The influence of different reclamation agents and microorganisms on the aggregative stability of the colloidal fraction of meadow chernozem soil

The influence of various reclamation agents (montmorillonite, peat, activated sludge microbocenosis) on the stability of dispersions of the colloidal fraction of meadow chernozem soil is studied. It is established that biocolloids possess the strongest coagulating action in the aforementioned series of reclamation agents. It is shown that, in the process of microorganism growth involving glucose or polypeptides as a carbon source, exopolymers are synthesized that caused the coagulation of soil dispersions. Upon the growth of microorganisms on polypeptides (alkaligeneous metabolism), precipitates are formed that are denser and less peptized by water than those grown on glucose (acidogeneous metabolism). The addition of montmorillonite and peat intensifies the aggregation processes in soil-microbe heterodispersions. The inverse relationship between the content of an organic substance in a colloidal system and the stability of aggregates of soil colloids is revealed.     

Influence of chemical modification of the surface of polyethylene with phosphorus, boron, titanium, vanadium, and silicon halides on its vapor permeability

The influence of a gas-phase chemical modification of low-density polyethylene with volatile halides of various elements [PCl₃, TiCl₄, VOCl₃, BBr₃, and Si(CH₃)₂Cl₂] on the surface layer morphology and vapor permeability of polymeric formulations was examined by atomic-force microscopy, chemical analysis, and adsorption method.     

Phase-transfer catalysis in reactions of 5-alkyl-3H-furan-2-ones with dichlorocarbene

Treatment of 5-alkyl-3H-furan-2-ones and 5-alkyl-3H-thiophen-2-ones with dichlorocarbene under conditions of phase-transfer catalysis at 20–90 °C results in insertion of the carbene at the C=C bond followed by skeletal rearrangement.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1995–1997, October, 1995.     

Experimental evidence of high-beta plasma confinement in an axially symmetric gas dynamic trap

In the axially symmetric magnetic mirror device gas dynamic trap (GDT), on-axis transverse beta (ratio of the transverse plasma pressure to magnetic field pressure) exceeding 0.4 in the fast ion turning points has been first achieved. The plasma has been heated by injection of neutral beams, which at the same time produced anisotropic fast ions. Neither enhanced losses of the plasma nor anomalies in the fast ion scattering and slowing down were observed. This observation confirms predicted magnetohydrodynamic stability of plasma in the axially symmetric mirror devices with average min-B, like the GDT is. The measured beta value is rather close to that expected in different versions of the GDT based 14 MeV neutron source for fusion materials testing.     

Optimal State Estimation in Networked Systems with Asynchronous Communication Channels and Switched Sensors

We study a linear discrete-time partially observed system perturbed by a white noise. The observations are transmitted to the estimator via communication channels with irregular transmission times. Various measurement signals may incur independent delays, arrive at the estimator out of order, and be lost or corrupted. The estimator is given a dynamic control over the sensors by taking part in producing the signals to be sent via the channels. The minimum variance state estimate and the optimal sensor control strategy are obtained. Ideas of model predictive control are applied to derive a nonoptimal but implementable in real time method for sensor control This work was supported by the Australian Research Council.     

A criterion for Banach manifolds to be finite-dimensional

We extend the results obtained in [1] to the case of arbitrary Banach spaces and manifolds. We give an example of a continuous bijective mapping with discontinuous inverse which acts in a Banach space and differs from the identical mapping only in an open unit ball. A criterion for a Banach manifold to be finite-dimensional is established in terms of the continuity of inverse operators.Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 47, No. 12, pp. 1712–1713, December, 1995.     

New Approach to Model Validation and Fault Diagnosis

The paper presents a new approach to model validation and fault diagnosis problems for a class of uncertain systems in which the uncertainty is described by an integral quadratic constraint. The new approach is developed by applying methods from linear quadratic optimal control theory. This leads to a method for model validation and fault diagnosis which is based around a robust Kalman filter type structure.     

Anisotropy of the spatial distribution of CO molecules desorbing from tungsten

The desorption of CO from an anisotropic surface of polycrystalline tungsten after different periods of annealing has been studied. Anisotropy in the spatial distribution of CO molecules in the desorbing flux was detected at early stages of annealing. Smoothing out of the surface texture during annealing recorded by means of STM resulted in the disappearance of the spatial distribution anisotropy. The results are quantitatively explained by the model of a rough surface.⁷ Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 999–1002, June, 1994.The authors express their profound gratitude to Prof. V. I. Panov and his collaborators for making it possible to carry out measurements with a tunneling microscope and for their help.