scholarly journals RESEARCH THERMAL CHARACTERISTICS OF THE PROCESS OF PYROLYSIS OF METHANE IN THE ELECTROTHERMAL FLUIDISED BED

2018 ◽  
Vol 40 (4) ◽  
pp. 83-90
Author(s):  
K.V. Simeiko
Keyword(s):  
Fluidized Bed ◽  
Experimental Studies ◽  
Thermal Characteristics ◽  
Chemical Properties ◽  
Electric Heating ◽  
Dielectric Materials ◽  
Gas Analysis ◽  
Fluidised Bed ◽  
Different Types ◽  
Methane Pyrolysis

The main products of high-temperature pyrolysis of methane are carbon and hydrogen. Due to their unique physical and chemical properties, pyrocarbon and pyrographite can be used in various industries and energy. Hydrogen is an energy-efficient and environmentally friendly energy carrier. Despite the large number of research works on methane pyrolysis, carrying out of this process in the electrothermal fluidized bed (ETFB) is not studied enough. The purpose of the study is to determine the thermophysical characteristics of the process of methane pyrolysis (the main products of the reaction are hydrogen and pyrocarbon) in reactors with different types of ETFB. The temperature of the complete disposition of methane to carbon and hydrogen is 800 K. This value is based on the thermodynamic calculations. A laboratory and a pilot plant with a different type of ETFB have been created for this process. Experimental studies of the process of methane pyrolysis had been carried out on these plants and experimental data were compared with the calculations. The method which allows to determine the amount of precipitated carbon has been developed. It is based on the gas analysis data. Nusselt's criterion for different types of reactors with ETFB has been calculated. It was showed that electrothermal heating of a fluidized bed of conductive particles is much more efficient than the external electric heating of a fluidized bed. This result is based on previous researches. It is explained by the direct influence of the plasma of microcircuits and by advantages of heat generation directly in the middle of the fluidized bed. Taking into account the obtained results and the specifics of the application of the pyrocarbon coating on dielectric materials, a scheme of a reactor with ETFB, which allows to use both external heating and classical ETFB at the same time, has been developed.

METHODS FOR SIMULATION OF ACUTE BRAIN ISCHEMIA: PATHOPHYSIOLOGICAL SUBSTANTIATION OF SELECTION AND IMPORTANCE FOR CLINICAL PRACTICE

2019 ◽  
pp. 142-152
Author(s):  
Б.И. Гельцер ◽  
Э.В. Слабенко ◽  
Ю.В. Заяц ◽  
В.Н. Котельников
Keyword(s):  
Clinical Practice ◽  
Experimental Studies ◽  
Cerebrovascular Diseases ◽  
Experimental Models ◽  
Pathological Process ◽  
Ischemic Brain ◽  
Actual Clinical Practice ◽  
Acute Cerebral Ischemia ◽  
Different Types ◽  
Acute Brain Ischemia

Одним из основных требований к разработке экспериментальных моделей цереброваскулярных заболеваний является их максимальная приближенность к реальной клинической практике. В работе систематизированы данные по основным методам моделирования острой ишемии головного мозга (ОИГМ), представлена их классификация, анализируются данные о преимуществах и недостатках той или иной модели. Обсуждаются результаты экспериментальных исследований по изучению патогенеза ОИГМ с использованием различных моделей (полной и неполной глобальной, локальной и мультифокальной ишемии) и способов их реализации (перевязка артерий, клипирование, коагуляция, эмболизация и др.). Особое внимание уделяется «стабильности» последствий острого нарушения мозгового кровообращения: необратимых ишемических повреждений головного мозга или обратимых с реперфузией заданной продолжительности. Отмечается, что важное значение в этих исследованиях должно принадлежать современным методам прижизненной визуализации очагов острого ишемического повреждения, что позволяет оценивать динамику патологического процесса. Предлагаемый метод отвечает требованиям гуманного обращения с животными. Подчеркивается, что выбор релевантной модели ОИГМ определяется задачами предстоящего исследования и технологическими ресурсами научной лаборатории. Development of experimental models for acute forms of cerebrovascular diseases is essential for implementation of methods for their prevention and treatment. One of the principal requirements to such models is their maximum approximation to actual clinical practice. This review systematized major models of acute cerebral ischemia (ACI), their classification, and presented information about their advantages and shortcomings. Also, the review presented results of experimental studies on pathophysiological mechanisms of different types of modeled ACI (complete and incomplete global, local, and multifocal ischemia) and methods for creating these models (arterial ligation, clipping, coagulation, embolization, etc.). Particular attention was paid to “stability” of the consequences of acutely impaired cerebral circulation - an irreversible ischemic brain injury or a reversible injury with reperfusion of a given duration. The authors emphasized that in such studies, a special significance should be given to intravital imaging of acute ischemic damage foci using modern methods, which allow assessing the dynamics of the pathological process and meet the requirements to humane treatment of animals. The choice of a relevant ACI model is determined by objectives of the planned study and the technological resources available at the research laboratory.

scholarly journals Melatonin in Cancer Treatment: Current Knowledge and Future Opportunities

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2506
Author(s):  
Wamidh H. Talib ◽  
Ahmad Riyad Alsayed ◽  
Alaa Abuawad ◽  
Safa Daoud ◽  
Asma Ismail Mahmod
Keyword(s):  
Clinical Trials ◽  
Current Knowledge ◽  
Biological Activities ◽  
Experimental Studies ◽  
Therapeutic Effects ◽  
Cell Proliferation Inhibition ◽  
Different Types ◽  
Solid Foundation

Melatonin is a pleotropic molecule with numerous biological activities. Epidemiological and experimental studies have documented that melatonin could inhibit different types of cancer in vitro and in vivo. Results showed the involvement of melatonin in different anticancer mechanisms including apoptosis induction, cell proliferation inhibition, reduction in tumor growth and metastases, reduction in the side effects associated with chemotherapy and radiotherapy, decreasing drug resistance in cancer therapy, and augmentation of the therapeutic effects of conventional anticancer therapies. Clinical trials revealed that melatonin is an effective adjuvant drug to all conventional therapies. This review summarized melatonin biosynthesis, availability from natural sources, metabolism, bioavailability, anticancer mechanisms of melatonin, its use in clinical trials, and pharmaceutical formulation. Studies discussed in this review will provide a solid foundation for researchers and physicians to design and develop new therapies to treat and prevent cancer using melatonin.

scholarly journals Effects of Concrete Core Technological Defects on the Strength of Tube Confined Concrete Elements

2018 ◽  
Vol 7 (3.2) ◽  
pp. 376
Author(s):  
Oleksandr Semko ◽  
Olga Gukasian ◽  
Serhii Skliarenko
Keyword(s):  
Concrete Strength ◽  
Experimental Studies ◽  
Fracture Pattern ◽  
Confined Concrete ◽  
Concrete Core ◽  
Different Types ◽  
Technological Defects ◽  
Concrete Elements ◽  
Core Production ◽  
Physical And Mechanical Characteristics

The paper sums up a series of experimental studies describing the influence of most types of concreting common defects, such as core weakening: weak compression inclusions, voids, height heterogeneity of concrete. The basis of the experimental study is the research on the concrete core production conditions influence on tube confined concrete elements and the change in physical and mechanical characteristics of the elements. The concrete strength is estimated based on the results of the study of specially shaped samples with given dimensions. According to the results of concreting samples with different types of modeled defects (abnormalities) inspection, the most dangerous damages of the concrete core were identified and different variants of the height strength retrogression of the elements under study were analyzed. As a result, the degree and type of damage to the tube confined concrete elements core of the samples, which affect the fracture pattern, was established. 

scholarly journals Experimental study on production and emission characteristics of PM2.5 from industrial fluidized bed boilers

2020 ◽  
Vol 24 (5 Part A) ◽  
pp. 2665-2675
Author(s):  
Songsong Zhang ◽  
Qian Du ◽  
Guoli Qi
Keyword(s):  
Fluidized Bed ◽  
Removal Efficiency ◽  
Mass Concentration ◽  
Great Influence ◽  
Chemical Properties ◽  
Dust Removal ◽  
Dust Collector ◽  
Bag Filter ◽  
Physical And Chemical ◽  
Fluidized Bed Boilers

Particle size distributions, concentrations, morphological characteristics, and elemental compositions of eight fluidized bed boilers with different capacities and different dust collectors were determined experimentally. The PM2.5 particle concentration and mass concentration were monitored in real-time before and after the boiler dust collector by electric low pressure impactor, and the physical and chemical properties of PM2.5 were analyzed by membrane sampling. We found that the PM2.5 particle concentration produced by industrial fluidized bed boilers displayed bimodal distributions, peaking at 0.2 ?m and 0.76 ?m, the formed mechanism of these two parts particles is vaporization-condensation of mineral matter and residual ash particles and the adsorbent wear or tear. Mass concentration exhibits a single peak characteristic with a peak at 0.12 ?m. The removal efficiency for PM2.5 of dust collectors varies with different dust removal mechanisms. The electrostatic precipitator and bag filter have high dust removal efficiency, and the water film dust collector has low dust removal efficiency. The normal operation of the bag filter has a great influence on the dust removal efficiency. The physical and chemical properties of PM2.5 showed that the single-particle morphology was mainly composed of irregular particles, containing a small amount of solid spherical particles and more agglomerates. The content of Si and Al in PM2.5 elemental analysis is the highest, which decreases after a dust collector. Some fluidized bed boilers use desulfurization in the furnace, which has great influence on the mass concentration of Ca and S elements, and the lowest Hg content in trace elements, about a few ppm. <br><br><font color="red"><b> This article has been corrected. Link to the correction <u><a href="http://dx.doi.org/10.2298/TSCI200901242E">10.2298/TSCI200901242E</a><u></b></font>

scholarly journals Investigation of a Turbogenerator Based on the Vortex Expansion Machine with a Peripheral Side Channel

2021 ◽  
Vol 8 (1) ◽  
pp. F11-F18
Author(s):  
S.M. Vaneev ◽  
V.S. Martsynkovskyy ◽  
A. Kulikov ◽  
D.V. Miroshnichenko ◽  
Ya.І. Bilyk ◽  
...  
Keyword(s):  
Electricity Generation ◽  
Experimental Studies ◽  
Geometric Parameters ◽  
Working Fluid ◽  
Advantages And Disadvantages ◽  
Lateral Channel ◽  
Different Types ◽  
Flow Part ◽  
Special Stand ◽  
Constant Improvement

The creation of energy-saving turbogenerators is an essential component of the development of small energy systems. The gradual growth of interest in distributed electricity generation necessitates the constant improvement of these units. Moreover, they implement a more environmentally friendly generation method than when using microturbine units that use fuel to carry out the work process. Nowadays, turbogenerators are created based on different types of expansion machines, which have their advantages and disadvantages, given in this article. Compared to competitors, vortex expansion machines have good prospects and the necessary potential to expand their research and produce turbogenerators. An experimental vortex expansion machine with a peripheral-lateral channel and ability to change the geometric parameters of its flowing part was created to meet these needs. Experimental studies of the machine were performed on a special stand with air as a working fluid. As a result of the tests, the data were successfully obtained and processed. They are presented in the form of tables and graphical dependencies. The nature of the influence of thermodynamic parameters and geometric parameters of the flow part on the efficiency of the vortex expansion machine and turbogenerator based on it to further improve and create new turbogenerators is clarified.

scholarly journals Experimental and Theoretical Study of the Axial Distribution of Solid Phase Particles in a Fluidized Bed

2021 ◽  
Vol 64 (4) ◽  
pp. 349-362
Author(s):  
A. V. Mitrofanov ◽  
V. E. Mizonov ◽  
N. S. Shpeynova ◽  
S. V. Vasilevich ◽  
N. K. Kasatkina
Keyword(s):  
Fluidized Bed ◽  
Field Experiments ◽  
Solid Phase ◽  
Cell Model ◽  
Experimental Studies ◽  
Parametric Identification ◽  
Resistance Coefficient ◽  
Model Material ◽  
Spherical Particles ◽  
Axial Distribution

The article presents the results of computational and experimental studies of the distribution of a model material (plastic spherical particles with a size of 6 mm) along the height of a laboratory two-dimensional apparatus of the fluidized bed of the periodic principle of action. To experimentally determine the distribution of the solid phase over the height of the apparatus, digital photographs of the fluidized bed were taken, which were then analyzed using an algorithm that had been specially developed for this purpose. The algorithm involved splitting the image by height into separate rectangular areas, identifying the particles and counting their number in each of these areas. Numerical experiments were performed using the previously proposed one-dimensional cell model of the fluidization process, constructed on the basis of the mathematical apparatus of the theory of Markov chains with discrete space and time. The design scheme of the model assumes the spatial decomposition of the layer in height into individual elements of small finite sizes. Thus, the numerically obtained results qualitatively corresponded to the full-scale field experiment that had been set up. To ensure the quantitative reliability of the calculated forecasts, a parametric identification of the model was performed using known empirical dependencies to calculate the particle resistance coefficient and estimate the coefficient of their macrodiffusion. A comparison of the results of numerical and field experiments made us possible to identify the most productive empirical dependencies that correspond to the cellular scheme of modeling the process. The resulting physical and mathematical model has a high predictive efficiency and can be used for engineering calculations of devices with a fluidized bed, as well as for setting and solving problems of optimal control of technological processes in these devices for various target functions.

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