Theoretical UBVRI colors of iron core white dwarfs

We explore photometric properties of hypothetical iron core white dwarfs and compute their expected colors in UBVRI Johnson broadband system. Atmospheres of iron core WDs in this paper consist of pure iron covered by a pure hydrogen layer of an arbitrary column mass. LTE model atmospheres and theoretical spectra are calculated on the basis of Los Alamos TOPS opacities and the equation of state from the OPAL project, suitable for nonideal Fe and H gases. We have also computed UBVRI colors of the models and determined an area on the B-V vs. U-B and U-B vs. V-I planes, occupied by both pure Fe, and pure H model atmospheres of WD stars. Finally, we search for iron core white dwarf candidates in the available literature.Comment: 13 pages, 12 figures, Astronomy & Astrophysics (2003) in prin

The properties of diamond - like carbon (DLC) coatings on titanium alloys for biomedical applications

The paper presents the results of DLC coating of produced by the method of physical vapor deposition (PVD) on the titanium alloy for biomedical applications. Surface morphology and elemental composition were determined with the use of Scanning electron microscopy (SEM)/ Energy dispersive spectroscopy (EDS). Hardness was determined by instrumental indentation. Tribological tests were carried out under technically dry friction and friction with lubrication of Ringer’s solution. The DLC”s are characterized by high hardness (increased by an 4-fold) and anti-wear properties. In the case of technically dry friction and in the case of Ringer’s solution, the coefficient of friction decreased by an 5-fold compared to the results obtained for substrate

Dark-state suppression and optimization of laser cooling and fluorescence in a trapped alkaline-earth-metal single ion

We study the formation and destabilization of dark states in a single trapped 88Sr+ ion caused by the cooling and repumping laser fields required for Doppler cooling and fluorescence detection of the ion. By numerically solving the time-dependent density matrix equations for the eight-level system consisting of the sublevels of the 5s 2S1/2, 5p 2P1/2, and 4d 2D3/2 states, we analyze the different types of dark states and how to prevent them in order to maximize the scattering rate, which is crucial for both the cooling and the detection of the ion. The influence of the laser linewidths and ion motion on the scattering rate and the dark resonances is studied. The calculations are then compared with experimental results obtained with an endcap ion trap system located at the National Research Council of Canada and found to be in good agreement. The results are applicable also to other alkaline earth ions and isotopes without hyperfine structure

Influence of TiO2 coating deposited with the atomic layer deposition ALD technique on the properties of Ti13Nb13Zr titanium alloy

The paper presents the geometric structure of the surface, hardness and the results of tribological tests for TiO2 layers obtained by the ALD technique. The geometrical structure of the surface before and after the tribological tests was assessed using a confocal microscope with interferometry mode. An instrumental indentation was used to measure nanohardness. Model tribo tests were carried out for reciprocating motion under conditions of dry friction and friction lubricated with artificial saliva and saline. The tests showed that the TiO2 samples showed lower wear and higher hardness

Diamond-like carbon (DLC) coatings on roller bearing elements of belt conveyors

The aim of the study was to analyse the anti-wear diamond-like carbon (DLC) coatings produced by Plasma-Enhanced Chemical Vapour Deposition. The DLC coatings were deposited on the rings of rolling bearings operating in belt conveyors. The service life of the bearings was 1,5 years. The bearings were exposed to harsh environmental conditions. After the disassembly of the bearings, the influence of the coatings on the improvement of tribosystem characteristics was assessed. Characterization of the bearing geometry was carried out using an optical surface profilometer. The use of diamond-like coatings on rolling bearings extended the tribosystem service life in industrial conditions threefold

Structure and mechanical properties of diamond-like carbon (DLC) coatings doped with silicon

This paper reports the study of silicon-doped diamond-like carbon coatings a-C:H:Si prepared by Plasma-Assisted Chemical Vapour Deposition (PACVD) on 100Cr6 steel. Surface morphology and elemental composition were determined with the use of Scanning Electron Microscopy (SEM) / Energy Dispersive Spectroscopy (EDS). Surface topography measurements were performed using Atomic Force Microscopy (AFM). The scratch test assessment of the influence of a-C:H:Si coatings on mechanical properties was based on the measurements of nanohardness and adhesion to the substrate. The results show that silicon-doped diamond-like carbon coatings a-C:H:Si are characterized by a uniform surface structure, high hardness and good adhesion to the substrate

Influence of TiO2 coating deposited with the atomic layer deposition ALD technique on the properties of Ti13Nb13Zr titanium alloy

The paper presents the geometric structure of the surface, hardness and the results of tribological tests for TiO2 layers obtained by the ALD technique. The geometrical structure of the surface before and after the tribological tests was assessed using a confocal microscope with interferometry mode. An instrumental indentation was used to measure nanohardness. Model tribo tests were carried out for reciprocating motion under conditions of dry friction and friction lubricated with artificial saliva and saline. The tests showed that the TiO2 samples showed lower wear and higher hardness

Influence of coating application parameters on selected properties

In this paper, titanium coatings were deposited on steel using the plasma-assisted chemical vapor deposition (PACVD) process. These coatings were deposited at the same gas flow and power parameters, but at different times. This resulted in the creation of coatings with different properties. Increasing the time by half increased the thickness of the coating by about 78 %