Contact Interaction of Turbine Blade Interlock Elements Under Creep

Strength of Materials - The effect of the creep of materials of a structure on the nature of the contact interaction between its elements during long-term operation is investigated. The problem of...     

An optimized FAIRE procedure for low cell numbers in yeast

We report an optimized low‐input FAIRE‐seq (Formaldehyde‐Assisted Isolation of Regulatory Elements‐sequencing) procedure to assay chromatin accessibility from limited amounts of yeast cells. We demonstrate that the method performs well on as little as 4 mg of cells scraped directly from a few colonies. Sensitivity, specificity and reproducibility of the scaled‐down method are comparable with those of regular, higher input amounts, and allow the use of 100‐fold fewer cells than existing procedures. The method enables epigenetic analysis of chromatin structure without the need for cell multiplication of exponentially growing cells in liquid culture, thus opening the possibility of studying colony cell subpopulations, or those that can be isolated directly from environmental samples.     

Study of the influence of the structural grain size on the mechanical properties of technical materials

The mechanical properties of technical materials depend on their structure. They are influenced not only by their chemical composition, but particularly by the structural grain size. Significant changes in the mechanical behaviour of materials are related both to surface and volume properties, and not only in the field of mechanical parameters. A wide range of physical and chemical parameters changes as well. Nano‐materials are the materials, the structural grain size of which is in the dimensional area from 10^?9 to 10^?7 m. Nano‐particles and nanostructures are thus so small that their behaviour is affected by atomic forces, properties of chemical bonding, and quantum phenomena. The wave nature of the very small particles begins to manifest itself. The aim of the authors is to contribute by their paper to the solution of the problems in the field of material engineering. This means to investigate the specifics in the behaviour of technical materials depending on the change in the structural grain size towards the nano‐areas, as well as the design and use of new techniques of mathematical and physical modelling including the operative measurement method.     

Reverse reconstruction of surface topography from residual stress after chip-forming machining of the material

Residual stress is induced in the sample of a material stressed by external forces (tension, pressure, thermal stress, etc.) from the beginning of the stress. An instantaneous level is a function of the intensity of the external deformation work, the time and speed of the deformation, and the degree of immediate surface and volume deformation. It is proportional to the individual deformation limits, i. e., the elastic limit, yield point, flexural strength and breach limit; the maximum is reached at the level of the breach limit. Furthermore, it is dependent on the physical-mechanical properties of the material and on the method, i. e., the technology of straining, or machining. The same applies to the roughness distribution and other topographical features on the machined surface. The tension that has not been exhausted is partly returned to the volume of the sample and partly acts in contact with space, within a certain distance and time. This paper aims to present a reverse reconstruction of the surface topography from residual stresses after chip-forming machining of the material. Our original approach to the solution fully exploits the rules of roughness distribution and other topographic features of the surfaces of the given materials after machining, not only by chip-forming machining.