Wyniki wyszukiwania - Biblioteka Nauki

1

Influence of cadmium and lead partitioning in water and sediment on their deposition in the sediment of a eutrophic dam reservoir

100%

Szarek-Gwiazda E. , Mazurkiewicz-Boroń G.

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2006

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tom Vol. 35, No.2

141-157

EN

This study was conducted in the submontane and eutrophic Dobczyce Reservoir (southern Poland). Cadmium and lead concentrations in the water and sediment were relatively low. The partitioning coefficient (Kd) indicated that dissolved Cd and Pb dominated in the water column at depths of 1 and 15 m, and that they were present in the particulate phase in near-bottom water. The relation of dissolved Cd and Pb with physical and chemical parameters of the water is discussed. Binding forms of Cd and Pb in the sediment showed that Cd was potentially a more “mobile’ element than Pb; therefore, Cd had probably accumulated in the sediment in considerably lower amounts than Pb (K=8400 and K=33000, respectively).

2

Physico chemical properties of irradiated i-SANEX diluents

86%

Mossini E. , Macerata E. , Giola M. , Brambilla L. , Castiglioni C. , Mariani M.

Nukleonika

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2015

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tom 60

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nr 4

893-898

EN

The development of effective processes to recover minor actinides from spent nuclear fuel cannot leave out of consideration the evaluation of the impact of ionizing radiations on safety, fluid dynamics and extraction efficiency. It is common knowledge from the literature that radiation damage mainly affects the diluents and, indirectly, the extractants [1], but a lack of knowledge remains regarding the radiolytic behavior of innovative selective actinide extraction (i-SANEX) diluents [2, 3]. As natural prosecution of the work already performed on diluted nitric acid solutions [4], 0.44 M nitric acid solutions were irradiated in contact with a mixture of kerosene + 5 vol.% 1-octanol by a Co-60 source at 2.5 kGy/h dose rate and up to 100 kGy absorbed dose, conditions of interest for the future industrial facility. Density, viscosity, acidity, nitrate anion concentration and phase transfers were systematically measured before and after γ-irradiation. This was performed because radiation-induced modifications of these parameters may induce alterations of both the fluid dynamics and the separation performances of the extracting system. The results suggest that the fluid-dynamics of the system should be unaltered. In fact, only slight alterations of the organic phase viscosity and of the aqueous phase acidity were measured after irradiation, suggesting the occurrence of limited phase transfers and of diluent by-products formation.

3

Gamma radiolytic stability of CyMe4BTBP and the effect of nitric acid

86%

Schmidt H. , Wilden A. , Modolo G. , Švehla J. , Grüner B. , Ekberg C.

Nukleonika

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2015

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tom 60

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nr 4

879-884

EN

The highly selective nitrogen donor ligand CyMe4BTBP for An(III) separation by solvent extraction was irradiated in a 60Co γ-source under varying conditions. Organic solutions of 10 mmol/L ligand in 1-octanol were contacted with different concentrations of nitric acid to observe the influence of an aqueous phase during irradiation. In subsequent liquid-liquid extraction experiments, distribution ratios of 241Am and 152Eu were determined. Distribution ratios decreased with increasing absorbed dose when irradiation was performed in the absence of nitric acid. With addition of nitric acid, initial distribution ratios remained constant over the whole examined dose range up to 300 kGy. For qualitative determination of radiolysis products, HPLC-MS measurements were performed. The protective effect of nitric acid was confirmed, since in samples irradiated with acid contact, no degradation products were observed, but only addition products of the 1-octanol molecule to the CyMe4BTBP molecule.

4

SACSESS – the EURATOM FP7 project on actinide separation from spent nuclear fuels

86%

Bourg S. , Geist A. , Narbutt J.

Nukleonika

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2015

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tom 60

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nr 4

809-814

EN

Recycling of actinides by their separation from spent nuclear fuel, followed by transmutation in fast neutron reactors of Generation IV, is considered the most promising strategy for nuclear waste management. Closing the fuel cycle and burning long-lived actinides allows optimizing the use of natural resources and minimizing the long-term hazard of high-level nuclear waste. Moreover, improving the safety and sustainability of nuclear power worldwide. This paper presents the activities striving to meet these challenges, carried out under the Euratom FP7 collaborative project SACSESS (Safety of Actinide Separation Processes). Emphasis is put on the safety issues of fuel reprocessing and waste storage. Two types of actinide separation processes, hydrometallurgical and pyrometallurgical, are considered, as well as related aspects of material studies, process modeling and the radiolytic stability of solvent extraction systems. Education and training of young researchers in nuclear chemistry is of particular importance for further development of this field.

5

A formalization of autonomous dynamic reconfiguration in distributed constraint satisfaction

86%

Hannebauer M.

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2000

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tom Vol. 43, Nr 1-4

129-151

EN

Several interesting practical problems in process control, planning and scheduling can be expressed and solved using the model of constraint satisfaction problems. At least four drawbacks of this classical model directly relate to areas of distribution: complexity, scalability, privacy and robustness. Hence, research on distributed constraint satis-faction problems is a new direction in the area of multi-agent systems. A typical engineering task in distributed constraint satisfaction is the design of the distribution itself. A careful look at this task reveals that the design of distribution is critical to the quality and efficiency of the problem solving process and is itself an optimization problem. In this article we formalize different variants of this configuration problem and prove them to be all at least NP-complete. For solving these problems, we present two local operators, agent melting and agent splitting, that can be combined to allow for an autonomous and dynamic reconfiguration of the organizational structure of the problem-solving agents. We prove sequences of these operators to be sufficient for solving any given configuration problem. We also briefly describe what practical steps are necessary to exploit the rather theoretical result of the proof in realistic applications.

6

Dekompozycja wierszowa w syntezie logicznej przeznaczonej dla struktur matrycowych

72%

Kania D.

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2006

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tom Vol. 52, z. 4

521-543

PL

Jądrem większości układów matrycowych (ang. CPLD — Complex Programmable Logic Devices) jest blok logiczny typu PAL. Celem artykułu jest przedstawienie nowej metody dekompozycji dedykowanej dla struktur matrycowych typu PAL. Zaproponowana metoda jest alternatywą dla metody klasycznej opartej na dwupoziomowej minimalizacji. Istota metody polega na sekwencyjnym wyszukiwaniu odpowiedniej dekompozycji wierszowej. Poszczególne kroki procesu syntezy zostały dostosowane do zasobów logicznych struktur matrycowych typu PAL. Dostosowanie dekompozycji do zasobów logicznych scharakteryzowanych przez blok logiczny typu PAL doprowadziło do znaczącej poprawy efektywności syntezy w porównaniu z metodą klasyczną. Wyniki eksperymentów pokazują, że proponowana metoda syntezy prowadzi do znaczącej redukcji powierzchni wykorzystywanego układu w porównaniu z metodą klasyczną, szczególnie dla struktur matrycowych składających się z bloków logicznych typu PAL zawierających 4 lub 8 iloczynów.

EN

A PAL-based logic block is the core of the most CPLDs. The aim of the paper is to present a new method of decomposition dedicated for PAL-based CPLDs. The proposed approach is an alternative to the classical method based on two-level minimization. The idea of the method consists in sequential search for appropriate row decomposition. Individual steps of the synthesis process are adapted to logical resources of PAL-based CPLDs. Adjusting decomposition to logical resources characteristic for a PAL-based logic block allows for significant improvement of synthesis effectiveness in relation to the classical approach. Results of experiments show that the proposed logic synthesis method leads to significant reduction of chip area in relation to the classical method, especially for CPLD structures consisting of PAL-based logic blocks with 4 or 8 product terms.

7

Dekompozycja skończonych automatów stanów

72%

Bukowiec A.

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2010

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tom nr 2 (23)

5-13

PL

Celem tego artykułu było przedstawienie i omówienie algorytmu partycjonowania skonczonych automatów stanów i narzedzia CAD, które go implementuje. Algorytm został zilustrowany w pełni działajacym przykładem. W dalszych pracach należałoby się skupić nad opracowaniem algorytmów umożliwiających automatyczne uzyskanie zbioru podziału. W tym celu należy jednak przetworzyć dodatkowe informacje takie, jak wymagany czas wykonania, czy prawdopodobieństwo wystąpienia przejścia. Implementacja takiego algorytmu może być bardzo złożona i należy rozważyc zastosowanie algorytmów genetycznych lub systemu wnioskujacego do tego celu.

EN

Popular way for realization of control units are finite state machines. Up-to-date control unit circuits very often are implemented using PLDs. Microprocessors can be also considered as a solution taking costs into account. But very often microprocessors are too slow for realization control units of digital systems. The partitioning of state machines can be a solution for this problem allowing a parallel execution of state machines, keeping performance and cost at adequate levels. In this case, the time critical part of the control unit can be implemented in fast FPGA device and other parts can be realized by cheaper platforms. The problems and algorithms of partitioning of state machines are discussed in this paper. A CAD tool for partitioning implementing the proposed algorithm is also presented.