On modeling of processes of moisture circulation and electric charge separation in the atmosphere

The possibilities of obtaining water and electric energy from the atmosphere by means of simulation of the local atmospheric moisture cycle as well as electrical phenomena which accompany it in both natural and laboratory conditions are discussed. The basic possibility of achieving these goals according to the natural analogy is shown experimentally.     

Extension of thick-walled cylindrical anisotropic blanks,with thinning of the wall

The stress-strain state of thick-walled anisotropic cylindrical blanks during extension with wall thinning is considered. The forces acting on the blanks and the limiting shape changes are investigated.     

“Super-overtaking” optimal policies for Markov control processes

In this paper we study the average cost optimization problem for discrete-time Markov control processes on Borel space with possibly unbounded costs. Under proper ergodicity assumptions we show the existence of stationary policies for which asymptotic (as N → ∞) behavior of some functions of N-horizon costs can be better than for overtaking optimal policies.     

Boiling heat transfer in the field of electric forces

Comparative estimations of the vapor generation conditions on a heating surface with boiling both in the field and without it depending on the value of heat flux and the field strength are given. The pattern of the motion of the convective flows and vapor bubbles in connection with the heat transfer intensity is analyzed on the basis of high-speed filming of the boiling process.     

Hole‐rich host materials for blue‐phosphorescent OLEDs

Abstract— Stable and efficient organic light‐emitting devices (OLEDs) are an integral part of the future of lighting and displays. The hole accumulation at the hole‐transport/emissive‐layer interface in such devices is considered to be a major pathway for degradation and efficiency loss. Here, the design and synthesis of two charge‐transporting host materials, based on the phosphine oxide (PO) moiety, engineered to improve hole transport of the emissive layer, will be reported. The compounds are an extension of a molecular design strategy which incorporates a hole‐transporting moiety and an electron‐transporting moiety. These materials were designed with two hole‐transport moieties (HTms) to further improve hole transport, compared to the first‐generation host materials that were designed with one hole‐transport functional group. The triplet exciton energy was maintained at a level greater than that of FIrpic (2.7 eV) to prevent exciton quenching. The EHOMO and ELUMO of the two classes of molecules (i.e., 1 HTm vs. 2 HTms) were similar; however, their device performance varied greatly. Emission zone experiments were conducted to further characterize the difference in charge transport between the molecules.     

Condensation of a gas-vapor mixture under the conditions of a corona discharge

The experimental data on the condensation of vapor from a gas-vapor mixture in the presence of an electric field are discussed. It is assumed that a corona discharge or, to be more accurate, its accompanying phenomena such as the unipolar charging of the medium and the electric wind, which produces intense mixing both of the medium and the condensate film, is the main factor influencing the intensification of the condensation in an electric field. The criteria of the similarity of the process, among which the main attention is drawn to the “electric” Reynolds number, which characterizes the interaction of the electric field with the medium, are considered. We also discuss the parameters of vapor-air mixtures, such as their density, viscosity, and ion mobility. A simplified method of the generalization of the experimental data on condensation in the presence of an electric field based on the concepts of a corona discharge is proposed.     

Heat transfer at the condensation of a gas-vapor mixture in an electric field

The problems associated with the investigation of heat transfer processes at the condensation of vapor from a vapor-air mixture in the presence of an electric field have been considered. It is established that even very small additions of air impair vapor condensation and, hence, the heat transfer. It is shown that the application of an electric field to a vapor-air mixture can be an effective factor for eliminating the negative effects of the presence of air on the condensation process. It has been found out that a corona discharge specially created by means of notches on the surface of the inner electrode of a cylindrical system and its effects are the main reason for this. The experimental characteristics of the relative heat transfer coefficient at condensation as functions of the air concentration, the rate of the mixture’s delivery into the vapor condenser, and the specific heat flux at different electric field intensities have been obtained. The results are explained by the electric charging of the medium in the corona charge field, by the electric wind, and by the charging of the “vapor-liquid” interface. There has been derived a formula according to which the process of condensation is strongly influenced by the molecule effective diameter (ψ∼d _*⁶) increasing in the electric field due to the solvation of ions by water molecules resulting in a new mechanism for the intensification of the condensation process in an electric field.     

Experimental Investigation of Gas/Slag/Matte/Tridymite Equilibria in the Cu-Fe-O-S-Si System in Controlled Atmospheres: Development of Technique

The majority of primary pyrometallurgical copper making processes involve the formation of two immiscible liquid phases, i.e., matte product and the slag phase. There are significant gaps and discrepancies in the phase equilibria data of the slag and the matte systems due to issues and difficulties in performing the experiments and phase analysis. The present study aims to develop an improved experimental methodology for accurate characterisation of gas/slag/matte/tridymite equilibria in the Cu-Fe-O-S-Si system under controlled atmospheres. The experiments involve high-temperature equilibration of synthetic mixtures on silica substrates in CO/CO₂/SO₂/Ar atmospheres, rapid quenching of samples into water, and direct composition measurement of the equilibrium phases using Electron Probe X-ray Microanalysis (EPMA). A four-point-test procedure was applied to ensure the achievement of equilibrium, which included the following: (i) investigation of equilibration as a function of time, (ii) assessment of phase homogeneity, (iii) confirmation of equilibrium by approaching from different starting conditions, and (iv) systematic analysis of the reactions specific to the system. An iterative improved experimental methodology was developed using this four-point-test approach to characterize the complex multi-component, multi-phase equilibria with high accuracy and precision. The present study is a part of a broader overall research program on the characterisation of the multi-component (Cu-Fe-O-S-Si-Al-Ca-Mg), multi-phase (gas/slag/matte/metal/solids) systems with minor elements (Pb, Zn, As, Bi, Sn, Sb, Ag, and Au).     

Thermal conductivity of the insulation system of the stator winding of a high-power turbogenerator with air cooling

Values of the thermal-conductivity coefficient of specimens of the frame insulation manufactured from pre- and unimpregnated, mica-containing tapes are determined. It is established that the tape structure, temperature, epoxy binding content, and type of packing materials (filling compounds) have an effect on the thermal conductivity of the insulation system of the stator winding of turbogenerators with air cooling.     

The Integration of Plant Sample Analysis,Laboratory Studies,and Thermodynamic Modeling to Predict Slag-Matte Equilibria in Nickel Sulfide Converting

The Kalgoorlie Nickel Smelter (KNS) produces low Fe, low Cu nickel matte in its Peirce–Smith converter operations. To inform process development in the plant, new fundamental data are required on the effect of CaO in slag on the distribution of arsenic between slag and matte. A combination of plant sample analysis, high-temperature laboratory experiments, and thermodynamic modeling was carried out to identify process conditions in the converter and to investigate the effect of slag composition on the chemical behavior of the system. The high-temperature experiments involved re-equilibration of industrial matte-slag-lime samples at 1498 K (1225 °C) and P(SO₂) = 0.12 atm on a magnetite/quartz substrate, rapid quenching in water, and direct measurement of phase compositions using electron probe X-ray microanalysis (EPMA) and laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS). A private thermodynamic database for the Ca-Cu-Fe-Mg-Ni-O-S-Si-(As) system was used together with the FactSage software package to assist in the analysis. Thermodynamic predictions combined with plant sample characterization and the present experimental data provide a quantitative basis for the analysis of the effect of CaO fluxing on the slag-matte thermochemistry during nickel sulfide converting, in particular on the spinel liquidus and the distribution of elements between slag and matte as a function of CaO addition.