Refractive index sensor based on the diamond like carbon diffraction grating

In this work we present an optical refractive index (RI) sensor based on the spectral analysis of anomalies in the optical response from the diffraction grating employing polarized polychromatic light. The sensor consists of holographic diffraction grating (period 423.5 nm) coated with a thin (110 nm) SiO_x doped diamond like carbon film (DLC) that defines sensitivity of the sensor as well as the range of the spectral analysis. The deposition of the DLC film (synthesized by the direct ion beam deposition from the hydrocarbon source) has influence on the shape but not on the position of the anomalies observed in the specular reflection spectrum. From the reflection spectra the RI dispersion curve of liquid analyte-water was obtained.     

A simple model of radiation swelling of silicon

The radiation swelling of silicon is explained as a diffusion-like process where the flux of interstitials out of the plane is defined by the gradient of the concentration of interstitials and the gradient of mechanical stresses in the ion-implanted region of the solid. This model was applied to describe the dynamics and the main regularities (dependence of strain on the ion flux density, ion energy, substrate temperature) of ion implanted silicon (Ni⁺, E = 40–160 keV, j = 5–180 μA cm⁻²). It is demonstrated that suppression of radiation swelling at high temperatures of the substrate or high ion beam current density can be explained by the annihilation of radiation defects.     

Experimental Investigation of Heat Transfer and Flow Mixing in Pebble Beds

The purpose of this paper is to investigate the thermal hydraulic characteristics of two types of test sections: pebble beds placed between cylinders and thin annular pebble beds (i.e., spheres dumped in thin annular slots). The investigations were performed for axial air flow. The experimental results of heat transfer from the spheres, as well as the results of heat transfer from a cylinder for both types of test sections, are presented. In addition, the results of flow-mixing investigations in pebble beds between axially streamlined cylinders are described. From these results, correlations were developed that can be used to predict the heat transfer characteristics.

The results of the experimental investigation of pebble beds between cylinders demonstrated that the randomly arranged pebble bed is preferable to the regular rhombic structure from the points of view of design simplicity, heat transfer from the cylinder, drag coefficient, and flow mixing. The results of the experiments in the case of thin annular pebble beds demonstrated that the maximum heat transfer from the spheres is at the relative width of the annular slot K, equal to 1.07 and 1.75 of the sphere's diameter     

Strength evaluation of a steam distribution device in the Ignalina NPP accident localisation system

The Ignalina NPP has a pressure suppression type of confinement, which is referred to as the accident localization system (ALS). The ALS prevents the release of the radioactive material from the NPP to the environment during a loss-of-coolant accident (LOCA). Ten water pools are located in the two ALS towers (five pools in each tower), which separate the dry well from the wet well. These water pools condense the accident-generated steam and prevent high overpressures in the compartments.The steam distribution device (SDD), with the vertical vent pipes (nozzles) that are inserted under the water of the condensing pools, connects the dry well and the wet well. In case of an accident, these components must be capable of withstanding the dynamic loads generated by a LOCA for successful pressure suppression function.This paper presents the transient analysis of the SDD and their connections to the vertical steam corridors following a LOCA. A thermo-hydraulic analysis of the SDD was performed using the state-of-the-art COCOSYS code to determine pressure and temperature histories resulting from a LOCA. The finite element code NEPTUNE was used to evaluate the structural integrity of the SDD and its supporting reinforced concrete wall. Results show that, although portions of the SDD undergo plastic response and the outside surface of the vertical steam corridor reinforced concrete wall cracks, the structural integrity of the SDD and wall are maintained during a LOCA.     

Vacuum plasma spray deposition of YSZ-NiO-Ni coatings at different Ar and H2 gas flow rates

The work presents results of the experimental investigation of vacuum sprayed yttria stabilized zirconia, nickel oxide, nickel (YSZ-NiO-Ni) ceramic composite coatings deposited on Al₂O₃ ceramic and stainless steel substrates produced at different Ar and H₂ gas flow rates. The Ar and H₂ gas flow was varied according to the factorial plan design. It is shown that for the used vacuum plasma spray YSZ and NiO powder mixture the produced coatings were composed of three phases mainly: cubic YSZ (c-YSZ), cubic NiO (c-NiO), and cubic Ni (c-Ni). The quantitative X-ray diffraction (XRD) analysis was used to evaluate each phase amount in the coatings. It was found that the vacuum spray technique enables formation of composite layers with a variable composition and that phase content in the coatings can be controlled choosing the Ar and H₂ gas flow rates. The electrical conductivity measurements revealed that a variation of the phase content in the YSZ-NiO-Ni composites is responsible for the existence of different electrical conduction mechanism and rapid change in the conductivity of coatings with the used powder content. The surface morphology and the cross-section analysis by scanning electron microscope (SEM) have shown porous structures of the deposited coatings.     

Formation and characterization of melt-spun polypropylene fibers with propolis for medical applications

The search of possibilities to improve the functional properties of textile materials has been continuing for years with the aim to provide higher hygiene characteristics offer advanced therapeutic functionality. One of available approaches to provide new properties for textiles is the inclusion of natural ingredients. Propolis extracts are successfully used in practical therapeutics for accelerated wound healing and cell proliferation processes. In this study, pure multi-filament yarns and yarns saturated with propolis were developed and characterized. The effect of preparation and formulation parameters on the characteristics of yarns was evaluated; the release of propolis extract components from yarns and their possible cytotoxicity on cell formation was also determined.     

Growth of ITO thin films by magnetron sputtering: OES study,opticaland electrical properties

In this work tin doped indium oxide (ITO) thin films were deposited onto soda lime glass substrates by the direct current magnetron sputtering system analyzing process of deposition with optical emission spectroscopy (OES). The dependence of electro-optical characteristics of the deposited films on the sputtering pressure, O₂/Ar working gas flow ratio and the discharge power was investigated. Transparency of the ITO films was measured using the ultraviolet and visible light spectrometer (UV–vis). The X-Ray photoelectron spectroscopy (XPS) method was applied for analysis of thin films surface chemical composition. It was found that in-situ measurement of plasma emission spectra allowed prediction and control of parameters of ITO thin films, namely resistivity and transparency. The correlation between the thin films resistivity, optical transparency and kinetics of deposition was examined.     

Long-term prediction of creep strains of mineral wool slabs under constant compressive stress

The results obtained in determining the creep strain of mineral wool slabs under compressive stress, used for insulating flat roofs and facades, cast-in-place floors, curtain and external basement walls, as well as for sound insulation of floors, are presented. The creep strain tests were conducted under a compressive stress of σ _c =0.35σ _10%. Interval forecasting of creep strain was made by extrapolating the creep behaviour and approximated in accordance with EN 1606 by a power equation and reduced to a linear form using logarithms. This was performed for a lead time of 10 years. The extension of the range of the confidence interval due to discount of the prediction data, i.e. a decrease in their informativity was allowed for by an additional coefficient. Analysis of the experimental data obtained from the tests having 65 and 122 days duration showed that the prediction of creep strains for 10 years can be made based on data obtained in experiments with durations shorter than the 122 days as specified by EN 13162. Interval prediction of creep strains (with a confidence probability of 90%) was based on using the mean square deviation of the actual direct observations of creep strains in logarithmic form to have the linear trend in a retrospective area.