Anwendung eines Stranggieß-Simulationsmodells bei Štore Steel – II

This paper represents the elements and the use of the upgraded simulation system, developed in the last half decade for ?tore Steel billet caster. The simulation system is used in the context of the state-of-the-art automation and information of the twenty-five year-old three-strand Concast billet continuous caster for dimensions square 140 and 180 mm with the capacity of 160,000 tons/year. The simulation system is used in the off-line and on-line modes. The off-line mode is used in order to set the proper process parameters and to calculate the temperature field, macrosegregation, and grain structure of the strand. It is also used to calculate the changes in the caster design such as the secondary cooling and the position of the SEN. The on-line model is used in automatic casting control system. The paper represents an update of our BHM publication of 2005 (Application of Continous Casting Simulation at ?tore Steel, BHM, Vol. 150, No. 9, 300–306).     

Advances in Catalyst Systems for the Asymmetric Hydrogenation and Transfer Hydrogenation of Ketones

Hydrogenation of prochiral ketones using chiral transition-metal catalysts represents the cleanest way to access enantiomerically enriched secondary alcohols, which are important building blocks in fine chemicals synthesis. Despite excellent activity, selectivity and compatibility of metal complexes with variety of functional groups, no universal catalysts exist. In this article we summarize the advances in catalyst systems for the asymmetric homogenous and heterogenous hydrogenation of ketones that have been made in past decade. The development of catalysts is oriented in reaching as high as activity with low catalyst loadings, using “greener’’ conditions, and ensuring good recyclability of catalysts. Even though ruthenium complexes represent the largest part of the catalysts, other metals rapidly penetrate this field.     

The influence of spiral jet-milling on the physicochemical properties of carbamazepine form III crystals: Quality by design approach

The purpose of this study was to investigate the influence of spiral jet-milling process on the physicochemical characteristics of α polymorphic active pharmaceutical ingredient, using Carbamazepine form III as a model drug, and taking into consideration Quality by Design (QbD) approach to pharmaceutical development. A 2^(4-1) factorial screening design was implemented to identify the spiral jet-milling process variables that significantly affect the particle size distribution of milled samples. Diameter of injector nozzles, diameter of ring nozzles and air pressure were selected for further analysis using a 2^(3-1) factorial experimental design. Particle size distribution of additional samples was determined, while physicochemical properties were examined by differential scanning calorimetry (DSC), hot-stage polarized microscopy (HSPM), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), and compared to those of un-milled drug. The gathered results shown that applied experimental design approach is capable to predict material behavior and could help in better understanding of material behavior during jet-milling process. Created design space (DS) provides assurance of product quality, expressed as the powder particle sizes lower than 5 μm, as well as, in initial polymorph form existence after jet-milling through combination and interaction of input variables.     

Explaining prediction models and individual predictions with feature contributions

We present a sensitivity analysis-based method for explaining prediction models that can be applied to any type of classification or regression model. Its advantage over existing general methods is that all subsets of input features are perturbed, so interactions and redundancies between features are taken into account. Furthermore, when explaining an additive model, the method is equivalent to commonly used additive model-specific methods. We illustrate the method’s usefulness with examples from artificial and real-world data sets and an empirical analysis of running times. Results from a controlled experiment with 122 participants suggest that the method’s explanations improved the participants’ understanding of the model.     

Connective stability of large-scale stochastic systems†

In this work, we will introduce the notion of connective stability in the mean for large-scale stochastic systems under structural perturbations. Sufficient conditions for this kind of stability are obtained by the decomposition-aggregation method in the context of vector Liapuiiov functions.     

Control of mineral wool thickness using predictive functional control

The production process of mineral wool is affected by several constantly changing factors. The ingredients for the mineral wool are melted in a furnace. The molten mineral charge exits the bottom of the furnace in a water-cooled trough and falls into a fiberization device (the centrifuge). The centrifuge forms the fibers. At this stage binders are injected to bind the fibers together. To ensure the quality of the end product (the consistent thickness) the flow of the bounded fibers must be as constant as possible. One way to ensure that is to control the speed of the conveyor belt that transports the bounded fibers from the centrifuge to the curing process. Predictive functional controller and PID controller are considered to replace an existing algorithm. Both can easily replace an existing one as they do not require any new sensor installation. All three algorithms are presented and tested on a developed plant model. The study showed that the predictive control gives better results than the existing and PID controller.     

Full theory of speckle displacement and decorrelation in the image field by wave and geometrical descriptions and its application in mechanics

Abstract

The paper describes the possibility of using the speckle pattern decorrelation for determination of small deformation tensor components of an elementary object surface area in an optical image field. The relationship between the small-deformation tensor and the speckle field displacement is analysed in detail. The studied problem is presented from the approximation viewpoint of both wave and geometrical optics.     

The pin power distribution in theVVER-1000 mock-up on the LR-0 research reactor

The pin power density distribution in reactor is an important quantity, necessary for the adequate assessment of fuel conditions and of core structures and pressure vessel radiation embrittlement as well.The paper shows the detailed comparison of calculated and experimentally determined pin by pin power distribution. To verify the reliability of measured data used for comparison with calculated data, the symmetrically located pins were measured. The calculations have been done with deterministic and Monte Carlo approach. The effect of different data libraries used for calculations are discussed as well.