Effect of reduction parameters on the particle size of tungsten monocarbide obtained from the blue tungsten oxide

Conclusions A study was made, using the methods of particle size analysis and metallographic examination, of the effects of temperature and bed thickness in the reduction of the blue tungsten oxide upon some properties of tungsten and tungsten monocarbide powders and sintered 6 wt.% Co hard alloys produced from the monocarbide powders. Quantitative results were obtained showing the relationship between these reduction parameters on the one hand and the particle size of the resultant powders and the physicomechanical properties of hard alloys on the other. It was established that the particle size grows with rise in reduction temperature and with increase in the thickness of the blue oxide bed.Translated from Poroshkovaya Metallurgiya, No. 11(143), pp. 102–107, November, 1974.     

A study of the electrical conductivity processes in amorphous semiconductors using the computer simulation method I. One-dimensional case

In this paper we present a computational model of electrical conductivity processes via variable range hopping of electrons between localized states (‘sites’) in quasi one-dimensional disordered systems. For two, slightly different models, the temperature dependence of the conductivity of parallel connected systems of filaments and of quasi-infinite, single filaments are discussed and compared with theoretical and experimental results.     

Extraction of copper from acid sulphate solutions by 2-hydroxy-5-n-nonyl and 2-hydroxy-4′-n-nonylbenzophenone oximes

The study of copper extraction shows that the position of the chain (5 or 4′) does not influence the statics of copper extraction from ammonia solutions by alkyl derivatives of 2-hydroxybenzophenone oxime. Acid solutions of 2-hydroxy-4′-n-nonylbenzo-phenone oxime can extract more copper than 2-hydroxy-5-n-nonylbenzophenone oxime, but less than 2-hydroxy-5-n-alkylbenzaldehyde oxime.     

Method for the synthesis of semitransparent wide band dielectric mirrors

A general method for the numerical design of wide band dielectric mirrors with non-zero transmission is given. The values of the optical parameters for twenty mirrors designed by this method are presented and discussed.     

Structural investigation of chemically crosslinked low density polyethylene

The effects of chemical crosslinking on low density polyethylene are investigated, using electron microscopy, X-ray diffraction, n.m.r., and gel fraction determination. The results of these studies are discussed in terms of the degree of crosslinking estimated on the basis of peroxide content.     

Computer simulation of heuristic reinforcement-learning systems for nuclear power plant load changes control

This paper describes two ideas and sample simulation results of a heuristic reinforcement-learning system and its application to the problem of digital computer control of a simple nuclear plant model. The idea of the system is interconnection between the well known reactor control heuristic rules [8,9], and the reinforcement learning algorithms [4,5]. The control signal is proposed as a vector depending on complex physical properties of the plant. Such an approach is far more flexible than deterministic or stochastic techniques when dealing with unknown processes and novel control situations.     

A study of the electrical conductivity processes in amorphous semiconductors using the computer simulation method III. Three-dimensional case

A numerical model for the hopping conductivity in 3-D disordered systems is presented. The relation between variable-range hopping conductivity and temperature for the low-temperature range is found. The advantage of the proposed model is that the size of the system investigated is not limited by the computer memory.     

Ionic association equilibria in the dimethyl sulphoxide solutions of Mn(CF3COO)2, Co(CF3COO)2 and Ni(CF3COO)2

The molar conductivity curves have been determined for Mn(CFR₃COO)₂, Co(CF₃COO)₂ and Ni(CF₃COO)₂ in dimethyl sulphoxide at 25°C. The first step association constants are derived. Auxiliary measurements of the visible absorption spectra and the nmr chemical shifts of the solvent protons indicate lack of coordination¹ of the anion in the solutions of Ni(CF₃COO)₂. On the other hand, bidentate coordination of the anion, taking place to a small extent in addition to the outer-sphere association, is inferred for Co(CF₃COO)₂. On the assumption that the outer-sphere association constants are approximately the same for the three metal trifluoroacetates, the highest extent of the inner-sphere association is inferred for Mn(CF₃COO)₂.     

Determination of the ash yield and the mineral matter content of brown coals by density measurements

A method of measuring the density of bed-moist brown coals based on their plastic properties is described and the feasibility of using the method for determination of the ash yield of the coal is evaluated.