Iron carburization in CO‐H2‐He gases,Part II: Numerical model

A numerical model for the carburization of iron in CO‐H₂‐He mixtures was developed and compared with experimental data over the temperature range of 850°C–1150°C, CO partial pressures from 1% to 12%, and H₂ partial pressures from 5% to 99%. The reaction mechanism was established on the basis of data input from recent quantum mechanical and molecular dynamics calculations as well as from rate constant estimates from kinetic and transition state theory. Sensitivity and reaction flux analyses were performed to identify the rate‐controlling and fastest reactions. Model predictions of carbon weight gain in iron samples versus time were compared with experimental data. The most sensitive reactions were refined by least‐squares fitting the model to the experiment. The resulting model can simulate and predict the trends of iron carburization in CO‐H₂‐He‐CO₂‐H₂O mixtures for most conditions studied experimentally. Critical reactions and model parameters are identified for additional study to improve the model and understanding of the carburization mechanism. © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 41: 337–348, 2009     

Intercalation of Toluidines into α-Zirconium Hydrogenphosphate

Intercalates of o-, m-, and p-toluidine into α-Zr(HPO₄)₂ · H₂O were prepared and characterized by powder X-ray diffraction, thermogravimetric analysis and infrared spectroscopy. As follows from IR, toludine molecules are protonated in the interlayer space. Toluidine molecules are arranged in a bimolecular way in the intercalates containing more than 1.5 toluidine molecules per Zr atom. On the other hand, a monolayer of the toluidine molecules is supposed in the intercalates with less than one toluidine molecule per Zr atom.     

Absolute Asymmetric Synthesis: The Origin, Control, and Amplification of Chirality

Biomolecular homochirality, the origin of which is still a puzzle, has challenged scientists to design chemical systems that provide chiral molecules through absolute asymmetric synthesis and to amplify a small stereochemical bias in such systems. The photoresolution of the enantiomers of helical-shaped, sterically overcrowded alkene 1 with circularly polarized light and the transduction of the stereochemical information by triggering the helical arrangement of a large collection of achiral molecules in a twisted nematic liquid crystalline phase (2) are examples of control and amplification of chirality.     

Measurable Categories and 2-Groups

Using the theory of measurable categories developed in [10], we provide a notion of representations of 2-groups better suited to physically and geometrically interesting examples than that using 2-VECT (cf. [8]). Using this theory we sketch a 2-categorical approach to the state-sum model for Lorentzian quantum gravity proposed in [6], and suggest state-integral constructions for 4-manifold invariants.