The theory of reconstruction temperature field based on ultrasonic sensing dual-layer walls of reactors

Работа посвящена совершенствованию теоретической модели реструктуризации теплового профиля Т(x,t) в двухслойной пластине с односторонним доступом по данным измерений средней по толщине стенки х температуры (t) при тепловом воздействии на недоступную поверхность пластины. Модель предназначена для использования в методе ультразвукового неразрушающего контроля УЗНК температурных полей и обусловленных ими термических напряжений в корпусах ядерных реакторов ЯР типа ВВЭР в нестационарных тепловых условиях. Он реализуется путем регистрации при внешних тепловых воздействиях изменений в реальном времени t времени задержки УЗ сигнала τ(t) на выделенном участке стенки корпуса реактора, определении по данным УЗ измерений средней по толщине стенки х температуры (t)=f(τ,t), реструктуризации по установленному на основе теоретической модели алгоритму теплового профиля и расчета соответствующих Т(x,t) термических напряжений σ(x,t). В предыдущих работах с участием авторов основой для расчета теплового профиля по данным (t) использована модель одно- или двухслойной полубесконечной пластины, а также однослойной пластины конечной толщины. При этом модель, несмотря на хорошую согласованность с экспериментом при малых временах УЗНК и вблизи приконтактной с теплоносителем зоны, не учитывает изменений температуры на поверхности конструкции, что ограничивает временные рамки УЗ мониторинга и увеличивает погрешность контроля. В данной работе получены выражения для теплового профиля Т(х,t) в двухслойной пластине конечной толщины, которая нагревается с одной поверхности. Выражения использованы для сравнительного анализа двух теоретических моделей при расчете теплового профиля по данным предыдущих комплексных УЗ и термометрических исследований массивных образцов из корпусной стали 15Х2МФА при импульсной тепловой нагрузке. Установлено, что теоретическая и экспериментальная временные зависимости температуры в сечении пластины (массивного образца) на фиксированном расстоянии от зоны контакта с источником нагрева х=const хорошо описываются полиномом третьей степени. Результаты реструктуризации Т(х,t) по алгоритму усовершенствованной модели для х=const хорошо согласуются с данными термометрических измерений.The paper is devoted to improvement of the theoretical model of restructuring thermal profile Т(x,t) in the two-layer plate with one-way access based on measurements of average temperature (t) by thickness wall x under the thermal action on inaccessible plate surface. The model is designed to be used it in the method of ultrasonic nondestructive testing (UNDT) of temperature fields and caused by them thermal stresses in reactor vessels of the WWER type at non-stationary thermal conditions. It is implemented by recording during the thermal actions of changes in real-time t delay signal τ(t) on a dedicated section of the reactor wall, determining of the average temperature by wall thickness (t)=f(τ,t) according to the ultrasound measurements data, restructuring thermal profile via algorithm based on the theoretical model and calculating corresponding to Т(x,t) thermal stresses σ(x,t). In previous researches, in which the authors were involved, the basis for calculating the thermal profile according (t) a one- or two-layer semi-infinite plate model and the one-layer plate of finite thickness were used. Despite of good consistency with experiment at small times UNDT and around near-contact with the coolant zone the model does not take into account the temperature changes on the construction surface, which limits the time frame of ultrasound monitoring and increases method error. In this paper expressions for the thermal profile Т(х,t) in two-layer plate of finite thickness, which is heated on one surface were obtained. The expressions were used for comparative analysis of two theoretical models for the calculation of the thermal profile according to the previous complex ultrasound and thermometric studies of bulk samples of the vessel steel 15Cr2MFA under pulsed thermal loading. It was found that the theoretical and experimental temperature time dependence in the cross section of plate (bulk sample) at a fixed distance from the contact with a heat source х=const is well described by the third degree polynomial. Restructuring results of Т(х,t) by the algorithm of improved model for х=const are in good agreement with the thermometric measurements data

ДЕНДРОФЛОРА БАЛКИ ШИРОКА (ОСТРІВ ХОРТИЦЯ)

Ravine forests are samples of intrazonal vegetation where numerous representatives of the fauna live, as well as plants of forest, steppe, meadow and other types of phytocoenosis, many of which are rare and endemic species. Сonsequently, the study of the taxonomic structure of their flora and the impact of recreational activities on the biodiversity of these natural forests is relevant. The route method based on the biogeocenotical principle for the defining of the species composition of the dendroflora represents the research technique. The research provides data on the species composition of the dendroflora of ravine Shyroka ravine, Khortytsya (recreational area of tourists and residents of Zaporizhzhia), where 54 species of woody plants belonging to 43 genera and 26 families grow. As a result, the study reviled that the Rosaceae Adans family is characterized by the highest species diversity. In the composition of the dendroflora of the birch forest, 48.1 % are native species, 51.9 % are introduced. The largest share of the introduced species belongs to the species of North American origin (11 species, or 39.3 % of the total number of alien species). Amorpha fruticosa, Robinia pseudoacacia, Morus alba and Celtis occidentalis represent the introductants. The main forest-forming aboriginal species of the plantation are Acer platanoides, Quercusrobur, Ulmusscabra, A. tataricum. The study demonstrates the pedigree composition of the overstorey and undergrowth on the territory of various morphological parts of the ravine. Ravine forest has a significant resource potential, including honey and vitamin plants. Species with high invasive capacity (Acer negundo, Amorpha fruticosa, Robinia pseudoacacia) and those recognized as invasive (Parthenocissus quinquifolia) occur in the plantation. Сonsequently, the directions for future research is a detailed study of the natural renewal of native and introduced tree species, which are part of the plantation of the ravine forest, as well as further monitoring of the distribution of invasive species on the territory of the ravine.Байрачні ліси Запорізької обл. відносять до байраків порожистої частини Дніпра. Вони мають важливе кліматичне та ґрунтозахисне значення, у них трапляються представники лісових, степових, лугових фітоценозів, часто – рідкісні й ендемічні види, а також місцева фауна. Такі заліснені балки характеризуються високою атракторною здатністю для рекреантів, діяльність яких призводить до трансформації рослинності байрачно-лісових фітоценозів. З огляду на це актуальною є інформація про стан їх дендрофлори для створення банку даних та оперативного моніторингу. Наведено дані про видовий склад дендрофлори балки Широка, розташованої на о. Хортиця (зона рекреаційної діяльності туристів та мешканців м. Запоріжжя), де зареєстровано 54 види деревних рослин, що належать до 43 родів і 26 родин. Встановлено, що найбільшим видовим насиченням характеризується родина Rosaceae Adans. У складі дендрофлори байрачного лісу аборигенні види становлять 48,1 %, інтродуковані – 51,9 %. Найбільша частка участі серед інтродукованих видів належить породам північноамериканського походження (11 видів, або 39,3 % від усієї кількості інтродуцентів). Інтродуценти представлені здебільшого Amorpha fruticosa, Robinia pseudoacacia, Morus alba та Celtis occidentalis. Основними лісотвірними аборигенними породами насадження є Acer platanoides, Quercus robur, Ulmus scabra, A. tataricum. З'ясовано породний склад верхніх ярусів деревостану та підліску, що зростають на території різних морфологічних частин балки. Байрачний ліс має значний ресурсний потенціал, включаючи медоносні та вітамінні рослини. У складі насадження виявлено види з високою інвазійною здатністю (Acer negundo, Amorpha fruticosa, Robinia pseudoacacia) та той, що визнано інвазійним у списках близьких до України територій (Parthenocіssus quinquifolia)

ATP-sensitive potassium transport in rat brain mitochondria is highly sensitive to mK(ATP) channels openers: a light scattering study

The aspects of ATP-sensitive K+ transport regulation by mitochondrial K+,ATP-sensitive (mKATP) channels openers are important for understanding the properties of these channels. The effect of KATP channels openers (KCOs) diazoxide and pinacidil on ATP-sensitive K+ transport in isolated brain mitochondria was studied in the absence and the presence of MgATP using light scattering technique. Without MgATP we observed high sensitivity of ATP-sensitive K+ transport to both drugs with full activation at ≤ 0.5 µM. ATP-sensitive K+ transport was specifically blocked by ATP in the presence of Mg2+. Neither Mg2+ nor ATP affected Vmax of ATP-sensitive K+ transport activated by KCOs, but MgATP shifted the activation curve to micromolar scale. The blockage of ATP-sensitive K+ transport by KATP channels blockers glibenclamide and 5-hydroxydecanoate in the absence and the presence of MgATP proved the sensitivity of ATP-sensitive K+ transport to the blockers of mKATP channel. Full activation of mKATP channel by diazoxide and pinacidil on sub-micromolar scale in the absence of MgATP was shown. The sensitivity of ATP-sensitive K+ transport to the known modulators of mKATP channel (diazoxide, pinacidil, glibenclamide, 5-HD and MgATP) proved the identity of ATP-sensitive K+ transport with mKATP channel activity. Based on our studies, we hypothesized that mKATP channel might comprise high affinity sites for KCOs binding screened by MgATP. The results of this work reveal novel not described earlier aspects of the regulation of ATP-sensitive K+ transport by mKATP channels openers, important for understanding of mKATP channel properties

A Europe-wide inventory of citizen-led energy action with data from 29 countries and over 10000 initiatives

Numerous case studies show that citizens engage in various ways in renewable and low carbon energy projects, thereby contributing to the sustainable energy transition. To date, however, a systematic and cross-country database on citizen-led initiatives and projects is lacking. By performing a major compilation and reviewing copious data sources from websites to official registries, we provide a Europe-wide inventory with over 10,000 initiatives and 16,000 production units in 29 countries, focusing on the past 20 years. Our data allow cross-country statistical analysis, supporting the elicitation of empirical insights capable of extending beyond the perspective of single case studies. Our data also align with ongoing efforts to implement two EU Directives that aim at strengthening the active role of citizens in the energy transition. While the focus of our data collection is on Europe, the data and methodology can contribute to the global analysis of citizen-led energy action

Dynamics of non-structural carbohydrates in Pinus pallasiana D. Don needles under different forest growth conditions of ravine anti-erosion plantations

The research was aimed at analysing the peculiarities of non-structural carbohydrate metabolism in the needles of Pinus pallasiana D. Don in anti-erosion plantations on the slope and in the thalweg of the Viyskovyi ravine under different forest growth conditions. The ravine is located in the Dnipropetrovsk region and belongs to the southern geographical variant of ravine forests. The studied plants grew at three experimental sites of man-made plantation: in the thalweg (forest growth conditions – mesophilic, fresh, CL2), in the middle part of the slope of the southern exposure (mesoxerophilic, somewhat dry, or semi-arid, CL1) and on the upper part of this slope (xerophilic, arid, CL0–1). Changes in glucose, fructose, reducing sugars, sucrose and starch during the period from May to October were studied. The concentration of osmotically active substances (glucose, sucrose) increases in the months with the most unfavourable hydrothermal parameters, especially in plants of mesoxerophilic and xerophilic forest growth conditions. The dynamics of fructose content revealed two maxima (July and October), when the concentration of glucose tends to increase steadily, with the highest values found in October. During the study period, the level of fructose in the needles under the arid conditions of the upper and middle parts of the slope was much lower than under the fresh conditions of the thalweg. The dynamics curve of the starch content tends to decrease from the maximum values in May to the first minimum in August. It is followed by some increase in the concentration of this polysaccharide that does not reach the previous values. The second minimum is registered in October. Such changes in the level of starch in the needles of plants are observed under all forest growth conditions. The decrease in polysaccharide content is consistent with the increase in glucose and sucrose, especially in August. A more significant increase in the concentration of soluble osmoprotective sugars (glucose, sucrose) in P. pallasiana needles under unfavourable hydrothermal conditions compared to normal moisture conditions indicates the ability of plants to adapt to mesoxerophilic and xerophilic conditions

Estimation of ATP-dependent K(+)-channel contribution to potential-dependent potassium uptake in the rat brain mitochondria

The effect of potassium on state 4 respiration (substrate oxidation in the absence of ADP) was investigated. It was shown that potential-dependent potassium uptake in the brain mitochondria results in mitochondrial depolarization. Taking into account depolarization effect of potassium, the contribution of the endo­genous proton leak as well as K+-uptake to the re­spiration rate was calculated. It was shown that such estimation allows the share of ATP-dependent potassium channel contribution to potential-dependent potassium uptake to be determined by polarographic method

Tryptophan Prevents the Development of Non-Alcoholic Fatty Liver Disease

Roman Yanko,1,* Mikhail Levashov,1,* Olena Georgievna Chaka,1 Valentina Nosar,1 Sergey G Khasabov,2 Iryna Khasabova2,* 1Department of Clinical Physiology of Connective Tissue, Bogomoletz Institute of Physiology National Academy of Sciences of Ukraine, Kiev, Ukraine; 2Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN, USA*These authors contributed equally to this workCorrespondence: Roman Yanko, Department of Clinical Physiology of Connective Tissue, Bogomoletz Institute of Physiology National Academy of Sciences of Ukraine, Bogomoletz Street 4, Kiev, 01024, Ukraine, Tel +380442562477, Email [email protected]: The main aim of this research is to study the protective effects of tryptophan on the histomorphological and biochemical abnormalities in the liver caused by a high-calorie diet (HCD), as well as its ability to normalize mitochondrial functions in order to prevent the development of non-alcoholic fatty liver disease (NAFLD).Methods: The study was conducted in male Wistar rats aged 3 months at the start of the experiment. Control animals (group I) were fed a standard diet. Group II experimental animals were fed a diet with an excess of fat (45%) and carbohydrates (31%) for 12 weeks. Group III experimental animals also received L-tryptophan at a dose of 80 mg/kg body weight in addition to the HCD. The presence of NAFLD, functional activity, physiological regeneration, and the state of the liver parenchyma and connective tissue were assessed using physiological, morphological, histo-morphometric, biochemical, and biophysical research methods.Results: HCD induced the development of NAFLD, which is characterized by an increase in liver weight, hypertrophy of hepatocytes and an increase in the concentration of lipids, cholesterol and triglycerides in liver tissue. Increased alanine aminotransferase activity in the liver of obese rats also confirm hepatocytes damage. Tryptophan added to the diet lowered the severity of NAFLD by reducing fat accumulation and violations of bioelectric properties, and prevented a decrease in mitochondrial ATP synthesis.Conclusion: The addition of tryptophan can have a potential positive effect on the liver, reducing the severity of structural, biochemical, mitochondrial and bioelectric damage caused by HCD.Keywords: fatty liver disease, essential amino acids, obesit

The effect of ATP-dependent K(+)-channel opener on transmembrane potassium exchange and reactive oxygen species production upon the opening of mitochondrial pore

The effect of mitochondrial ATP-dependent K+-channel (K+ATP-channel) opener diazoxide (DZ) on transmembrane potassium exchange and reactive oxygen species (ROS) formation under the opening of mitochondrial permeability transition pore (MPTP) was studied in rat liver mitochondria. The activation of K+-cycling (K+-uptake and K+/H+-exchange) by DZ was established with peak effect at ≤500 nM. It was shown that MPTP opening as well resulted in the activation of K+-cycling together with simultaneous activation of Ca2+-cycle in mitochondria. In the absence of depolarization Ca2+-cycle is supported by MPTP and Ca2+-uniporter. The stimulation of K+/H+-exchange by MPTP opening led to the activation of K+-cycle, but further activation of K+/H+-exchange resulted in MPTP inhibition. Under the same conditions the decrease in mitochondrial ROS production was observed. It was proposed that the decrease in ROS formation together with K+/Н+-exchange activation could be the constituents of the complex effect of MPTP inhibition induced by K+ATP-channel opener

The effect of ATP-dependent K(+)-channel opener on the functional state and the opening of cyclosporine-sensitive pore in rat liver mitochondria

The effect of mitochondrial ATP-dependent K+-channel (K+АТР-channel) opener diazoxide (DZ) on the oxygen consumption, functional state and the opening of cyclosporine-sensitive pore in the rat liver mitochondria has been studied. It has been established that K+АТР-channel activation results in the increase of the oxygen consumption rate (V4S) and the uncoupling due to the acceleration of K+-cycling, the decrease in state 3 respiration rate (V3) and the respiratory control ratio (RCR). Under K+АТР-channel activation an inhibition of oxidative phosphorylation takes place which reduces the rate of ATP synthesis and hydrolysis as well as ATP production and consequently results in the seeming increase of P/O ratio. It has been shown that the increase in ATP-dependent K+-uptake accompanied by the opening of mitochondrial permeability transition pore (MPTP) leads to dramatic uncoupling of the respiratory chain due to simultaneous activation of K+– and Ca2+-cycling supported by MPTP and Ca2+-uniporter as well as K+-channels and K+/H+-exchange. K+АТР-channel activation leads to the partial inhibition of MPTP, but insufficient for the restoration of mitochondrial functions. Elimination of Ca2+-cycling after MPTP opening is necessary to return mitochondrial functions back to the control level which shows that MPTP could serve as the mechanism of reversible modulation of bioenergetic effects of K+АТР-channel activation

The effect of potential-dependent potassium uptake on membrane potential in rat brain mitochondria

The effect of potential-dependent potassium uptake on the transmembrane potential difference (ΔΨm) in rat brain mitochondria has been studied­. It was shown that in potassium concentration range of 0-120 mM the potential-dependent K+-uptake into matrix leads to the increase in respiration rate and mitochondrial depolarization. ATP-dependent potassium channel (K+ATP-channel) blockers, gliben­clamide and 5-hydroxydecanoate, block ~35% of potential-dependent potassium uptake in the brain mitochondria. It was shown that K+ATP-channel blockage results in membrane repolarization by ~20% of control, which is consistent with experimental dependence of ΔΨm on the rate of potential-dependent potassium uptake. Obtained experimental data give the evidence that functional activity of K+ATP-channel is physiologically important in the regulation of membrane potential and energy-dependent processes in brain mitochondria