Quantitative estimates of gas maldistribution and methods for their localization in absorption columns

In the present work, we carry out evaluation of gas flow maldistribution in different types of gas distributing devices (GDD) and packings by using experimental data for the output velocity profiles for both the absorption pilot column and industrial column. Two GDD construction types—with circular and with local tube gas feed, together with their modifications—are investigated. Two pilot columns—with random packing RSRM 1.5″ and with structured ceramic Honey-comb packing, and one industrial contact economizer with Honey-comb and inclined rings—have been studied. Six types of quantitative estimations of GDD and packings maldistribution are determined by the help of MATHCAD. Then, their sensitivity toward several factors, such as the type of GDD and packing, the initial gas flow velocity, the number and dimension of measuring cells on the column cross-section, the measurement error, and so on, is investigated. It is found that only two of the quantitative maldistribution estimations take into account the formation of maldistribution clusters, which deteriorates the uniform gas distribution. A novel method for quantitative determination of these clusters and also for identification of the zones at column cross-section, in which they appeared, has been developed. It is established that the measurement error and the dimension of measuring cell deeply influence the number, the area, and spatial distribution of these zones on the cross-section, as well as the values of maldistribution estimates.     

Properties of TiO2 films on silicon substrate

Influence of the substrate material and the effect of oxygen plasma on the microprofile and electrical properties of TiO₂ films deposited by radio-frequency magnetron sputtering are studied. It is shown that the most continuous films with the smallest roughness are obtained when deposited onto silicon substrates. The change in the capacitance-voltage and conductance-voltage characteristics of the structures upon their exposure to oxygen plasma is accounted for by the diffusion of oxygen atoms across the titanium-dioxide film and by the appearance of a SiO₂ layer at the Si-TiO₂ interface.     

Growth of single crystals of Hg(BrxI1−x)2 and their detection capability

Hg(Br_xI_1−x)₂ crystals were grown by the Bridgman method for 0.2 < x < 1.0. They were tested for potential implementation as X- and γ-ray detectors at room temperature. ²⁴¹Am and ⁵⁵Fe were used as radioactive sources. From the corresponding energy spectra, it is evident that crystals with x = 0.2 show enhanced resolution at low energies (below 200 keV), competing those fabricated from HgI₂ and CdTe. Crystals with higher x's were of lower resolution.     

Factors of Fracture Toughness of Plate Steel “In the Third Direction”

The contribution of dendrites of eutectic sulfides and oxides in the fracture of plate steel to the specific work of fracture is evaluated by comparing the fracture toughness of plates in the plane of rolling (Z-direction) and results of studies of fracture surfaces.__________Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 1, pp. 26 – 31, January, 2005.     

Modern methods of medical rehabilitation in traumatic detachment of retina

Condition was studied of collective specific immunity against diphtheria in vaccinated children who ranged from 2 to 15 years old, living in the industrial region of Pridneprovye, with special reference for the degree of the technogenous environmental pollution. To determine specific cellular sensibilization to diphtherial antigen. LAIT was used for the first time. The studies made showed that in a region under health-hazard conditions lower level of antitoxic antidiphtherial immunity occurs more frequently than in non-polluted areas (twice as much of the values), which fact suggests that technologeous pollution may have a suppressive effect on formation of postvaccinal immunity. Apart from measuring the level of specific antibodies for control of the formation of the immune responsiveness to be monitored you may use LAIT and measure levels of R-proteins.     

Structural Wear-Resistant Sintered Materials Based on Titanium

A principle is proposed for increasing the wear resistance of structural titanium materials by addition (together with a moderate number of hard inclusions) of alloying elements which, without decreasing the strength and ductility of titanium, increase the wear resistance of the material thanks to the formation of oxide films during friction that prevent seizing of the contacting surfaces. Requirements for the hard inclusions and alloying additions were defined, the basic of which is a high affinity of the alloying elements for oxygen. Grades of wear-resistant structural titanium materials were created and recommended for use in the production of components operating in friction units at room temperature (IT20, IT15V) and at 250-550°C (IT16M). The mechanical properties and operating conditions (sliding rate, pressure, temperature, counterbody material, atmosphere) of the sintered titanium materials were investigated.     

High-Temperature Nitriding of Refractory Alloys

Processes of high-temperature internal nitriding of refractory alloys based on nickel and cobalt are described. Thermodynamic backgrounds for formation of zones of internal nitriding with optimum phase compositions in alloys containing alloying elements with different affinity for nitrogen are considered. It is shown experimentally that the structures obtained in zones of internal nitriding with segregations of stable fine nitride phases depend on the ratio of concentrations of the nitride-forming elements, on the nitriding temperature, and on the composition of the saturating atmosphere. The kinetic parameters of the process of internal nitriding and the conditions of formation of through diffusion layers are determined. It is shown experimentally that the refractory characteristics of the nitrided layers are enhanced.     

A comparative study of the sorption capacity of activated charcoal, soot, and fullerenes for organochlorine compounds

New experimental data on the sorption properties of fullerenes are presented. Fullerenes are approximately ten times more effective physical adsorbents of organic impurities from water than traditional activated carbons.     

Fullerene single crystals as adsorbents of organic compounds

The results of investigations of the adsorption properties of fullerenes are presented. Fullerenes acting as adsorbents are compared with soot and activated carbon. From its adsorption properties, soot is similar to activated carbon. Fullerenes do not manifest themselves in the composition of soot material. As an independent adsorbent, fullerenes are considerably more effective than activated carbon. Possible mechanisms of fullerene adsorption are discussed. It is concluded that the adsorptivity of fullerenes is realized mainly through dispersion interactions. Certain theoretical estimates are presented.