Traces of Wood and Bone Processing on the Volcanic Flint of the Dunda- Aga Paleovolcano: The Preliminary Experimental Data

The article is a description of an experiment on planing the raw and dry wood, as well as boiled bone, which was carried out by flakes from volcanic flint from the raw material source of the Dunda-Aga paleovolcano, located in the Aginsky Buryat district of the Transbaikal region. In its course, changes in the working edge of the tools were monitored using binocular and metallographic microscopes, as well as photographic recording of these results using digital cameras and Helicon Focus v. 5.3. During the experiment, it was possible to identify a tendency for the formation of macro and micro wear of the surface of the working edge of objects, depending on the material processed by planing. It was found that on volcanic flint, in places of the most intense contact with a hard surface to be treated, micropolishing in individual microsections is formed already within the first 30 minutes of operation. Then these areas expand and close along the length of the working edge. Over time, tools that work dry wood show a fine micro-polish line, while wet wood forms a more discontinuous line of different widths. Bone processing showed the strongest modification of the tool. After an hour of work, it became dull due to intense rounding, and after two hours it almost completely lost its effectiveness. The results of this experiment clarify the dynamics of the formation of macro and micro wear on tools made of volcanic flint when processing dry and damp wood, as well as bone. Keywords: microwear analysis, petroarcheology, the sources of raw materials, Stone Age, Transbaikalia, Dunda-Aga paleovolcano, volcanic flint Acknowledgements: The work was supported by a grant from the Transbaikal State University No. 292‑ГР.

Deformation Behaviors of Non-Metallic Inclusion in FGH96 Superalloy during Different Plastic Processes

The non-metallic inclusions in FGH96 superalloy during different plastic processes were studied. The results show that SiO2 react with aluminum and titanium in FGH96 superalloy and the reaction zone is formed in the interface between SiO2 and alloy, whereas Al2O3 react with no elements in FGH96 superalloy and the transition zone between them is mechanical combination during the plastic processes. In addition the sizes of non-metallic inclusions increase in the direction perpendicular to deformation during isothermal forging process. The non-metallic inclusions are pulled into a discontinuous line in extrusion direction and areas of non-metallic inclusions in each direction are constricted during extrusion process. The non-metallic inclusions of FGH96 superalloy is conditioned by the state of the as-extrusion inclusions during extrusion+isothermal forging process. In summary, extrusion process with large extrusion ratio can break the non-metallic inclusions in FGH96 alloy effectively and improve forging quality.

Forced Response of Continuous System With Hysteresis Loop Characteristics: System With Quadrilateral Hysteresis Loop Characteristics

This paper deals with steady-state response of a continuous system with collision characteristics. Considering the energy loss in a collision, an analytical method of approximate solution for the continuous system with symmetrical hysteresis loop characteristics is presented. The resonance curves of nonlinear response obtained from approximate solution are shown as discontinuous line, and are discussed the phenomenon.