The Theory of Naphthidogenesis: A Quantitative Model of the Catagenetic Evolution of Aquatic Organic Matter

—This study discusses the evolution of the composition of dispersed organic matter from the Bazhenov Formation (West Siberian petroleum basin) and the products of its catagenetic transformation on the basis of the balance and kinetic approaches to modeling of the catagenetic transformation of organic matter and its individual components, primarily kerogen. The results show that the variations in the elemental composition of kerogen and the extent of generation of both hydrocarbons and nonhydrocarbons can be quantitatively described using a simplified kinetic model. Preliminary estimates of the model parameters are given for the averaged Bazhenov-type kerogen. It is shown that numerical modeling of the catagenetic transformation of dispersed organic matter confirms the validity of the recognition of the main phase (zone) of oil generation and the main phase (zone) of gas generation.

Chemical vapor deposition of titanium nitride thin films: kinetics and experiments

Titanium nitride (TiN) films were grown by chemical vapor deposition (CVD) from titanium chlorides, ammonia (NH3) and hydrogen (H2) on single crystal c-plane sapphire, WC–Co, stainless steel and amorphous graphite substrates. The preferred orientation and color of TiN layer are studied by combining a simplified kinetic model with experiments.

Dimethyldisulphide Hydrodesulphurization on NiCoMo / Al2O3 Catalyst

Hydrodesulphurization of dimethyldisulphide was performed on Ni-Co-Mo /�-Al2O3 catalyst. The catalyst was characterized by determining the adsorption isotherms, the pore size distribution and the acid strength. Experiments were carried out on a laboratory echipament in continuous system using a fixed bed catalytic reactor at 50-100�C, pressure from 10 barr to 50 barr, the liquid hourly space velocity from 1h-1 to 4h-1 and the molar ratio H2 / dimethyldisulphide 60/1. A simplified kinetic model based on the Langmuir�Hinshelwood theory, for the dimethyldisulphide hydrodesulfurization process of dimethyldisulphide has been proposed. The results show the good accuracy of the model.

Metabolic constraints and quantitative design principles in gene expression during adaption of yeast to heat shock

Microorganisms evolved adaptive responses that enable them to survive stressful challenges in ever changing environments by adjusting metabolism through the modulation of gene expression, protein levels and activity, and flow of metabolites. More frequent challenges allow natural selection ampler opportunities to select from a larger number of phenotypes that are compatible with survival. Understanding the causal relationships between physiological and metabolic requirements that are needed for cellular stress adaptation and gene expression changes that are used by organisms to achieve those requirements may have a significant impact in our ability to interpret and/or guide evolution.Here, we study those causal relationships during heat shock adaptation in the yeast Saccharomyces cerevisiae. We do so by combining dozens of independent experiments measuring whole genome gene expression changes during stress response with a nonlinear simplified kinetic model of central metabolism.This combination is used to create a quantitative, multidimensional, genotype-to-phenotype mapping of the metabolic and physiological requirements that enable cell survival to the feasible changes in gene expression that modulate metabolism to achieve those requirements. Our results clearly show that the feasible changes in gene expression that enable survival to heat shock are specific for this stress. In addition, they suggest that genetic programs for adaptive responses to desiccation/rehydration and to pH shifts might be selected by physiological requirements that are qualitatively similar, but quantitatively different to those for heat shock adaptation. In contrast, adaptive responses to other types of stress do not appear to be constrained by the same qualitative physiological requirements. Our model also explains at the mechanistic level how evolution might find different sets of changes in gene expression that lead to metabolic adaptations that are equivalent in meeting physiological requirements for survival. Finally, our results also suggest that physiological requirements for heat shock adaptation might be similar between unicellular ascomycetes that live in similar environments. Our analysis is likely to be scalable to other adaptive response and might inform efforts in developing biotechnological applications to manipulate cells for medical, biotechnological, or synthetic biology purposes.

Simplified Kinetic Model for Thermal Combustion of Lean Methane–Air Mixtures in a Wide Range of Temperatures

The paper presents results of kinetic studies on thermal methane combustion over honeycomb monoliths. An analysis of the previous experiments [1] has shown that equations proposed there and their kinetic parameters satisfactorily describe kinetics only for relatively low temperatures up to approx. 700°C. The present study corresponds to that related and supplements the previous data with new kinetic parameters obtained in higher temperatures in the reaction zone up to 900°C. A method of the reaction rate calculation for further simulation studies combining the kinetic parameters obtained in both ranges of low (LT) according to Gosiewski et al. [1] and high temperatures (HT) are also presented in the paper.