Kinetic modeling of lipase‐mediated one‐pot chemo‐bio cascade synthesis of R‐1‐phenyl ethyl acetate starting from acetophenone

BACKGROUND: A systematic investigation of mutual interference between a hydrogenation catalyst, Pd/Al₂O₃, and an immobilized lipase in a one‐pot synthesis of R‐1‐phenyl ethyl acetate at 70 °C has been undertaken. This paper reports the kinetic modeling of lipase‐mediated chemo‐bio cascade synthesis of R‐1‐phenyl ethyl acetate starting from acetophenone. RESULTS: The kinetic results revealed that these catalysts were not acting independently but in concert. A mechanism which predicts the experimental observations for this reaction is proposed. CONCLUSION: The parameters of the kinetic model, which are in good agreement with the experimental data, were estimated through numerical data fitting. The reliability of the estimated parameters was analyzed using the Markov Chain Monte Carlo (MCMC) method. Copyright © 2009 Society of Chemical Industry     

Enhancement in Viscoplastic Self-Consistent FLD Prediction Model and Its Application for Austenitic and Ferritic Stainless Steels

Metals and Materials International - The computational algorithm of a crystal-plastic-based FLD predictive model (VPSC-FLD) developed in Jeong et al. (Model Simul Mater Sci Eng, 2016....     

Memory-based scheduling of scientific computing clusters

This study looks at how increased memory utilisation affects throughput and energy consumption in scientific computing, especially in high-energy physics. Our aim is to minimise energy consumed by a set of jobs without increasing the processing time. The earlier tests indicated that, especially in data analysis, throughput can increase over 100% and energy consumption decrease 50% by processing multiple jobs in parallel per CPU core. Since jobs are heterogeneous, it is not possible to find an optimum value for the number of parallel jobs. A better solution is based on memory utilisation, but finding an optimum memory threshold is not straightforward. Therefore, a fuzzy logic-based algorithm was developed that can dynamically adapt the memory threshold based on the overall load. In this way, it is possible to keep memory consumption stable with different workloads while achieving significantly higher throughput and energy-efficiency than using a traditional fixed number of jobs or fixed memory threshold approaches.     

Isomerization of α-Pinene Oxide Over Iron-Modified Zeolites

Fe-modified mordenite, ferrierite, Y, ZSM-5, ZSM-12 and beta zeolite catalysts were prepared by solid state ion-exchange and conventional liquid phase ion-exchange methods from aqueous solutions. Sn- modified H-beta-300 zeolite catalyst was prepared by the later method. The characterization of proton form, Fe and Sn modified zeolites was carried out using X-ray powder diffraction, scanning electron microscopy, Mössbauer spectroscopy with magnetic measurements, transmission electron microscopy, nitrogen adsorption, X-ray absorption spectroscopy, X-ray photoelectron spectroscopy, inductively coupled plasma spectroscopy, thermo-gravimetric analysis and FTIR spectroscopy using pyridine as a probe molecule. Isomerization of α-pinene oxide over the Fe and Sn modified zeolite catalysts was carried out in the liquid phase using a batch-wise glass reactor. Formation of campholenic aldehyde and fencholenic aldehyde were observed to be influenced by the structure, acidity of zeolite and contents of Fe and Sn, reaction temperature and the catalysts pretreatment.     

Comparison of certain MINLP algorithms when applied to a model structure determination and parameter estimation problem

The maximum likelihood method is frequently used in parameter estimation. If the structure of the model is unknown, the maximization of the likelihood function can be replaced by minimizing an information criterion. One criterion that allows this to be done is Akaike’s information criterion (AIC). Minimizing the AIC is a mixed integer non-linear programming (MINLP) problem. In this paper, three different MINLP algorithms are compared in the solution of a simultaneous model structure determination and parameter estimation problem by minimizing the AIC criterion. The problem considered appears in quantitative Fourier transformed infra red (FTIR) spectroscopy where concentration estimates of certain gas components are to be obtained from measured absorbances at different wave numbers. The resulting problem is a large MINLP problem containing several hundreds, or even thousands, of variables including a huge number of possible model structures. It is, however, found that the studied algorithms solve the considered problem in quite a small number of iterations and a reasonable CPU-time.     

Recent Progress in Synthesis of Fine and Specialty Chemicals from Wood and Other Biomass by Heterogeneous Catalytic Processes

Synthesis of fine and specialty chemicals involving heterogeneous catalysts is discussed according to the type of reactions (e.g., hydrogenation, oxidation, isomerization, etc.) for various biomass derived feedstocks (carbohydrates, lignans, phenols, flavonoids, tannins, and stilbenes, tall oil, and fatty acids).     

Pollution diminishes intra-specific aggressiveness between wood ant colonies

A variety of common environmental pollutants are known to affect the animal behaviour, but the occurrence and extent of pollution-induced behavioural changes in wild populations are practically unknown. Here we show that heavy metal pollution reduces the normal intra-specific aggressive behaviour in wild populations of the wood ant, Formica aquilonia, a dominant territorial ant species in boreal forests. Ants exposed to long-term pollution around a copper smelter showed higher heavy metal concentrations and were less aggressive towards the member of foreign unpolluted colony than the ants from an uncontaminated area. A pollution-related decline in the level of aggressiveness in this keystone general predator species may potentially affect the structure of invertebrate community of boreal and temperate forests. Further studies are needed to find out whether the change in aggressiveness is directly caused by metal toxicity or indirectly via secondary pollution effects, such as changed resource levels.     

Infinite Photography: New Mathematical Model for High-Resolution Images

A new mathematical image model is introduced using the photographic process as the starting point. Images are represented as infinite sequences of photons allowing analysis at arbitrarily high resolution and leading to novel computational methods for processing, representation, transmission and storage of images. The resulting space of infinite photographs is proved to have a metric structure and to be intimately connected with bounded Borel measures. Theorems are proved indicating that the imaging power of the photographic process exceeds function spaces in the high resolution limit; this implies in particular that natural photographic images need to be modelled by generalized functions. Furthermore, computational results are presented to illustrate the novel algorithms based on photon sequences. The algorithms include stochastic halftoning, representation of cartoon images with outlines, anti-aliasing, blurring and singularity extraction.