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Количество страниц: 13 с.
In contemporary material’s science, the development of high-strength composite materials derived from polymers represents a significant strategic focus. A promising method to enhance the mechanical properties of these materials involves the incorporation of fibrous fillers as modifiers within the polymer matrix, which markedly improves loadbearing capacity. This research investigates the effects of basalt and carbon fibers on the mechanical and tribological characteristics, and on the structural formation processes in ultra-high molecular weight polyethylene (UHMWPE). The fibrous fillers were introduced into the polymer matrix without prior modification at concentrations of 5, 10, and 20 weight percent. Notably, composites containing 20 weight percent carbon fiber exhibited the most pronounced enhancement in elastic modulus, achieving an impressive increase of 66 %. Additionally, a significant reduction in the coefficient of friction was observed, with a decrease of 65 % relative to the unmodified polymer. Furthermore, the wear rate was found to decrease by 23 %. The addition of both carbon and basalt fibers into UHMWPE led to substantial improvements in tensile strength, with increases of 37 % and 28 %, respectively. Analysis of the friction surfaces of the composites through infrared spectroscopy indicated that neither type of fiber influenced the tribochemical processes during wear. The morphological examination of the friction surfaces suggested that carbon fiber possesses a comparative advantage over basalt, contributing to orientation effects and the formation of a wear-resistant layer. The materials developed in this study hold potential applications in the production of antifriction components, particularly for highly loaded sliding bearing elements in bridge structures.
Разработка композиционных материалов на основе СВМПЭ и углеродного и базальтового волокон / С. Н. Данилова, А. А. Охлопкова, А. В. Оконешникова ; Северо-Восточный федеральный университет им. М. К. Аммосова // Природные ресурсы Арктики и Субарктики. - 2024. - N 4, Т. 29. - C. 661-674. - DOI: 10.31242/2618-9712-2024-29-4-661-674
DOI: 10.31242/2618-9712-2024-29-4-661-674
Количество страниц: 10 с.
- Математика. Естественные науки > Физика,
- Прикладные науки. Медицина. Ветеринария. Техника. Сельское хозяйство > Строительство. Строительные материалы. Строительно-монтажные работы,
- НАУКА ЯКУТИИ > ПРИКЛАДНЫЕ НАУКИ. МЕДИЦИНА. ТЕХНИКА. СЕЛЬСКОЕ ХОЗЯЙСТВО > Строительство. Строительные материалы. Строительно-монтажные работы,
- НАУКА ЯКУТИИ > МАТЕМАТИКА. ЕСТЕСТВЕННЫЕ НАУКИ > Физика.
The present study outlines the synthesis of carbon that include graphene flakes. The production process employed rapid Joule heating of a mixture consisting of finely dispersed polypropylene powder and carbon black in a 1:1 ratio. An experimental model of the installation was developed and constructed, based on a capacitor bank with a total capacitance of 32 mF and an inductor with a nominal value of 24 mH for production purposes. A solution was prepared that included a colloidal dispersion of epoxy resins, an amine hardener in a mixture of deionized water and ethyl alcohol in a ratio of 4:0.6:10, along with 1 wt. % of the resulting carbon powder and carbon black, to be used as an impregnating compound for glass fibers. The estimated synthesis temperature reached up to 2200 °C, with a duration of approximately 32 ms. Studies of Raman spectra and optical density in the UV range indicate that the synthesized carbon powders contain graphene flakes with lateral dimensions of up to 13 nm. The results of elemental analysis reveal a significant increase in the carbon atom content in the impregnated fiber compared to the original glass fiber. Electrical measurements of the temperature dependence of the current-voltage (C-V) characteristics demonstrated the presence of electrical conductivity at low temperatures, corresponding to a resistance of up to 8 MΩ/sq. In the future, electrical conductivity may be enhanced by increasing the discharge power. The developed configuration for fast Joule heating has the potential to be integrated into the field of efficient recycling of plastic waste. The resulting carbon powders can serve as modifying additives for glass fiber used in the production of fiberglass concretes.
Получение быстрым джоулевым нагревом углеродных графенсодержащих порошков и их применение в качестве модификаторов для стекловолокна / А. Р. Прокопьев, Е. Д. Васильева, Н. Н. Лоскин, Д. Н. Попов ; Академия наук Республики Саха (Якутия), Северо-Восточный федеральный университет им. М. К. Аммосова // Природные ресурсы Арктики и Субарктики. - 2024.- N 4, Т. 29. - C. 651-660. - DOI: 10.31242/2618-9712-2024-29-4-651-660
DOI: 10.31242/2618-9712-2024-29-4-651-660
Издательство: Якутский край
Год выпуска: 2001
Количество страниц: 100 с.
Количество страниц: 12 с.
The catastrophic wildfires that occurred in Central Yakutia in 2021 resulted in extensive forest destruction, leading to the complete incineration of significant forested areas. This devastation has caused the loss of tree stands and the degradation of forest litter, as well as the upper organic layers of the soil. Consequently, there has been a substantial alteration in the water-temperature regime of permafrost soils, which are formed under permafrost conditions. The objective of this study is to investigate the impact of these fires on the morphological, physical, and chemical characteristics of pale soils during the initial years following the fire event, specifically after the destruction of the tree stand and the combustion of the litter and organic soil layers. This research primarily focuses on pale, slightly solodized soils located within the larch forests of the Lena-Vilyui watershed. This research presents comprehensive insights into vegetation and the morphogenetic characteristics of soil profiles, alongside the parameterization of various soil properties, including field moisture, humus content, loss on ignition, , reactions of the soil environment, exchangeable base quantities, and granulometric composition. The findings indicate that the deposition of combustion byproducts, specifically in the form of ash, results in soil alkalization, which is associated with a marked decrease in organic carbon levels within the surface strata. Notably, the morphological characteristics of soils in the control area exhibit significant differences compared to those in the burned region; a thin pyrogenic layer with minimal screening effects has developed in the burned region, soil mixing processes have become more pronounced, and the natural horizontal boundaries of soil horizons have been disrupted. The degradation of heat-insulating ground cover and organic matter contributes to substantial soil heating, leading to elevated soil mass temperatures and an extended seasonal thaw. The thawing of upper permafrost layers and the release of previously sequestered moisture result in soil saturation, which, upon winter freeze, triggers cryoturbation. In contrast, soils that have not experienced fire exhibit only a weak expression of permafrost mixing within the soil profile. Furthermore, the temporary waterlogging of poorly drained soils in the initial years post-fire exacerbates tree.
Влияние крупных лесных пожаров на мерзлотные палевые почвы Лено-Вилюйского водораздела / Р. В. Десяткин, А. З. Иванова, А. Р. Десяткин [и др.] ; Институт биологических проблем криолитозоны СО РАН, Институт мерзлотоведения им. П. И. Мельникова СО РАН // Природные ресурсы Арктики и Субарктики. - 2024. - N 4, Т. 29. - C. 562-573. - DOI: 10.31242/2618-9712-2024-29-4-562-573
DOI: 10.31242/2618-9712-2024-29-4-562-573
Количество страниц: 9 с.
The article shows the relevance of the theory and practice of deep coal processing. The increasing relevance is based on modern trends in the development of the global coal industry and forecasts regarding the decrease in demand for coal in the energy sector due to the introduction of alternative energy sources. The Russian Federation has the richest raw material base of coals, including lignite. Due to the low degree of metamorphism, lignite’s are unique in their properties and are very promising as a raw material for the production of sorbents for the treatment of industrial, municipal and industrial wastewater. The aim of the study is to develop a process flow chart for alkaline activation of lignite coals in the Far Eastern region to obtain high-quality sorbents for adsorption from the liquid phase. The laboratory study was conducted on lignite coals from four deposits in the Far Eastern region (Kharanorskoye, Kangalasskoye, Kirovskoye, Okino-Klyuchevskoye deposits). General scientific and empirical methods were used: analysis and generalization of scientific literature on the research problem, experiment, analysis, comparison and mathematical processing of the obtained experimental data. A study was conducted of various options for carrying out three stages of the process of obtaining sorbents (preparation of lignite coal for activation, alkaline activation and final processing). Analysis of the obtained data on the sorption properties of the obtained samples made it possible to determine the optimal parameters and sequence of operations in the process of alkaline activation of lignite coals. A process flow chart for alkaline activation of lignite coals with potassium hydroxide has been developed, consisting of 14 operations, including thermal leaching and mechanical activation. Carrying out the process of alkaline activation of lignite according to this technological scheme allows obtaining sorbents with high adsorption activity for iodine (more than 90 %). The results of the research allow us to speak about the technological feasibility, high efficiency and prospects of processing lignite coals from deposits in the Far Eastern into sorbents.
Ворсина, Е. В.
Технологическая схема щелочной активации бурых углей Дальневосточного региона / Е. В. Ворсина, Т. В. Москаленко, В. А. Михеев ; Институт горного дела Севера им. Н. В. Черского // Природные ресурсы Арктики и Субарктики. - 2024. - N 4, Т. 29. - C. 553-561. - DOI: 10.31242/2618-9712-2024-29-4-553-561
DOI: 10.31242/2618-9712-2024-29-4-553-561
Издательство: Книжное издательство
Год выпуска: 1965
Количество страниц: 156 с.
Издательство: Медицина
Год выпуска: 1966
Количество страниц: 198 с.
Издательство: [б. и.]
Год выпуска: 1971
Количество страниц: 164 с.
Издательство: Триада
Год выпуска: 2003
Количество страниц: 208 с.
В работе представлен анализ заболеваемости и смертности от злокачественных новообразований населения Республики Саха за 2000 г., а также тенденции частоты их в 1965-2000 гг. и прогноз до 2005 г. Впервые опубликованы результаты оценки влияния изменения факторов риска наприрост заболеваемости отдельными формами злокачественных опухолей, приведены показатели социально-экономического ущерба в связи со смертностью от отдельных форм раковой патологии.В самостоятельном разделе впервые представлен уровень смертности от разных причин и данаоценка их социально-экономическим последствиям
Издательство: Институт биологии
Год выпуска: 1977
Количество страниц: 180 с.