Nests of Eufriesea aff. auriceps (Hymenoptera, Apidae, Euglossini) in remnants of Atlantic Forest and reforested areas

In recent decades, the use of the trap-nest technique has helped to increase knowledge on the nest architecture of many orchid bee species. This study describes the nest architecture of Eufriesea aff. auriceps constructed in trap-nests made of dried bamboo internodes (canes). The nests were placed in remnants of Atlantic forest and in reforested areas next to forest remnants and monitored monthly from August 2015 to August 2016 and from August 2018 to August 2019 in southern Brazil. The bamboo internodes occupied by bees varied in internal diameter from 1.0cm to 2.0 cm (`X = 1.7; SD = 0.3; N = 12) and in length from 11.0 cm to 28.0 cm (`X = 19.5; SD = 4.8; N = 12). The total size of the nests inside the bamboo internodes ranged from 9.0 cm to 19.9 cm (`X = 14.3; SD= 3.9; N = 12). The number of brood cells constructed per nest varied from 1 to 10 (`X = 4.0; SD = 2.3; N = 15). The cells were built with small pieces of bark cemented with resin, linearly arranged along the bamboo tube. Internally, the cell wall was lined with resin. The cells measured 1.5-3.0 cm (`X = 2.3 ± 0.5; N = 48) in length and 1.4-1.7 (`X = 1.5 ± 0.1; N = 17) cm in width. The internal contour of the cells was elliptical. Females of Eufriesea aff. auriceps occupied trap-nests in both the forest remnants and in areas undergoing restoration.

Determination of Stressed-Deformed State of Fine Disc Tools with Inner Cutting Section under Conditions of their Pre-Stressing

The work is dedicated to investigation of the particulars of stressed-deformed state of fine disc tool with internal cutting section under conditions of its pre-stressing. It was suggested for reduction of tools oscillations at cutting to apply pre-stressing of the tools disc by means of controlling elements. The elements, which control the elements stress allowed to eliminate self-oscillations and resonance oscillations of the tool at high-speed materials cutting. In the paper the problem of evaluation of stress and deformed state of fine disc cutting tools with application of the method of finite elements (FEM) was solved. The article also contains epures of tangential stresses inside the internal contour of disc tools. On the basis of the investigations performed the synthesis for design of the main elements of fine disc tools with inner cutting section was carried out. The performed investigation was aimed at improving of the quality and stability of cutting with fine disc tools under conditions of high-velocity cutting and in presence of a dynamic component of the cutting process, ensuring improvement in durability and productivity of the tool.

Conjugate Heat Transfer in the Interaction of the Viscous Liquid with Technological Elements of Energy Systems in Conditions of their Internal Contour Moving

The paper presents the numerical research of conjugate heat exchange and hydrodynamics in the motion of viscous fluid in the technological elements of energy systems (cavities) in the consideration of its damage. The hydrodynamic figure of the motion viscous fluid and its temperature fields for solid and fluid phases obtained. The model parameters influence on the motion of the heat carrier and the distribution of temperatures in two phases have been studied. The impact of dynamic parameters and geometrical characteristics for the formation of contours generating craters studied.

Internal Contour Extraction Algorithm Based on Quadratic B-spline for Images of Hot Long Shaft Forgings

It is necessary that the internal and external contours are extracted from the image of hot long shaft forgings, while the forgings are measured by CCD measurement method. In the light of the blurry internal edges in the image of the hot forging, a method based on quadratic B-spline curve is employed to extract feature points. In order to remove the pseudo features, a method based on maximum correlation is presented. In accordance with continuity of the internal contours, quadratic B-spline curve is used to fit the internal contours. Experiments show that this algorithm can effectively extract accurate internal contours for images of hot squaring and chamfering forgings. The extracted contours could provide basic data for subsequent 3D reconstruction and geometric measurements.