an algebraic modeling language, providing cheap and accurate derivative information. By contrast, black box systems may be computationally expensive and derivatives are unavailable. The TRF method, as first introduced in our previous work (Eason and Biegler, AIChE J. 2016; 62:3124–3136), is able to handle hybrid systems containing both glass and black box components, which can frequently arise in chemical engineering, for example, when a multiphase reactor model is included in a flow sheet optimization problem. We discuss several recent modifications in the algorithm such as the sampling region, which maintains the algorithm's global convergence properties without requiring the trust region to shrink to zero in the limit. To benchmark the development of this optimization method, a test set of problems is generated based on modified problems from the CUTEr and COPS sets. The modified algorithm demonstrates improved performance using the test problem set. Finally, the algorithm is implemented within the Pyomo environment and demonstrated on a rigorous process optimization case study for carbon capture. © 2018 American Institute of Chemical Engineers AIChE J, 64: 3934–3943, 2018