Wyniki wyszukiwania - Biblioteka Nauki

1

The Erosion Resistance and Microstructure Evaluation of Laser Surface Alloyed Sintered Stainless Steels

100%

Brytan Z.

Archives of Metallurgy and Materials

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2018

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tom Vol. 63, iss. 4

2039--2049

EN

The sintered stainless steels of different microstructures (austenitic, ferritic and duplex) were laser surface alloyed with hard powders (SiC, Si3 N4 ) and elemental alloying powders (Cr, FeCr, FeNi) to obtain a complex steel microstructure of improved properties. Laser surface alloying (LSA) involved different strategies of powder placing: the direct powder feeding to the molten metal pool and filling grooves machined on the sample surface by powder, and then laser surface melting. Obtained microstructures were characterised and summarised, basing on LOM, SEM and XRD analysis. The links between base material properties, like superficial hardness and microhardness, derived microstructures and erosion resistance was described. The LSA conditions and alloying powder placement strategies on erosion resistance was evaluated. The erosion wear is lower for Cr, FeCr, FeNi laser alloying, where powders were dissolved in the steel microstructure, and hard phases were not precipitated. Precipitations of hard phases (carbides, silicides, martensite formation) reduce erosion resistance of SiC alloyed stainless steel. The LSA with Si3 N4 works better due to lack of precipitates and formation of a soft and ductile austenitic microstructure. The erosion wear at the impingement angle of 90° is high for hard and therefore brittle surface layers obtained as a result of alloying by hard particles (SiC, Si3 N4 ). The softer and ductile austenitic stainless steel resist better than harder ferritic and duplex stainless steel material at studied erodent im pingement angle.

2

Detection and differentiation of Newcastle disease virus and influenza virus by using duplex real-time PCR

75%

Nidzworski D. , Wasilewska E. , Smietanka K. , Szewczyk B. , Minta Z.

Acta Biochimica Polonica

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2013

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tom 60

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nr 3

475-480

EN

Newcastle disease virus (NDV), member of the Paramyxoviridae family and avian influenza virus (AIV), member of the Orthomyxoviridae family, are two main avian pathogens causing serious economic problems in poultry health. Both are enveloped, single-stranded, negative-sense RNA viruses and cause similar symptoms, ranging from sub-clinical infections to severe diseases, including decrease in egg production, acute respiratory syndrome, and high mortality. Similar symptoms hinder the differentiation of infection with the two viruses by standard veterinary procedures like clinical examination or necropsy. To overcome this problem, we have developed a new duplex real-time PCR assay for the detection and differentiation of these two viruses. Eighteen NDV strains, fourteen AIV strains, and twelve other (negative control) strains viruses were isolated from allantoic fluids of specific pathogen-free (SPF), embryonated eggs. Four-weeks-old SPF chickens were co-infected with both viruses (NDV - LaSota and AIV - H7N1). Swabs from cloaca and trachea were collected and examined. The results obtained in this study show that by using duplex real-time PCR, it was possible to detect and distinguish both viruses within less than three hours and with high sensitivity, even in case a bird was co-infected. Additionally, the results show the applicability of the real-time PCR assay in laboratory practice for the identification and differentiation of Newcastle disease and influenza A viruses in birds.

3

Podwyższanie trwałości eksploatacyjnej narzędzi do obróbki drewna

63%

Warcholiński B. , Gilewicz A. , Szymański W. , Pinkowski G. , Olik R.

Inżynieria Powierzchni

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2011

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tom nr 2

73-80

PL

W pracy przedstawiono wyniki badań powłok wielowarstwowych CrCN/CrN o grubości modułu 400 nm i równym podziale grubości warstw CrCN i CrN w module, nanoszonych metodą katodowego odparowania łukowego. Powłoki nakładano na noże, wykonane ze stali SW7M i węglików spiekanych HM, do głowic strugarskich stosowane w obróbce drewna. Powłoki charakteryzują się wysoką twardością, 25 GPa, wysoką przyczepnością do podłoża, około 105 N i stosunkowo niskim współczynnikiem tarcia – 0,5. Wyniki półprzemysłowych badań eksploatacyjnych wskazują na poprawę trwałości narzędzi z powłokami, a także poprawę jakości obrabianego materiału. Badania laboratoryjne właściwości tribologicznych powłok CrN osadzanych na podłożach: ze stali SW7M oraz poddanej azotowaniu stali SW7M wskazują na wyższość kompozytu powłoka-stal azotowana.

EN

The paper presents the results of the tests of CrCN/CrN multilayer coatings with a thickness of module of 400 nm and an equal thickness of the CrN and CrCN layers in a module deposited by cathodic arc evaporation. The coatings were deposited on planer knives from SW7M steel and HM carbide, used in the woodworking. Coatings are characterized by high hardness, 25 GPa, high adhesion to the substrate, about 105 N and a relatively low coefficient of friction - 0.5. Results of semi-industrial tests show an improvement in durability of coated tools, as well as improving the quality of the workpiece. Laboratory studies of tribological properties of CrN coatings deposited on substrates: HS6-5-2 steel and nitrided HS6-5-2 steel show the superiority of the composite system coating PVD-nitrided steel.

4

Influence of parameters of laser beam welding on structure of 2205 duplex stainless steel

63%

Landowski M.

Advances in Materials Science

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2019

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tom Vol. 19, nr 1(59)

21--31

EN

Laser welding is used in modern industry, having many advantages comparing to traditional welding technologies. Nowadays, industry sectors such as shipbuilding, automotive and aviation can’t be imagined without laser processing technologies. Possibility of increase of welded joint properties, autogenous welding and high level of process automation makes the technology of laser welding perspective part of the industry. Physical multidimensional processes complexity requires a deeper understanding of the impact of laser welding parameters on the quality of welded joints for industrial implementation. The paper presents results of microstructure investigations of laser beam welded stainless steel under various welding parameters. Welded joints was achieved by Ytterbium fiber laser type without the use of the filler material. Material for test was 2205 ferritic-austenitic duplex stainless steel (DSS) plates with thickness of 8 mm in delivery condition. The objectives of this research was to investigate influence of laser welding parameters on weld geometry of butt-welded joints. Investigations of bead shape revealed correlation between laser beam focus position and weld penetration depth.

5

Wpływ obróbki powierzchniowej typu duplex na pitting

63%

Mańkowska-Snopczyńska A. , Michalak M. , Piekoszewski W. , Szczerek M. , Rzepkowski A.

Inżynieria Materiałowa

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2014

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tom Vol. 35, nr 6

519--522

PL

zmęczeniowej próbek wykonanych ze stali 17HMN, które poddano technologii nawęglania niskociśnieniowego wspomaganego azotowaniem PreNitLPC® oraz próbek nawęglonych z naniesionymi technologią PVD powłokami niskotarciowymi typu: a-C:H:W (WC/C) a-C:H (DLC Comp) oraz Si-DLC (DLC SiliComp). Temperatura procesu nanoszenia powłok we wszystkich przypadkach nie przekraczała 200˚C. Badane skojarzenie było smarowane czystym olejem syntetycznym bez dodatków. Na podstawie przeprowadzonych badań stwierdzono, że cienkie powłoki PVD nanoszone na wysokoobciążone stalowe elementy węzłów tarcia znacząco i w zróżnicowany sposób wpływają na powierzchniową trwałość zmęczeniową. Wydaje się więc konieczne, aby oprócz badań trwałości przeprowadzić dogłębne badania analityczne, mające na celu wyjaśnienie tak odmiennych zachowań elementów pracujących w smarowanym styku skoncentrowanym.

EN

resistance to pitting) of low-pressured carburized 17HNM steel samples, subjected to two kinds of surface modification. The first set of specimens were nitrided by means of PreNitLPC® process, while on each specimen of the second set, one of the following PVD coatings was deposited: a-C:H:W (trademark: WC/C), a-C:H (DLC Comp), Si-DLC (DLC SiliComp).The coating process temperature in all the cases did not exceed 200˚C. The investigated tribosystems were lubricated with a synthetic oil without additives. On the base of the research results it can be stated that thin PVD coatings, deposited onto heavy-loaded steel tribosystems, significantly and in a differentiated way affect the surface fatigue life. It seems necessary, apart from the fatigue wear investigation, to conduct profound analytical examinations aimed at explaining such a strongly different behaviour of elements working in a lubricated non-conformal contact.

6

The assessment of the microstructure and selected mechanical properties of butt joints in ferritic-austenitic duplex steel

63%

Gądek K. , Tuz L.

Biuletyn Instytutu Spawalnictwa w Gliwicach

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2019

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tom Vol. 63, No. 2

33--40

EN

The paper presents results of microscopic tests as well as results of tests concerning mechanical properties of MAG (136) welded joints in duplex steel X2CrNiMoN22-5-3 (1.4462). The research involved metallographic tests of the base material, heat affected zone and weld metal as well as Vickers hardness tests, static tensile tests, bend tests and the identification of a ferrite content obtained using a ferritiscope. The results of observations involving the microstructure of the particular zones of the welded joint as well as the quantitative analysis of phases and the results of the tests concerning the mechanical properties of the joints enabled the formulation of conclusions regarding the microstructure and the mechanical properties of the test joints.

PL

Przedstawiono wyniki badań metalograficznych oraz badań własności mechanicznych złącza doczołowego wykonanego metodą MAG(136) stali dwufazowej ferrytyczno- austenitycznej (duplex) X2CrNiMoN22-5-3 (1.4462). Przeprowadzono badania metalograficzne materiału rodzimego, strefy wpływu ciepła i spoiny oraz pomiary twardości metodą Vickersa, próbę statycznego jednoosiowego rozciągania, próbę zginania bocznego oraz pomiar zawartości fazy magnetycznej za pomocą ferrytoskopu. Na podstawie otrzymanych mikrostruktur z poszczególnych stref złącza, analizy ilościowej występujących faz oraz wyników badań własności mechanicznych wyciągnięto wnioski na temat mikrostruktury badanego złącza oraz jego własności.

7

Dializa równowagowa. Metoda badania selektywności oddziaływań ligand.DNA

51%

Czerwińska I. , Głuszyńska A. , Juskowiak B.

Wiadomości Chemiczne

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2010

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tom [Z] 64, 1-2

105-122

EN

Equilibrium or competition dialysis is a powerful tool for binding study of ligands that are expected to bind to nucleic acids with selectivity related to their structure or sequence. In the equilibrium dialysis experiment, a set of nucleic acid samples that differ in structure and sequence is dialyzed against a test ligand solution. After equilibration, the concentration of ligand bound to each structure or sequence is determined by UV-Vis absorption or fluorescence spectroscopy in each dialysis unit. Since all nucleic acid samples are in equilibrium with the same free ligand concentration, the amount of bound ligand is directly related to the ligand binding affinity. Thus, equilibrium provides a direct measure of selectivity and identifies the nucleic acid sample, which is preferred by a particular ligand. We describe here the principles and practice of the method. Examples of an application of the method are limited to the discovery of small molecules that selectively recognize the unique structural features of G-quadruplexes. There are proofs for important functional roles of G-quadruplex structures in biology (maintenance of telomeres, transcriptional regulation, and modulation of mRNA translation). G-quadruplex DNA can exist in a variety of structural forms that may possess numerous potential binding sites for small molecules. Therefore equilibrium dialysis provides a useful tool for discovery of new mall-molecule therapeutic agents targeting G-quadruplexes.