Quantitative Determination of Hydroxycoric Acids and the Analysis of the Dynamics of Their Accumulation in Malus sylvestris Leaves

Abstract—The presence of hydroxycinnamic acids in the leaves of Malus sylvestris Mill. and Malus domestica Borkh. is established by using HPLC analysis. The quantitative determination of hydroxycinnamic acids is carried out by spectrophotometric analysis. It is found that the maximum amount of hydroxycinnamic acids accumulates in the plant during the fruiting phase.     

Mobile robots with two independent coaxial drive wheels: Dynamics and the schemes of control

A two-wheeled robot and a robot composed of a snakelike chain of two-wheeled objects are considered. The problem of trajectory synthesis and the problem of motion planning and control are studied for these mobile robots. The mobile robots with two independently controlled coaxial wheels and with one or several passive wheels are called robots with differential drive. These problems are formulated in such a way that the construction of dynamically correct and precise control becomes possible for such robots.     

The Limits of Porous Materials in the Topology Optimization of Stokes Flows

We consider a problem concerning the distribution of a solid material in a given bounded control volume with the goal to minimize the potential power of the Stokes flow with given velocities at the boundary through the material-free part of the domain.We also study the relaxed problem of the optimal distribution of the porous material with a spatially varying Darcy permeability tensor, where the governing equations are known as the Darcy–Stokes, or Brinkman, equations. We show that the introduction of the requirement of zero power dissipation due to the flow through the porous material into the relaxed problem results in it becoming a well-posed mathematical problem, which admits optimal solutions that have extreme permeability properties (i.e., assume only zero or infinite permeability); thus, they are also optimal in the original (non-relaxed) problem. Two numerical techniques are presented for the solution of the constrained problem. One is based on a sequence of optimal Brinkman flows with increasing viscosities, from the mathematical point of view nothing but the exterior penalty approach applied to the problem. Another technique is more special, and is based on the “sizing” approximation of the problem using a mix of two different porous materials with high and low permeabilities, respectively. This paper thus complements the study of Borrvall and Petersson (Internat. J. Numer. Methods Fluids, vol. 41, no. 1, pp. 77–107, 2003), where only sizing optimization problems are treated.     

On the Existence of Solutions to Stochastic Mathematical Programs with Equilibrium Constraints

We generalize stochastic mathematical programs with equilibrium constraints (SMPEC) introduced by Patriksson and Wynter (Ref. 1) to allow for the inclusion of joint upper-level constraints and to change the continuity assumptions with respect to the uncertainty parameters assumed before by measurability assumptions. For this problem, we prove the existence of solutions. We discuss also algorithmic aspects of the problem, in particular the construction of an inexact penalty function for the SMPEC problem. We apply the theory to the problem of structural topology optimization.     

Quantitative Determination of Arbutin in Malus sylvestris Leaves by High-Performance Liquid Chromatography

Moscow University Chemistry Bulletin - As a result of our research, we propose the chromatographic conditions for the separation of arbutin and the conditions for the sample preparation of the raw...     

Determination of the Component Composition of Essential Oil of Thyme Species by the Method of Gas Chromatography

Abstract—A comparative study of the component composition of the essential oil of cultivars of Thymus serpyllum L. and similar kinds to expose marker connections for the authentication of raw material is conducted by the method of gas chromatography. In the essential oil of one of the specimen the propionates discovered are typical representatives of the Lamiaceae family.