Analysis Of Physical Effects Research Articles

Analysis of Physical Effects in Cutting Machining

This contribution focuses on hole drilling into grey cast iron and steel 11 523. The most used method of hole machining is the one using a screw drill HSS to reach the accuracy class from IT 11 up to IT 14. Surface roughness ranging between Ra 3.2 μm and Ra 6.3 μm depends on the parameters of the drill used and drilled material. An emphasis is put on the accuracy of shape and dimension as well as on meeting the tolerance limits of holes [1,2,3,4,5]. In most cases, it is possible to reach those conditions using the common methods of hole drilling. Finishing such as roughing, reaming and countersinking is used for meeting high-quality requirements [6,7,8,9].

Analysis of physical effects on the electrode surfaces in rail launchers

This paper analyzes some physical effects that occur on the electrode surface in plasma-armature rail launchers when the linear current density is higher than the critical value. The melt on the electrode surface is found to be unstable. An analysis of the possible development of a number of instabilities showed that under experimental conditions, Rayleigh-Taylor and Kelvin-Helmholtz instabilities and magnetohydrodynamic instabilities due to the interaction of the current with the self-magnetic field can develop over times much smaller than the discharge time. As a result, the electrode material can enter the plasma armature, thus limiting projectile velocity. X-ray recording of the electrode surface confirmed the presence of small-scale inhomogeneity and ejection of the electrode material from the surface. Under certain conditions, the emergence of conducting metal jets from the electrode surface was detected.

Zero-range potentials in boundary-contact problems of acoustics

The problems of acoustic waves diffraction by elastic plates or shells with edges, conjunctions, cracks, inclusions and stiffeners attract wide interest caused by the needs of shipbuilding, acoustics of the ocean and other sciences. Much attention in paid to problems that can be solved exactly. Then the analysis of physical effects is the most simple. Up to present practically all the explicit solutions have been already examined. To analyse new physical effects one needs to use more and more cumbrous approaches with large computer resources needed for realization. Nevertheless, the set of problems having explicit solution is not yet exhausted. One must apply new not traditional for that type of problems mathematical apparatus. In this paper the operator extension theory is suggested to formulate the models of asymptotically small inhomogeneities of plates. The main problem arising in that approach is in the choice of the parameters of the model adéquate to the inhomogeneity. The inverse problem for finding the parameters of the zero—range potential is solved for a particular problem of scattering by a narrow crack in fluid loaded elastic plate. the components of the zero—range potential model are compared to the models in simpler problems. One is that for the isolated plate and the corresponding component of the zero—range potential allows to propose general procedure for choosing the parameters of the model.

Binding of yeast TFIIIC to tRNA gene bipartite internal promoters: Analysis of physical effects on the intervening DNA

Complexes between transcription factor TFIIIC and eukaryotic tRNA gene internal promoter A and B boxes are unusual in that the binding to the two distinct sites tolerates considerable variation in both distance and helical orientation between the sites. Electrophoretic mobility of Saccharomyces cerevisiae TFIIIC complexes with circularly permuted tRNA gene fragments and sensitivity of the complexes to a single stranded-specific reagent, potassium permanganate, indicated that no significant bend or distortion was introduced into the DNA by simultaneous binding to both internal promoters. These data support a model in which variability in the relative positions of the two binding sites is compensated by flexibility in the structure of TFIIIC.