Армирование грунтов основания вертикальными столбами из щебня в криолитозоне

Stabilization of permafrost soils of the roadbed base, constructed with assumption of thawing, thanks to improvement of their strength characteristics, requires development and selection of rational structural and technological solutions. The objective of the study was to analyze the effectiveness of use of vertical columns of crushed stone in the permafrost zone and their influence on strength characteristics of the soil base. The study has used general scientific methods, modeling, simulation and comparative analysis. This article proposes a method for improving strength properties of soil of the roadbed base within Obskaya–Salekhard section of the Northern Latitudinal Railway thanks to reinforcement of the roadbed base made with vertical columns of crushed stone, which increases stability of the structure. The proposed basic technological model of construction of the roadbed includes the following main stages: preparatory stage, 1 stage – arrangement of vertical columns of crushed stone and granular subbases, 2 stage – additional compaction with a vibratory roller in case of mismatch of stability of bearing capacity and precipitation of the base to operating standards. The studied object of the transport infrastructure was simulated both without the use of technology for reinforcing it with vertical columns of crushed stone and with its use. The stability coefficient was calculated, and the theoretical surface of embankment collapse was obtained using Midas GTS NX and Plaxis 2D software packages. The stability test of this structure was carried out both in a flat and in a threedimensional setting. The efficiency of using vertical columns of crushed stone to strengthen the embankments constructed on permafrost soils has been shown.Стабилизация многолетнемёрзлых грунтов основания земляного полотна, сооружаемого с допущением оттаивания, за счёт улучшения их прочностных характеристик требует разработки и выбора рациональных конструктивно-технологических решений. Целью исследования является анализ эффективности использования вертикальных столбов из щебня в криолитозоне и их влияния на прочностные характеристики грунтов основания. В исследовании использовались общенаучные методы, моделирование и сравнительный анализ. Предлагается метод улучшения прочностных свойств грунтов основания земляного полотна на участке Обская–Салехард Северного широтного хода за счёт армирования вертикальными столбами из щебня, что повышает устойчивость сооружения. Обосновывается принципиальная технологическая схема сооружения земляного полотна, которая включает в себя следующие основные этапы: подготовительный этап, 1 стадия – устройство вертикальных столбов из щебня и щебёночной подушки, 2 стадия – дополнительное уплотнение виброкатком в случае несоответствия устойчивости несущей способности и осадки основания нормам эксплуатации. Выполнено моделирование исследуемого объекта транспортной инфраструктуры как без использования технологии армирования вертикальными столбами из щебня, так и с её применением. Рассчитан коэффициент устойчивости иполучена теоретическая поверхность обрушения насыпи с использованием программных комплексов Midas GTS NX и Plaxis 2D. Проверка устойчивости данного сооружения велась как в плоской, так и в трёхмерной постановке. Показана эффективность использования вертикальных столбов из щебня для усиления насыпей, сооружаемых на многолетнемёрзлых грунтах

Monte Carlo simulation of signals in digital diaphanoscopy of the maxillary sinuses

Digital diaphanoscopy method has potential to separate normal and pathological conditions of the maxillary sinuses. The entirety of all the features of the investigated area (the presence or absence of pathology, its etiology and morphological features) affects the resulting images of the maxillary sinuses by the digital diaphanoscopy. In this work, the MonteCarlo numerical simulation method was used to determine the patterns of propagation of light radiation in biological tissue. A biologically heterogeneous environment, represented by structures of the skull and maxillary sinuses, as well as pathological changes in them was modelled in the TracePro software

Optical Diagnostics of the Maxillary Sinuses by Digital Diaphanoscopy Technology

The work is devoted to the development of a scientific and technical basis for instrument implementation of a digital diaphanoscopy technology for the diagnosis of maxillary sinus inflammatory diseases taking into account the anatomical features of patients (differences in skin structure, skull bone thickness, and sinus size), the optical properties of exercised tissues, and the age and gender characteristics of patients. The technology is based on visualization and analysis of scattering patterns of low-intensity radiation as it passes through the maxillary sinuses. The article presents the experimental data obtained using the digital diaphanoscopy method and the results of numerical simulation of the optical radiation passage through the study area. The experimental setup has been modernized through the installation of a a device for controlling the LED applicator brightness. The approach proposed may have considerable promise for creating diagnostic criteria for various pathological changes and can be used to assess the differences in the optical and anatomical features of males and females

System of Forest Insect Pheromone Communication: Stability of «Information» Molecules to Environmental Factors

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала.Features of external environmental factors (such as electromagnetic radiation in certain spectral bands) influencing pheromone molecules, which are carriers of information for forest insects in the search of the opposite sex, were examined. Stability of pheromone molecules for external influences has been studied for siberian moth Dendrolimus superans sibiricusTschetv., pine moth Dendrilimus piniL., gypsy moth Lymantria disparL., for xylophages Ips typographus L., Monochamus urussovi Fish. and Monochamus galloprovincialis Oliv. Properties of pheromone molecules were evaluated by calculations using quantum-chemical method B3LYP. Existing methods of quantum-chemical calculations are useful for analyzing the properties of quite small and uncomplicated molecules of forest insect pheromones. The calculations showed that the molecules of insect pheromones are able to absorb light in the ultraviolet range and move into an excited state. The values of dipole moments, the wavelengths of the absorption, atomic and molecular electronic properties of pheromones in the ground and excited states were calculated. The calculations showed that for the reaction of pheromones with oxygen an energy barrier is somewhat higher than for reactions of pheromones with water vapor. The worst reaction of pheromones with water molecules likely to pheromones such molecules whose dipole moment is comparable to the dipole moment of water. Quantum-chemical characteristics of the pheromone molecules can be linked to specific behavior of the insects

System of Forest Insect Pheromone Communication: Stability of «Information» Molecules to Environmental Factors

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала.Features of external environmental factors (such as electromagnetic radiation in certain spectral bands) influencing pheromone molecules, which are carriers of information for forest insects in the search of the opposite sex, were examined. Stability of pheromone molecules for external influences has been studied for siberian moth Dendrolimus superans sibiricusTschetv., pine moth Dendrilimus piniL., gypsy moth Lymantria disparL., for xylophages Ips typographus L., Monochamus urussovi Fish. and Monochamus galloprovincialis Oliv. Properties of pheromone molecules were evaluated by calculations using quantum-chemical method B3LYP. Existing methods of quantum-chemical calculations are useful for analyzing the properties of quite small and uncomplicated molecules of forest insect pheromones. The calculations showed that the molecules of insect pheromones are able to absorb light in the ultraviolet range and move into an excited state. The values of dipole moments, the wavelengths of the absorption, atomic and molecular electronic properties of pheromones in the ground and excited states were calculated. The calculations showed that for the reaction of pheromones with oxygen an energy barrier is somewhat higher than for reactions of pheromones with water vapor. The worst reaction of pheromones with water molecules likely to pheromones such molecules whose dipole moment is comparable to the dipole moment of water. Quantum-chemical characteristics of the pheromone molecules can be linked to specific behavior of the insects

Estimation of the thermal and photochemical stabilities of pheromones Estimation of the thermal and photochemical stabilities of pheromones

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала.The correlation between the kinetic stability of molecules against temperature and variations in their geometric structure under optical excitation is investigated by the example of different organic pheromone molecules sensitive to temperature or ultraviolet radiation using the density functional theory. The kinetic stability is determined by the previously developed method based on the calculation of the probability of extension of any structural bond by a value exceeding the limit value Lмах corresponding to the breaking of the bond under temperature excitation. The kinetic stability calculation only requires the eigenfrequencies and vibrational mode vectors in the molecule ground state to be calculated, without determining the transition states. The weakest bonds in molecules determined by the kinetic stability method are compared with the bond length variations in molecules in the excited state upon absorption of light by a molecule. Good agreement between the results obtained is demonstrated and the difference between them is discussed. The universality of formulations within both approaches used to estimate the stability of different pheromone molecules containing strained cycles and conjugated, double, and single bonds allows these approaches to be applied for studying other molecules

Action of the Atomic and Electronic Structure of Pheromone Molecules on the Effectiveness of Communication in Xylophagous Insects

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала.The B3LYР/6-31(p,d) density functional method is applied to pheromones of the forest xylophagous insects Ips typographus L., Monochamus urussovi Fisch., and Monochamus galloprovincialis Oliv. to calculate the absorption spectra and find excited states. The calculated results are used to assess the possible activity of the molecules when they are affected by solar radiation

The Stability of the Pheromones of Xylophagous Insects to Environmental Factors: An Evaluation by Quantum Chemical Analysis

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала.Abstract—The ground and excited states of the pheromone molecules produced by xylophagous insects (the bark beetle Ips typographus L., the black fir sawyer beetle Monochamus urussovi Fisch., and the black pine sawyer M. galloprovincialis Oliv.) were modeled using a quantum chemical method utilizing DFT (density functional theory) with the B3LYP functional. The absorption wavelengths (energies) and dipole moments were calculated; the transitions of electrons from occupied to empty molecular orbitals were considered. The computed data were used to assess the stability of pheromone molecules exposed to environmental factors, such as solar radiation and humidity

Action of the Atomic and Electronic Structure of Pheromone Molecules on the Effectiveness of Communication in Xylophagous Insects

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала.The B3LYР/6-31(p,d) density functional method is applied to pheromones of the forest xylophagous insects Ips typographus L., Monochamus urussovi Fisch., and Monochamus galloprovincialis Oliv. to calculate the absorption spectra and find excited states. The calculated results are used to assess the possible activity of the molecules when they are affected by solar radiation