Studies on a dirhodium tetraphosphine hydroformylation catalyst

The dirhodium tetraphosphine catalyst [Rh2(nbd)2(rac-et,ph-P4)](BF4)2 was investigated in acetone and water/acetone in order to explain better hydroformylation results in the latter solvent. In-situ NMR spectroscopy showed slower degradation in water/acetone. Less tendency to form penta/hexacarbonyl complexes in water/acetone was shown by 31P{1H} NMR and FT-IR. A pH decrease and hydroformylation studies in presence of a base indicated formation of a monocationic monohydride species. A new reaction mechanism was suggested that takes into account the observed differences from the acetone solvent system. The presence of water enabled production of hydride species when the dirhodium catalyst was exposed to CO gas. We believe this was caused by water-gas shift chemistry (H2O + CO = H2 + CO2). However, a subsequent experiment in a Parr autoclave showed that the process was not fast or efficient enough to serve as a hydrogen source for hydroformylation. The cationic character of the dirhodium catalyst was utilized for its attachment to the surface of silica gel. The purpose of immobilization is to enable easy separation of the catalyst from hydroformylation products. At room temperature in dichloromethane solution the immobilization was successful, but during hydroformylation conditions in acetone, the catalyst was released into solution

INNOVATIVE TRENDS IN RAW MATERIALS HEAT TREATMENT

The purpose of research and development in the field of raw materials extraction and treatment, is a significant component of the Slovak economy, is economical, efficiency and sustainable use of available raw materials in compliance with principles of environmental protection. This complex problem involves a wide range of necessary activities from the exploration, extraction, processing to final utilization of mineral resources. Innovations of higher level based on scientific knowledge that lead to change of research focus from operational research on conceptual issues are desirable. Present research results show that qualitative innovations may ensure higher order improvement. In complex systems, such as the area of mineral resources, is necessary to find the complex optimum involving the entire value chain from research through mining, processing, primary and secondary (recycling) processing of raw materials to creation of new products and technologies. Environmentally friendly innovative and intelligent raw materials processing can only be achieved with the active support of information and communication technology (ICT), information and digitization of the processes and equipments and advanced automation - SMARTization of the processes and technological nodes. Thereby, it ensures the autonomy of these intelligent nodes and their functional verification under pilot and operating conditions. Thus, the substantiation of an advanced technology implementation into the mining companies practice can be shown

VARIOUS METHODS OF ALUMINUM MELTING DUST DROSS FRACTION GRANUTATION AND THE RESEARCH OF CONTINUOUS GRANULATION POSSIBILITIES

Dust fractions from aluminum dross treatment are environmental load for every company in this industry sector. They are classified as waste due to their physical and primarily chemical parameters and require thus higher attention. On the other hand, the same parameters classify them as a possible source of chemical materials usable in other industry sectors. Dross treatment and the following treatment of their dust non-melting fractions are also important for such waste type producers as well as for product consumers produced from this wast

INTEGRATED APPARATUS FOR THE GRANULAR MATERIAL THERMAL TREATMENT

Integrated thermal apparatus represents an advanced technology focused on low granular materials thermal treatment. ITA technology is based on compact, vertical, dynamic thin layer principals. Processes in the layer are executed in the cross flow. Advantage of the vertical arrangement is the possibility to influence layer permeability. Permeable layer enables significantly increase furnace performance and product quality. Furnace research was based on physical a mathematical modeling. Process verification was executed on the experimental laboratory and pilot furnaces. Co temporally research is focused on caustic magnesia production. Achieved results confirmed high potential of ITA technology for low granular materials thermal processing and for preheating and cooling processes

Discourse Relations and Connectives in Higher Text Structure

The present article investigates possibilities and limits of local (shallow) analysis of discourse coherence with respect to the phenomena of global coherence and higher composition of texts. We study corpora annotated with local discourse relations in Czech and partly in English to try and find clues in the local annotation indicating a higher discourse structure. First, we classify patterns of subsequent or overlapping pairs of local relations, and hierarchies formed by nested local relations. Special attention is then given to relations crossing paragraph boundaries and their semantic types, and to paragraph-initial discourse connectives. In the third part, we examine situations in which annotators incline to marking a large argument (larger than one sentence) of a discourse relation even with a minimality principle annotation rule in place. Our analyses bring (i) new linguistic insights regarding coherence signals in local and higher contexts, e.g. detection and description of hierarchies of local discourse relations up to 5 levels in Czech and English, description of distribution differences in semantic types in cross-paragraph and other settings, identification of Czech connectives only typical for higher structures, or the detection of prevalence of large left-sided arguments in locally annotated data; (ii) as another type of contribution, some new reflections on methodologies of the approaches under scrutiny

Nature-Inspired Algorithms in Real-World Optimization Problems

Eight popular nature inspired algorithms are compared with the blind random search and three advanced adaptive variants of differential evolution (DE) on real-world problems benchmark collected for CEC 2011 algorithms competition. The results show the good performance of the adaptive DE variants and their superiority over the other algorithms in the test problems. Some of the nature-inspired algorithms perform even worse that the blind random search in some problems. This is a strong argument for recommendation for application, where well-verified algorithm successful in competitions should be preferred instead of developing some new algorithms