Cпастичность-важнейшая составляющая синдрома поражения верхнего двигательного нейрона, которая выявляется более чем у 12 млн больных в мире и по разным данным, является причиной инвалидизации 12-27% из них [1, 2]. Перечень нозологических форм, при которых в структуре синдрома поражения верхнего мотонейрона (ПВМ) наблюдается спастический гипертонус, значителен. Он определяется примерно у 20-40% выживших после инсульта, у 65-78% пациентов с поражениями спинного мозга и у 85% больных рассеянным склерозом [3-5]. Интерес к этиопатогенезу, клинике, диагностике и лечению спастичности проявлялся со времени формирования неврологии, но особенно интенсивно спастичность из
The object to be studied is a spacecraft with a deployable pantograph structure as a solar-battery carrier. The objective of research is to design a mathematical model of this structure taking the elasticity of pantograph elements into account. The Lagrangian formalism is followed. To model the dynamic processes in the system, a software package has been developed, which can be adapted, if necessary, to study deployable structures of other types. The behavior of the structure during deployment, collapse, and redeployment under the action of various perturbations is modeled numerically. Plots illustrating the variation of characteristic variables are presented Introduction. Dynamics of reconfigurable systems is one of the promising and important areas of research in mechanics [1,2,5,[8][9][10][11]. Modern spacecraft incorporate elements that transform when in orbit (solar batteries, gravity-gradient booms, antennas, etc.). Such mechanical systems are delivered into orbit compactly packaged and then are deployed into the operational configuration.Issues of current importance in research of reconfigurable systems are minimization of deployment time and energy and the effect of reconfigurable structures on the motion and attitude of the spacecraft. Also, of vital importance is mass reduction for such systems. Their elements should be considered as elastic bodies.1. Mechanical Model. The object of study is a pantograph structure consisting of two connected parallelogram-type linkages (Fig. 1). The mechanical model is a reconfigurable structure with a pantograph-like deployment mechanism mounted on a rigid body.
Analysis of production data for tight gas reservoirs is based on pressure transient (PT) analysis, which is now a conventional procedure for fractured tight gas reservoirs. Key parameters can be estimated during the analysis: fracture conductivity, fracture half-length and reservoir properties. Most PT analysis methods deal with bilinear, formation linear, and pseudo-radial flow regimes. It is well known that an elliptical flow regime can appear between formation linear and pseudo-linear flow regimes. Sometimes the period is very short and cannot be identified. But there are many cases when only formation linear and elliptical flow regimes are present in production data records and the time needed to reach the pseudo-radial period is more than decades. Most PT analysis methods substitute elliptical flow regime for pseudo-radial, which may lead to the incorrect calculation of key parameters of reservoirs and fractured wells. In this study, we present the development of an approach for elliptical regime analysis in the production data record for calculation of key parameters of finite-conductivity fractured wells and reservoirs: fracture conductivity, fracture half-length, reservoir permeability, and effective drainage area. This method uses an analytical equation for elliptical flow period and estimation of parameters from the equation. The development is based on more stable deconvolution analysis of production data with variable rate/pressure and more reliable analysis of response function after deconvolution. We present here some synthetic and field cases to demonstrate the results of calculations. Introduction Classic well testing approaches for fractured wells involving pseudo-radial flow models cannot be applied since the pseudo-radial regime is reached in decades or years of production in tight gas reservoirs. In many cases, we cannot observe pseudo-radial flow. Really, we deal with elliptical flow after the formation linear period. To receive more realistic results of production data analysis, the best solution is to use elliptical flow model for early- and mid-time production periods (which could actually last for years). Under this assumption we are able to extract approximate permeability and fracture half-length and conductivity values. At the moment, there is literature (Cheng et al. 2007; Hale and Evers 1981; Amini et al. 2007) that presents methods of work with elliptical data. It is reasonable for commercial tools to have robust algorithms for work with production data where elliptical flow regime is exhibited. Integration of the algorithms in production modeling workflow will allow more reliable results of production data analysis. Reservoir characterization and well completion efficiency evaluation involve a multilayer commingled reservoir using commingled system well production performance data. Commingled well production data from a system with a number of different layers with varying reservoir and well completion properties generally should not be evaluated using an equivalent single layer reservoir analog. The results of the analysis for determining estimates of the reservoir properties and completion efficiencies of each of the individual reservoir layers will be very inaccurate in this case. Splitting production data for each layer is an important step for correct analysis. Helpful information on splitting can be found in (Poe et al. 2006).
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