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1
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Hydrogen adsorption on Pd(133) surface

100%
Tomaszewska A., Stępień Z. a.
Open Physics
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2009
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vol. 7
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issue 2
286-290
EN
An approach based on measurements of the total energy distribution (TED) of field emitted electrons is used in order to examine properties of the Pd(133) from the aspect of hydrogen adsorption. The most favourable sites offered to a hydrogen atom to be adsorbed are indicated and an attempt to ascribe the peaks of the enhancement factor R in the TED spectrum to the specific adsorption sites is made.
2
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Domestic hydrogen installation in Poland – technical and economic analysis

100%
Cholewiński M., Tomków Ł.
Archives of Electrical Engineering
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2015
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vol. 64
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issue 2
3
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Dynamic characteristics of the proton exchange membrane fuel cell module

100%
Cieśliński J. T., Kaczmarczyk T. Z., Dawidowicz B.
Archives of Thermodynamics
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2018
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vol. 39
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issue 4
4
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Harvesting Energy and Hydrogen from Microbes

100%
Sobieszuk P., Zamojska-Jaroszewicz A., Kołtuniewicz A.
Chemical and Process Engineering
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2012
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vol. 33
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issue 4
603-610
EN
This article presents a critical mini-review of research conducted on bioelectrochemical reactors with emphasis placed on microbial fuel cells (MFC) and microbial electrolysis cells (MEC). The principle of operation and typical constructions of MFCs and MECs were presented. The types of anodes and cathodes, ion-selective membranes and microorganisms used were discussed along with their limitations.
5
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Characterization of FeCo based catalyst for ammonia decomposition. The effect of potassium oxide

100%
Lendzion-Bieluń Z., Pelka R., Czekajło Ł.
Polish Journal of Chemical Technology
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2014
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vol. 16
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issue 4
111-116
EN
FeCo fused catalyst was obtained by fusing iron and cobalt oxides with an addition of calcium, aluminium, and potassium oxides (CaO, Al2O3, K2O). An additional amount of potassium oxide was inserted by wet impregnation. Chemical composition of the prepared catalysts was determined with an aid of the XRF method. On the basis of XRD analysis it was found that cobalt was built into the structure of magnetite and solid solution of CoFe2O4 was formed. An increase in potassium content develops surface area of the reduced form of the catalyst, number of adsorption sites for hydrogen, and the ammonia decomposition rate. The nitriding process of the catalyst slows down the ammonia decomposition.
6
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Anomalously large kinetic isotope effect

100%
Krinkin D.
Open Chemistry
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2007
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vol. 5
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issue 4
1019-1063
EN
Activated diffusion of water between macromolecules in swollen cellulose is accompanied by anomalously high kinetic isotope effects of oxygen. The separation factor of heavy-oxygen water (H218O /H216O) is thousands of permilles instead of tens of permilles according to modern Absolute Rate Theory. This anomalous separation under usual conditions is disguised by the opposing process of very fast equalization to equilibrium through water-filled cellulose pores. This process is quicker by approximately 3 orders of magnitude than diffusion through the cellulose body. As a consequence, this opposition-directed equalization virtually eliminates the results of isotope separation. To reveal this anomaly it is necessary to suppress equalization, which was the primary problem for both discovery of this anomaly and its investigation. The method of investigating the anomalous separation in cellulose was developed with suppression of this negative influence. Discussion of the theoretical nature of the anomalous kinetic isotope effect is presented. This theoretical study would probably permit the discovery and use for isotope separation of the anomalously high isotope effect for other chemical elements, in particular, for those heavier than oxygen. [...]
7
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CFD modeling of passive autocatalytic recombiners*

100%
Orszulik M., Fic A., Bury T.
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issue 2
347-353
EN
This study deals with numerical modeling of passive autocatalytic hydrogen recombiners (PARs). Such devices are installed within containments of many nuclear reactors in order to remove hydrogen and convert it to steam. The main purpose of this work is to develop a numerical model of passive autocatalytic recombiner (PAR) using the commercial computational fluid dynamics (CFD) software ANSYS-FLUENT and tuning the model using experimental results. The REKO 3 experiment was used for this purpose. Experiment was made in the Institute for Safety Research and Reactor Technology in Julich (Germany). It has been performed for different hydrogen concentrations, different flow rates, the presence of steam, and different initial temperatures of the inlet mixture. The model of this experimental recombiner was elaborated within the framework of this work. The influence of mesh, gas thermal conductivity coefficient, mass diffusivity coefficients, and turbulence model was investigated. The best results with a good agreement with REKO 3 data were received for k-ɛ model of turbulence, gas thermal conductivity dependent on the temperature and mass diffusivity coefficients taken from CHEMKIN program. The validated model of the PAR was next implemented into simple two-dimensional simulations of hydrogen behavior within a subcompartment of a containment building.
8
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Evaluation of passive autocatalytic recombiners operation efficiency by means of the lumped parameter approach*

100%
Bury T.
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issue 2
339-345
EN
The problem of hydrogen behavior in containment buildings of nuclear reactors belongs to thermal-hydraulic area. Taking into account the size of systems under consideration and, first of all, safety issues, such type of analyses cannot be done by means of full-scale experiments. Therefore, mathematical modeling and numerical simulations are widely used for these purposes. A lumped parameter approach based code HEPCAL has been elaborated in the Institute of Thermal Technology of the Silesian University of Technology for simulations of pressurized water reactor containment transient response. The VVER-440/213 and European pressurised water reactor (EPR) reactors containments are the subjects of analysis within the framework of this paper. Simulations have been realized for the loss-of-coolant accident scenarios with emergency core cooling system failure. These scenarios include core overheating and hydrogen generation. Passive autocatalytic recombiners installed for removal of hydrogen has been taken into account. The operational efficiency of the hydrogen removal system has been evaluated by comparing with an actual hydrogen concentration and flammability limit. This limit has been determined for the three-component mixture of air, steam and hydrogen. Some problems related to the lumped parameter approach application have been also identified.
9
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The excitation and ionization of the hydrogen atom in strong laser fields

100%
Borbély S., Kiss G., Nagy L.
Open Physics
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2010
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vol. 8
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issue 2
249-257
EN
The probability of excitation and ionization of the hydrogen atom by short strong laser pulses is calculated by solving numerically the time-dependent Schrödinger equation. The probability of excitation to different states is investigated, which helps to identify the important ionization mechanisms. The ionization probability density was also calculated and a good agreement with the other theoretical results was found.
10
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Small intestine bacterial overgrowth is frequent in cystic fibrosis: combined hydrogen and methane measurements are required for its detection

88%
Lisowska A., Wójtowicz J., Walkowiak J.
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issue 4
631-634
EN
Introduction: Hydrogen breath test (BT) is commonly used as a diagnostic tool for the detection of small intestine bacterial overgrowth (SIBO). It was reported that colonic methane production is far more frequent in cystic fibrosis (CF) patients than in other subjects. Therefore, measuring exclusively hydrogen in the diagnostic breath test for diagnosing SIBO might be of limited value. We aimed to assess the usefulness of combined measurement of hydrogen and methane expiration for the diagnosis of SIBO in CF. Material and Methods: The study comprised 62 CF patients aged 5 to 18 years. Three-hundred-ninety subjects assessed due to gastrointestinal symptoms for the presence of SIBO served as a comparative group. In all subjects hydrogen/methane BT using glucose was performed. A positive BT was defined as fasting hydrogen ≥ 20 ppm or fasting methane ≥ 10 ppm or a rise of ≥ 12 ppm hydrogen or ≥ 6 ppm methane over baseline during the test. Results: In 23 (37.1%) CF patients and in 52 (13.3%) subjects from the comparative group abnormal BT results were found. In seven (11.3%) CF patients and 29 (7.4%) of the other subjects studied methane measurement allowed diagnosis of SIBO. Conclusions: Small intestine bacterial overgrowth is frequent in cystic fibrosis. For its detection in cystic fibrosis and other gastrointestinal patients, combined hydrogen and methane measurement instead of hydrogen breath test should be applied. Without the additional measurement of methane a significant percentage of SIBO will be missed.
11
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A Mechanistic Model of a Passive Autocatalytic Hydrogen Recombiner

88%
Rożeń A.
Chemical and Process Engineering
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2015
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vol. 36
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issue 1
3-19
EN
: A passive autocatalytic hydrogen recombiner (PAR) is a self-starting device, without operator action or external power input, installed in nuclear power plants to remove hydrogen from the containment building of a nuclear reactor. A new mechanistic model of PAR has been presented and validated by experimental data and results of Computational Fluid Dynamics (CFD) simulations. The model allows to quickly and accurately predict gas temperature and composition, catalyst temperature and hydrogen recombination rate. It is assumed in the model that an exothermic recombination reaction of hydrogen and oxygen proceeds at the catalyst surface only, while processes of heat and mass transport occur by assisted natural and forced convection in non-isothermal and laminar gas flow conditions in vertical channels between catalyst plates. The model accounts for heat radiation from a hot catalyst surface and has no adjustable parameters. It can be combined with an equation of chimney draft and become a useful engineering tool for selection and optimisation of catalytic recombiner geometry.
12
Publication available in full text mode
Content available

Harvesting Energy and Hydrogen from Microbes

88%
Sobieszuk P., Zamojska-Jaroszewicz A., Kołtuniewicz A.
Chemical and Process Engineering
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2012
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issue 4
13
Content available remote

Hydrogen gas sensors based on nanocrystalline TiO2 thin films

88%
Haidry A., Schlosser P., Durina P., Mikula M., Tomasek M., Plecenik T., Roch T., Pidik A., Stefecka M., Noskovic J., Zahoran M., Kus P., Plecenik A.
Open Physics
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2011
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vol. 9
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issue 5
1351-1356
EN
Titanium dioxide thin films are extensively studied for applications in solid state gas sensor devices. Their gas sensing properties are strongly dependent on deposition technique, annealing temperature, film thickness and consequent properties like crystalline structure, grain size or amount of defects and impurities. In this work we report the gas sensing properties of TiO2 thin films prepared by reactive magnetron sputtering technique and subsequently annealed at temperatures 600°C and 900°C. The films were exposed to different concentrations of H2 gas up to 10 000 ppm. Their sensitivity to gas at various operating temperatures, ranging from 250°C to 450°C, was obtained by measuring their resistance.
14
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Analysis of Energy Storage System with Distributed Hydrogen Production and Gas Turbine

88%
Kotowicz J., Bartela Ł., Dubiel-Jurgaś K.
Archives of Thermodynamics
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2017
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issue 4
15
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Glycerol steam reforming over ceria-zirconia supported metallic catalysts

88%
Cichy M.
Annales Universitatis Mariae Curie-Skłodowska, sectio AA – Chemia
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2019
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vol. 74
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issue 1
EN
Glycerol is a main by-product of transesterification reaction of plants oils to its methyl esters which are used as a substitute or as an additive to diesel fuel. Still growing so-called biodiesel production leads to large amounts of glycerol fraction flooding the market. One of the possible ways of its utilization is steam reforming reaction which main product is synthesis gas containing high concentration of hydrogen for which is still growing demand. In this work four metallic (Ni, Pt, Ru and Re) catalysts supported on ceria-zirconia mixed oxides have been investigated in glycerol steam reforming reaction.
16
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Modelling of a passive autocatalytic hydrogen recombiner – a parametric study

88%
Rożeń A.
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issue 1
161-169
EN
Operation of a passive autocatalytic hydrogen recombiner (PAR) has been investigated by means of computational fluid dynamics methods (CFD). The recombiner is a self-active and self-adaptive device used to remove hydrogen from safety containments of light water nuclear reactors (LWR) by means of a highly exothermic reaction with oxygen at the surface of a platinum or palladium catalyst. Different turbulence models (k-ω, k-ɛ, intermittency, RSM) were applied in numerical simulations of: gas flow, heat and mass transport and chemical surface reactions occurring in PAR. Turbulence was found to improve mixing and mass transfer and increase hydrogen recombination rate for high gas flow rates. At low gas flow rates, simulation results converged to those obtained for the limiting case of laminar flow. The large eddy simulation technique (LES) was used to select the best RANS (Reynolds average stress) model. Comparison of simulation results obtained for two- and three-dimensional computational grids showed that heat and mass transfer occurring in PAR were virtually two-dimensional processes. The effect of hydrogen thermal diffusion was also discussed in the context of possible hydrogen ignition inside the recombiner.
17
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A model of hydrogen passive autocatalytic recombiner and its validation via CFD simulations

75%
Orszulik M., Fic A., Bury T., Składzień J.
Archives of Thermodynamics
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2013
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issue 4
18
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A Mechanistic Model of a Passive Autocatalytic Hydrogen Recombiner

75%
Rożeń A.
Chemical and Process Engineering
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2015
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issue 1
19
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Concepts of energy use of municipal solid waste

75%
Primus A., Chmielniak T., Rosik-Dulewska C., Primus A., Chmielniak T., Rosik-Dulewska C.
Archives of Environmental Protection
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2021
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vol. 47
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issue 2
20
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Hydrogen in the Strategies of the European Union Member States

75%
Koneczna R., Cader J., Koneczna R., Cader J.
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issue 3
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