Wyniki wyszukiwania - Biblioteka Nauki

1

Rola wodoru w inżynierii i eksploatacji warstwy wierzchniej

100%

Kula P.

Zeszyty Naukowe Politechniki Świętokrzyskiej. Mechanika

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2000

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tom Z. 72

131-143

PL

W pracy omówiono genezę poznania, teorię i praktykę zużycia wodorowego części maszyn, jak również technologiczne metody przeciwdziałania tej katastrofalnej postaci eksploatacyjnego niszczenia tworzyw metalowych. Przedstawiono wyniki badań porównawczy odporności na objętościowe nawodorowanie próbek poddanych różnym procesom powierzchniowej obróbki cieplnej i cieplno-chemicznej. Zaproponowano i potwierdzono wynikami badań doświadczalnych model niejednorodnego stężenia wodoru w utwardzanych warstwach wierzchnich wytwarzanych poprzez różnorodne odmiany procesu azotowania. Na jego podstawie wyprowadzono teoretycznie i potwierdzono doświadczalnie zjawisko "smarowania wodorem" przy tarciu suchym. Wykazano również korelacji pomiędzy zawartością wodoru w warstwie wierzchniej a trwałością warstwy granicznej oleju w warunkach smarowania elastohydrodynamicznego.

EN

The subject of the paper is the hydrogen's behaviour in the field of surface engineering, as well as during friction both in dry and lubricated frictional couples. The recently discovered phenomena, namely: the blocking of hydrogen diffusion by nitrided layers, selflubrication by hydrogen and the activity of absorbed hydrogen in the chemisorption of lubricants have been presented and explained.

2

Future hydrogen technologies in power engineering and semi-closed gas turbine system

100%

Iki N. , Hama J. , Takahashi S. , Miller A. , Kiryk S.

Prace Naukowe Politechniki Warszawskiej. Mechanika

|

1999

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tom z. 181

97-106

EN

This paper introduces one of the utilisation of the hydrogen as a power systems` fuel in Japanese program, which has been progressed to establish the global energy network by using hydrogen as a secondary clean energy. And it introduces semi-closed gas turbine systems with steam recirculation. They are not only capable of the high efficiency with hydrogen-oxygen combustion but useful with fuel-oxygen combustion for CO(sub 2) separation. This paper also describes the key technologies to evaluate the possibilities of a semi-closed gas turbine system with higher efficiency.

PL

Niniejszy artykuł przedstawia jedną z możliwych technologii wykorzystania wodoru jako paliwa dla systemów wytwarzania energii, zaproponowaną w japońskim programie badawczym. Program ten ma za zadanie stworzenie globalnej sieci energetycznej z wykorzystaniem wodoru jako wtórnego nośnika czystej energii użytkowej. Przedstawiono także układ z turbiną gazową i recylkulacją pary, który może z dużą sprawnością produkować energię zarówno dla spalania wodór-tlen, jak też dla spalania gaz/olej-tlen przy separacji CO(sub 2). W artykule wymieniono kluczowe technologie, których rozwój ma wpływ na uzyskanie wysokiej sprawności powyższego układu.

3

The current state and prospects for hydrogenisation of motor transport in Northwestern Europe and Poland

85%

Gis M. , Gis W.

Combustion Engines

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2022

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tom R. 61, nr 3

61--71

EN

The article presents the situation regarding the hydrogenisation of motor transport in Northwestern Europe, a region leading in this regard in Europe. The following countries were included in the analysis of national plans in this area, taking into account both technical issues - among others - concerning HRS and FCEV, their number, as well as economic issues (among other things relating to the costs of using hydrogen): Belgium, Denmark, France, Germany, the Netherlands, Norway and England. Reference was also made to the situation in Poland, where major fuel and energy companies (among others: Orlen, Lotos, PGNiG and ZE PAK Capital Group) are strongly interested in hydrogenisation of motor transport and manufacturers of vehicles - for example - Solaris or Autosan in producing vehicles equipped with fuel cells. Based on the analyses carried out at the Institute of Motor Transport, it was found that the good location of basic hydrogen refuelling stations is along the TEN-T corridors running across Poland. The order of their location is as follows: 1 - Poznan, 2 - Warsaw,3 - Bialystok, 4 - Szczecin, 5 - Łódź region, 6 - Tricity, 7 - Wroclaw, 8 - Katowice region, 9 - Kraków.

4

Obecne i perspektywiczne metody otrzymywania wodoru

80%

Surygała J.

Przemysł Chemiczny

|

2006

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tom T. 85, nr 8-9

661-664

PL

Omówiono aktualnie stosowane metody otrzymywania wodoru z lekkich węglowodorów, węgla, wody i pozostałości rafineryjnych, oraz oceniono ich efektywność. Przedstawiono również istotne cechy procesów perspektywicznych - fotoelektrochemicznych, termokatalitycznych, membranowych, wykorzystujących biomasę oraz biologicznych.

EN

A review with 40 refs. covering partial oxidn. of refinery residues, recovery of H2 from refinery gases and by low-temp. methods, electrolysis of H2O, gasification of C, efficiency of H2 production and perspectives like biomass as a raw material, new methods for recovery from syngas, biol. and photoelectrochem. methods, thermocatalytic and thermal dissocn. of hydrocarbons.

5

CFD modeling of passive autocatalytic recombiners*

80%

Orszulik M. , Fic A. , Bury T.

Nukleonika

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2015

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tom 60

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nr 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.

6

Evaluation of passive autocatalytic recombiners operation efficiency by means of the lumped parameter approach*

80%

Bury T.

Nukleonika

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2015

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tom 60

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nr 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.

7

Hydrogen fuel in transportation

80%

Machač J. , Majer M.

Multidisciplinary Aspects of Production Engineering

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2019

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tom Vol. 2, Iss. 1

161--171

EN

In the time, when the whole world is increasingly engaged in environmental protection, it is necessary to come up with a fuel alternative for transportation, which means generally abandon the use of non-renewable resources (petrol, oil and fossil fuel in general), as they are one of the many factors influencing the emergence of greenhouse gases and the associated global warming. In today's Europe, the pressure is put mainly on automotive companies, to search for sources other than conventional fuels. At present, there is a big boom in the area of electric cars powered from the power network – the vast majority of electric energy, however, is produced in fossil fuel power plants. The second option of possible development in this area is the use of hydrogen as an alternative fuel. This technology, whether it be direct combustion as in diesel or eventually in petrol engines, or energy production in a hydrogen fuel cell, is certainly the way suitable for further development. With hydrogen as a fuel, it is possible to reduce pollutants almost to zero. The article presents a comparison of electricity generated using renewable and non-renewable sources and focuses on a closer understanding of the myth of the dangers connected with using hydrogen as fuel. Furthermore, compares conventional fuels to re-newable hydrogen technologies and focuses on the hydrogen combustion engines together with hydrogen storage and application in transportation.

8

Anomalously large kinetic isotope effect

80%

Krinkin D.

Open Chemistry

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2007

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tom 5

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nr 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. [...]

9

Wodór - paliwo przyszłości

80%

Biernat K. , Samson-Bręk I. A.

Studia Ecologiae et Bioethicae

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2008

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tom 6

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nr 1

331-344

EN

Hydrogen it one of most spread radical on earth, this gas has to become alternative due to so general occurrence for mineral fuels exactly chance. Low is unchallenged advantage of employment of hydrogen in car engines emission, then hydrogen is fuel ecological completely. On way to general employment of hydrogen biggest barrier stagnant as storage of this gas is fuel and high cost of its production.

10

Possibilities for the production and use of hydrogen as a fuel in existing boilers

80%

Sigal O. , Paderno D. , Nizhnyk N.

Journal of New Technologies in Environmental Science

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2022

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tom Vol. 6, nr 2

65--66

EN

The process scheme is developed for climate neutral production and use of hydrogen as a fuel in existing boilers at heat supply enterprises.

11

The future of the hydrogen economy : bright or bleak?

80%

Bossel U. , Eliasson B. , Taylor G.

Journal of KONES

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2004

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tom Vol. 11, No. 1-2

87-111

EN

In the past, many have considered the production and use of hydrogen, assuming that it is just another gaseous fuel and can be handled much like natural gas in todays energy economy. With this study we present an analysis of the energy required to operate an elemental hydrogen economy, with particular reference to rond transport. High-grade electricity from renewable or nuclear sources is needed not only to generate hydrogen, hut also for all the other essential stages. However, because of the molecular structure of hydrogen, the infrastructure is much more energy-intensive than in an oil and natural gas economy. In a "Hydrogen Economy" the hydrogen like any other commercial product, is subject to several stages between production and use. Hydrogen has to be packaged by compression or liquefaction. transported by surface vehicles or pipelines, stored, and transferred to the end user. Whether generated by electrolysis or by chemistry, and even produced locally at filling stations, the gaseous or liquid hydrogen has to undergo these market processes before it can be used by the customer. Hydrogen can also be derived chemically at relatively Iow cost from natural gas or other hydrocarbons. However as there are no energetic or environmental advantages, we do not consider this option. In this study, the energy consumed by each stage is related to the true energy content - the higher heating value (HHV) - of the delivered hydrogen. The analysis reveals that much more energy is needed to operate a hydrogen economy than is required for fossil energy supply and distribution today. In fact, the input of electrical energy to make, package, transport, store and transfer hydrogen may easily exceed the hydrogen energy delivered to the end user - implying an well-totank efficiency of less than 50 per cent. However, precious energy can be saved by packaging hydrogen chemically in a synthetic liąuid hydrocarbon like in ethanol or ethanol. To de-couple energy use front global warming, the use of "geocarbons" from fossil sources should be avoided. However, carbon atoms from biomass, organic waste materials or recycled carbon dioxide could become the carriers for hydrogen atoms. Furthermore, energy intensive electrolysis may be partially replaced by the less energy intensive chemical transformation of water and carbon to natural and synthetic hydrocarbons, including bio-methanol and bio-ethanol. Hence, the closed natural hydrogen (water) cycle and the closed natural carbon (CO2) cycle may be used to produce synthetic hydrocarbons for a post-fossil fuel energy economy. As long as the carbon comes from the biosphere ("bio-carbon"), the synthetic hydrocarbon economy would be far better than the elemental hydrogen economy - both energetically and environmentally.

12

Evaluation of the possibility to improve the efficiency of SI engine fueled with low-carbon gaseous fuels

80%

Kubica G.

Journal of Mechanical and Transport Engineering

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2014

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tom Vol. 66, No. 1

39--50

EN

A detailed analysis of the issues related to improving the efficiency of energy conversion in spark ignition engine, powered by low-carbon gaseous fuels are presented in that monograph. The research was conducted on engine powered by compressed natural gas (CNG), and methane/hydrogen blends. Selected for tests group of fuels was consisted of eight blends, with various hydrogen share (by volume): 0% (pure methane), 5%, 10%, 15%, 20%, 30%, 40% i 50%. The object of the research was a 4-cylinder engine with a capacity of 1.6 dm3, the pre-installed in car Opel Astra F. The engine was equipped with an alternative CNG injection system. An influences of ignition advance angle and fuel composition on engine performance and total efficiency were determined in the final analysis. The proposed solutions were compared with the base configuration of the power supply in the summary of work.

PL

W artykule przedstawiono szczegółową analizę zagadnień związanych z poprawą efektywności konwersji energii w silniku o zapłonie iskrowym, zasilanym paliwami gazowymi o zmniejszonym udziale węgla. W badaniach stanowiskowych silnik zasilano sprężonym gazem ziemnym (CNG) oraz mieszaninami metanu z wodorem. Obiektem badań był 4-cylindrowy silnik o pojemności 1,6 dm3, zamontowany fabrycznie w samochodzie Opel Astra F. Jednostkę napędową wyposażono w alternatywną instalację zasilania wtryskowego CNG. W końcowej analizie określono wpływ kąta wyprzedzenia zapłonu i składu paliwa gazowego na podstawowe wskaźniki pracy silnika i jego ogólną sprawność. W podsumowaniu porównano proponowane rozwiązania z bazową konfiguracją układu zasilania.

13

Studies of PEM-type Fuel Cell System Cooperating with the Generation of Hydrogen

80%

Węcel D. , Ogulewicz W. , Wiciak G. , Łukowicz H.

Archivum Combustionis

|

2010

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tom Vol. 30 nr 3

247-260

EN

Selected problems connected to the use of fuel cells in energy-system are introduced in the paper. The studies concerning the system for electricity and heat generation, consisting of a photovoltaic panels, hydrogen generators and PEM-type fuel cell are presented. For the generation of hydrogen with the use of electrolysis method electricity generated by renewable energy sources is used. A system for transformation of the electricity generated in photovoltaic panels and used for powering hydrogen generators was developed and realized. The fuel cells used consist of two stacks of electrical output, 360 W each. They are equipped with a complex supply system of: hydrogen fuel, air, cells cooling together with regulatory and protection system. It allowed to make the analysis of working parameters of the fuel cell for different electrical loads and with various amounts of supplied air, as well as for different conditions of cell cooling. The developed system for data collecting and acquisition allows for simultaneous recording of the data from all elements of the measuring position. The aim of the study is the development of a demonstration installation of an autonomous system for electricity generation using renewable energy sources and having the possibility of hydrogen fuel storage, in the case of reduced electricity demand.

14

Hydrogen rich gases combustion in the IC engine

80%

Szwaja S.

Journal of KONES

|

2009

|

tom Vol. 16, No. 4

447-454

EN

Experimental results of combusting three different syngases in an internal combustion (IC) spark ignition engine are presented in this paper. The syngases used for tests varied each from the other with hydrogen content, which was of 10,15 and 60%. Other combustible gases as CO and CH4 were also changed. Thus, the lower heating value of the syngases was of 2.7, 4.6 and 17.2 MJ/nm3, respectively. Combustion tests were performed at stoichiometric ratio of syngas-air mixture, with variable spark timing and constant compression ratio of 10. On the basis of in-cylinder combustion pressure histories the indicated mean effective pressure (IMEP) was computed and presented versus spark timing and vs location of the middle combustion phase expressed by the 50% of mass fraction burned (MFB). Additionally, the 0-10% MFB and 10-90% MFB were also determined. Furthermore, the paper contains theoretical determination of the three fuel quantities, which can affect combustion duration and heat release rate during burning the syngases in the IC engine. They are as follows: laminar flame speed, ignition delay and adiabatic flame temperature. Final results does not show satisfactory correlation between LFS computed at NTP and real combustion phasing. Furthermore, both long combustion duration and long 0-10% MFB leading to unstable combustion were observed for the syngas with the lowest LHV of 2.7 MJ/nm3.

15

Investigation of Stress Corrosion Cracking in Magnesium Alloys by Quantitative Fractography Methods

80%

Sozańska M. , Mościcki A. , Chmiela B.

Archives of Metallurgy and Materials

|

2017

|

tom Vol. 62, iss. 2A

557--562

EN

The article shows that the use of quantitative fracture description may lead to significant progress in research on the phenomenon of stress corrosion cracking of the WE43 magnesium alloy. Tests were carried out on samples in air, and after hydrogenation in 0.1 M Na2SO4 with cathodic polarization. Fracture surfaces were analyzed after different variants of the Slow Strain Rate Test. It was demonstrated that the parameters for quantitative evaluation of fracture surface microcracks can be closely linked with the susceptibility of the WE43 magnesium alloy operating under complex state of the mechanical load in corrosive environments. The final result of the study was the determination of the quantitative relationship between Slow Strain Rate Test parameters, the mechanical properties, and the parameters of the quantitative evaluation of fracture surface (microcracks).

16

A numerical and experimental study of marine hydrogen–natural gas–diesel tri–fuel engines

80%

Zhao R. , Xu L. , Su X. , Feng S. , Li C. , Tan Q. , Wang Z.

Polish Maritime Research

|

2020

|

tom nr 4

80--90

EN

Maritime shipping is a key component of the global economy, representing 80–90% of international trade. To deal with the energy crisis and marine environmental pollution, hydrogen-natural gas-diesel tri-fuel engines have become an attractive option for use in the maritime industry. In this study, numerical simulations and experimental tests were used to evaluate the effects of different hydrogen ratios on the combustion and emissions from these engines. The results show that, in terms of combustion performance, as the hydrogen proportion increases, the combustion ignition delay time in the cylinder decreases and the laminar flame speed increases. The pressure and temperature in the cylinder increase and the temperature field distribution expands more rapidly with a higher hydrogen ratio. This means that the tri-fuel engine (H2 +CH4 +Diesel) has a faster response and better power performance than the dual-fuel engine (CH4 +Diesel). In terms of emission performance, as the hydrogen proportion increases, the NO emissions increase, and CO and CO2 emissions decrease. If factors such as methane escape into the atmosphere from the engine are considered, the contribution of marine tri-fuel engines to reducing ship exhaust emissions will be even more significant. Therefore, this study shows that marine hydrogen-natural gas-diesel tri-fuel engines have significant application and research prospects.

17

Characteristic studies of micron zinc particle hydrolysis in a fixed bed reactor

80%

Lv M. , Liu H. , Nie X. , Ashraf M. A.

Polish Maritime Research

|

2015

|

tom S 1

112--120

EN

Zinc fuel is considered as a kind of promising energy sources for marine propeller. As one of the key steps for zinc marine energy power system, zinc hydrolysis process had been studied experimentally in a fixed bed reactor. In this study, we focus on the characteristics of micron zinc particle hydrolysis. The experimental results suggested that the steam inner diffusion is the controlling step of accumulative zinc particles hydrolysis reaction at a relative lower temperature and a relative higher water partial pressure. In other conditions, the chemical reaction kinetics was the controlling step. And two kinds of chemical reaction kinetics appeared in experiments: the surface reaction and the gas-gas reaction. The latter one occurs usually for larger zinc particles and high reaction temperature. Temperature seems to be one of the most important parameters for the dividing of different reaction mechanisms. Several parameters of the hydrolysis process including heating rate, water partial pressure, the particle size and temperature were also studied in this paper. Results show that the initial reaction temperature of zinc hydrolysis in fixed bed is about 410 oC. And the initial reaction temperature increases as the heating rate increases and as the water partial pressure decreases. The total hydrogen yield increases as the heating rate decreases, as the water partial pressure increases, as the zinc particle size decreases, and as the reaction temperature increases. A hydrogen yield of more than 81.5% was obtained in the fixed bed experiments.

18

The Use of Methane in Practical Solutions of Environmental Engineering

80%

Skorek A. , Włodarczyk R.

Journal of Ecological Engineering

|

2018

|

tom Vol. 19, nr 2

172--178

EN

Methane is the main component of the basic conventional fuels used in modern energetics – natural gas, as well as an essential component of renewable fuel like biogas. As a result of technological processes, methane can be extracted from hydrogen fuel which is dedicated to low-temperature fuel cells, generators or electric current and heat. The article presents an analysis of the possibilities of using methane to produce electricity, practical solutions and the problems that inhibit the implementation of fuel cell technology.

19

Research on possibilities of application of nondestructive testing in degradation evaluation of materials used in infrastructure working under the influence of agressive hydrogen environment

80%

Paradowski K. , Manaj W. , Spychalski L. , Zagórski K. , Lubińska D. , Kukla D. , Płowiec J. , Kurzydłowski K. J.

Advances in Materials Science

|

2007

|

tom Vol. 7, nr 2(12)

276-283

EN

Widely applied materials, used in construction of installations exposed to influence of hydrogen environment, are low-alloy Cr-Mo steels. Unfavorable effect of hydrogen on metals is described as hydrogen stress corrosion or hydrogen embrittlement. The process, in extreme cases, leads to a significant decrease of utilitarian properties of construction materials. In true conditions, a consequence of hydrogen degradation may be a failure, brought about by a los s of construction's integrity. Usage of modem inspection techniques constituting non-destructive testing methods enables monitoring and evaluation of degradation degree of materials, out of which the equipment was built, in a way that does not effect a change of their properties and utili-tarian functions. The presented in the paper research results, obtained under laboratory conditions, are a base for creation of a non-destructive tests methodology that enables performing inspections in true conditions and allows for a better interpretation of results obtained.

20

Interaction of hydrogen with palladium atoms and clusters

80%

Tomaszewska A. , Stępień Z. M.

Prace Naukowe. Chemia i Ochrona Środowiska / Akademia im. Jana Długosza w Częstochowie

|

2005

|

tom Vol. 10

125-131

EN

The interaction between hydrogen and palladium atoms leading to the formation of palladium hydrides has been studied theoretically. Ab initio calculations with, Becke's Three Parameter Hybrid Functional using the LYP Correlation Functional (B3LYP) have been performed to establish the binding characteristics of palladium hydrides species. The interaction of hydrogen with four- and six- atom clusters (like tetra- and octahedral voids) has been compared. It has been proved that the binding of hydrogen with the tetrahedral void is stronger than in the second case.