Marek Opielak

Structural analysis of multilayer metal nitride films CrN/MoN using electron backscatter diffraction (EBSD)

The electron backscatter diffraction (EBSD) analysis method was used for studying structure and properties of multilayer nitride CrN/MoN coatings fabricated by cathode arc physical vapour deposition (Arc-PVD). Samples were deposited on steel substrate with different single layer thickness from tens nanometers to 1 micron and with total thickness of coatings up to 8-13 μm. Colour grains mapping, grain size distribution profiles, pole figures and texture analyses were the main research instruments. Studying of obtained coatings was performed on specially prepared polished cross-section samples. The dependence between single layer thickness and grain size of materials, which is also changing through depth profile of the coating, was observed. In addition, it was possible to study phase composition, prevailing crystals orientation, dominant texture and grains growth. Studying of grains size, as well as other indicated parameters, is a very important task because it gives an information about grains interfaces volume, which causes changes in mechanical properties of material. Obtained results were cross-checked by X-ray diffraction analysis (XRD) where it was possible.

Accuracy Control in the Machining of Low Rigidity Shafts

The study determines the most suitable pattern of alignment and fixing of low-rigidity shafts; it also presents factors that determine such choice. The part is fixed both by force closing and kinematic closing. A new method for machining low rigidity shafts is developed to control the elastic-deformable state of these shafts in a technological system and to produce parts with the required accuracy during turning. To implement this new developed method for low rigidity shafts, an apparatus is designed. The apparatus allows to increase the rigidity of shafts during machining by the application of axial tensile force to the workpiece. Rational prime costs of preparing technological alignment centers at the stage of production preparation are determined; knowing these costs, it is possible to select a suitable machining technology for low rigidity shafts, to produce a technology-oriented design, and to reduce the costs of machining these shafts.

Assessment of Energy Use and Elimination of Co2 Emissions in the Life Cycle of an Offshore Wind Power Plant Farm

Abstract Power stations in marine locations cause multi-faceted impact on the environment, man and the economy. There are not many studies devoted to modeling energy benefits for CO2 emissions. The paper presents the issues of assessing the efficiency of offshore wind farms, defined as the ratio of benefits to life cycle inputs. The scientific goal was to develop a mathematical model for efficiency in the design, manufacture, use and management of offshore wind power. The papers practical purpose is the experimental designation of the impact of selected post-use management methods, time of use and maritime location, i.e. average annual productivity of wind power plants on the efficiency of energy benefits from greenhouse gas emissions. The mathematical model of the integrated cost-benefit ratio has been developed for energy use assessment, taking into account the benefits generated by electricity production and the life-cycle CO2 emissions based on the LCA analysis using the CML method. Mathematical model validation was performed by determining the value of the indicator for an existing 2 MW offshore wind farm and comparatively for fossil fuel production: lignite, stone, fuel oil and natural gas. Analytical and research work carried out showed that the higher the efficiency index, the higher the value of the indicator. It has been shown that the location of the power station at sea produces more favorable CO2 elimination rates, due to higher productivity compared to in-land wind power plants. A more favorable form of post-consumer management for CO2 has been determined as recycling. It was found that for electricity generated from offshore wind farms, the value of the energy efficiency benefit from CO2 emissions is higher than for fossil fuel energy production.

Charge sensitive techniques in tribology studies

The goal of the present work was to study of changes occurring at the surface materials during friction by the continuous non-destructive testing of electron work function. The paper describes the electronic work function measurements by the contact potential difference techniques (the Kelvin-Zisman, the Non-vibration and the Ionization capacitors), and experimental demonstration of the possibility of their application for the analysing of the friction processes. The techniques of tribological studies using charge sensitive probes are developed. Examples of measurements work function during friction for the bronze and steel samples are present. The study work function directly in the process of friction possible to determine the modes of friction and dynamics of defects on the surface friction identify spots of destruction on local microroughnesses, the surface topology evolution.

Dynamic System of Grinding of Low-Rigidity Shafts

The paper presents a methodology of building a mathematical model of dynamic system of shaft grinding under the condition of elastic strain, and the model itself. The model was worked out basing on analytical identification. The system of equations and general structural pattern of MM system of dynamic grinding are introduced. Such prepared system of equations and structural pattern of MM takes into account the geometry of machined layer and forces of cutting during the grinding, elastic properties of DS and the process of forming the section of the machined layer (ML). The specification of DS identifying for grinding the small stiffness shafts is shown.

Optimal Controlling the Dynamical System of Machine Tool by Elastic-Deformable Shafts Machining

In article has been presented machining process mathematical model of elastic-deformable shafts. It has been presented problem of optimal regulation of technological system in automated production systems too.