An algorithm for searching hidden oscillations in dynamic systems is developed to help solve the Aizerman’s, Kalman’s and Markus-Yamabe’s conjectures well-known in control theory. The first step of ...the algorithm consists in applying modified harmonic linearization methods. A strict mathematical substantiation of these methods is given using special Poincare maps. Subsequent steps of the proposed algorithms rely on the modern applied theory of bifurcations and numerical methods of solving differential equations. These algorithms help find and localize hidden strange attractors (i.e., such that a basin of attraction of which does not contain neighborhoods of equilibria), as well as hidden periodic oscillations. One of these algorithms is used here to discover, for the first time, a hidden strange attractor in the dynamic system describing a nonlinear Chua’s circuit, viz. an electronic circuit with nonlinear feedback.
This paper reports the obtained isotope–chemical data on the Tavatum thermal water deposit (Sea of Okhotsk coast, Magadanskaya oblast), as well as on surrounding underground and surface waters. The O ...and H isotope contents were obtained in the underground and surface waters, and trace elements were analyzed for the first time. According to the results, the chloride Na–Ca mesohalinous thermal waters of the Tavatum deposit are atmogenic. The two main formation processes of the chemical composition include: (1) involvement of deep brines (including cryopeg waters) and (2) cationic exchange in the interaction of sea waters (buried during the Holocene marine transgression) with rocks. The chemical composition of thermal waters is characterized by indicator chemical elements that reflect the impact of deep high-temperature processes. The deep fluid temperature as estimated using different geothermometers is 117–128°C, while the formation depth is at least 3 km.
Abstract
The paper presents the results of half-century geochemical parameters monitoring of thermal spring, called Teply Klyuch, occurring outside volcanic activity territory of the Russian Far ...East. The case of unique tectonic and geological conditions leading to formation of such deposits is being discussed as well. The waters of the deposit are characterized as warm, ultra-fresh, alkaline, and siliceous. It is controlled by the active part of the fault, which runs along the bed of the Amgu River and its watercourses, in the zone of intersection by a shallower fault. Formation of thermal waters probably took place in open fractures of deep faults, where atmospheric waters by downward flow penetrated to a depth of about 1.0–1.5 km and under the influence of heat of locally heated in the fault zone rocks acquired the temperature of +30 +40°C. The movement of heated water to the surface is caused by the thermolift. Discharge area goes along the opened cracks in the weakened zones located in the river valleys. In practical terms, the waters of the investigated deposit are applicable for therapeutic and prophylactic purposes, externally, in the form of baths for diseases of the musculoskeletal system, skin diseases, consequences of burns.
The article proves the promising nature of using functionalized magnetic nano particles in extraction of metals from process solutions and in treatment of industrial effluents. The experimental ...copper extraction from solutions using a magnetic nanosorbent made of lipoic acid-functionalized magnetite is described. Sorption efficiency is determined as function of the initial concentration of solutions as compared with non-functionalized nano-size magnetite. The copper-bearing sedimentation mechanism includes chemosorption at active centers of lipoic acid, adsorption at clean magnetite surface and re-crystallization of sorbate in intrinsic copper-bearing phases. The phase composition of copper in the sediments is examined, and the copper extractability is illustrated. The conditioning technology is proposed for copper-bearing solutions. The stage-wise use of the magnetic nanosorbent enables process solution purification up to the maximum allowable concentration at simultaneous production of a concentrate suitable for hydrometallurgical processing.
The results of the studies on the use of collector reagents in the form of a reverse microemulsion (RME) of the water-in-oil type (i.e., water droplets are suspended in the oil phase) for the ...flotation extraction of lead and zinc minerals are presented. Lead and zinc concentrates and a lead–zinc ore are used as the initial samples for flotation. The concentration of galena in the lead concentrate is 74.7%, and the concentration of sphalerite in the zinc concentrate is 78.7%. Basic collector reagents in the composition of the RME are potassium butyl xanthate (PBX) and kerosene. A nonionic surfactant (NSA) is used to stabilize the RME. Casein is used as additives to the main reagents to eliminate the negative effect of osmotic pressure upon preparing the RME. The transformation of casein to the active soluble form is carried out using sodium sulfide. The particle size in the reverse microemulsion is 12.38 nm. The following options for supplying reagents to the flotation pulp are studied in flotation tests: RME, RME + foaming agent, and potassium butyl xanthate + foaming agent. A T-92 reagent is used as the foaming agent. The consumption of PBX in the composition of the RME and in the classical supply is 26 g/t. The results of laboratory tests show that the method of supplying flotation reagents in the form of an RME leads to an increase both in the flotation rate of lead and zinc sulfides and in their recovery into a foam product. Tests with the use of an RME in the collective flotation cycle of a lead–zinc ore show an increase in the extraction of lead into the total concentrate by 10.8% and zinc by 38.5% in comparison with the classical supply of reagents (collector + foaming agent) in addition to an increase in the flotation rate. An increased selectivity of the action of an RME in relation to zinc sulfides in comparison with lead sulfides is noted. The flotation rate coefficient of sphalerite is 7.8-fold higher when compared to galena. The gain in the extraction into the total zinc concentrate is also higher and is 16.78%, while the gain into the lead concentrate is 1.9% under the same conditions.
Abstract
A method and a measuring device designed to determine the thermal conductivity of existing and newly created composite materials used in superconducting magnets and other objects of ...cryogenic technology are considered. The results of studies of the temperature dependence of the modern advanced materials thermal conductivity in the range from 7 to 80 K are shown.
The largest CO
2
-rich mineral water resource in the Sikhote-Alin ridge of Eastern Russia at Gornovodnoe village was studied. The high-pCO
2
groundwaters are cold (5.8–10 °C) with pH 5.9–6.5, TDS ...varied from 1.2 to 2.7 g/l and belong to Ca–Mg (Ca–Na)–HCO
3
type. New data on geology, mineralogy, hydrogeology and hydrogeochemistry, in conjunction with isotope data of water and gas phases, have provided a much better understanding of the origin of this distinctive groundwater. It was found that this water is of meteoric origin, but its unusual chemical composition is controlled by interactions of CO
2
-rich groundwater and the aquifer materials. The dissolved CO
2
gas makes the water slightly acidic (at about pH 6.2) which increased the leaching of many trace elements from host volcanic rocks typically considered immobile at these pH values.
3
He/
4
He ratios and δ
13
C indicate that mantle degassing is important as a source of deep exogenic fluids. The cold CO
2
-rich groundwater of the Eastern Sikhote-Alin ridge is the result of interactions between fresh groundwater of meteoric origin, mantle gases and the host volcanic rocks. It thus highlights connectivity between deep and shallow fluids along with deep fractures related to ancient terrane boundaries.
This paper proposes a method for quickly estimating the average flotation capacity of minerals according to the kinetic experiment without finding the flotation spectrum at which the first moments of ...distribution are calculated by the coefficients of the polynomial approximation of the logarithmic form of the kinetics. Using the example of copper-nickel ore, it is shown that the application of this method is effective in the multiparameter problem of comparative assessment of reagents. The ten parameters assessed included the average floatability of the target minerals (chalcopyrite and pentlandite), pyrrhotite and rock; the flotation selectivity coefficients of target minerals relative to pyrrhotite and rock; and the levels of copper and nickel losses from bulk flotation tailings. A visual representation of the interdependencies of parameters is achieved using diagrams showing the effect of flotation reagents on groups of parameters: average flotation, selectivity coefficients, metal losses, and selectivity relative to rock. The influence of butyl xanthate, Aeroflot, diesel fuel, and waste rock depressants—carboxymethyl cellulose (CMC) and acidified water glass (with a total consumption of 130 g/t collectors, 5–10 g/t diesel fuel, 200 g/t CMC, acidified water glass—500 g/t)—on the estimated parameters under conditions of collective flotation is determined. It is found that the addition of Aeroflot and diesel fuel to the main reagent collector xanthate increases the selectivity of pentlandite and chalcopyrite flotation relative to pyrrhotite and rock-forming component. The introduction of acidified liquid glass into the reagent mode increases the selectivity of the flotation of nickel and copper sulfides relative to the rock. CMC additives impair the selectivity of copper flotation. The quantitative effects of each individual parameter are taken into account in the integral rating assessment of the prospects of using reagent combinations for copper-nickel ore in terms of a set of ten parameters. The proposed method can be further used for a mass comparative evaluation of flotation reagents.
The particle size distribution and the material constitution of samples taken from old milltailings of sulfide and oxidized ore are studied. It is shown that more than 50% of gold occurs in fine size ...grade of −0.044 mm. The method of gas adsorption reveals large specific area in the samples, which is important for re-entrainment and migration of gold and associate components. It is found that gold correlates with iron-bearing species, which is useful for the magnetic separation of gold. The differential scanning calorimetry shows that the samples of the milltailings lack significant quantity of carbon black capable to adsorb gold. It is found that it is possible to generate insoluble residuum of iron cyanoferrates in the tailings, and microne size particles of mobile gold will self-settle on them.
The results of studies are presented for the influence of hydrodynamic factors on the occurrence of nitric thermal waters in crystalline massifs based on the example of the Kuldur field. The results ...of two-dimensional modeling based on the FEFLOW software are considered for several versions of the formation and circulation of thermal waters in the treated area. The modeling parameters included temperature within 130–140°C calculated on the basis of geothermometers, as well as the residence time of the waters in the rock massif (68 000–254 000 years) evaluated by
14
C- and
4
He-dating. The modeling results show that the filtration parameters of the granite massif are the main factors that control the fluid motion dynamics and, hence, the relative age of thermal waters. It was also found that the filtration characteristics of the fault zone considerably affect the discharge temperature of thermal waters.
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