Collaborative interpretation of the data obtained by resistivity and ground penetrating radar methods for assessing the permeability of sandy clay soils

A method for estimating the filtration factor of sandy clay soils is considered on the basis of a joint interpretation of the data of a set of methods of engineering electrical exploration, including electrical resistivity tomography and ground penetrating radar studies. The solution of this problem is based on the use of known empirical connections between the imaginary and real parts of the complex dielectric permittivity, specific electrical resistance, and Q factor. An example of the effective joint use of the ground penetrating radar and non-contact electrical resistivity tomography shows how to obtain qualitative and quantitative estimates of a changing filtration factor in a draining road layer. It is necessary to use precise engineering geological information in order to provide the required estimates. The proposed approach makes it possible to describe continuous profiles of a pavement and underlying layers by ground penetrating radar and electrical resistivity tomography, as well as to assess soil properties when conducting an electrical survey from the surface of asphalt concrete pavement. Recommendations for the implementation of the developed methods of complex engineering and geophysical research are given for solving issues of repair work design, supervision, and quality control of road construction

Mathematical investigation of pressure pulsations characteristics and natural acoustic frequencies in the gas-dynamic channel

Paper presents a numerical simulation of the occurrence of flow instability and pressure self-oscillations for a complex configuration of the gas-dynamic tract in combustion chamber. Unsteady axisymmetric two-dimensional Navier-Stokes equations are used for mathematical modelling of compressible one-phase medium. To simulate turbulence, the k-ε and LES models were used. Fast Fourier Transform (FFT) determined the frequency spectrum of pressure pulsations in the combustion chamber. It is shown that in the case of a simple geometry of the free gas cavity in combustion chamber, both models of turbulence make it possible to determine the spectrum of the natural acoustic frequencies. Using the LES model in the case of complex geometry makes it possible to predict the hydrodynamic structure of a flow accurately. The flow, in this case, has an intensive vortex generation. Formation of small-scale vortex occurs in the near-wall regions and large eddies in the core of a flow. Frequency of large eddies formation can be combined with the natural acoustic frequencies of combustion chamber and can affect the amplitude of pressure pulsation

The universal algorithm for solving the gas dynamics equations on the mesh with arbitrary number of cell faces

The paper presents methodology and algorithm for calculating the equations of gas dynamics on arbitrary computational meshes with a mixed type of cells. The calculation method is based on the method of linear reconstruction proposed by Barth and Jesperson. The algorithm for determining the geometric parameters of arbitrary computational cell is presented. To implement the calculation algorithm, a data storage system has been proposed and tested. The algorithm of the solver and the algorithm of docking the computational meshes in the case of using block-structured meshes are proposed. The efficiency of methodology and developed program of calculation are demonstrated by the calculation example of the air flow in flat air intakes. The structure of flow and position of the bow shock wave are determined. These results with the theoretical values were compared. The application of the proposed methodology and calculation algorithm to arbitrary computational meshes with a mixed cell type makes it possible to optimize the process of constructing computational mesh and conduct numerical studies of gas dynamics in regions of complex geometry

Improving the reliability of 3D modelling of a landslide slope based on engineering geophysics data

Landslides are among the most dangerous geological processes, posing a threat to all engineering structures. In order to assess the stability of slopes, complex engineering surveys are used, the results of which are necessary to perform computations of the stability of soil masses and assess the risks of landslide development. The results of integ-rated geological and geophysical studies of a typical landslide slope in the North-Western Caucasus spurs, composed of clayey soils, are presented. The purpose of the work is to increase the reliability of assessing the stability of a landslide mass by constructing a 3D model of the slope, including its main structural elements, identified using modern methods of engineering geophysics. Accounting for geophysical data in the formation of the computed 3D model of the slope made it possible to identify important structural elements of the landslide, which significantly affected the correct computation of its stability

Calculation and experimental study on high-speed impact of heat-resistant coating materials with a meteoric particle

The given article presents the conducted calculation and experimental study on destruction of heat-resistant coating material of an aircraft in the process of high-speed interaction of the steel spherical projectile. The projectile is imitating a meteoric particle. The study was conducted in the wide range of velocities. The mathematical behavioral model of heat-resistant coating under high-speed impact was developed. The interaction of ameteoric particle with an element of the protective structure has especially individual character and depends on impact velocity and angle, materials of the interacting solids

Телязиоз, вызванный Thelazia callipaeda Railliet et Henry, 1910 (обзор литературы)

The purpose of the research is to analyze literature data on epizootology, morphology and biology of Thelazia callipaeda, and on clinical signs of thelaziosis.Thelaziosis caused by Th. callipaeda is widespread and not limited to Southeast Asian countries. At the end of the last century, autochtonous infection cases of thelaziosis were noted in Italy, and later the disease was recorded in France, Switzerland, Germany, Spain, Belgium, Portugal, Romania, Bosnia, Herzegovina, Croatia, Greece, Slovakia, Serbia, Turkey, Hungary, Moldova, Austria, Czech Republic, Poland, etc. Cases of thelaziosis recorded in the United States of America and the Russian Federation were most likely allochthonous and imported from contaminated areas. In Russia, canine thelaziosis was recorded in Moscow, St. Petersburg and Tyumen. It was found that definitive hosts of Th. callipaeda were not only cats, dogs or humans, but also many species of wild animals, namely, gray wolf, red fox, pine marten, hare, wild cat, Iberian wolf, European grey rabbit, beech marten, pine marten, golden jackal, European badger and brown bear. The prevalence of Thelazia infection among populations of wild animals reached 38.1%. The maximum number of helminths found in one animal was 96 specimens. In the life cycle of Th. callipaeda, males of the fruit fly Phortica variegata and Ph. okadai, which can keep Thelazia larvae in their bodies for up to 180 days are involved. Phylogenetic analysis of the cox1 gene showed that Th. callipaeda isolated from diseased animals in different countries belonged to haplotype-1, which was common in Europe.Цель исследований – проанализировать данные литературы по эпизоотологии, морфологии и биологии Thelazia callipaeda, клиническим признакам телязиоза.Телязиоз, вызываемый Th. callipaeda, широко распространен и не ограничивается странами юго-восточной Азии. В конце прошлого века аутохтонные случаи телязиоза отмечены в Италии, позже болезнь была зарегистрирована во Франции, Швейцарии, Германии, Испании, Бельгии, Португалии, Румынии, Боснии и Герцеговине, Хорватии, Греции, Словакии, Сербии, Турции, Венгрии, Молдове, Австрии, Чехии, Польши и т. д. Случаи телязиоза, зафиксированные в Соединенных штатах Америки и Российской Федерации, вероятнее всего, являются аллохтонными и завозятся с неблагополучных территорий. В России телязиоз собак зарегистрирован в Москве, Санкт-Петербурге и Тюмени. Установлено, что окончательными хозяевами Th. callipaeda являются не только кошки, собаки и человек, но и многие виды диких животных: серый волк, рыжая лиса, лесная куница, заяц-русак, дикая кошка, иберийский волк, дикий европейский кролик, буковая куница, лесная куница, золотистый шакал, европейский барсук и бурый медведь. Экстенсивность телязиозной инвазии среди популяций диких животных достигала 38,1%. Максимальное число гельминтов, обнаруженное у одного животного, составило 96 экз. В жизненном цикле Th. callipaeda в качестве промежуточного хозяина принимают участие самцы плодовой мушки Phortica variegata и Ph. okadai, которые могут сохранять своем теле личинок телязий до 180 сут. Филогенетический анализ гена cox1 показал, что Th. callipaeda, выделенные от больных животных в разных странах, принадлежат к гаплотипу-1, распространенному в Европе

Structure and nonlinear optical properties of novel transparent glass-ceramics based on Co2+:ZnO nanocrystals

Transparent glass-ceramics (GCs) based on Co2+:ZnO nanocrystals (mean diameter, 11 nm) are synthesized on the basis of cobalt-doped glasses of the K2O–ZnO–Al2O3–SiO2 system. For these GCs, the absorption band related to the 4A2(4F) → 4T1(4F) transition of Co2+ ions in tetrahedral sites spans until ~1.73 μm. Saturation of the absorption is demonstrated at 1.54 μm, with a saturation fluence Fs = 0.8 ± 0.1 Jcm−2 (σGSA = 1.7 ± 0.2 × 10−19 cm2) and a recovery time of 890 ± 10 ns. Passive Q-switching of an Er,Yb:glass laser is realized with the synthesized GCs. This laser generated 0.37 mJ/100 ns pulses at 1.54 μm. The developed GCs are promising as saturable absorbers for 1.6–1.7 μm crystalline erbium lasers

ПРИБОР ДЛЯ ИЗМЕРЕНИЯ ВРЕМЕНИ РЕЛАКСАЦИИ ПРОСВЕТЛЕННОГО СОСТОЯНИЯ ОПТИЧЕСКИХ МАТЕРИАЛОВ МЕТОДОМ «ВОЗБУЖДЕНИЕ-ЗОНДИРОВАНИЕ» В СУБМИКРОСЕКУНДНОМ ДИАПАЗОНЕ

The use of passive shutters to control the duration of the light pulses is an important aspect in the miniature and microchip lasers. One of the key spectroscopic characteristics which determine the properties of the material, which can be used as a passive shutter is relaxation time of its bleached state.We describe a device for determination of relaxation time of the bleached state in optical materials by the «pump-probe» method in the sub-μs time domain. This device allows one to determine relaxation times for materials which absorb at the light wavelength of 1.5 μm, e.g., materials doped with cobalt ions Co2+. The results of test examinations of the device are described, and the relaxation time of the bleached state of Co2+ ions is measured for a novel material – transparent glass-ceramics with Co2+:Ga2 O3 nanophase – amounting to 190 ± 6 ns. Применение пассивных затворов для управления длительностью импульсов оптического излучения является актуальной задачей в миниатюрных и микрочип лазерах. Одной из ключевых спектроскопических характеристик, определяющих свойства материала, который может быть использован в качестве пассивного затвора, является время релаксации его просветленного состояния. В статье описан прибор для измерения времени релаксации просветленного состояния оптических материалов методом «возбуждение-зондирование» в субмикросекундном временном диапазоне. Представлены его структура и характеристики. Прибор позволяет измерять времена релаксации просветления у материалов, поглощающих на длине волны 1,5 мкм, т.е., в частности, у сред, легированных ионами кобальта Co2+. Приведены результаты тестовых испытаний прибора, а также измерено время релаксации просветленного состояния нового материала – ситалла с кристаллической фазой Co2+:Ga2 O3 – оно составило 190 ± 6 нс.

Новые виды и наиболее интересные находки для флоры Урала и прилегающих территорий

The article provides information about rare and newly described species for the flora of the Urals and adjacent territories, namely: Astragalus saphronovae Kulikov, Atraphaxis decipiens Jaub. et Spach., Carex amgunensis F. Schmidt, Galium densiflorum Ledeb., Jovibarba globifera (L.) J. Parn., Najas minor All., Potamogeton nodosus Poir., Pseudorchis albida (L.) Á. Löve et D. Löve, Salix myrsinites L., Veronica agrestis L. Essays include the information on the species ecology and short taxonomic notes. © 2021 Altai State University. All rights reserved.The work was supported by the state assignments: АААА-А19-119031290052-1 “Sosudistye rasteniia Evrazii: sistematika, flora, rastitelʹnye resursy” [“Vascular plants of Eurasia: systematics, flora, plant resources”], АААА-А18-118011990151-7 “Izucheniye, sokhraneniye i rasshireniye bioraznoobraziya rasteniy v prirode i pri introduktsii na Yuzh nom Urale i Priuralye” [“Study, conservation and expansion of plant biodiversity in nature and during introduction in the Southern Urals and the Cis- and Trans-Urals region”], AAAA-A17-117050400146-5 “Otsenka prostranstvennovremennoy izmenchivosti bioraznoobraziya i usloviy yego formirovaniya na Severe Zapadnoy Sibiri v svyazi s izmeneniyem klimata i osvoyeniyem neftegazovykh resursov” [“Assessment of the spatio-temporal variability of biodiversity and the conditions for its formation in the north of Western Siberia in connection with climate change and the development of oil and gas resources”], and by “Programmoy povysheniya konkurentosposobnosti Uralskogo federalnogo universiteta” [“The program for improving the competitiveness of the Ural Federal University”] (the decree no. 211 of the Government of the Russian Federation, contract no. 02.A03.21.0006)