Statistical analysis of emotions and opinions at Digg website

We performed statistical analysis on data from the Digg.com website, which enables its users to express their opinion on news stories by taking part in forum-like discussions as well as directly evaluate previous posts and stories by assigning so called "diggs". Owing to fact that the content of each post has been annotated with its emotional value, apart from the strictly structural properties, the study also includes an analysis of the average emotional response of the posts commenting the main story. While analysing correlations at the story level, an interesting relationship between the number of diggs and the number of comments received by a story was found. The correlation between the two quantities is high for data where small threads dominate and consistently decreases for longer threads. However, while the correlation of the number of diggs and the average emotional response tends to grow for longer threads, correlations between numbers of comments and the average emotional response are almost zero. We also show that the initial set of comments given to a story has a substantial impact on the further "life" of the discussion: high negative average emotions in the first 10 comments lead to longer threads while the opposite situation results in shorter discussions. We also suggest presence of two different mechanisms governing the evolution of the discussion and, consequently, its length.Comment: 26 pages, 16 figures, 6 table

Optimization of a Complex Industrial Process – Role of Process Modelling

Oxidation of cyclohexane in the liquid phase is an important step in production of caprolactam, subsequently converted into polyamide plastics (Nylon 6, Nylon 66). One of the processes commercially employed to oxidize cyclohexane is the Polish CYCLOPOL process. In order to keep pace with other leading companies, the owners of the CYCLOPOL process continue to carry on research and development work, aimed at increasing productivity and selectivity of the process. A model of the process of the catalytic cyclohexane oxidation in the liquid phase, including both reaction kinetics and mass transfer, is presented. The reaction rate constant as well as the activation energies were determined on the basis of the experimental results obtained in a laboratory reactor. The model of the hydrodynamics of gas bubbling through a liquid layer is also presented. This model has been verified experimentally for different organic liquids and columns of different scale. The model has been subsequently used to establish a theoretically based correlation for the bubble diameter by means of a numerical experiment using “virtual liquids”. The two models (of chemical kinetics on the system hydrodynamics) have been integrated to give a comprehensive model of the whole process of cyclohexane oxidation in industrial reactors. Numerical simulation of industrial rectors gave good agreement with the operating data. 2. Keywords: process modelling, cyclohexane oxidation, chemical kinetics, hydrodynamics of gas bubblin