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  • Stability of linear delay-differential equation of milling process

    A stability problem of milling process is under consideration. A novel analytical tool is presented to assess the optimal cutting parameters which provide a chatter free machining. Chatter instability is broadly studied in the literature. However, the problem of simultaneous optimization of radial and axial depths of cut is kept out of scope. To describe the optimization method a single-degree-of-freedom model of milling process is investigated as well as corresponding equation of motion and function of cutting force. A unified delay-differential equation is proposed. A theorem of asymptotic stability is suggested. Suggested optimization technique allows to create a diagram of radial and axial depth-of-cut dependence.  As shown, there exists an extremum of function of axial and radial depth-of-cut dependence.  

    Keywords: chatter, stability, delay-differential equation, oscilations, self-excited vibrations, optimization

  • Local logistic centers in urban environment

    The article presents the local type of logistic centers in urban environment as an essential part of freight network and its place in hierarchic logistic system of a country. Transport, compositional, ecologic and other aspects that have impact on spacial concept of local logistic centers are under examination. Thus generalized models of local logistic centers are put forward. They are developed by the authors with large volume of handled cargo, turnover capacity, and are space-saving. The main concepts of such models are following:  vertical development of storage volume due to construction of several floor and shelf storage levels with different ramps as well as provision of comfort one-way transport of minimum maneuvers and without crossing and conflicting traffic.

    Keywords: architectural spatial concepts, logistic centers, warehousing types , generalized spacial model

  • Stability analysis of deep loosening slopes.

    The results of calculations on the stability of slope lands treated in a new way. Device intrasoil walls combined with loosened intervals allows prevent subsurface runoff water, which reduces surface erosion slopes, improves the fertility of farmland returns a highly eroded areas in turn, eliminates the wetlands at the foot of the slopes. Established that the stability of the treated soil layer on the slope ample.

    Keywords: stability of sloping land, subsurface walls, soil subsurface runoff, soil erosion, wetlands, deep tillage, moisture saturation slope.

  • To the question of sources and volumes of oil components, input into Black sea

    The paper is devoted with the analysis of sources and volumes of oil components’ input into the Black sea. The topicality of this problem is connected with of transboundary the status of water object that contributes to the complexity of such works. Black Sea has important significance for transport and development in the coastal zone of the oil complex, combined with a great recreational potential. As a result, ecosystems are technogenic impact. The paper describes the main natural and anthropogenic sources of oil components in the Black Sea. On the basis of the results of our expeditionary research and analysis of sources of pollutant concluded chronic character oil pollution of the Black Sea. And the conclusion that the most optimistic estimates, entrance of oil components in the ecosystem in the Black Sea is approximately 270 thousand tons per year, which is higher than the currently accepted values of 2−2.5 times. 

    Keywords: sources, volumes, oil components, the Black Sea, hydrocarbons

  • Mathematical modeling of heat transfer processes in energy-saving solar plants

    A mathematical model of heat transfer processes, the discrete model is based on the finite difference method, and the results of calculations of the temperature distribution also will be developed. In addition the program was created which allows to calculate the distribution of temperature over its entire length for given values ​​of insolation, ambient air temperature and air velocity inside the collector  

    Keywords: mathematical modeling, finite difference method, heat transfer processes, solar collector

  • The methodology of rock strenght testing by the non-destructive way in the transport tunnel

    This article describes a method of testing rock and semi rock strength non-destructively using the device "Schmidt Hammer." The article justified by the benefits of this method, as well as features and test procedures.

    Keywords: rocks, strength, fracture, the value of drip, soil tests, the angle of incidence, dip azimuth.

  • Development of a new resource-saving technology for treatment of sloping lands

    A new resource-saving technology for treatment of sloping lands providing for deep ripping to reduce erosion processes on irrigated and dry-farming lands as described in the article. The experimental results on determination of geometric characteristics for loosing scopes of chisel plows are given.

    Keywords: sloping lands, deep ripping, soil overcompactness, moisture accumulation, intrasoil moisture accumulation, loosing scope, intrasoil walls

  • Modern technology to improve the accuracy of implantation of less invasive knee replacement on the basis of mathematical modeling

    In order to improve techniques of minimally invasive total knee arthroplasty (IEAC) based on anatomical studies, we have developed a mathematical model and a computer program IEAC preoperative planning that takes into account the anthropometric data of the patient (body type, size patellar index Insall-Salvati), type and size of prosthesis and allows to calculate minimal incision and maximum elongation wound during surgery. Use of this software improves the accuracy of the planning and preparation of surgery, to improve the accuracy of implantation of the prosthesis.

    Keywords: minimally invasive replacement of knee joint, computer modelling, preoperative planning, computer software preoperative planning

  • Stability analysis of slope cultivated wetland soils

      The article describes a new technology reclamation processing sloping land without recourse reservoir using subs oiler chisel type. Shows a model of stability of slopes wetland soils processed by the proposed method. 

    Keywords: stability, subsurface wall area loosening, sloping lands, accumulation of moisture-treated layer, wetland soils, deep loosening

  • Application of the Galerkin method in the calculation of the stability of compressed rods with the creep

    The resolving equations for the calculation of the stability of polymer compressed rods with the creep using Galerkin method are obtained. The problem is solved in the case of a simply supported pivotally-rod having an initial bending in the plane of the lower stiffness, and in the case of off-center application of force. Galerkin method used in combination with the finite element method, that is the shape functions are taken as the basis functions . The solution is made numerically, using the software package Matlab. There are two variants considered: a variant of the rod with constant and variable in length stiffness. It is shown that for rods with variable cross-sections and the same mass, a critical time has increased by almost 4.5 times. The solution for the rods of constant cross section agrees well with the solutions obtained by the method of finite differences. This may indicate the reliability of the proposed method  

    Keywords: polymer rod, creep, Galerkin method, stability, variable stiffness