PyQCstrc.ico: a computing package for structural modelling of icosahedral quasicrystals

The atomic structure of quasicrystals (QCs) is described as a section of a higher-dimensional structure that consists of a periodic arrangement of occupation domains (ODs). Determination of the shape of ODs and their partitioning is crucial in the structural analysis of QCs. However, owing to the complicated shape of ODs, building the initial structure model requires a great deal of time and effort. Thus, a computer program for building structure models of QCs is needed. Presented here is a Python3 package for structure modelling of icosahedral QCs.

On Natural Oscillations of a Thin Elastic Wavy Shell of an Open Profile

The article touches upon the problem of natural oscillations of a thin elastic wavy shell of an open profile. The proposed method for determining the numerical values of the lowest frequencies and the corresponding forms of natural oscillations of shells of a complicated shape is based on the Rayleigh-Ritz energy method. The results of numerical calculation of this thin wavy shell with a hinge-fixed attachment along the lower contour along the generatrix are presented.

Assist system for remote manipulation of electric drills by the robot “WAREC-1R” using deep reinforcement learning

Operation of tools has long been studied in robotics. Although appropriate hold of the tool by robots is the base of successful tool operation, it is not with ease especially for tools with complicated shape. In this paper, an assist system for a four-limbed robot is proposed for remote operation of reaching and grasping electric drills using deep reinforcement learning. Through comparative evaluation experiments, the increase of success rate for reaching and grasping is verified and the decrease in both physical and mental workload of the operator is also validated by the index of NASA-TLX.

Influence of Contact Efforts on the Surface Quality of Difficult Profile under Finishing Hardening Machining

This work presents the research and development data in the field of finishing and hardening processes for parts with complicated shape surface. The comparable effectiveness of different surface finishing and hardening processes were studied, and intensification possibilities of processes of vibration finishing - hardening machining of narrow ducts by means of combined methods with metal anodic dissolution were shown. The results of experimental researches of influence of extrusion conditions of granular media on the surface layer quality are presented.

Generation of Biocompatible Titanium Alloy Surfaces Including Calcium and Phosphorus Elements by Laser-Induced Mist Spraying Wet Treatment

Titanium alloys are widely used for the hard tissue substitute implants. However, it is necessary to improve interfacial biocompatibility to reduce adhesion period. For improvement of biocompatibility of Ti-6Al-4V ELI alloys, texture and chemical composition on contact part with biological tissue play very important roles. In this research, micro texture was generated on the Ti-6Al-4V ELI alloy surfaces utilizing laser irradiation, in order to improve biocompatibility. The biocompatibility was evaluated by osteoblast cell culture assays. The results indicated the surface having micro texture improve biocompatibility as compared with untreated surface. This was considered in order the fact that the formed modified surface had hydrophilicity, thereby improving the cell compatibility, and the cell adhesion due to the complicated shape. In addition, mist of glycerophosphoric acid calcium aqueous solution was applied on the laser irradiated area. As result, micro texture including Ca and P elements was generated on the Ti-6Al-4V ELI alloy surfaces. When laser was irradiated, glycerophosphoric acid calcium aqueous solution was applied as mist flowed on the test pieces as droplet. The velocity of droplet fluid was relatively fast, so that laser irradiation was unhindered access to the surface of test pieces and the treatment was stable. In order to estimate biocompatibility, culture assays using osteoblast cells were conducted on the treated surface having micro texture including Ca and P elements. As results, it was clearly that biocompatibility of the specimen treated by laser with glycerophosphoric acid calcium aqueous solution mist more improved than either untreated specimen or treated specimen soaked in glycerophosphoric acid calcium aqueous solution.

Defect Investigation of Sand Casted Aluminum Cooling Fan

Sand casting is one of manufacturing process that still exist today. Numerous products are produced to serve industrial and domestic use. Defect could lead to product performance, and unfortunately inevitable in a casting process. This paper aim to investigate typical defect resulted from sand casting process. An aluminum cooling fan was selected as the model since it has complicated shape with different thicknesses. The casted fan was investigated under photo micro for defect analysis. Porosity, gas inclusion, pinhole, and shrinkage were found as the common defects occured at different part of the fan.

Increase of formation efficiency of gears contact spot at electrochemical-mechanical running-in

The analysis of literature sources showed that gears are the most common types of mechanical gears. They are widely used in all branches of mechanical engineering, in particular in metal-cutting machines, cars, tractors, agricultural machines, etc. Among the many advantages of this type of gear, there are disadvantages, among which it is worth noting increased demands on precision manufacturing and Assembly, which results in a greater complexity of the collaborative process of finishing gears in view of their complicated shape and heavy-duty loads for contour and complex mode of interaction. This makes it particularly difficult to increase the durability when running gears. They require increased surface hardness, which is associated with small contact areas (in most cases-in line) and large specific loads. Even small distortions in this case lead to a significant complication of the process of their burn-in. The results of experimental studies have shown that for elimination of inaccuracies of form of details and errors of assembling mechanism expose to running-in which running- in of the surfaces take place. The most effective factor of acceleration of running-in is to use the combined processes at running- in surfaces. One of them is the electrochemical - mechanical running-in (ECMR)