Segmentation of Laterally Symmetric Overlapping Objects: Application to Images of Collective Animal Behavior

Video analysis is currently the main non-intrusive method for the study of collective behavior. However, 3D-to-2D projection leads to overlapping of observed objects. The situation is further complicated by the absence of stall shapes for the majority of living objects. Fortunately, living objects often possess a certain symmetry which was used as a basis for morphological fingerprinting. This technique allowed us to record forms of symmetrical objects in a pose-invariant way. When combined with image skeletonization, this gives a robust, nonlinear, optimization-free, and fast method for detection of overlapping objects, even without any rigid pattern. This novel method was verified on fish (European bass, Dicentrarchus labrax, and tiger barbs, Puntius tetrazona) swimming in a reasonably small tank, which forced them to exhibit a large variety of shapes. Compared with manual detection, the correct number of objects was determined for up to almost 90 % of overlaps, and the mean Dice-Sørensen coefficient was around 0.83 . This implies that this method is feasible in real-life applications such as toxicity testing.

Engineering design of a grain silo and a bucket elevator for a combined unit for hopper preparation and seeding of grain crops

In this paper, we present the results of engineering design of components of a grain hopper and a bucket elevator for a combined unit for soil preparation and sowing of grain crops. The grain hopper has compartments for seeds and fertilizers. A coil-type metering device is also separated for seeds and fertilizers. The drive of the metering device for seeds and fertilizers is done by the rear wheels of the rolling device through a variator, which also serves to adjust seeds supply. On the same shaft with the metering device there is a sprocket, which transmits rotation moment to the bucket elevator through a chain of PR type. Due to special design characteristics of the grain hopper shape, seeds enter the coil type metering device by gravity. A similar operation is done for fertilizers. Portions of fertilizers and seeds fall into a small tank, joint for grain and fertilizers, from where the elevator's buckets deliver them to the distribution device. Seeds and fertilizer fall on the distributing device along the tray and then on rotating cone with blades, which uniformly distribute grain and fertilizers to all drill tubes. The developed units were organically included in the design of the entire combined unit. The obtained results allowed us to distinguish the following advantages of the developed designs of the hopper and the bucket elevator: a single metering unit for all sowing machines; easy access to the main units and mechanisms and their maintainability; ease of off-season maintenance; use of a large number of typical domestically produced units and mechanisms.

KINETIC PROPERTY OF A PRESSURE VESSEL MADE FROM CFRP FABRICATED A FILAMENT WINDING METHOD

Since the specific strength and the specific elasticity of carbon fiber reinforced plastics (CFRPs) are the greatest in practical materials, they are used abundantly in transport structures. This CFRP can also be used for a pressure vessel which stores liquid hydrazine, the required burst pressure is approximately 22MPa. Many researchers have been studying pressure vessels made from a CFRP fabricated by a filament winding (FW) method. In order to acquire the fundamental mechanical properties of a CFRP container, the small cylinder made from CFRP fabricated by the spiral winding type FW method is designed and manufactured. The winding angle of a carbon fiber of this cylinder is ±45 degrees. The plastic deformation of this cylinder generates from the strain range of 0.7%. So as to confirm by the analytical method that a small tank made from CFRP fabricated by the FW method can be utilized as a tank for liquid hydrazine, an analysis model is created. Since the pressure to which the strain of this CFRP tank reaches to 0.7% is approximately 35MPa, this small tank can be used as a fuel tank for micro satellites.