Kazimierz Rozniakowski

Some experimental results of laser beam interaction with surface layer of brick

Abstract Preservation of cultural heritage is gaining increasing attention all over the world. Restoration of ancient artwork and architecture requires even more effective cleaning techniques than are currently available. Laser cleaning appears to be a suitable method for removing surface contaminants from porous materials like masonry. This paper presents some effects of laser beam interaction (ruby laser, free generation regime) with clean and contaminated surface of brick which was subjected to long term exposure to atmospheric conditions. The effects of the laser beam interaction have been examined by the optical microscopy method, scanning electron microscopy and X-ray microanalysis. The present research revealed the potential application of laser irradiation for cleaning of the surface layer from contaminants and possible modification of the chemical composition of cleaned surfaces.

The phenomena of the interaction of Nd3+-glass laser light with 6H13 alloy steel

Abstract The variation in the physical and chemical structure of the 6H13 alloy steel irradiated by laser light have been investigated. The phenomena of the capillary waves within the power density range (4.3×10 9 9 ) watt/m 2 have been observed and the hydrodynamic parameters of alloy steel have been determinated. The nature of the laser light interaction with metal is discussed in electronmicroscopy and X-rays analysis terms.

Non-contact methods of measuring moisture concentration in external layers of building partitions: II—Monitoring of the water vapour condensation on porous surfaces

This paper present the results of the investigation into a potential application of laser radiation for the detection of phase transition processes occurring on the surface layers of porous materials. An attempt was made to discuss in the approximation equations, the relationships between coefficients of the reflected light, the temperature and humidity of the surrounding environment. Laser light reflected from the porous surface carries information about the roughness of the structure. The presence of water microdrop on the surface of the porous material, as a result of condensation and thus a phase transition, leads to the phase displacement of individual rays, which is represented by different images. Therefore, a comprehensive analysis of the reflected light parameters allows a dynamic study of the phase transition phenomena without mechanical intervention.

Studies on interaction of Nd3+ — Glass laser light with armco-Fe high pressure nitrogen medium

Abstract Some effects of the interaction of Nd 3+ -glass laser, working in ordinary generation regime, with Armco-Fe surrounded by nitrogen in the pressure range (1–109) atm. have been investigated. Thephenomenon of capillary waves and the increase of the N 2 content have been observed in the irradiated area. The mechanism of the laser light interaction with the metal is discussed in terms of plasma theory and X-ray analysis.

Non-contact methods of measuring moisture concentration in external layers of building partitions. I—The influence of geometrical microstructure on the kinetics of moisture condensation on glass surfaces

Abstract This paper presents the results of the larger study on the potential application of laser radiation for the detection of phase transition processes. The proposed experimental method allows a dynamic study of the phenomena without mechanical intervention. This seems to be the best practical solution particularly when the access for the other methods is very restricted. The investigations give an evidence of the strong relationships between the rapid growth of water vapour condensate and the roughness of the surface. Condensation process therefore can be modified by a careful design of the geometrical structure of surface.

Non-contact methods of measuring moisture concentration in external layers of building partitions. III-Water vapour condensation on the cementitious surfaces

Abstract This paper presents the results of the larger study into a potential application of laser radiation for the detection of phase transition processes in low temperatures occurring on the surface layers of cementitious materials. An attempt was made to identify relationships between the environmental conditions—temperature and air humidity, and the selected parameters of the reflected light. Onset of the condensation process and formation of water microdrops on the surface of the material leads to the phase displacement of individual laser rays, which are represented by different speckle images. Although the analysis of parameters of the reflected light are very difficult in the case of porous materials because of highly developed roughness of the surface structure it has been proved that a dynamic study of the phase transition phenomena can be successfully carried out without mechanical intervention.

Studies on capillary waves generated by light pulses of Nd3+ - glass laser with ultrasonic Q-switch

Abstract In the paper some results of the studies on parameters of capillary waves generated in 18H2N4WA type steel by means of light pulses of Nd 3+ - glass laser with ultrasonic modulation of Q-factor of the optical resonator have been presented.

Thermal diffusivity of building materials measured by the laser flash method

Mesure de la diffusivite thermique de plusieurs materiaux de construction (panneaux de fibres, amiante, brique, liege, plâtre) par la methode flash laser. Cette methode est rapide, offre une bonne reproductibilite et un bon accord avec les autres methodes et ne demande aucune preparation speciale des echantillons

On some parameters of interaction of glass neodymium laser beam with metal surfaces having different roughness

Abstract Samples of 45 steel and MO60 brass with the surface roughness ranging from 0.5 ÷ 8 μ m were irradiated with strong pulses of a glass neodymium laser working in ordinary generation regime ( λ = 1.06 μ m, E = 6 J, τ = 2 ms). The parameter of roughness h was determined by means of an optical reflexometric method. The dependences of the chosen parameters of the interaction, i.e. the amount of the mass Δ m removed from the crater, the depth H and the mean radius r o of deep cavities being formed were examined as a function of h.

Determination of surface tension coefficient of liquid metals and alloys using the phenomenon of capillary wave formation

Abstract A possibility of determining the surface tension coefficient of 6H13 liquid steel and of technically pure iron (ArmcoFe) has been presented. In the investigation the phenomenon of ring structure formation (capillary waves) on the surface of a molten metal affected by light pulses of a glass neodymium laser ( λ = 1,06 μ m, τ i ≈ 1 ms, E i ≈ 6J) has been considered. The values obtained for the surface tension coefficient are in good agreement with those determined by other methods (for liquid metals in the temperature range 2000K – 5000K).