scholarly journals PLANNING OF EXPERIMENTAL STUDIES OF THE "FOUNDATION-BASE" SYSTEM IN CASE OF SUDDEN OVERLOADS

2020 ◽  
pp. 5-12
Author(s):  
I. M. Diakov ◽  
M. I. Diakov ◽  
B. Y. Barykin
Keyword(s):  
Experimental Studies ◽  
Normal Operation ◽  
Base System ◽  
System Operation ◽  
Foundation Soil ◽  
Soil System ◽  
Emergency Situations ◽  
Foundation Base ◽  
Sudden Loading ◽  
Experimental And Theoretical Studies

The relevance of experimental and theoretical studies of the work of the foundation-foundation system in sudden burdens is justified. It was established that sudden loads can occur both in emergency situations and in the course of normal operation. The main criterion of sudden loading is the rate of additional or main (operational) loading, which is higher than the rate of stress redistribution in the base. In order to identify the main features of the foundation-foundation system and plan further studies, the results of preliminary experiments of the interaction of foundations with the soil base during sudden loads were analyzed. The accepted method of experimental research is described, the characteristics of the models of foundations and the power system used for testing are given. Some features of "foundation-soil" system operation in case of sudden loading are defined. Based on the conducted experiments, the need for further study of the foundation-foundation system in case of sudden loading was substantiated and the experiments were planned.

Strong coupling: resonant effects

2017 ◽  
Author(s):  
Alexey V. Kavokin ◽  
Jeremy J. Baumberg ◽  
Guillaume Malpuech ◽  
Fabrice P. Laussy
Keyword(s):  
Strong Coupling ◽  
Experimental Studies ◽  
Strong Coupling Regime ◽  
Theoretical Studies ◽  
Stimulated Scattering ◽  
Quantum Theories ◽  
Pump Probe ◽  
Exciton Polaritons ◽  
Linear Optical Properties ◽  
Experimental And Theoretical Studies

This chapter presents experimental studies performed on planar semiconductor microcavities in the strong-coupling regime. The first section reviews linear experiments performed in the 1990s that evidence the linear optical properties of cavity exciton-polaritons. The chapter is then focused on experimental and theoretical studies of resonantly excited microcavity emission. We mainly describe experimental configuations in which stimulated scattering was observed due to formation of a dynamical condensate of polaritons. Pump-probe and cw experiments are described in addition. Dressing of the polariton dispersion and bistability of the polariton system due to inter-condensate interactions are discussed. The semiclassical and the quantum theories of these effects are presented and their results analysed. The potential for realization of devices is also discussed.

Development of an Evaporating Type Air Cooler for Ventilation Systems

2021 ◽  
pp. 37-44
Author(s):  
А. В. Бараков ◽  
В. Ю. Дубанин ◽  
Д. А. Прутских ◽  
А. А. Надеев
Keyword(s):  
Experimental Studies ◽  
Engineering Calculation ◽  
Design Calculation ◽  
Efficiency Coefficient ◽  
Empirical Relationships ◽  
Additional Energy ◽  
Air Cooler ◽  
Hot Season ◽  
Experimental And Theoretical Studies ◽  
Ventilation Systems

Постановка задачи. Подаваемый в помещения воздух в жаркое время года должен быть охлажден до комфортных температур. В связи с тем, что дополнительного расхода энергии на это охлаждение не предусмотрено, возможно применить воздухоохладитель испарительного типа. Однако известные в настоящее время результаты экспериментальных и теоретических исследований таких аппаратов не позволяют их проектировать, что препятствует их распространению. Рассмотрено строение такого аппарата и выполнены его теоретические и экспериментальные исследования, результаты которых могут быть использованы для инженерного расчета и конструирования подобных аппаратов. Результаты. Описан сконструированный авторами воздухоохладитель испарительного типа для систем вентиляции. Проведено теоретическое и экспериментальное исследование воздухоохладителя. Получены аналитические соотношения для определения времени движения насадки в «мокрой» камере аппарата, температуры охлажденного воздуха и температуры насадки в любом сечении контура циркуляции. Получены эмпирические соотношения для коэффициента эффективности охладителя и его гидравлического сопротивления. Выводы. Полученные зависимости послужат основой для разработки методики проектного расчета воздухоохладителей косвенно-испарительного типа с перемещающимся псевдоожиженным слоем в поле центробежных сил. Statement of the problem. The air supplied to the premises during the hot season must be cooled to comfortable temperatures. Due to the fact that additional energy consumption for this cooling is not provided, it is possible to use an evaporative-type air cooler. However, the currently known results of experimental and theoretical studies of such devices do not allow for their design, which prevents their spread. The structure of such an apparatus is considered and its theoretical and experimental studies are carried out, the results of which can be used for engineering calculation and design of such apparatus. Results. An evaporative-type air cooler designed by the authors for ventilation systems is described. A theoretical and experimental study of the air cooler has been carried out. Analytical relationships were obtained for determining the time of movement of the material checker in the «wet» chamber of the apparatus, the temperature of the cooled air and the temperature of the checker in any section of the circulation loop. Empirical relationships have been obtained for the efficiency coefficient of the cooler and its hydraulic resistance. Сonclusions. The obtained dependencies will serve as the basis for the development of a methodology for the design calculation of indirect-evaporative air coolers with a moving fluidized bed in the field of centrifugal forces.

Results of experimental studies of changes in the level and heating of the main condensate in mixing-type LPH

2021 ◽  
Vol 13 (4) ◽  
pp. 290-295
Author(s):  
E. A. Sukhorukova ◽  
N. N. Trifonov ◽  
S. P. Kolpakov
Keyword(s):  
Water Distribution ◽  
Technical Problem ◽  
Experimental Studies ◽  
Check Valve ◽  
Normal Operation ◽  
Steam Turbines ◽  
Manufacturing Defects ◽  
Water Chamber ◽  
Heating Section ◽  
Hydraulic Shocks

In the thermal circuits of domestic steam turbines, mixing-type low-pressure heaters (LPH) with free-flow jet water distribution and counter-flow of water and steam are widely used. The choice of the counterflow variant of the media movement ensures the most efficient heat transfer. However, the technical problem of ensuring reliable operation of LPH in the entire range of design loads of TPP and NPP power units is still relevant.During the commissioning and operation of mixing-type LPH in 800÷1200 MW turbines of TPP and NPP, the presence of metal knocks in the zone of the check valve, hydraulic shocks in the heating section were revealed. A priori, these phenomena indicated design flaws in LPH or manufacturing defects in their production. Research carried out by NPO CKTI specialists showed that periodic hydraulic shocks in the heating section and metal knocks occur as a result of uneven distribution around the circumference of the main condensate and steam supply. This leads to a breakdown of the check valve and the destruction of perforated plates and off-design heating of water in the volume of the annular LPH water chamber. To clarify the causes of the damage, develop recommendations for the reconstruction of the apparatus and further account for the design, two series of experimental studies were carried out on mixing-type heaters of 800 MW turbine units PNSV-2000-1 and PNSV-2000-2 manufactured at PJSC Krasny Kotelshchik. The purpose of the experimental studies was to determine the change in the water level in the water chamber and the heating of the main condensate in the elements of the heating compartment during normal operation of the power unit at loads of 400÷850 MW. Based on the results of the research, the method for calculating the mixing-type LPH has been refined, taking into account the revealed non-uniformity of water heating in the water chamber, recommendations for their reconstruction have been developed and implemented. 

Soil-Structure Interaction in Buildings from Earthquake Records

1990 ◽  
Vol 6 (4) ◽  
pp. 641-655 ◽  
Author(s):  
Gregory L. Fenves ◽  
Giorgio Serino
Keyword(s):  
Soil Structure ◽  
Dynamic Properties ◽  
Strong Motion ◽  
Longitudinal Direction ◽  
Soil Structure Interaction ◽  
Base Shear ◽  
Foundation Soil ◽  
Soil System ◽  
Structure Interaction ◽  
Building Foundation

An evaluation of the response of a fourteen story reinforced concrete building to the 1 October 1987 Whittier earthquake and 4 October 1987 aftershock shows significant effects of soil-structure interaction. A mathematical model of the building-foundation-soil system provides response quantities not directly available from the records. The model is calibrated using the dynamic properties of the building as determined from the processed strong motion records. Soil-structure interaction reduces the base shear force in the longitudinal direction of the building compared with the typical assumption in which interaction is neglected. The reduction in base shear for this building and earthquake is approximately represented by proposed building code provisions for soil-structure interaction.

scholarly journals MHD-waves in the geomagnetic tail: A review

10.12737/7168 ◽  
2015 ◽  
Vol 1 (1) ◽  
pp. 4-22 ◽  
Author(s):  
Анатолий Леонович ◽  
Anatoliy Leonovich ◽  
Виталий Мазур ◽  
Vitaliy Mazur ◽  
Даниил Козлов ◽  
...  
Keyword(s):  
Numerical Models ◽  
Experimental Studies ◽  
Low Frequency ◽  
Detailed Comparison ◽  
Mhd Waves ◽  
Theoretical Studies ◽  
Geomagnetic Tail ◽  
Magnetopause Oscillations ◽  
Experimental And Theoretical Studies ◽  
Theoretical Results

This article presents the review of experimental and theoretical studies on ultra-low-frequency MHD oscillations of the geomagnetic tail. We consider the Kelvin–Helmholtz instability at the magnetopause, oscillations with a discrete spectrum in the “magic frequencies” range, the ballooning instability of coupled Alfvén and slow magnetosonic waves, and “flapping” oscillations of the current sheet of the geomagnetic tail. Over the last decade, observations from THEMIS, CLUSTER and Double Star satellites have been of great importance for experimental studies. The use of several spacecraft allows us to study the structure of MHD oscillations with high spatial resolution. Due to this, we can make a detailed comparison between theoretical results and those obtained from multi-spacecraft studies. To make such comparisons in theoretical studies, in turn, we have to use the numerical models closest to the real magnetosphere.

Effect of Existing Building Walls on the Geotechnical Behavior of Foundation under Earthquake Loading

2021 ◽  
Vol 6 (4) ◽  
pp. 100-104
Author(s):  
M. N. Massoud Elsiragy
Keyword(s):  
Large Scale ◽  
Bending Moment ◽  
Horizontal Displacement ◽  
Scale Model ◽  
Earthquake Loading ◽  
Three Dimensional Model ◽  
Foundation Soil ◽  
Soil System ◽  
Existing Building ◽  
Building Walls

— Structure’s systems are subjected to additional loads due to earthquakes that may be produces progressive failures. The building illustrates dissimilar categories of failure mechanism for the minor to major earthquake conditions. These structures categorized to the most susceptible type of building has experienced serious hazard or even full failure for the period of seismic activities, therefore their investigation is a complex thing to do. Consequently, this research aims at studying the behaviour of large-scale model of structures constructed with and without brick walls under seismic conditions. The effect of building walls on the performance of the structure during earthquake loading is investigated numerically using PLAXIS 3D software. An eight story building with basement designed on a mat foundation is simulated as three-dimensional model in case of brick walls existing and without brick walls case. The effect of existence such wall building on the stability of foundation soil system is discussed in the form of lateral, horizontal deformation, and foundation acceleration. The studied showed that the reduction of extreme horizontal displacement and bending moment for building foundation with brick walls reached to 43%, and 68% respectively compared to the building without walls. The consideration of wall as filling for super structure significantly reduce the foundation acceleration by as much as 72% of its initial value, which lead to considerable effect of increasing the foundation stability.

RISK MANAGEMENT OF EMERGENCIES OF BUSINESS STRUCTURES IN THE CONTEXT OF GLOBAL INFORMATIZATION

2017 ◽  
Author(s):  
Hamed Rashed Sayed Abdullah Alnuaimi ◽  
Keyword(s):  
Risk Management ◽  
Management System ◽  
Living Conditions ◽  
Normal Operation ◽  
Natural Phenomenon ◽  
Emergency Situations ◽  
Risk Management System ◽  
Business Structures ◽  
The Impact ◽  
Business Structure

Modern processes in a society increasingly began to take on the character of emergencies, namely, the situation in a certain territory, which developed as a result of an accident, a dangerous natural phenomenon, a catastrophe, the spread of a disease, a natural or other disasters that may or did entail human casualties, damage to health people or the environment, significant material losses and disruption of the living conditions of people. At the current time, such a situation is the COVID-19 pandemic, which has already claimed the lives of many people and brought significant economic consequences, including a complete shutdown of the activities of business structures. In this regard, the purpose of the study is to develop a conceptual framework for a risk management system for emergency situations, which can ensure the normal operation of a business structure and prevent its death in the event of an emergency event of any nature. The author analyzed the impact of the COVID-19 pandemic on society and the activities of business structures as one of the latest and most striking examples of emergencies. The analysis revealed that this event could completely destroy the business; therefore, the primary and indispensable criterion for the normal viability of a modern business structure is the ability of top management, based on a strictly scientific basis, to predict, carry out prevention, rationally control and effectively manage risks. Based on the analysis, the author proposed conceptual risk management of emergencies for business structures in the context of global informatization of digitalization. The proposed system is based on the fact that modern processes in society are a symbiosis of two concepts - emergency situations and "black swan", i.e. this is difficult to predict an event that has significant financial and material losses and a violation of the living conditions of an economic entity up to its complete dysfunction. The proposed comprehensive emergency risk management system will allow neutralizing two main and most ambitious consequences: catastrophic losses (financial, labour) and suddenness of the event.

scholarly journals Numerical simulation of the stress-strain state of complex-reinforced elements

2019 ◽  
Vol 13 (2) ◽  
pp. 110-115
Author(s):  
Olena Krantovska ◽  
Mykola Petrov ◽  
Liubov Ksonshkevych ◽  
Matija Orešković ◽  
Sergii Synii ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Strain State ◽  
Theoretical Calculations ◽  
Experimental Studies ◽  
Theoretical Studies ◽  
Stress Strain ◽  
Narrow Strip ◽  
Stress Strain State ◽  
Graphical Environment ◽  
Experimental And Theoretical Studies

The article describes a developed technique of a numerical simulation of the stress-strain state of complex-reinforced elements, which allows you to create models of double-span continuous. The performed experimental and theoretical studies allowed us to carry out the testing of the developed design model and to justify the reliability of the proposed numerical simulation methodology. The results of the experimental studies were compared with those of the theoretical studies. The theoretical calculus algorithm was developed by using the finite element method. Theoretical calculations were performed by using the mathematical-graphical environment software system LIRA-SOFT and the mathematical and computer program MATLAB. On the basis of the experimental research, the iso-fields of displacements and stresses in the materials of an eccentrically compressed beam with a small bend of the slab were constructed, which collapse behind the inclined narrow strip of concrete and displacements and stresses in the materials of the eccentrically stretched beam, which is destroyed due to the yield of the upper mounting armature.

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