Модификация ускоренной термостабилизации полиакрилонитрильных волокон созданием градиента концентрации кислорода при получении углеродного волокна

Objectives. The work set out to modify the technology of accelerated thermal stabilization of polyacrylonitrile (PAN) fibers used in the production of high-strength carbon fibers by reducing the formation of a heterophase core–shell structure to create an oxygen concentration gradient in heat treatment furnaces while maintaining a total thermal stabilization time of 30 min. The optimized process conditions led to milder thermal stabilization conditions, reducing both the final heat treatment temperature and the temperature difference between the thermal stabilization zones while simultaneously maintaining the target volume density parameter with respect to the previously developed accelerated thermal stabilization technology.Methods. The thermal stabilization study of an industrially produced 12S precursor under different conditions on an experimental carbon fiber production line included measurement of bulk density, analysis of the thermal effects of the oxidation reaction by differential scanning calorimetry (DSC), and a study of micrographs of the resulting samples.Results. The optimum process of thermal stabilization of PAN fiber was determined in four stabilization zones using selected compositions. The formation of the core–shell structure is significantly reduced when the target volume density and DSC thermal oxidation reaction effect of the stabilized polymer fiber are achieved in a given time (30 min).Conclusions. The resulting technology regime is promising for the production of high strength (4.5 GPa, 4.9 GPa) PAN fibers at a reduced cost. While maintaining the total thermal stabilization time of PAN at the level of 30 min, which is three times less than the industrial processes used, it was possible to reduce the formation of a heterophase structure, as well as lowering the final processing temperature and reducing the temperature difference between the stabilization zones. This is promising in terms of a positive effect on the stability and safety of the industrial process, as well as ensuring the quality of the obtained products.Цели. Модифицировать технологию ускоренной термостабилизации полиакрилонитрильного (ПАН) волокна при производстве высокопрочных углеродных волокон, при помощи которой удастся уменьшить образование гетерофазной структуры «ядро–оболочка» путем создания градиента концентрации кислорода в печах термообработки при сохранении общего времени термостабилизации ПАН (30 мин); оптимизировать процесс на основании предлагаемого режима с целью получения более мягких условий термостабилизации: снижения конечной температуры термообработки и разницы температур между зонами термостабилизации при сохранении целевого параметра объемной плотности (относительно ранее разработанной технологии ускоренной термостабилизации).Методы. Термостабилизация промышленно выпускаемого прекурсора марки 12S в различных условиях на опытной линии получения углеродных волокон, последующее измерение объемной плотности, анализ тепловых эффектов реакции окисления методом дифференциальной сканирующей калориметрии (ДСК) и изучение микрофотографий шлифов получаемых образцов.Результаты. Определен оптимальный процесс термостабилизации ПАН волокна в 4 зонах стабилизации с использованием подобранных составов, при котором существенно снижается образование структуры «ядро–оболочка» при достижении целевой объемной плотности и теплового эффекта реакции окисления ДСК стабилизируемого полимерного волокна за установленное время (30 мин).Выводы. Полученный технологический режим является перспективным для получения высокопрочных (4.5 ГПа, 4.9 ГПа) ПАН волокон со сниженной себестоимостью. При сохранении общего времени термостабилизации ПАН на уровне 30 мин, что в 3 раза меньше используемых промышленных процессов, удалось снизить образование гетерофазной структуры, уменьшить конечную температуру обработки и снизить перепад температур между зонами стабилизации, что должно положительно сказаться на стабильности и безопасности ведения промышленного процесса и качестве получаемой продукции

Cognitive neural prosthetics – the way from experiment to clinical application

Accepted: September 3, 2021. Objective of this review is to highlight some aspects of the development and use of cognitive neuroprostheses, such as the technological background for their developing and key modern projects in this field. The literature sources were analyzed and the place of neuroprostheses among other artificial organs and tissues, which are under development or already used in clinical practice, was defined. The main principles of their implementation, structural elements and operating conditions were described. Also, this review presents some examples of diseases which can be corrected by cognitive neuroprostheses. The mechanisms of compensation for the functions of the damaged brain structures when using neuroprostheses are described on the basis of the principles of their interaction with biological neural networks. Descriptions of advanced developments that are currently relevant are given. Moreover, information is provided on the protocols and results of tests on animals and humans of the artificial hippocampus, as well as the results of testing a prosthesis that allows restoring the functions of the prefrontal cortex in animals. The examples considered in the review allow us to conclude that cognitive neuroprostheses are not just a hypothetic concept. They are implemented as specialized experimental solutions for practical clinical issues. Currently, the greatest success has been achieved in restoring the hippocampus functions

Development and use of GIS database for tasks of normative monetary evaluation of land of settlements

The paper presents the results of research on the development of a GIS database for the tasks of normative monetary valuation of lands of settlements and highlights the applied aspects of its use on the example of Lychanka village, Dmytriv territorial community, Bucha district, Kyiv region. An algorithm for developing a GIS database for normative monetary valuation of settlement lands is presented. The presented estimation algorithm allows to carry out with high accuracy normative monetary estimation of settlements, to carry out its automated updating on a certain date, to receive necessary information on request, to carry out analytical operations and construction of specialized estimation maps. The development of the GIS database involved the implementation of two stages. At the first stage of formation of the initial land assessment base, the attribute table included data from the Public Cadastral Map of Ukraine on land plots within the settlement by the following items: cadastral number of land plot, area, form of ownership, purpose and functional use of land plot , the number of the cadastral zone in which each land is located, the number of the land assessment area of the settlement, the value of the base value of land, the value of the zonal coefficient (Km2), the coefficient characterizing the functional purpose of the land (Kf), information on the location (street name). The second stage involved the calculation of the value of the normative monetary valuation of each of the 1279 land plots and was performed using the built-in Arc Map function "Calculation of numerical values". After the development of the GIS database, the testing stage of the developed land assessment database was performed, which involved the use of various query execution, geospatial analysis, the use of buffering functions, topological overlay (intersection). As a result of the analysis, the following maps were constructed: "Influence of local factors on the distance of land from the center of the settlement", "Influence of local factors on the distance of land from highways", "Influence of local factors on the environmental situation", "Influence of local factors on security electricity", "Influence of local factors on the distance from paved roads", "Influence of local factors on the provision  of centralized water supply", "Influence of local factors on the provision of centralized sewerage", "Influence of local factors on the provision of centralized gas supply", "Map plots according to the results of normative monetary assessment" , "Map of the establishment of buffer zones by the value of local coefficients" , "Map of coastal protection strips around water bodies with the allocation of zones of their intersection with land". Due to the application of special functions of geospatial analysis available in the GIS environment, examples of development of highly informative cartographic materials in the form of special pricing zoning of the territory of the settlement are shown. The expediency of the application of the GIS database for the tasks of monitoring the quality of land, compliance with their legal regime and the possibility of monitoring the implementation of fiscal obligations by landowners and users. Key words: normative monetary valuation, GIS database, geospatial analysis, buffering, land valuation zoning, maps

A forecast model for a road network’s section traffic capacity assessment on a territory of the cryolithozone in conditions of the climate change

A model is proposed in which the capacity of the road network section depends on the technical and operational condition of the road surface – the presence of sinkholes, potholes, ruts, as well as their predictive depth. Appearing of these defects on the road surface is associated with excessive thawing and permafrost soil settlement in the formation occurring under the influence of the climate change. The soil thawing depth is modelled on the basis of predictive climatic parameters during the full average year, and then the maximum thawing depth and the corresponding soil settlement is determined. Three main scenarios of the climate change are considered: temperature contrast increasing, uniform warming and their combination. The assumed value of warming or temperature contrast increasing is considered to be a random value distributed according to the normal law; the predicted decrease in the road section capacity is defined as a weighted average over the entire range of possible climate changes. According to the results of the numerical implementation of the model on the road network sections for natural and climatic conditions of Yakutia, it is shown that in the third scenario of the climate change the road network section capacity is predicted to decrease from 17% (the formation is dry sandy permafrost soil) to 50% (the formation is clay soil of high humidity). The impact of natural and climatic features of the territory is predicted to be at a level up to 10% of the total reduction in the capacity of road network sections

Antiatherogenic Potential of Transcranial Electrical Stimulation in a High-Fructose/High-Fat Diet: Experimental Randomized Trial

Background. Transcranial electrical stimulation is a promising method for correction of malnutrition-induced hyperlipidemia, in the absence of indications for drug hypolipidemic therapy in young and middle-aged patients with low and moderate cardiovascular risk. Objectives — to study the effect of transcranial electrical stimulation on lipid metabolism in a high-fructose/high-fat (HFHF) diet in rats.Methods. An experimental randomized trial was performed to study the effect of transcranial electrical stimulation on lipid metabolism in a high-calorie diet enriched with fructose and saturated animal fat in rats. The experiments involved 180 outbred male rats and were carried out on the basis of the vivarium of Kuban State Medical University. The animals were divided into three groups: group 1 (control group, n = 60) — followed a standard diet; group 2 (comparison group, n = 60) — followed a HFHF diet; group 3 (experimental group, n = 60) — underwent transcranial electrical stimulation against the background of a HFHF diet. According to the target reference point of the study, the groups were divided into three equal subgroups of 20 rats each: subgroup A — day 30, subgroup B — day 60, and subgroup C — day 90 (biomaterial sampling and euthanasia were carried out on those days). In the obtained blood samples, the following lipid metabolism parameters were evaluated: total cholesterol, triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and atherogenic index. Statistical analysis was performed using Microsoft Office Excel 2021 (Microsoft, USA), GraphPadPrism 9 (GraphPad Software, USA) and Statistica 13.3 (StatSoft, USA).Results. On the 30th day of the study, it was noted that in group 3, the concentration of low-density lipoprotein cholesterol was 14.9% lower and the atherogenic index was 30.8% lower (p < 0.05) than in group 2, while total cholesterol concentration, triglycerides, and high-density lipoprotein cholesterol had no statistically significant differences (p > 0.05). On the 60th day of the study, in group 3, when compared to group 2, the concentration of total cholesterol was 18.7% lower, low-density lipoprotein cholesterol was 42.9% lower, high-density lipoprotein cholesterol was 16.7% higher, and the atherogenic index was 56.3% lower (p < 0.05), while triglycerides had no statistically significant differences (p > 0.05). On the 90th day of the study, in group 3, when compared to group 2, the concentration of total cholesterol was 29.2% lower, the concentration of triglycerides was 36.0% lower, low-density lipoprotein cholesterol was 42.8% lower, and the atherogenic index was 57.0% lower (p < 0.05), while the concentration of high-density lipoprotein cholesterol had no statistically significant differences (p > 0.05).Conclusion. High-fructose/high-fat diet leads to a progressive increase in the serum concentration of low-density lipoprotein cholesterol, total cholesterol, triglycerides, as well as to a moderate decrease in high-density lipoprotein cholesterol and a growth in the atherogenic index. Transcranial electrical stimulation has a moderate lipid-lowering effect, manifested in the form of a decrease in the serum concentration of low-density lipoprotein cholesterol, total cholesterol and atherogenic index, while the effect on the concentration of triglycerides and high-density lipoprotein cholesterol is insignificant

Direct characterization of circulating DNA in blood plasma using μLAS technology

Circulating cell-free DNA (cfDNA) is a powerful cancer biomarker for establishing targeted therapies or monitoring patients' treatment. However, current cfDNA characterization is severely limited by its low concentration, requiring the extensive use of amplification techniques. Here we report that the μLAS technology allows us to quantitatively characterize the size distribution of purified cfDNA in a few minutes, even when its concentration is as low as 1 pg/μL. Moreover, we show that DNA profiles can be directly measured in blood plasma with a minimal conditioning process to speed up considerably speed up the cfDNA analytical chain

Программный подход к расчету цепей нуклеиновых кислот и белковой молекулы при биосинтезе белка

Трофименко Е. Г. Программный подход к расчету цепей нуклеиновых кислот и белковой молекулы при биосинтезе белка / Е. Г. Трофименко, В. А. Издебский // Моделирование в прикладных научных исследованиях : материалы ХVI семинара. – Одесса : ОНПУ, 2008. – С. 88-89

Программная реализация расчета нуклеотидных последовательностей при биосинтезе белка

Трофименко Е. Г. Программная реализация расчета нуклеотидных последовательностей при биосинтезе белка / Е. Г. Трофименко, В. А. Издебский // Моделирование в прикладных научных исследованиях : материалы ХVII семинара. – Одесса : ОНПУ, 2009. – С. 88-91

Управление процессами нагревания подвижными источниками тепла

Трофименко Е. Г. Управление процессами нагревания подвижными источниками тепла / Е. Г. Трофименко, В. А. Полиновский, В. В Симонов // Моделирование в прикладных научных исследованиях : материалы VIII семинара. – Одесса : ОГПУ, 2001. – С. 34-35

Організація “швидкого” виведення графіки засобами мови Тurbo Pascal 7.0.

Трофименко О. Г. Організація “швидкого” виведення графіки засобами мови Тurbo Pascal 7.0. / О. Г. Трофименко, В. В. Дубовой, В. А. Лалим // Вісник Черкаського технологічного університету. – Черкаси : ЧДТУ, 2002. – Вип. 2. – С. 42-45.У статті розглянуто особливості формування і виведення графічних зображень для різних відеорежимів. Запропоновано алгоритми, що дозволяють прискорити виведення графіки засобами Turbo Pascal 7.0.В статье рассмотрены особенности формирования и вывода графических изображений для различных видеорежимов. Предложены алгоритмы, позволяющие ускорить вывод графики средствами Turbo Pascal 7.0 .Investigation is given to the peculiarities of the formation and graphic images output for different videomodes. Algorithms are suggested allowing to speed up an output of the graphics by means of Turbo Pascal 7.0