Modeling of helicopter behavior dynamics under the controlling action of the stabilization and control system

A possibility of evaluating dynamic response of a mechanical system to controlling actions of the automatic stabilization and control system is considered on the basis of a numerical experiment. Examples of design analysis are presented for a light-weight helicopter in which an autopilot is part of the control system. The finite element analysis is used in this paper.     

Intensification of heat exchange on the convex surface of an annular channel with continuous flow swirling

In this paper, the results of an experimental study concerning average heat transfer in an annular channel with flow swirling by an endless screw and spherical grooves on the convex surface are presented. Also analyzed is the heat and hydraulic efficiency of grooves application under conditions being considered.     

High temperature alters the growth reaction of Pottia protonemata.

Under gravistimulation, dark-grown protonemata of Pottia intermedia revealed negative gravitropism with a growth rate of approximately 28 μm·h⁻¹ at room temperature (20 °C). In 7 days, the protonema formed a bundle of vertically oriented filaments. At an elevated temperature (30 °C), bundles of vertically growing filaments were also formed. However, both filament growth rate and amplitude of the gravicurvature were reduced. Red light (RL) irradiation induced a positive phototropism of most apical protonemal cells at 20 °C. In a following period of darkness, approximately two-thirds of such cells began to grow upward again, recovering their negative gravitropism. RL irradiation at the elevated temperature caused a partial increase in the number of protonemal cells with negative phototropism, but the protonemata did not exhibit negative gravitropism after transfer to darkness. The negative gravitropic reaction was renewed only when protonemata were placed at 20 °C. A dramatic decrease in starch amount in protonemal apical cells, which are sensitive to both gravity and light, occurred at the higher temperature. Such a decrease may be one of the reasons for the inhibition of the protonemal gravireaction at the higher temperature. The observation has a bearing on the starch-statolith theory.     

Sampled-Data Control System Analysis Using the Poisson Summation Rule

A technique is presented which simplifies the analysis of sampled-data control systems. The use of a finite-term approximation to the Poisson summation rule, in conjunction with digital computer evaluation, is presented as a good alternative to use of the Z transform whenever frequency-domain analysis is required. The Poisson summation rule is reviewed and its application to sampled-data system analysis is discussed. The form of the computer program used in the analysis is presented, along with a design criterion to evaluate the accuracy of the technique. A detailed example of a typical application is presented.     

Effect of clinostating on photosynthetic apparatus of pea plants.

The photosynthetic membrane composition and low temperature fluorescence spectra were analyzed for pea chloroplasts from control and clinostated plants. Clinorotation induces a decrease in the amount of the oligomeric form of the light-harvesting chlorophyll a/b complex (LHCII) and an increase of its monomeric form. Some changes in organization of photosystem 1 (PS1) complex were revealed as well. These changes are in accordance with the variations of fluorescence characteristics and photochemical activity.     

Modelling of genetically engineered microorganisms introduction in closed artificial microcosms.

The possibility of introducing genetically engineered microorganisms (GEM) into simple biotic cycles of laboratory water microcosms was investigated. The survival of the recombinant strain Escherichia coli Z905 (Apr, Lux+) in microcosms depends on the type of model ecosystems. During the absence of algae blooming in the model ecosystem, the part of plasmid-containing cells E. coli decreased fast, and the structure of the plasmid was also modified. In conditions of algae blooming (Ankistrodesmus sp.) an almost total maintenance of plasmid-containing cells was observed in E. coli population. A mathematics model of GEM's behavior in water ecosystems with different level of complexity has been formulated. Mechanisms causing the difference in luminescent exhibition of different species are discussed, and attempts are made to forecast the GEM's behavior in water ecosystems.     

Avionics systems maintenance improvement: a perception

This paper explores the possibility of applying recent developments in various fields of electronics, especially wireless personal communication services, to reduce avionics systems repair cycle time and to generally improve maintenance services. But before scaling these prospects, present-day maintenance services are touched upon and advances in associated technologies are also mentioned