A new protocol for the identification of two sibling species of voles
Microtus arvalis
and
M
.
rossiaemeridionalis
was proposed by electrophoresis of blood proteins in polyacrylamide gel (PAGE). ...Animals captured in ten districts of Moscow, Kaluga, and Samara oblasts and Moscow natural territories (1030 individuals), as well as those taken from vivarium collections (five hybrids of the two species), were studied. A comparison of electrophoresis in PAGE, agarose gel, and cellulose acetate plates was carried out. The use of different organs and tissues for species identification was assessed. The relative electrophoretic mobility and the mass of a species-specific blood protein of the southern vole were determined.
The results of the numerical study of oil recovery enhancement using nanosuspension are presented. The research was carried out using the volume of fluid method (VOF) for a 2D microporous core model. ...Experimentally measured values of interfacial tension (IFT) and the contact angle (CA) were used for numerical modeling. An aqueous suspension with silicon oxide nanoparticles (5 nm) is used. It was shown that when 1 wt% of nanoparticles are added to the displacing liquid, its density increases by about 1%, the viscosity increases by 10%, the IFT decreases by 10%, and the contact angle increases from 70 to 145
∘
. The results of numerical study showed that the injection of nanoparticles has a significant effect on the displacement front movement in the microporous model. It has been shown that the nanosuspension can increase the oil recovery factor (ORF) almost twice as compared to water. To clarify the mechanisms of increasing the oil recovery during the reservoir flooding with nanofluid, a systematic study of factors affecting the displacement process efficiency was carried out. Viscosity, interfacial tension and the wetting angle of the displacing fluid were considered as such factors. As a result of systematic research, it has been shown that the main factor affecting the increase in the oil recovery flooding of nanosuspensions is a variation of wettability.
•The experiment investigation of turbulent forced convection of nanofluids was carried out.•The dependence of heat transfer coefficient from the concentration and nanoparticle size was studied.•The ...dependence of heat transfer coefficient from the material of nanoparticle was analyzed.•The dependence of pressure drop from the concentration and nanoparticle size was studied.•The dependence of pressure drop from the material of nanoparticle was analyzed.
The experiment investigation of turbulent forced convection of nanofluids with SiO2 and Al2O3 nanoparticles was carried out. Nanoparticle concentration varied in the range from 0.5 to 2vol.% in the experiments. The nanoparticle size ranged from 10 to 100nm. The dependence of heat transfer coefficient and pressure drop from the concentration, size, material of the nanoparticles and temperature was studied. It was shown that adding nanoparticles to the coolant significantly influences the heat transfer coefficient in the turbulent flow regime. It is shown that with increasing nanoparticles concentration, the local and average heat transfer coefficients at a fixed Reynolds number increase. Decrease in heat transfer coefficient with increasing particles concentration may take place at a fixed flow rate. It is shown that, the heat transfer coefficient of the nanofluid in turbulent regime increases with increasing nanoparticles size at a fixed flow rate, while has a certain maximum at a fixed Reynolds number. The effect of nanoparticles material on the heat transfer coefficient and pressure loss has been also demonstrated. It is found that the inlet temperature is another factor having a significant effect on turbulent heat transfer performance of nanofluids.
The unique properties of supercritical fluid technology have found wide application in various industry sectors. Supercritical fluids allow for the obtainment of new types of products with special ...characteristics, or development and design of technological processes that are cost-effective and friendly to the environment. One of the promising areas where supercritical fluids, especially carbon dioxide, can be used is the oil industry. In this regard, the present review article summarizes the results of theoretical and experimental studies of the use of supercritical fluids in the oil and gas industry for supercritical extraction in the course of oil refining, increasing oil recovery in the production of heavy oil, hydraulic fracturing, as well as processing and disposal of oil sludge and asphaltenes. At the end of the present review, the issue of the impact of supercritical fluid on the corrosion of oil and gas equipment is considered. It is found that supercritical fluid technologies are very promising for the oil industry, but supercritical fluids also have disadvantages, such as expansion or incompatibility with materials (for example, rubber).
The paper presents the results of an experimental study of oil displacement by distilled water and an aqueous suspension of aluminum oxide nanoparticles. The correlation of extracted oil volume on ...the flow rate of the displacing fluid is obtained, and the pressure drop during the pumping of the displacing fluid through the rock sample is measured. It has been revealed that the suspension of nanoparticles can significantly improve the extraction of oil from sandstone.
The forest–steppe is an ecotone biome that has been greatly transformed by humans. Rodents are an important component of most forest–steppe biotopes. This group of mammals is distinguished by high ...species diversity and its representatives occupy many ecological niches. Rodents are also important to humans due to their impacts on agriculture, health, and other areas of life. The human impact on rodents is also multifaceted and complex, especially in the most heavily modified areas. In Russia, this includes the European part of the forest–steppe zone. The protection of rodents in the forest–steppe of European Russia, its effectiveness, and especially its current state require analysis. The protection of rodent species in this article is considered through the Red Books of the federal and regional levels, as well as through an analysis of the location of specially protected natural areas and the composition of their rodent fauna. Data on protected species and their status were extracted from the regional Red Books. The specially protected natural areas under consideration are briefly characterized. The participation of each rodent species in the fauna of these territories was analyzed. A map of the location of the areas under discussion and a table of the presence of rodent species in them have been compiled. The forest–steppe of European Russia is represented by three biomes: Dnieper–Volga, Zavolzhsky, and Crimean–Caucasian, in which 45 species of rodents were recorded, of which 35 are in the Dnieper–Volga biome, 27 in the Zavolzhsky, 27 in the Caucasian part of the Crimean–Caucasian biome, and 19 in the Crimean part of the Crimean–Caucasian biome. These biomes are located within 21 constituent entities of the Russian Federation. At the regional level, in the forest–steppe of European Russia, from 2 (Bashkortostan, Tula oblast) to 12 species of rodents (Chuvashia) are protected. There are 24 species that are protected in at least one region. One species is protected at the federal level, the speckled ground squirrel. In the forest–steppe of the European part of Russia there are 14 specially protected natural areas federal level: 7 nature reserves, 4 federal reserves, and 3 national parks, of which 9 have data on the species composition of rodents. A total of 33 species of rodents have been recorded in federal reserves. On each specially protected area from 11 (Voroninsky Reserve) to 26 (Belogorye) species were noted.
The steppe marmot (baibak) is one of the typical rodents of the Eastern European forest–steppe and steppe. In the mid-twentieth century, European populations of the species were on the verge of ...extinction, but then, thanks to conservation measures and reintroductions, the population of boibak and range were largely restored. This work collects and presents data on two restored marmot colonies in the forest–steppe of European Russia. The research was carried out in the Central Black Earth Nature Reserve (Streletskaya steppe, two sections) and in the Volga Forest–Steppe Nature Reserve (Ostrovtsovskaya forest–steppe, three sections). The number and age composition of marmots are described. Maps of settlements with burrows and trails of marmots have been compiled; for each burrow the coordinates and type (temporary or permanent) are indicated. The population density and the number of burrows per marmot were calculated. In total, 12 marmots live in the Streletskaya steppe: ten on the “Pasture” site and two on the “Restored Steppe” site. In the first area, seven adult and three young marmots were noted, in the second, two adult marmots. Here, the reintroduction of the boibak was not entirely successful. From 2015 to 2023 the number of marmots decreased sharply, from 38 to 12 individuals, and the area of the inhabited territory fell from 10 to 3.7 hectares. In the Ostrovtsovskaya forest–steppe, 48 marmots (eight families) were recorded, of which 40 were in the first area (six families), two were in the second area (one family), and six were in the third area (one family). Of the 48 individuals, 29 (61%) are underyearlings. The reintroduction of the bobak into the Ostrovtsovskaya forest–steppe was relatively successful: the total number of animals is comparable to the number of marmots initially released (48 and 64).
Ultrasonic treatment is a promising crude oil preparation method implemented using emitters of ultrasonic vibrations in the 1–100 kHz frequency range. The optimum conditions of applicability of this ...method and the impact parameters are determined and ultrasonic oil treatment technology is investigated for different volume water contents of the emulsion. It is shown that under the impact of acoustic vibrations the disperse phase droplets coalesce and the demulsification process occurs more actively than in traditional thermochemical dewatering process. The conditions of applicability of the method is analyzed and the technological advantage of breaking stable water-oil emulsions for field oil preparation in the Perm Krai (Perm Region) is assessed. Based on the experimental data, relationships describing the nature of the effect of ultrasonic impact parameters on stable water-oil emulsions breaking at different water contents and under phase inversion conditions are investigated.
Abstract
The paper presents a comprehensive mathematical model of a diesel-generator units with a valve-inductor generator. The calculated data obtained using this model allows optimizing the ...operation of fuel injectors and adjust the injection characteristics. The electromagnetic part of the model allows taking into account the power losses and efficiency of the generator, calculating the phase windings and their connection schemes, methods for setting the voltage or current of any shape that feeds the windings of the valve-inductor generator, as well as the characteristics of the rotor, stator, and winding materials to obtain the most effective operation parameters of the engine in various operating modes as part of the generator unit.
The results of experimental studies of the microsuspensions filtration with silicon oxide nanoparticles additions through a porous medium with different permeability are presented. The particle ...concentration in fluids ranged from 0.25 to 4 wt.%. The microparticle size was 1.2 μm. The nanoparticle size was 5 nm. The nanoparticle concentration was 2 wt.%. Dependences of the filtration losses of microsuspensions on the microparticle concentration and the permeability of a porous medium were established.
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