Currently, several outdoor navigation and orientation electronic traveling aid (ETA) solutions for visually impaired (VI) people are commercially available or in active development. This paper’s survey of blind experts has shown that after outdoor navigation, the second most important ETA feature for VI persons is indoor navigation and orientation (in public institutions, supermarkets, office buildings, homes, etc.). VI persons need ETA for orientation and navigation in unfamiliar indoor environments with embedded features for the detection and recognition of obstacles (not only on the ground but also at head level) and desired destinations such as rooms, staircases, and elevators. The development of such indoor navigation systems, which do not have Global Positioning System (GPS) locational references, is challenging and requires an overview and evaluation of existing systems with different navigation technologies. This paper presents an evaluation and comparison of state-of-the-art indoor navigation solutions, and the research implications provide a summary of the critical observations, some insights, and directions for further developments. The paper maps VI needs in relation to research and development (R&D) trends using the evaluation criteria deemed most important by blind experts.

The aim of this work is to evaluate the possibility of inexpensively producing small-batch polymer sheet components using robotized single point incremental forming (SPIF) without backing plate support. An innovative method of thermal and ultrasound assisted deformation of a polymer sheet is proposed using a tool with a sphere mounted in a ring-shaped magnetic holder, the friction of which with the tool holder is reduced by ultrasound, and the heating is performed by a laser. The heated tool moving on the sheet surface locally increases the plasticity of the polyvinyl chloride (PVC) polymer in the contact zone with less deforming force does not reducing the stiffness of the polymer around the tool contact area and eliminating the need for a backing plate. The free 3D rotating ball also changes the slip of the tool on the surface of the polymer sheet by the rolling, thereby improving the surface quality of the product. The finite element method (FEM) allowed the virtual evaluation of the deformation parameters of the SPIF. Significant process parameters were found, and the behavior of the heated polymer sheet was determined.

This article is the second part of the 3D numerical analysis of the thermal and hydro dynamical processes which take place inside the fuel channel of the RBMK-1500 reactor during the interaction between the coolant and the fuel bundles. This article covers the results devoted to the upper part of the fuel channel, meanwhile, the preceding investigation [3] focuses on the processes, which run inside the lower part of the fuel channels of the RBMK-1500 reactor. The evaluation of the pressure drop, coolant temperature rise, flow velocity and steam mass fraction changes at the distance grids (spacers) and at the heat transfer intensification grids-intensifiers of the upper part of the fuel channel was carried out using the ANSYS CFX software. It was stated that the heat transfer intensification grids (intensifiers) increased the turbulence of the coolant (water-steam mixture) and influenced on the rise of the heat transfer rate and on the intensity of the steam generation. The average value of the heat transfer coefficient in the upper part of the channel was equal to 40000 W/(m²·K) and was about 14% higher than in the lower part of the channel. Differently from the lower part of the channel, the heat transfer coefficient increased at the heat transfer intensification grids and did not return back to the previous values after passing through them. The main reason of that was the turbulence of the water-steam mixture and vortex formation. All those processes have influenced on the more intensive wetting of the fuel elements by the water droplets and on the more intensive droplets evaporation. DOI: http://dx.doi.org/10.5755/j01.mech.24.1.19468