Protective properties of detonation-deposited coatings from powders alloyed with aluminum and boron

Conclusions The corrosion resistance of detonation-deposited coatings from aluminum- and boron-containing PKh20N80 alloy, nickel, and stainless steel powders markedly surpasses that of constructional steel. The electrochemical properties of such detonation-deposited coatings are determined by their composition and thickness. The basis material is effectively protected against corrosion by 600-Mm-thick coatings. Under conditions of corrosive and mechanical wear detonation-deposited coatings from aluminum- and boron-containing 20% Cr-80% Ni alloy, nickel, and stainless steel powders operate satisfactorily under loads of not more than 5 MPa. The results of service tests have demonstrated the usefulness of detonation-deposited coatings from alloyed powders. Coating with powder of composition III was found to increase the useful life of certain parts of spraying equipment two to two and a half times.Translated from Poroshkovaya Metallurgiya, No. 8 (272), pp. 52–55, August, 1985.     

Scandinavian Thins on Top of Cake: New and Improved Algorithms for Stacking and Packing

We show how to compute the smallest rectangle that can enclose any polygon, from a given set of polygons, in nearly linear time; we also present a PTAS for the problem, as well as a linear-time algorithm for the case when the polygons are rectangles themselves. We prove that finding a smallest convex polygon that encloses any of the given polygons is NP-hard, and give a PTAS for minimizing the perimeter of the convex enclosure. We also give efficient algorithms to find the smallest rectangle simultaneously enclosing a given pair of convex polygons.     

Selecting the thermal circuit and profile of a Russian large new-generation power-generating gas turbine unit and a combined-cycle plant built around it

Proposals on the most advisable lines in which the Russian industry can develop advanced new-generation gas-turbine units and combined-cycle plants competitive in the first half of the 21st century are formulated.     

Obtaining and Studying Films of Tungsten,Titanium and Their Oxides

Glass Physics and Chemistry - The initial polycrystalline films of tungsten and titanium, whose surface has predominantly ultrananodispersed morphology and a thickness of 50 to 100 nm, are obtained...     

Twenty-Fourth Kargin's Readings

The regular Kargin's Readings were held on January 24, 1994, in the Chemistry Department of Moscow State University. They were the 24th readings, Professor Valentin A. Kargin, the founder of polymer science in our country, the head of the Scientific Council on Macromol-ecules of the USSR Academy of Sciences (1948–1960), and the head of the Chair of Macromolecules of the Moscow State University, having passed away in 1969. Professor Kargin had founded the great school of experts in the area of physics and chemistry of polymers. He was very active in the science and his contribution mainly concerned the structural approach to synthesis, technology, and physical and chemical properties of polymers. Now Russian and foreign colleagues and disciples of Professor Kargin are preparing a memorial book about this outstanding scientist.     

National Russian Conference on the Occasion of the 60th Anniversary of the Chair of Chemistry,Physics, and Processing of Polymers of Lomonosov Moscow State Academy of Fine Chemical Technology (MSAFCT)

The Scientific Conference was held on December 15, 1993. In addition to the 60th anniversary of the Chair, it was also dedicated to the 95th anniversary of the founder of the Chair, Professor Boris A. Dogadkin, who was a famous Soviet scientist in the area of natural and synthetic rubber. Professor Dogadkin had founded a scientific school in the Soviet Union, and following his ideas many plants had been built to produce synthetic rubber. Participants in the conference were 120 scientists from 20 research centers of the former Soviet Union. Most of these scientists graduated from the Chair of Chemistry, Physics, and Processing of Polymers.     

Diffusion of electrolytes in hydrolyzable glassy polymers: Acetic acid in poly(vinyl acetate), poly(vinyl alcohol), and polyesters

Engineering materials containing poly(vinyl acetate) (PVAc) as the key component undergo hydrolytic degradation, which must be minimized or, at least, controlled. To characterize PVAc hydrolysis quantitatively, the diffusion of acetic acid (HAc) in PVAc, poly(vinyl alcohol) (PVA), unsaturated polyester (UPE), and a UPE/PVAc blend was studied in detail. The permeability cell earlier developed by the authors was modified here to reduce experimental error. As the diffusion and solubility coefficients of water and HAc in the above materials were measured at different temperatures, a mathematical model was developed, which takes proper account of the combined water and HAc diffusion in PVAc undergoing partial hydrolysis. The model was further validated by the experimental data obtained at 70°C for UPE/PVAc film, simulating a matrix of sheet‐molding compounds composite materials. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1157–1166, 2002     

A Study of Moisture Effects on Ti/Porous Silicon/Silicon Schottky Barrier

Results of capacitance-voltage and current-voltage measurements performed on Ti/porous silicon (PS)/p-Si diode structures are presented. A 5–10 increase of conductivity and capacity has been observed at f < 10000 Hz in response to the moisture change from 0 to 50%. Model of Schottky contact on thin PS layer with the charge carriers inside of pores and PS/Si interface is applied to explain the frequency dependence of conductivity/capacity as well as moisture effect.