ОЦІНЮВАННЯ ГЕОМЕТРИЧНИХ ПАРАМЕТРІВ ПОЛЮСНОЇ СИСТЕМИ МАТРИЦІ ЕЛЕКТРОМАГНІТНОГО СЕПАРАТОРА

Purpose. The choice of the geometric dimensions ratios of system of matrix poles of electromagnetic polygradient separator to increase productivity with maintaining the reliability of extracting of ferromagnetic impurities from bulk material.Methodology. To solve the dynamic problem of motion of a ferromagnetic body in the working gap of pole system of matrix of polygradient separator under the influence of an external magnetic field the known methods of solving linear inhomogeneous differential equations are used. To confirm the reliability of obtained results the method of experimental research is used.Findings. The formulation of dynamic problem of movement of ferromagnetic body in the working gap of plate pole system of matrix of polygradient separator is carried out. Parametric equation for the trajectory of ferromagnetic body removal and a calculated relation connecting the main geometric dimensions of the system of matrix poles are obtained. The calculation results are confirmed experimentally and by operating practice of known magnetic separating devices.Originality. The mathematical description of working process of a polygradient electromagnetic separator with a plate matrix was further developed, which made it possible to obtain an analytical expression that takes into account the main geometric dimensions of the working space of matrix of separator.Practical value. Accounting of obtained analytical dependences between the length of separation zone and air gap, which characterizes the thickness of the separated material layer through which the ferromagnetic body must pass during the separation process, will ensure the necessary purity and productivity of separation.

Сверхзвуковое ламинарное обтекание затупленного ребра: двойственность численного решения

Results of numerical simulation of supersonic flow past a blunt fin mounted on a plate with a developing laminar boundary layer are presented. Generally, the case considered corresponds to the flow configuration used in the experimental and computational study by Tutty et al (2013), where the laminar air flow with the freestream Mach number of 6.7 is considered. The simulation was performed for different values of Reynolds number ranging from 5000·to 20000. Two stable solutions corresponding to metastable flow states with different configurations of the vortex structure were predicted within some range of Reynolds number. The bifurcation diagrams showing the main horseshoe vortex center location and the length of separation region versus the Reynolds number is presented, critical Reynolds number corresponding to occurrence of the second isolated solution is evaluated.

A Weighted path based Link Prediction in Social Networks using Bounded Length of Separation between Nodes

The problem of link prediction in online social networks like facebook, myspace, Hi5 and in other domains like biological network of molecules, gene network to model disease have became very popular because of the structural connections and relationships among the entities. The classical methods of link prediction based on the topological structure of the graph exploit all different paths of the network which are being computationally expensive for large size of networks. In this paper, incorporating the small world phenomenon, the proposed algorithm traverses all the paths of bounded length by considering clustering information and the connection pattern of the edges as weights on the edges in the graph. As a result, the proposed algorithm will be able to predict accurately than the existing link prediction algorithms. Our analysis and experiment on real world networks shows that our algorithm outperforms other approaches in terms of time complexity and the prediction accuracy.

EFFECTS OF FREQUENCY AND LENGTH OF SEPARATION BOUTS BETWEEN MOTHER AND OFFSPRING ON LATER EXPLORATIVE BEHAVIOUR OF YOUNG GUINEA-PIGS (CAVIA APEREA F.PORCELLUS)

Previous studies have shown that maternal behaviour is correlated with later explorative behaviour of the young. Exploring the eventual effects of maternal behaviour on the explorative behaviour of young guinea pigs, we examined the effects of frequency and length of separation bouts between mother and offspring. For 39 pups daily duration of contact with the mother was kept constant (17 hours) but the frequency of daily contact (and thus the length of the separation bouts) varied. Using a split-litter design three groups were created that were separated from the mother 3, 6 or 9 times each day from day 3 until day 20. Several precautions were taken to avoid distress of the pups during separation caused by heat loss, social isolation or unfamiliarity with the separation cage. The development of the explorative behaviour was assessed by means of a series of tests representing several aspects of explorative behaviour. All groups showed equal growth during the treatment period. It is shown that the group separated 3 times for a long period scored higher in explorative behaviour than the other groups that were separated more often but for shorter periods. In particular walking, duration of presence, and sniffing in the novel environment were increased compared to the groups separated 6 or 9 times but were also increased when compared to average scores of a previous study. It could be shown that individuals were persistent in time with regard to the maximum distance they entered into a novel environment.

Mean Separation and Reattachment in Turbulent Pipe Flow Due to an Orifice Plate

The mean flow in a pipe with turbulent separated flow due to an orifice plate is experimentally studied. Measurements of time-mean length of separation and reattachment regions, made using a surface fence gauge are presented for a range of orifice sizes. In a limited range of Reynolds number (based on orifice radial height) 3 × 104 to 7.3 × 104 studied, reattachment point location decreased from 12 to 9 step heights. The lengths of separation and reattachment regions are a function of orifice size and the Reynolds number based on the radial height of the orifice plate.

The Frictionless Contact Problem for an Elastic Layer Under Gravity

The paper presents a technique for solving the plane frictionless contact problems in the presence of gravity and/or uniform clamping pressure. The technique is described by applying it to a simple problem of lifting of an elastic layer lying on a horizontal, rigid, frictionless subspace by means of a concentrated vertical load. First, the problem of continuous contact is considered and the critical value of the load corresponding to the initiation of interface separation is determined. Then the mixed boundary-value problem of discontinuous contact is formulated in terms of a singular integral equation by closely following a technique developed for crack problems. The numerical results include the contact stress distribution and the length of separation region. One of the main conclusions of the study is that neither the separation length nor the contact stresses are dependent on the elastic constants of the layer.