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1. Skeletal Kinetics Reduction for Astrophysical Reaction Networks

   https://doi.org/10.3847/1538-4365/ad454a  

   Nouri, A G; Liu, Y; Givi, P; Babaee, H; Livescu, D (May 2024, The Astrophysical Journal Supplement Series)

   AAS (Ed.)

   Abstract A novel methodology is developed to extract accurate skeletal reaction models for nuclear combustion. Local sensitivities of isotope mass fractions with respect to reaction rates are modeled based on the forced optimally time-dependent (f-OTD) scheme. These sensitivities are then analyzed temporally to generate skeletal models. The methodology is demonstrated by conducting skeletal reduction of constant density and temperature burning of carbon and oxygen relevant to Type Ia supernovae (SNe Ia). The 495-isotopes Torch model is chosen as the detailed reaction network. A map of maximum production of⁵⁶Ni in SNe Ia is produced for different temperatures, densities, and proton-to-neutron ratios. The f-OTD simulations and the sensitivity analyses are then performed with initial conditions from this map. A series of skeletal models are derived and their performances are assessed by comparison against currently existing skeletal models. Previous models have been constructed intuitively by assuming the dominance ofα-chain reactions. The comparison of the newly generated skeletal models against previous models is based on the predicted energy release and⁴⁴Ti and⁵⁶Ni abundances by each model. The consequences ofy_e≠ 0.5 in the initial composition are also explored wherey_eis the electron fraction. The simulated results show that⁵⁶Ni production decreases by decreasingy_eas expected, and that the⁴³Sc is a key isotope in proton and neutron channels toward⁵⁶Ni production. It is shown that an f-OTD skeletal model with 150 isotopes can accurately predict the⁵⁶Ni abundance in SNe Ia fory_e≲ 0.5 initial conditions. 

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2. The structure of the toric locus of a reaction network

   https://doi.org/10.1088/1361-6544/ad9c0b  

   Craciun, Gheorghe; Jin, Jiaxin; Sorea, Miruna-Ştefana (December 2024, Nonlinearity)

   Abstract We considertoric dynamical systems, which are also calledcomplex-balanced mass-action systems. These are remarkably stable polynomial dynamical systems that arise from the analysis of mathematical models of reaction networks when, under the assumption of mass-action kinetics, they can give rise tocomplex-balanced equilibria. Given a reaction network, we study theset of parameter valuesfor which the network gives rise to toric dynamical systems, also calledthe toric locusof the network. The toric locus is an algebraic variety, and we are especially interested in its topological properties. We show that complex-balanced equilibriadepend continuouslyon the parameter values in the toric locus, and, using this result, we prove that the toric locus has a remarkableproduct structure: it is homeomorphic to the product of the set of complex-balanced flux vectors and the affine invariant polyhedron of the network. In particular, it follows that the toric locus is acontractible manifold. Finally, we show that the toric locus is invariant with respect to bijective affine transformations of the generating reaction network. 

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3. Superlocal chemical reaction equilibrium in low temperature plasma

   https://doi.org/10.1002/aic.16948  

   Uner, Necip_B; Thimsen, Elijah (February 2020, AIChE Journal)

   Abstract Low temperature plasmas (LTP) are a unique class of open‐driven systems in which chemical reactions are unpredictable using established concepts. The terminal state of chemical reactions in LTP, termed thesuperlocalequilibrium state, is hypothesized to be defined by a proposed set of state variables. Using a LTP reactor wherein the state variables have been measured, it is shown that CO₂spontaneously splits and the effluent speciation is independent of the influent speciation if the state variables are held constant and the residence time is long. CO₂conversion at long residence times, which is expected to be nominally zero from equilibrium thermodynamics, can be as high as 70% in the LTP. The employed low pressure plasma reactor (P= 10 mbar) had a similar volume, productivity, and energy efficiency compared to an atmospheric pressure dielectric barrier discharge reactor, thanks to reaction rates that were three orders of magnitude faster. 

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4. Reaction‐induced morphology control in block copolymers

   https://doi.org/10.1002/pi.6562  

   Robertson, Mark; Dunn, Carmen_B; Qiang, Zhe (July 2023, Polymer International)

   Abstract Controlling the self‐assembly behaviors of block copolymers (BCPs) is a focal point of many research thrusts due to their broad use in various applications. While BCP molecular weight, volume fraction, and chemical identities are key thermodynamic parameters to determine their morphology, an emergent method in this area is through reaction‐induced changes to the characteristics of a BCPin situ, which provides access to multiple morphologies and domain sizes from a single parent polymer, as well as enabling the formation of metastable morphologies which may be difficult to attain otherwise. This work provides a focused review about the current state of reaction‐induced morphology control in BCPs in both solution and solid states. Furthermore, we provide a forward‐looking perspective on the future opportunities of understanding and employing reaction engineering to manipulate and advance BCP self‐assembly. © 2023 Society of Industrial Chemistry. 

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5. Selective reaction at grain boundaries addressing organic field effect transistor trap states

   https://doi.org/10.1039/D4TC03579H  

   Li, Feifei; Williams, Matthew C; Waldrip, Matthew; Tyznik, Colin; Ambagaspitiya, Tharushi D; Dremann, Derek; Cimatu, Katherine_Leslee Asetre; Jurchescu, Oana D; Ciszek, Jacob W (February 2025, Journal of Materials Chemistry C)

   Pentacene thin-films OFETs show increased conductance and mobility after exposure to maleic anhydride which shifts the mean energy in the grain boundaryviaan applied dipole. 

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