Simulation of a Walking Robot-E xoskeleton Movement on a Movable Base

The paper studies the problem of movement of a two-legged walking machine on a movable base.This task is relevant for design rehabilitation and mechanotherapy complexes for people with impaired functions of the musculoskeletal system and presents a mathematical model that allows obtaining the kinematic and dynamic parameters of the movement of the executive units of the device under study.The paper presents a method for planning the trajectory of exoskeleton links,its algorithmic and software implementation.The paper proposes the structure of the automatic link position control system,which ensures the movement of the executive links along a given trajectory.A mathematical apparatus is proposed for studying the dynamics of the controlled movement of the links of the human-machine system of the exoskeleton.The article presents the results of numerical.experiments on the movement of the low-limb exoskeleton leg in the one step mode and analyzes them.

Novel Method Employing Accelerated-Oscillated Wave Saline Solutions to Unblock Blood Vessels—Physics and Fluid Dynamics Perspectives and Simulations

This research assesses the speed of blood flow across blood vessels and more specifically the veins in terms of Reynold’s number (laminar flow vs. turbulence flow) and in terms of overall speed of the blood when being injected with high-speed saline particles. The authors propose a novel technique to generate accelerated-waved particles built from saline solution to enable the unblocking of partially-blocked healthy-walled veins, and to restore normal operations of these veins. The novel technique encompasses a pump that accelerates saline solutions into the blood stream of the vein and these oscillated waves break down the fats or deposits inside the veins in order to help the blood to flow freely without any obstruction. This research simulated the vein with blood stream using characteristics of the vein in terms of vein diameter, blood density, venous blood flow, and the viscosity of the blood at the normal body temperature. The speed of the overall blood flow after the injection of the accelerated saline droplet solution was determined as well as the depth of penetration of the accelerated particles in order to cleanse the inside of the vein. Results are promising in terms of not altering significantly the overall speed of the bloodstream and also in terms of efficacy of the length of the vein which is being cleaned using this accelerated particle method.

Microscopic mechanism of periodical electroosmosis in reservoir rocks

Based on the electric double layer (EDL) theory and the momentum equation governing the electroosmosis flow, this paper presents an analytical solution to the periodical electroosmosis with a parallel straight capillary bundle model of reservoir rocks to reveal the microscopic mechanism of the electroosmotic flows in rocks. The theory shows that both the frequency dispersion characteristics of the macroscopic electroosmotic Darcy velocity in unsealed rocks and the electroosmotic pressure coefficient in sealed rocks depend on the porosity and electrochemical properties of reservoir rocks. The mathematical simulation indicates that the distribution of the periodical electroosmotic velocity is wavelike in the rock pore. The greater the porosity is, the greater electroosmotic the Darcy velocity and the smaller electroosmotic pressure coefficient are generated. The module values of the electroosmotic Darcy velocity and the electroosmotic pressure coefficient increase with the decreasing solution concentration or the increasing cation exchange capacity without affecting the phase of the electroosmotic Darcy velocity.

COMPLEX OPTICAL CHARACTERIZATION OF MESHIMPLANTS AND ENCAPSULATION AREA

Complex investigation of mesh implants was per formed involving laser confocal microscopy,backscattered probing and OCT imaging methods.The growth of endomysium and fat tissue with microcirculation vessels was observed in the mesh encapsulation region.Confocal microscopy analysis shows that such pat hologies complications such as necrosis formation and microcavities were localized in the area near implant fibers with the size compatible with fiber diameter.And the number of such formnations increase with the increase of the size,number and density of microdefects on the implant surface.Results of mumerical sinulations show that it is possible to control implant installation up to the depth to 4mm with a help of bac kscattering probing.The applicability of OCT imaging for mesh implant control was demonstrated.Special two stage OCT image noise reduction algorithm,including empirical mode decomposition,was proposed for contrast increase and better abnormalities visualization by halving the signal-to-noise ratio.Joint usage of backscattered probing and OCT allows to accurately ascertain implant and surrounding tissue conditions,which reduces the risk of relapse probability.

Developing and studying the dynamical behavior of a nonlinear mathematical model for cancers with tumor by considering immune system role

We are constrained by widespread cancerous diseases to improve treatment methods which save patients and provide better living conditions during and after the treatment period.Because of the complexity of the treatment process,mathematical models need to be used in order to have a better understanding of the process.However,deriving an adequate complex model that can capture the disease pattern which could be confirmed by simulations and experiments has its own barriers.In this paper,a new mathematical model is developed concerning immune system effect on cancer.The model is introduced using nonlinear ordinary differential equations.Also,the qualitative behavior of the proposed system is studied in order to examine the extent of the model with respect to the nature of tumor evolution.Thus,number and status of equilibria points in line with the existence of limit cycles are obtained for sub-systems and the whole system.Meanwhile,possible bifurcations are mentioned,and the consequent evolutions are described.It is shown that the model conforms well to natural possibilities,cancer growth or remission.Thus,the model would be fit for further studies for prediction and contemplating treatment method,especially for immune stimulating drugs and immunotherapy.

Application of heat absorption method to reduce macrosegregation during solidification of bearing steel ingot

The control of macrosegregation is still a difficult problem for the production of large steel ingots.In order to develop new techniques for producing low-macrosegregation and high-quality steel ingots,the effect of the heat absorption method(HAM)used by the inorganic material rods to cool the liquid steel on the formation of macrosegregation during solidification of a 5-t GCr15SiMn bearing steel ingot was studied using experiment and mathematical simulation.The inorganic material was a mixture of CaF2 and CaO.The levels of macrosegregation in the longitudinal sections of two ingots with and without HAM were compared.Experimental results showed that the application of HAM reduced the positive segregation in the upper part of the ingot and the negative segregation in the lower part.The levels of carbon segregation along the longitudinal centerline and horizontal direction at different heights were all alleviated and the fluctuation of carbon segregation was significantly reduced.The simulation results confirmed that the melting and floating of the inorganic material could carry the sensible heat to the top of the liquid steel quickly.This leads to the acceleration of the cooling rate of the liquid steel,thereby alleviating the level of macrosegregation.