Wyniki wyszukiwania - Biblioteka Nauki

1

Analiza skuteczności sterów lekkiego samolotu w korkociągu

100%

Baron A. , Goraj Z.

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tom Nr 4 (167)

45-53

PL

Artykuł skupia się głównie na eksperymentalnych badaniach korkociągowych prototypu I-23 lekkiego samolotu, zaprojektowanego i oblatanego i Instytucie Lotnictwa w Warszawie. Konstrukcja jest całkowicie kompozytowa, pposiada proste skrzydło i chowane podwozie. Układ aerodynamicany i system sterowania samolotu są klasyczne. Powierzchnia nośna wynosi 10m2, rozpiętość skrzydła 8.8m, max. masa startowa jest równa 1150kg. W pracy zawarto analizę i przedstawiono odpowiednie metody wyprowadzania samolotu z korkociągu, możliwe do rozważania na wczesnym etapie projektu samolotu. Zbadano trzy czynniki główne decydujące o charakterystykach korkociągowych lekkiego samolotu - względny rozkład masy pomiędzy skrzydło i kadłub, gęstość względną samolotu oraz konfigurację usterzenia. Wyznaczono tzw. współczynnik tłumienia usterzenia (TDPF) z uwzględnieniem tzw. nieosłoniętej powierzchni statecznika pionowego. Testy przeprowadzone na dużych kątach natarcia w tunelu aerodynamicznym na modelu samolotu w skali 1:3 pokazały, że nie ma różnic pomiędzy skutecznością steru kierunku w obecności i pod nieobecność usterzenia poziomego.

EN

This paper focuses mainly on the experimental and in-flight spin investigationsfor an executive lightairplane, named I-23 and built in Institute of Aviation. It is single-engine, all composite, straight wing, rectable undercarriage, conventional configuration and flight control system airplane. Gross wing area is 10m2, wing span - 8.8m, maximum take-off mass-1150kg. spin analysisand adequate treatment to spin recovery were considered earlyin the design stage. Very well known three principal factors,overriding importance in the spinning of light airplanes, were carefully investigated. among them were: the relative distribution of the mass of the airplane between the wing and fuselage, relative airplane density and the tail configuration. In setting up the tail-design requirements, the so-called taildamping power factor was computed using the unshieldedrudder volume coefficient and the tail-damping ratio. The wind tunnel tests, performed on the scaled (1:3) airplane model at high angles of attack showed that there were no differences between effectiveness of the rudder alone configuration (horizontal tail removed) and that of the full configuration (including horizontal tail).

2

EIS tests of electrochemical behaviour of Ti6Al4V and Ti6Al7Nb alloys

80%

Baron A. , Simka W. , Chrzanowski W.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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tom Vol. 21, nr 1

23-26

EN

Purpose: This study has been undertaken in order to establish the influence of parameters of the electrochemical treatment of Ti-alloys on their electrochemical behaviour in Tyrod solution. Design/methodology/approach: Surface of the Ti-alloys: Ti6Al4V and Ti6Al7Nb in the form of a rod submitted to grounding, electropolishing and anodic passivation. Electrochemical investigations were carried out by means of the electrochemical impedance spectroscopy method. Scope of this paper includes analysis of the impedance spectra based on Bode plot. Findings: Prolongation time of anodic passivation to 60 minutes caused formation of a two - layer model consisting of an inner layer which is compact and the barrier type, and outer layer which is porous. Research limitations/implications: Obtained results are the basis for the optimization of anodic passivation parameters of the Ti alloys as a metallic biomaterial. The future research should be focused on selected more suitable parameters of the electrochemical impedance spectroscopy test to better describe process on the solid/liquid interface. Practical implications: It has been found that a good resistance to corrosion and homogeneous oxide layer on the Ti6Al4V and Ti6Al7Nb alloys surface can be achieved due to the application of electrolytic polishing of these alloys in a special bath and anodic passivation in sulphuric acid (VI), phosphoric acid (V) and inorganic salts. Originality/value: Results of the experiments presents the influence of various conditions of anodic passivation of the surface of the Ti6Al4V and Ti6Al7Nb alloy. In this cases, when the surface roughness plays important role, this method can be applied in treatment of the material intended for medical applications especially.

3

Electrochemical behavior of Ni-Ti alloy after surface modification

70%

Kaczmarek M. , Simka W. , Baron A. , Szewczenko J. , Marciniak J.

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tom Vol. 18, nr 1-2

111--114

EN

Purpose: The shape memory effect and superelasticity make the nickel-titanium alloy an interesting material for medical applications. But the biocompatibility has been questioned due to conflicting results in the literature. The latest research has shown that this situation may be caused by a variation in NiTi surface treatment. The appropriate surface treatment increases the corrosion resistance. The paper presents the electrochemical behavior of NiTi alloy after surface modification with the use of various techniques. Design/methodology/approach: The evaluation of the electrochemical behavior of NiTi alloy was realized both by recording of anodic polarization curves with the use of the potentiodynamic method and by an electrochemical impedance spectroscopy technique (EIS). Findings: Surface condition of metallic biomaterial determines its corrosion resistance. In the course of the work it was observed that the lowest values of corrosion current were recorded for the sterilized and the thermally passivated samples. The highest values of corrosion current were recorded for the ground samples. These samples obviously had also the highest corrosion rate. Research limitations/implications: The obtained results are the basis for the optimization of physicochemical properties of the metallic biomaterial. The future research should be focused on selected specific implants specially with respect to their application features. Practical implications: On the basis of the obtained results it can be stated that the suggested surface treatment can be applicable for medical implants due to the increase of the corrosion resistance and in consequence the increase of biocompatibility. Originality/value: The paper presents the influence of various methods of the surface treatment on corrosion resistance of the NiTi alloy. The suggested methods can be applied in treatment of the material intended for medical applications especially in cases where the surface roughness plays important role.

4

Influence of electrolytic polishing on electrochemical behaviour of austenitic steel

70%

Baron A. , Simka W. , Nawrat G. , Szewieczek D. , Krzyżak A.

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tom Vol. 18, nr 1-2

55--58

EN

Purpose: The paper deals with investigations on the influence of the parameters of the electrochemical treatment of austenitic steel on their electrochemical behaviour in Tyrod solution. Design/methodology/approach: Electrochemical investigations concerning the corrosion resistance of austenitic steel samples were carried out by means of the potentiodynamic and elektrochemical impedance spectroscopy method. Findings: The analysis of the obtained results leads to the conclusion that chemical passivation affects also the chemical composition of the passive layer of steel and changes its resistance to corrosion. Electrolytic polishing improves corrosion resistance, as can be proved by the shift of the value of the corrosion potential and breakdown potential of the passive layer and the initiation of pittings. Practical implications: In result of the presented investigations it has been found that the best corrosion resistance can be achieved thanks to the application of electrolytic polishing of the steel in a special bath and chemical passivation in nitric (V) acid with an addition of chromic (VI) acid temperature t = 60°C for one hour. Originality/value: The enormous demand for metal implants has given rise to a search for cheap materials with a good biotolerance and resistance to corrosion. Most commonly used are steel implants assigned to remain in the organism for some limited time only. It was compare two electrochemical methods: potentiodynamic polarization and electrochemical impedance spectroscopy.

5

Profilaktyka epidemiologiczna rzęsistkowicy moczowo-płciowej w warunkach środowiska uzdrowiskowego

70%

Nowosad K. , Wawrzkiewicz M. , Robaczynski J. , Baron A. , Ziolkowski M.

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nr 3