Results of studying the ash pneumatic transport from ash trap hoppers in a pulse-mode

The results of studying the effects of ash layer density and the method of dynamic impact on the ash ability to flow are presented. A scheme of a pneumatic impulse pump and that of an impulse-type ash removal and transport system of high operating performance are proposed.     

Laser polishing of glass articles

A technique and equipment are proposed for polishing of glass articles with a carbon dioxide laser beam. The technique can be used as the finishing operation in the manufacture of lenses, expensive glassware, and light waveguides to enhance surface finish and to reduce surface roughness. Translated from Steklo i Keramika, No. 5, pp. 7–8, May, 1997.     

Thyroid gland and thyroid status in patients with chronic liver diseases

We have conducted a prospective study aimed to analyse contraceptive use among women seeking for legal abortion in the State University Hospital "Ma?chin dom"--Sofia. Our date demonstrate that the patients were well informed about the existing contraceptive methods. On the contrary the percentage of women-using contraception and especially those, using highly effective ones is relatively low. The patients claim the possible side effects of the high effective contraception as a reason against use.     

Testing Different Ensemble Configurations for Feature Selection

In recent years, ensemble learning has become a prolific area of study in pattern recognition, based on the assumption that using and combining different learning models in the same problem could lead to better performance results than using a single model. This idea of ensemble learning has traditionally been used for classification tasks, but has more recently been adapted to other machine learning tasks such as clustering and feature selection. We propose several feature selection ensemble configurations based on combining rankings of features from individual rankers according to the combination method and threshold value used. The performance of each proposed ensemble configuration was tested for synthetic datasets (to assess the adequacy of the selection), real classical datasets (with more samples than features), and DNA microarray datasets (with more features than samples). Five different classifiers were studied in order to test the suitability of the proposed ensemble configurations and assess the results.     

Determination of the Flory-Huggins parameter for a pair of polymer units from AFM data for thin films of block copolymers

The structures of thin films of the polystyrene-polybutadiene-polystyrene (SBS) and polystyrene-poly(methyl acrylate)-polystyrene (SMAS) triblock copolymers were studied. The film morphology was found to depend on the conditions of film formation. The average domain sizes of these films and the period of the lamellar structure of SMAS films were determined. The Flory-Huggins parameter was estimated for a pair of styrene and methyl acrylate units.     

Operational risks for gas pipelines at low temperatures

The fundamental causes of accidents in gas pipelines at low temperatures are investigated. Their frequency is determined, along with the critical crack size in the pipe.     

Kinetics of nucleation and growth of metal nanoparticles in heterogeneous media in the presence of surfactants

The computer simulation of the processes of the nucleation and growth of nanoparticles in heterogeneous media (for example, in polymer solution or porous polymer matrix) in the presence of surfactant has been carried out. Heterogeneous medium has been modeled by a system of pores that limit the region of the nanoparticle formation. It is assumed that surfactant molecules, which were present in the system initially, adsorb on the surface of the nanoparticles and slow down their growth in the oversaturated solution. The complete blocking of the nanoparticles occurs when their surface is covered by the surfactant molecules to a certain degree and their growth stops. It is shown that the degree of heterogeneity and the value of surfactant concentration significantly affect both the mean size of the nanoparticles and the character of their size distribution.     

A new type of plastic scintillators with excellent radiation resistance

Radiation processes in plastic scintillators (PSs) are studied to establish that, first, macroradicals are the main quenchers of radiation-induced luminescence in the PSs, and, second, molecular oxygen initiates the decay of macroradicals. Based on these principles, PSs of a new type, whose radiation resistance is by an order of magnitude higher than that of standard polystyrene scintillators, were developed and synthesized. The special nanoporous morphology of the new PSs is a system of open pores and channels, which provide efficient penetration of molecular oxygen into the polymer bulk to produce the antirad effect.