ON CALCULATION OF OXYGEN BALANCE OF MULTICOMPONENT THERMOBARIC EXPLOSIVE SUBSTANCE

Most modern military confrontations take place near or directly in inhabited area. The use in such conditions of munition (warheads) which hit typical targets based on fragmentation (high-explosive) or cumulative action is impractical due to insufficient “selectivity” of hitting targets with such munition. At present, modern world tendency is the development of the latest munition (warheads) with increased properties of “destruction selectivity”. One of the directions is the development of munition based on thermobaric explosives. Such munitions can cause maximum damage due to high temperature and the impact of a shock wave with a low level of collateral damage, since thermobaric munition, especially in the open area, have a clearly defined or even limited area of effective damage, which determines the significance of their further development. Since modern thermobaric explosives include a large number of chemical elements (including chemically active metals), there is a need to calculate the physical balance of oxygen and oxygen coefficient to take into account the physical characteristics of modern multicomponent thermobaric explosives. The oxygen balance of multicomponent thermobaric explosives largely determines the nature of the reaction of its explosive transformation, i.e the composition of the explosive products and, consequently, the value of thermodynamic characteristics such as heat, temperature, volume and pressure of gas-like explosive products. The calculated ratio and coefficients for complex multicomponent thermobaric explosives should be calculated during the development of explosives, taking into account the composition of components and elements and their possible chemical reactions during the explosion. The abovementioned improved calculations of oxygen balance and oxygen coefficient of thermobaric explosives, which include aluminum, allows taking into account the physical characteristics of destruction of typical targets by thermobaric munitions.

Cooperative excitations in superionic PbF 2

Links between dynamical Frenkel defects and collective diffusion of fluorides in β -PbF 2 are explored using Born–Oppenheimer molecular dynamics. The calculated self-diffusion coefficient and ionic conductivity are 3.2 × 10 −5 cm 2 s −1 and 2.4 Ω −1 cm −1 at 1000 K in excellent agreement with pulsed field gradient and conductivity measurements. The calculated ratio of the tracer-diffusion coefficient and the conductivity-diffusion coefficient (the Haven ratio) is slightly less than unity (about 0.85), which in previous work has been interpreted as providing evidence against collective ‘multi-ion’ diffusion. By contrast, our molecular dynamics simulations show that fluoride diffusion is highly collective. Analysis of different mechanisms shows a preference for direct collinear ‘kick-out’ chains where a fluoride enters an occupied tetrahedral hole/cavity and pushes the resident fluoride out of its cavity. Jumps into an occupied cavity leave behind a vacancy, thereby forming dynamic Frenkel defects which trigger a chain of migrating fluorides assisted by local relaxations of the lead ions to accommodate these chains. The calculated lifetime of the Frenkel defects and the collective chains is approximately 1 ps in good agreement with that found from neutron diffraction. This article is part of the Theo Murphy meeting issue ‘Understanding fast-ion conduction in solid electrolytes’.

Technology for Producing Fine Tungsten Carbide Powders

The article shows the advantage of electric arc synthesis and subsequent centrifugal spraying of tungsten carbide to obtain a high-quality highly dispersed powder. A tungsten electrode (anode) is fed to the surface of a rotating graphite electrode (cathode) until an electric arc occurs between the electrodes, and the cathode is made in the form of a ring. The angular speed of rotation of the annular graphite electrode is set in accordance with the calculated ratio, which provides fine-dispersed centrifugal atomization of the molten product particles. To prevent intense evaporation of tungsten and the formation of an excessive amount of fine particles, the power of the electric arc for melting the anode is limited to a set value.As a result, the uniformity of the powder increases and the dispersion of the particles of the main fraction decreases.

Geometric Analysis of the Bilobed Flap for Nasal Reconstruction Surgery

Background: Reconstruction of the nose can be difficult due to its complex anatomical features. In 1989, Zitelli described a modified version of the bilobed flap design technique using 45° and 90° angles to improve nasal reconstructions. While the bilobed flap is still frequently referenced in scholarly literature, there seems to be inconsistency in preoperative flap design; these deviations can lead to suboptimal outcomes. The authors aim to illustrate the variability in bilobed flap execution and provide guidelines in preoperative design to improve consistency. Methods: A geometrically-based approach was used to characterize the inconsistency of bilobed repair technique. The pre-operative design images from fifteen scholarly articles were analyzed via a series of measurements and computations to quantify the angle of rotation and dimensions for the primary and secondary lobes. The “Error Quotient” was a calculated ratio that objectively measured the extent to which a bilobed design deviated from Zitelli’s specifications. Results: There was a noticeable variability in the design of both the primary and secondary lobes. Bilobed designs with smaller angles of rotation, particularly of the first lobe, were associated with higher Error Quotients and greater amounts of deviation from Zitelli’s design. Designs with the smallest Error Quotients had a primary lobe rotation that approached 45°. Conclusion: Consistency of application of the bilobed flap should be established to allow for optimal results, particularly with emphasis on design of the primary lobe. This can be accomplished by including a disposable protractor and marker in their sterile kit to measure a 45° rotation.

Ecological assessment of the lake ecosystem sustainability as exemplified by Lake Gorkoye (Chelyabinsk Region)

The article is devoted to the assessment of the ecological sustainability of Lake Gorkoye in the Chelyabinsk region (Russia). The condition of aquatic ecosystems in industrial regions is mainly determined by the impact on them of anthropogenic factors. The ecological assessment of Lake Gorkoye was carried out according to organoleptic and hydrochemical indicators. The conducted physical and chemical analysis of water in Lake Gorkoye allows stating that water pH characterizes water as slightly alkaline and alkaline, water saturation with dissolved oxygen is within the norm for water fishery use. The excess of the norms of ammonium cations and nitrite ions, with normal levels of phosphate and nitrate ions, suggests that water in Lake Gorkoye belongs to the dirty water class, which is confirmed by the calculated ratio of nitrite-ions and ammonium cations (1.00:9.69). The revealed COD/BOD ratio is equal to 2.09, indicating that the biological purification process cannot fully occur. Lake Gorkoye is in an unstable state directly caused by business activities in the surrounding area.

The Role of Significant Digits of Fractal Dimension for the Measurement of Texture in SAR Images

The present work deals with fractal-based texture measurement of synthetic aperture radar (SAR) images. Various land classes have been identified by classifying SAR images, and the fractal dimension is estimated for differentiating the classes. Three types of SAR images, viz., synthetic images, simulated SAR images, and satellite SAR images, have been used in the study. An issue with fractal dimension-based measurement is how many digits after decimal point should be considered for estimating fractal dimension? Since fractal dimension is calculated as a ratio, the major challenge is the decidability of significant digits for land classes. The issue has been overcome by discussing the feasibility of fractal dimension for the land classes defined by USGS and the calculated ratio for 200×200 values. As an achievement of the work, it is concluded that two digits of the decimal are sufficient to represent the fractal dimension of land classes.

Pellucid marginal degeneration versus keratoconus: distinction with wide-field SD-OCT corneal sublayer pachymetry

PurposeTo evaluate the capability of wide-field spectral-domain optical coherence tomography (SD-OCT) corneal sublayer pachymetry to distinguish between keratoconus and pellucid marginal degeneration (PMD).MethodsThis prospective cross-sectional study included 69 eyes (59 with keratoconus and 10 with PMD) of 69 patients. All patients were examined three subsequent times with the RTVue XR system. Pachymetry maps of the total cornea (CT), the epithelium (ET) and the stroma were generated using the onboard software. For analysis of reliability, the coefficients of variation and intraclass correlation coefficients (ICC) were calculated. Receiver operating characteristic analyses were performed to elaborate the most accurate pachymetric parameters for distinguishing between PMD and keratoconus.ResultsOverall repeatability of (sublayer) pachymetry was comparably good in both keratoconus (ICC ranging between 0.827 and 0.986) and PMD (ICC ranging between 0.753 and 0.998). Measurement reliability in keratoconic eyes was a negative function of Kmax (p<0.05). As compared with keratoconus, PMD exhibited higher CT (526±31 µm vs 503±30 µm; p=0.02) and ET (56±7 µm vs 51±5 µm; p=0.02) in the inferotemporal 2–5 mm sector as well as lower ET in the inferior 7–9 mm sector (52±5 µm vs 57±5 µm; p<0.01). The calculated ratio between CT in the inferotemporal 2–5 mm and in the inferior 7–9 mm sector yielded the highest diagnostic accuracy for distinguishing between PMD and keratoconus with an area under the curve of 0.977 and an optimal cut-off value of 0.90.ConclusionWide-field SD-OCT corneal sublayer pachymetry showed good reliability in PMD and keratoconus and may be useful to differentiate between the two ectatic diseases.

Hybridization of Russian Sturgeon (Acipenser gueldenstaedtii, Brandt and Ratzeberg, 1833) and American Paddlefish (Polyodon spathula, Walbaum 1792) and Evaluation of Their Progeny

Two species from the families Acipenseridae and Polyodontidae, Russian sturgeon (Acipenser gueldenstaedtii, Brandt and Ratzeberg, 1833; functional tetraploid) and American paddlefish (Polyodon spathula, Walbaum 1792, functional diploid) were hybridized. The hybridization was repeated using eggs from three sturgeon and sperm from four paddlefish individuals. Survival in all hybrid family groups ranged from 62% to 74% 30 days after hatching. This was the first successful hybridization between these two species and between members of the family Acipenseridae and Polyodontidae. Flow cytometry and chromosome analysis revealed two ploidy levels in hybrids. The chromosome numbers of the hybrids ranged between 156–184 and 300–310, in “functional” triploids and “functional” pentaploids, respectively. The hybrid origin and the ploidy levels were also confirmed by microsatellite analyses. In hybrids, the size and the number of dorsal and ventral scutes correlated with the ploidy levels as well as with the calculated ratio of the maternal and paternal chromosome sets. An extra haploid cell lineage was found in three hybrid individuals irrespective of the ploidy level, suggesting polyspermy. Although the growth performance showed high variance in hybrids (mean: 1.2 kg, SD: 0.55), many individuals reached a size of approximately 1 kg by the age of one year under intensive rearing conditions.

Computing devices of cloud-based control systems and their status monitoring

Проанализированы типовые устройства вычислительной техники для реализации облачных систем управления на основе оборудования центров обработки данных. Поставлена задача сформулировать виды контроля исследуемых устройств; найти расчетные соотношения для определения показателей, характеризующих виды контроля; а также определить средства технического мониторинга, контролирующие облачные системы управления. Проанализированы характеристики широко применяющегося в облачных системах управления сервиса резервного копирования и восстановления данных. Разработаны оценки для контроля параметров облачных систем управления. Typical computing devices for implementing cloud-based control systems based on data center equipment are analyzed. The task is to formulate the types of control of the studied devices; find the calculated ratio to determine indicators characterizing the types of control; and identify technical monitoring tools that control cloud-based management systems. The characteristics of the backup and data recovery service widely used in cloud management systems are analyzed. Estimates have been developed to control the parameters of cloud-based management systems.

LONG-TERM MEASUREMENTS OF EQUILIBRIUM EQUIVALENT RADON AND THORON PROGENY CONCENTRATIONS IN REPUBLIC OF SRPSKA DWELLINGS

The long–term measurements of radon and thoron equilibrium equivalent concentrations (EERC and EETC) were carried out the first time in Republic of Srpska in 25 schools of its capital Banja Luka and in its wider surroundings. After this successful survey, the measurements continued using the same type of the LR 115 nuclear track detectors, i.e., Direct Radon Progeny Sensors/Direct Thoron Progeny Sensors (DRPS/DTPS), and they were deployed in the 36 dwellings nearby the investigated schools. The detectors were exposed for one year period at 15–20 cm distance from the walls. The EERC and EETC were found to vary in the range from 6.3 to 14.4 Bq/m3and from 0.10 to 1.1 Bq/m3, with geometric mean 9.3 and 0.36, respectively. The same variance of EER and EET concentrations, measured in living and bedrooms of buildings built with different construction materials as well at different floors have been obtained. The insignificant correlations between EERC and EETC, show that these concentrations appeared to be independent in investigated dwellings. The calculated ratio of EETC to EERC ranged from 0.01 to 0.16 with the geometric mean of 0.04. The aim of this study is to give possible scientific contribution considering the explanation of EERC and EETC behavior in an indoor environment.