Wyniki wyszukiwania - Biblioteka Nauki

1

Experimental study and modeling of an air-cooled proton exchange membrane fuel cell stack in the static and dynamic performance

100%

Pielecha I. , Szwajca F.

Eksploatacja i Niezawodność

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2024

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tom Vol. 26, no. 2

art. no. 184232

EN

Research on Proton Exchange Membrane fuel cells is an important area in the field of modern energy sources. Such fuel cells are characterized by high efficiency and fast response times, making them a promising solution for sustainable energy production. Fuel cells operate under both static and dynamic conditions. Such varying operating conditions result in achieving different efficiency of fuel cell systems. This study attempts an experimental and modeled efficiency evaluation of a 1.2 kW open-cathode air-cooled fuel cell stack under static and dynamic conditions. A Sankey energy balance and an analysis of the balance components were determined for the fuel cell stack operating in these two operating states. Simultaneous modeling of the fuel cell under both static and dynamic conditions was carried out. The efficiency values of the fuel cell stack were found to be slightly higher under static conditions than under dynamic conditions. Modeling fuel cells in static and dynamic conditions results in slightly different parameters (better conformance was obtained for static models).

2

Symulacja czujnika z wyjściem częstotliwościowym w stanach dynamicznych

75%

Pawłowski E.

Pomiary Automatyka Kontrola

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2006

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tom R. 52, nr 9 bis

104--106

PL

W referacie przedstawia się problematykę cyfrowego przetwarzania sygnału w systemach pomiarowych z czujnikami o wyjściu częstotliwościowym. W stanach dynamicznych, gdy chwilowe wartości przetwarzanego mezurandu są w systemie reprezentowane przez chwilowe wartości częstotliwości sygnału na wyjściu czujnika, a cyfrowemu pomiarowi podlega okres tego sygnału, wartości mezurandu otrzymywane są w chwilach czasowych nie równo odległych. Przetwarzanie takiego nierównomiernie próbkowanego sygnału wymaga zastosowania odpowiednich algorytmów. Prezentowany sposób symulacji pozwala na uzyskanie chwilowych wartości sygnału częstotliwościowego na wyjściu czujnika dla znanego, zadanego w postaci analitycznej przebiegu czasowego mezurandu wejściowego. Umożliwia to testowanie algorytmów cyfrowego przetwarzania sygnałów częstotliwościowych i ocenę wprowadzanych przez nie błędów.

EN

The paper presents a problems concerning digital processing of signals in measuring systems with sensors of frequency output. Under dynamic conditions instantaneous frequency values represent instantaneous values of a processed quantity and the signal samples are irregularly distributed in time. Such an irregularly sampled signal can be further analyzed with the application of resampling to extract a regularly sampled signal from the irregular data. The presented simulating algorithm can be applied in all the cases when frequency of a signal carries information about instantaneous values of a physical quantity processed in the system. The following tests commonly applied in practice make good examples of such situations: testing of angular motion in rotating machines with the application of an incremental encoder, testing of converters with frequency outputs in dynamic states including operation tests on oscillators controlled by voltage (VCO), stability testing of generators or frequency in power grids etc.

3

Simulation of an irrigation system for peat soils

75%

Kowalski D. , Olszta W. , Zaradny H.

Acta Agrophysica

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2002

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tom 68

4

The study of Saccharomyces cerevisiae brewery yeast strain capacity of binding with magnesium in dynamic conditions

75%

Blazejak S. , Duszkiewicz-Reinhard W. , Gniewosz M. , Rostkowska-Demner E. , Domurad E.

Electronic Journal of Polish Agricultural Universities. Series Food Science and Technology

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2002

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tom 05

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nr 2

EN

In this research, the No. 1 Sacharomyces cerevisiae brewery yeast strain capacity to bind the Mg2+ ions was studied. The yeast were cultivated in dynamic conditions in the YPD medium enriched with the MgSO4 · 7H2O or MgCl2 · 6H 2O magnesium salts. The salts were being added in such an amount, to make the sheer element content in the medium amounting to 0.25 g · dm-3; 0.5 g · dm-3 or 1.25 g · dm-3. The YPD medium was enriched with magnesium ions at the beginning of the cultivation or in the end of the logarithmic phase of yeast growth. In order to evaluate the durability of bonds of Mg2+ ions with brewery yeast cells, the magnesium content was indicated in the centrifuged yeast biomass that had and had not been washed with deionized water.

5

Efficiency of black DN adsorption onto chitin in an air-lift reactor

75%

Filipkowska U.

Polish Journal of Environmental Studies

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2004

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tom 13

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nr 5

EN

The efficiency of reactive dyes adsorption onto chitin under dynamic conditions was determined. The research was carried out in an air-lift reactor. A reactive dye with chlorotriazine moiety - Black DN was reactor. A reactive dye with chlorotriazine moiety - Black DN was used. The effect of inlet Black DN concentration, chitin concentration in the reactor and flow rate on the maximum adsorption capacity of chitin under dynamic conditions, on the utilisation of the adsorption capacity of chitin and on the real working time of the reactor were investigated. The results showed that the maximum adsorption capacity of chitin was affected most by inlet dye concentration. The utilisation of the adsorption capacity of chitin, at the assumed effectiveness of dye removal, depended on inlet dye concentration and chitin concentration in the reactor. The highest efficiency was obtained at the chitin concentration in the reactor of 5 g/dm3, inlet dye concentration of 100 mg/dm3 and flow rate of 0.1 V/h.

6

Ocena stanu dynamicznego turbodoładowarki okrętowego silnika spalinowego

63%

Adamkiewicz A. , Michalec G.

Problemy Eksploatacji

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1999

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tom nr 2

9-19

PL

Praca wskazuje na zasadność diagnostyki drganiowej turbodoładowarek silników spalinowych na tle współczesnych wymagań nadzoru technicznego. Zadanie sformułowano na potrzeby diagnostyki praktycznej jako dokonanie klasyfikacyjnej oceny stanu dynamicznego na podstawie zmierzonych i zarejestrowanych sygnałów drganiowych. W tym celu przeprowadzono klasyfikację wymuszeń drgań turbodoładowarki i opisano je matematycznie pod kątem dalszej diagnozy przyczynowej w relacji: zarejestrowany rzeczywiście sygnał - model. Dokonano wstępnej selekcji sygnałów pomiarowych. Opisano metodykę przeprowadzania eksperymentu identyfikacyjnego. Pokazano niektóre z otrzymanych wyników pomiarów, dokonano kwalifikacyjnej oceny stanu dynamicznego turbodoładowarki i wytyczono kierunki dalszych badań.

EN

The work shows the property of applying the combustion engine's vibratory diagnostics in relation to the contemporary engineering supervision requirements. The task has been formulated for the needs of practical diagnostics as the clasifying appraisal of the dynamic state and it has been based on the measured and recorded vibratory signals. To perform this task, the classification of the input function of the turbocharger's vibrations was conducted and the vibrations were described mathematically at the angle of a further causal diagnosis in the following relation: the actual signal recorded - the model. A preliminary selection of the measurment signals has been made. Methodics description of the identifying experiment has been described, hi addition, some of the obtained results have been shown, the classyfying appraisal of the dynamic state of the turbocharger has been carried out and directions for further experiments have been established.

7

Researches on the harvesting process of straw cereals by ear stripping

63%

Gangu V. , Popescu S.

Teka Komisji Motoryzacji i Energetyki Rolnictwa

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2003

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tom 03

8

Vistula River valley as the ecological corridor for mammals

63%

Romanowski J.

Polish Journal of Ecology

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2007

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tom 55

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nr 4

EN

River Vistula, one of the large (1047 km in length) European rivers preserved in semi-natural, dynamic condition, is recognized as important corridor that enables birds and fishes to migrate for long distances. To test whether the Vistula valley provides corridor function also for mammals, field surveys and habitat modelling for six target species: Bank vole Myodes glareolus, Yellow-necked mouse Apodemus flavicollis, Pine marten Martes martes, Beaver Castor fiber, Wild boar Sus scrofa, and Elk Alces alces, were undertaken in the 135 km long fragment of the valley from 529 (Warsaw) to 685 km (Włocławek). The data collected documented the occurrence of at least 51 mammals (5 Insectivora, 14 Chiroptera, 1 Lagomorpha, 16 Rodentia, 11 Carnivora, 4 Artiodactyla), and the highest species richness was noted in the fragment of river valley covered with mixed forests which makes up the protected area called Kampinos National Park. This protected area (385 km²) contains coniferous and mixed forests, inland dunes, wetlands, and mosaic of extensively used meadows, pastures, alder forests and fields. The LARCH (Landscape Ecological Analysis and Rules for the Configuration of Habitat) (Van der Sluis and Romanowski 2005) model outputs indicated the potential for large viable populations of species analysed in the river valley. The LARCH SCAN analysis showed that habitats of modelled species were well connected and their local populations formed highly sustainable network. The spatial cohesion of habitats was generally highest in Kampinos NP and along the fragment of River Vistula from 580 to 618 km. It is concluded that high cohesion of habitats facilitates dispersion of animals and provides potential for gene flow among the populations in the valley. Riparian forests and islands are important for connecting the local populations of mammals of two river banks and are the key elements to provide functional continuity of the corridor along the river in places, where it is discontinued on one bank. The scenario analysis demonstrates potentially negative effects of river regulation and construction of two dams on viability of mammalian populations and spatial cohesion of their habitats. The future corridor function of the River Vistula valley depends mostly on preservation of it’s dynamic, semi-natural condition.

9

Preliminary application of lidar to measurements of the marine aerosol concentration in the atmosphere over the Gulf of Gdansk at Sopot

51%

Zielinski T. , Korzeniewski K. , Falkowska L.

Oceanologia

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1992

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tom 33