OBTAINING OF FERROSILICOCHROMIUM POWDER ALLOY BY SILICOTHERMIC REDUCTION AND STUDY OF THE MECHANISM OF THIS PROCESS

The process of obtaining a powder ferrosilicochromic alloy by the method of silicothermic reduction of local chromites and slags of copper smelters was investigated. The mechanism of this process has been studied. It is established that the best results are obtained in the case of slag / chromite ratio = 1: 1, when an alloy with microdispersed structure and high strength is obtained. The optimum composition of the resulting alloy is as follows: 35,1% Fe; 36,35% Si and 28,53% Cr, with a metal yield of 98,4%. The obtained alloy powder can be used as an acidified and alloying additive to chromium- and silicon-containing stainless composite materials. The aspects of the process for obtaining FeSiCr alloy have been developed. The maximum temperature (Tc) and the linear propagation velocity of the combustion wave (Uv) are determined graphically. The mechanism of the formation of FeSiCr in the SHS process is explained.The process of obtaining a powder ferrosilicochromic alloy by the method of silicothermic reduction of local chromites and slags of copper smelters was investigated. The mechanism of this process has been studied. It is established that the best results are obtained in the case of slag / chromite ratio = 1: 1, when an alloy with microdispersed structure and high strength is obtained. The optimum composition of the resulting alloy is as follows: 35,1% Fe; 36,35% Si and 28,53% Cr, with a metal yield of 98,4%. The obtained alloy powder can be used as an acidified and alloying additive to chromium- and silicon-containing stainless composite materials. The aspects of the process for obtaining FeSiCr alloy have been developed. The maximum temperature (Tc) and the linear propagation velocity of the combustion wave (Uv) are determined graphically. The mechanism of the formation of FeSiCr in the SHS process is explained

Agroecological evaluation of interrelationships of soil properties in time and space

This paper assesses the relationship between the physico-chemical and agro-chemical properties of sod-podzolic soils in the Moscow region and ordinary heavy-loamy chernozems in the Krasnodar region within the catenas and down the soil profile. Soil properties changed significantly through seasonal dynamics. From the end of April to the middle of June in the soil solution of sod-podzolic soils, the value of Eh varied from 534 to 759 mv, the ratio of NO3/NH4 – from 0.2 to 15.4; the content of water-soluble manganese – from 4.0 to 10.1. At the same time, there was a delay in change of soil properties, as humidity and temperature varied. It is shown that in different intervals of soil properties between individual indicators of fertility, the effects of synergism and antagonism are manifested. The degree of mutual influence of soil properties depended on both the degree of soil fertilization and the degree of their cultivation. Information relationships were manifested not only between the soil properties, but also between the processes. Temporary excessive moistening of the soil led to acidification of the soil in the washing type of water mode, and to alkalinization in the non-washing type. It is proposed to account for the relationship of soil properties with humidity, temperature, pH, and Eh to adjust the components of farming systems

The nighttime ionosphere of Mars from Mars-4 and Mars-5 radio occultation dual-frequency measurements

Dual frequency radio sounding of the Martian nighttime ionosphere was carried out during the exits from behind the planet of the Mars-4 spacecraft on February 2, 1974 and the Mars-5 spacecraft on February 18, 1974. In these experiments, the spacecraft transmitter emitted two coherent monochromatic signals in decimeter and centimeter wavelength ranges. At the Earth receiving station, the reduced phase difference (or frequencies) of these signals was measured. The nighttime ionosphere of Mars measured in both cases had a peak electron density of approximately 5 X 1,000/cu cm at an altitude of 110 to 130 km. At the times of spacecraft exit, the solar zenith angles at the point of occultation were 127 deg and 106 deg, respectively. The height profiles of electron concentration were obtained assuming spherical symmetry of the Martian ionosphere

ОПРЕДЕЛЕНИЕ КРАЕВОГО УГЛА СМАЧИВАНИЯ НА ПЛОСКИХ ПОВЕРХНОСТЯХ / М Г

The paper considers an improved technique for determination of a contact wetting angle. Description of the devices that make it possible to determine a contact wetting angle with due account of surface roughness is given in the paper. A specified formula for calculation of a contact wetting angle has been derived.Усовершенствована  методика  определения  краевого  угла  смачивания.  Приводится  описание комплекса устройств, позволяющего определять краевой угол смачивания с учетом  шероховатости  поверхности.  Получена  уточненная  формула  для  расчета  краевого  угла смачивания.

On charged impurity structures in liquid helium

The thermoluminescence spectra of impurity-helium condensates (IHC) submerged in superfluid helium have been observed for the first time. Thermoluminescence of impurity-helium condensates submerged in superfluid helium is explained by neutralization reactions occurring in impurity nanoclusters. Optical spectra of excited products of neutralization reactions between nitrogen cations and thermoactivated electrons were rather different from the spectra observed at higher temperatures, when the luminescence due to nitrogen atom recombination dominates. New results on current detection during the IHC destruction are presented. Two different mechanisms of nanocluster charging are proposed to describe the phenomena observed during preparation and warmup of IHC samples in bulk superfluid helium, and destruction of IHC samples out of liquid helium

ПОЛУЧЕНИЕ ВЫСОКОПРОЧНЫХ ДЕФОРМИРУЕМЫХ АЛЮМИНИЕВЫХ СПЛАВОВ ТИПА АМг10

Traditional grades of aluminum alloys do not always meet the requirements of modern aerospace engineering. Al–Si foundry alloys possess insufficient mechanical strength characteristics and low plasticity due to their structural features (coarse brittle silicon inclusions and intermetallic phases). Therefore they cannot be exposed to pressure treatment. A technique for producing high-strength aluminum alloys, which consists in obtaining ring blanks by means of direct crystallization of melts with application of non-stationary centrifugal force fields and simultaneous introduction of modifiers, is proposed. The microstructure and plasticity of resulting tube-shaped blanks allow them to be exposed to sheeting for subsequent production of pipe workpieces with mechanical strength commensurate with mechanical strength of structural steel. The technique involves hydrothermal synthesis of nanostructured particles of aluminum oxide, which are overheated above the melt temperature prior to introduction into the molten aluminum alloy. This procedure enhances the processes of intercrystalline hardening with minimal fluctuations of internal stresses within the hardened material. The materials have tensile strength of up to 380 MPa (before modification by nanodispersed aluminum oxide it was 210 MPa). The microstructure has showed changes in the acicular dendrite component, which tends to become more dispersed and equiaxial. Eventually this leads to an increase in the mechanical strength by a factor of 1.25–1.32. Традиционные марки алюминиевых сплавов не всегда могут обеспечить выполнение требований современной ракетно-космической и авиационной техники. Литейные сплавы системы Al–Si из-за структурных особенностей – грубых хрупких включений кремния и интерметаллических фаз, имеют невысокий уровень прочностных свойств и низкую пластичность, не позволяющую проводить их обработку давлением. Предложена технология создания высокопрочных алюминиевых сплавов, заключающаяся в получении кольцевых заготовок методом направленной кристаллизации расплава при наложении нестационарных силовых полей центробежных сил и одновременном введении модификаторов. Полученные заготовки имеют микроструктуру и пластичность, позволяющую подвергать их раскатке, и форму трубных заготовок, механическая прочность которых соизмерима с конструкционной сталью. Технология включает в себя гидротермальный синтез наноструктурированных частиц оксида алюминия, которые перед введением в расплав алюминиевого сплава перегреваются выше температуры расплава, что повышает полноту протекания процессов интеркристаллического упрочнения при минимальных колебаниях по объему упрочненного материала внутренних напряжений. Материалы имеют предел прочности до 380 МПа (до модификации нанодисперсным оксидом алюминия – 210 МПа). В микроструктуре наблюдается изменение игольчатой дендритной составляющей, которая становится более дисперсной и равноосной, что и приводит к повышению механической прочности в 1,25–1,32 раза.

Вариант расчета экономической эффективности освоения новой техники, технологии и оборудования

The paper gives a variant of determination of economic efficiency while using new technique, technology and equipment under conditions of market economy. The calculation has been made for technological processes of machining steel, cast iron and aluminium alloy cases of automobile brake cylinders.Представлен вариант определения экономической эффективности при использовании новой техники, технологии и оборудования в условиях рыночной экономики. Расчет проведен для технологических процессов механической обработки корпусов автомобильных тормозных цилиндров, изготовленных из стали, чугуна и алюминиевого сплава