Determination of Quasiequilibrium Work of Adhesion of Elastic Coatings

Present methods for the determination of adhesion bonding of elastic polymeric materials entail certain experimental difficulties. In particular, the necessity of strict centering of the test specimen, and the difficulty associated with application of a homogeneously distributed stress over the whole cross-sectional area (homogeneous detachment or shear), or the excessive expenditure of work resulting from polymer deformation (peel).^1,2

We are suggesting a method to determine the quasi-equilibrium work of adhesion during the peeling process for elastic polymeric coatings, the value of which, as was demonstrated experimentally, does not depend on the coating thickness, deformation or rate of peeling.     

Developing a technology for the production of high-strength insulating refractories

Conclusions We developed and tested, in industrial conditions, the main technical parameters for preparing chamotte lightweight refractories with a compressive strength of not less than 10 MPa. The pore formation of the bodies can be attained by using a porous filler of coarse grain-size composition, obtained by expanding fireclays by heat treatment, and with small additions of combustibles. On the basis of the results of these tests we can recommend the development of the technology for introduction into industry.Yu. G. Kruglik took part in the work.Translated from Ogneupory, No. 4, pp. 42–46, April, 1985.     

Single - dose immunization of human subjects against tetanus

A study was performed on human subjects to assess the effectiveness of single-dose immunization with 20 CU (1 ml) of adsorbed tetanus toxoid followed by revaccination with 10 CU (0.5 ml) 1 year later. Out of 1187 students, only those were selected for observation whose blood serum did not contain tetanus antitoxin (titre less than 0.001 IU/ml); this group counted 283 students. After administering the 20 CU (1 ml) of toxoid the antitoxin titre was repeatedly checked on days 10--15 and persons whose titre had risen to over 0.01 IU/ml were excluded from observation. The remaining 109 persons were tested for the antitoxin level 1 year later and revaccinated with 10 CU of tetanus toxoid. After 10--15 days their postrevaccination titre was determined. The single-dose immunization with 20 CU of tetanus toxoid in human subjects not given tetanus antigen previously was accompanied by a gradul rise in the antitoxin titre up to the protective level and its maintenance for 1 year (observation time) until revaccination. Revaccination with 10 CU of toxoid provided in 10--15 days a multiple (100--197fold) increase of the antitoxin titre, many times exceeding the protective level. The usefulness of transition to the shortened immunization scheme for tetanus prophylaxis of the adult population is discussed.     

Effect of ultrasonic vibrations on scale formation

Results are shown of an experimental study concerning the effect of ultrasonic vibrations on scale formation on a heat-transfer surface. It is shown that an amplitude of flexural vibrations in excess of 3 ensures almost a scalefree performance of a heat-transfer surface.Translated from In-zhenerno-Fizicheskii Zhurnal, Vol. 24, No. 1, pp. 120–125, January, 1973.     

Influence of the calorimetric-element characteristics on the results of heat-flux measurements

The results of an experimental study of the influence of the dimensions of the calorimetric element and the properties of its material on the measured heat flux are examined. Recommendations for calculating the thickness of a heat-flux sensor are made, and two methods of measuring the thermal conductivity of various metals in the case of samples heated by a plasma jet are proposed.     

Features of reduction of high-magnesia nickel ore of the serov deposit

Parameters of reducing the roasting of high-magnesia oxide nickel ore containing, wt %, 1.2 Ni, 0.026 Co, 17.0 Fe₂O₃, 4.0 Al₂O₃, 20.2 MgO, and 46.0 SiO₂ are evaluated. The degrees of reduction and metallization upon heating the ore with the reducing agent in the range t = 800−1250°C and the sizes of metallic inclusions forming in the course of the process are determined. To separate the phases, the magnetic separation of reducing products at H = 40 and 80 kA/m is used. The best characteristics are attained upon roasting the ore with a reducing agent and a sulfidizing agent at t = 1300°C. In this case, the magnetic fraction contains 7.1% Ni, while the nonmagnetic one contains 0.18% Ni.