scholarly journals Specifics of Explosion-Venting Structures Providing Acceptable Indoor Explosion Loads

2021 ◽  
Vol 12 (1) ◽  
pp. 25
Author(s):  
Alexander Andreevich Komarov ◽  
Dmitry Aleksandrovich Korolchenko ◽  
Nikolay Viktorovich Gromov ◽  
Anton Dmitrievich Korolchenko
Keyword(s):  
Response Rate ◽  
Experimental Studies ◽  
Maximum Level ◽  
Physical Processes ◽  
Excessive Pressure ◽  
Safe Level ◽  
Open Pressure ◽  
Explosion Load ◽  
Level 2 ◽  
Selection Of

This article experimentally and theoretically demonstrates that the presence of blast-relief openings (windows) equipped with explosion-venting structures (EVS) allows explosive pressure to be reduced to a safe level (2–4 kPa). We provide results of model and full-scale experiments aimed at studying the influence of EVS parameters of blast-relief openings in explosion-hazardous buildings on the intensity of explosive loads. It was demonstrated that the maximum explosive-pressure value inside EVS-equipped buildings depends on the EVS start-to-open pressure, the structure’s response rate (lag), and characteristic dimension of the premises. Thus, each particular building requires individual selection of EVS parameters, which provide a safe level of excessive pressure in case of an explosive accident. This aspect, however, prevents the widespread use of EVS at explosion-hazardous sites. This article offers an modest upgrade of the explosion-venting structure that provides an indoor pressure equal to the EVS start-to-open pressure. The suggested innovation excludes the possibility of a significant increase in explosive pressure due to an EVS response delay. The efficiency of the suggested technical upgrade was proven by numerical experiments and indirectly by experimental studies aimed at exploring the physical processes associated with the opening of EVSs after an explosion accident. The use of upgraded EVSs will allow for provision of a known maximum level of the explosion load should an explosion event occur in an EVS-equipped room.

scholarly journals Functional Method of Designing Self-Compacting Concrete

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 267
Author(s):  
Tomasz Rudnicki
Keyword(s):  
Coarse Aggregate ◽  
Cement Mortar ◽  
Experimental Studies ◽  
Functional Method ◽  
Structural Viscosity ◽  
Self Compacting Concrete ◽  
Theoretical Assumptions ◽  
Concrete Mix ◽  
Selection Of ◽  
Double Coating

The article presents a new functional method of designing self-compacting concrete (SCC). The assumptions of the functional method of designing self-compacting concrete were based on the double coating assumption (i.e., it was assumed that the grains of coarse aggregate were coated with a layer of cement mortar, whereas the grains of sand with cement paste). The proposed method is composed of four stages, each of which is responsible for the selection of a different component of the concrete mix. The proposed designing procedure takes into consideration such a selection of the mineral skeleton in terms of the volumetric saturation of the mineral skeleton, which prevents the blocking of aggregate grains, and the designed liquid phase demonstrated high structural viscosity and low yield stress. The performed experimental studies, the simulation of the elaborated mathematical model fully allowed for the verification of the theoretical assumptions that are the basis for the development of the method of designing self-compacting concrete.

scholarly journals Adaptive Control Structure with Neural Data Processing Applied for Electrical Drive with Elastic Shaft

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3389
Author(s):  
Marcin Kamiński ◽  
Krzysztof Szabat
Keyword(s):  
Neural Network ◽  
Adaptive Control ◽  
Dynamic Properties ◽  
Experimental Studies ◽  
Drive System ◽  
Particle Swarm Optimizer ◽  
The Neural Network ◽  
Control Concept ◽  
Constant Coefficients ◽  
Selection Of

This paper presents issues related to the adaptive control of the drive system with an elastic clutch connecting the main motor and the load machine. Firstly, the problems and the main algorithms often implemented for the mentioned object are analyzed. Then, the control concept based on the RNN (recurrent neural network) for the drive system with the flexible coupling is thoroughly described. For this purpose, an adaptive model inspired by the Elman model is selected, which is related to internal feedback in the neural network. The indicated feature improves the processing of dynamic signals. During the design process, for the selection of constant coefficients of the controller, the PSO (particle swarm optimizer) is applied. Moreover, in order to obtain better dynamic properties and improve work in real conditions, one model based on the ADALINE (adaptive linear neuron) is introduced into the structure. Details of the algorithm used for the weights’ adaptation are presented (including stability analysis) to perform the shaft torque signal filtering. The effectiveness of the proposed approach is examined through simulation and experimental studies.

Constraints on the accuracy of messenger RNA movement

1985 ◽  
Vol 18 (4) ◽  
pp. 423-450 ◽  
Author(s):  
C. G. Kurland ◽  
Måns Ehrenberg
Keyword(s):  
Messenger Rna ◽  
Experimental Studies ◽  
Physical Problem ◽  
Translational Accuracy ◽  
Trna Species ◽  
Selection Of

SUMMARYTheoretical as well as experimental studies of translational accuracy have most often been concerned with the selection of aminoacyl-tRNA by codon-programmed ribosomes. The selection of the successive codons on the mRNA has received much less attention, probably because it represents both conceptually and experimentally, a much more demanding physical problem. Nevertheless, it would seem that errors in the selection of the codon are potentially much more destructive than errors in selection of aminoacyl-tRNA species. This can be appreciated from the following.

scholarly journals Collective Losses of Low Power Cage Induction Motors—A New Approach

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1749
Author(s):  
Elzbieta Szychta ◽  
Leszek Szychta
Keyword(s):  
Control System ◽  
Experimental Studies ◽  
Complex Problem ◽  
Accurate Estimation ◽  
New Approach ◽  
Water Pumping ◽  
Efficiency Control ◽  
Interacting Systems ◽  
Cage Induction Motor ◽  
Selection Of

Energy efficiency of systems of water pumping is a complex problem since efficiency of two distinct interacting systems needs to be combined: water and power supply. This paper introduces a non-intrusive method of calculating the so-called “collective losses” of a cage induction motor. The term “collective losses”, which the authors define, allows for accurate estimation of motor efficiency. Control system of a pump determines operating point of a pumping station, and thus its efficiency. General estimated performance characteristics of a motor, components of a control system, are assumed to serve selection of a range of pumping speed variations. Rotational speed has a direct effect on motor load torque, pump power and head, and thus on motor performance. Hellwig’s statistical method was used to specify characteristics of estimated collective losses on the basis of experimental studies of 21 motors rated at up to 2.2 kW. The results of simulations and experiments are used to verify validity and efficiency of the suggested method. The method is non-intrusive, simple to use, and requires minimum data.

Calculation of Technical Characteristics of the Technical Fleet Vessels Involved in Ensuring Safety of the Offshore Facilities of Oil and Gas Complex

2021 ◽  
pp. 7-13
Author(s):  
S.V. Matsenko ◽  
◽  
V.M. Minko ◽  
A.A. Koshelev ◽  
V.Yu. Piven ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Oil Pollution ◽  
Raw Materials ◽  
Experimental Studies ◽  
Industrial Safety ◽  
Theoretical Studies ◽  
Physical Processes ◽  
Oil Spill Response ◽  
Sea Area

Violation of industrial safety rules during the operation of offshore facilities for the production, storage and transportation of the hydrocarbon raw materials leads in the most cases to pollution of the marine environment with oil and its components. The works on localization and elimination of such pollution are carried out with the help of vessels of the technical support fleet and booms. When developing oil spill response plans at such facilities, a calculated determination of the technical characteristics of vessels and booms is required that are sufficient to carry out the planned activities. The basic design principles for determining the towing capacity of the technical fleet vessels involved in the localization and elimination of oil and oil product spills by trawling methods are given in the article. The calculation is based on theoretical studies performed by the authors of the physical processes occurring during the movement of objects of a mobile trawling order in the sea area. The results obtained during the course of theoretical studies were confirmed by the experimental studies carried out by the authors personally using the real pieces of equipment in the actual development of tasks for training spill containment by trawling. As a result, the empirical dependencies were obtained and experimentally confirmed, which can be used to calculate technical characteristics of the ships as part of the mobile orders and anchor systems as part of stationary orders intended for the localization and elimination of oil pollution. These results can be used, among other things, for the calculated substantiation of the technical characteristics of the technical fleet vessels designed to ensure safety of the offshore facilities for production, storage, and transportation of the hydrocarbon raw materials.

Cascade control of «smart home» heating

2022 ◽  
Vol 14 (4) ◽  
pp. 82-89
Author(s):  
Sergey Polyakov ◽  
V. Akimov ◽  
A. Polukazakov
Keyword(s):  
Structural Changes ◽  
Experimental Studies ◽  
Residential Building ◽  
Heating System ◽  
Cascade Control ◽  
Virtual Object ◽  
Coolant Temperature ◽  
Home Heating ◽  
Input Signals ◽  
Selection Of

The article discusses the issues of implementing the conversion of input signals of «smart» sensors for automation of the heating system, an algorithm for calculating the parameters of measuring circuits with a nonlinear element and an operational amplifier is developed. The issues of modeling cascade control of residential building heating systems are investigated. The results of the analysis and selection of parameters of the cascade control system are presented. An algorithm implementing the operation of a virtual object is given. The structures of management of residential building objects are proposed. The method of calculating the adjustment of the controller for cascade control is given. For the heating system stand, the procedure for setting the parameters of the process of PID control of the coolant temperature is considered. The results confirming the achievability of the proposed structural changes are obtained. The results of experimental studies are presented.

scholarly journals DETERMINATION OF DEFORMATION IN MESH COMPOSITE STRUCTURE UNDER THE ACTION OF COMPRESSIVE LOADS

2020 ◽  
Vol 17 (35) ◽  
pp. 599-608 ◽  
Author(s):  
Alexander A. OREKHOV ◽  
Yuri A. UTKIN ◽  
Polina F. PRONINA
Keyword(s):  
Composite Material ◽  
Carbon Fiber ◽  
Bearing Capacity ◽  
Polymer Composite ◽  
Experimental Studies ◽  
Polymer Composite Material ◽  
Lightweight Mesh ◽  
Carbon Filler ◽  
Selection Of

One of the significant innovative technologies is the creation of large-sized structures that work for a long time in space and meet stringent restrictions on overall mass characteristics. Among these structures, in the first place, is the section of bearing truss (BT). This article presents the results of experimental studies of sectors of load-bearing trusses of mesh design for compression. Recently, composite mesh cylindrical shells are used as spacecraft housings. The mesh shell is a supporting structure to which the instruments and mechanisms of the spacecraft are attached. The truss section is made of cross-linked polymer composite material with carbon fibers. The objective of the tests is to confirm the possibility of creating a lightweight mesh construction using a carbon fiber reinforced polymer composite material. To achieve this goal, the authors were assigned the following tasks: selection of carbon filler of polymer composite materials (PCM); selection of PCM binder; determination of the degree of carbon fiber reinforcement; choice of the number and orientation paths of spiral ribs, number of ring ribs and the sizes of individual ribs. As a result of the research, the calculated indicators for ensuring the bearing capacity and stiffness under the application of axial compressive load were obtained. At the same time, with the determination of bearing capacity, the deformation characteristics of the structure were twice determined in order to confirm their repeatability, as well as linear nature of the dependence of axial and radial deformations as a result of the applied load.

Hydraulic characteristics and calculation of the innovative systems of surface runoff disposal

2021 ◽  
pp. 46-51
Author(s):  
Ю.В. Брянская ◽  
А.Э. Тен ◽  
Н.Т. Джумагулова ◽  
Г.Н. Громов
Keyword(s):  
Cross Sections ◽  
Surface Runoff ◽  
Experimental Studies ◽  
Drainage System ◽  
Anthropogenic Pollution ◽  
Hydraulic Characteristics ◽  
Regulatory Requirements ◽  
The Subject ◽  
Intensive Development ◽  
Selection Of

В условиях интенсивного развития новых отечественных и зарубежных технологий, материалов и оборудования, применяемых для защиты окружающей природной среды от загрязнений техногенного происхождения, особую актуальность приобретают разработки новых систем отвода и очистки поверхностных сточных вод. Эти системы позволяют использовать последние достижения отраслевой науки и оптимизировать алгоритм выполнения операций и практических приемов их гидравлического расчета. Примером является инновационная система отвода поверхностных сточных вод АСО Qmax, которая относится к открытой системе каналов (лотков) для сбора и отведения поверхностных сточных вод, формирующихся при выпадении атмосферных осадков. Однако широкому применению данного вида конструкций в России препятствует отсутствие методики их гидравлического расчета, в том числе таблиц для подбора сечений (диаметров) каналов, которая бы удовлетворяла требованиям российской нормативно-методической базы проектирования систем отведения поверхностных сточных вод. В этой связи предметом данной статьи явилась оценка гидравлических характеристик трубопроводов, каналов (лотков) системы водоотвода АСО Qmax. Приведены результаты теоретических и экспериментальных исследований гидравлических характеристик системы АСО Qmaxс учетом адаптации для российских условий и нормативных требований, а также обоснование рекомендуемых параметров для их использования. In the context of the intensive development of new domestic and foreign technologies, materials and equipment used to protect the environment from anthropogenic pollution, the development of advanced systems for surface runoff removal and treatment is of special actuality. These systems provide for using the latest achievements of the sectoral science and optimizing the algorithm for performing operations and practical methods for the hydraulic calculations. An example of the innovative surface runoff disposal system is ASO Qmax, that refers to an open system of channels for the collection and disposal of surface runoff formed during precipitation. However, the widespread use of these facilities in Russia is hampered by the lack of a method for the hydraulic calculations, including tables for the selection of cross-sections (diameters) of channels that meet the requirements of the Russian guidelines and regulations for the design of surface runoff disposal systems. In this regard, the subject of this paper is the estimation of the hydraulic characteristics of pipelines, channels of ASO Qmax drainage system. The results of theoretical and experimental studies of the hydraulic characteristics of ASO Qmax system with account of the adaptation for the Russian conditions and regulatory requirements, as well as the justification of the recommended parameters for their use are presented.

Practical Application of the Similarity Law of Structures in the Reconstruction of the Surface Layer of Bricks

2021 ◽  
Vol 1017 ◽  
pp. 21-30
Author(s):  
Victor Danilov ◽  
Arkady Ayzenshtadt ◽  
Maria Frolova
Keyword(s):  
Surface Layer ◽  
Experimental Studies ◽  
Calcium Content ◽  
Degradation Process ◽  
The Body ◽  
Atmospheric Water ◽  
A Value ◽  
Architectural Monument ◽  
Similarity Law ◽  
Selection Of

This paper discusses the results of experimental studies on the selection of the repair mixture compound for recreating the surface layer of the historical brick of the 18th century architectural monument “Commercial Bank” in Arkhangelsk. According to the research results, it was found that the historical brick has a relatively higher density and increased calcium content than the modern one. The characteristics of the surfaces of the analyzed materials based on the component indicators of specific surface energy showed that the brick of 1859, characterized by the highest degree of destruction, has the maximum value of the polar energy component. This fact may indicate a greater hydrophilicity of the surface in relation to atmospheric water and, as a result, a more intensive degradation process. It is established that the composition of the repair mixture with the addition of brick crumbs in the amount of 50 % has a value of the polar part of the surface tension equal to similar parameters for historical bricks (1786 and 1859) after their preliminary priming. The use of this mixture to recreate the surface layer of the brick will allow atmospheric water to pass freely through the repair compound and the body of the brick, without concentrating on the interface and without causing its destruction and detachment when drying.

scholarly journals The use of various species of fungi in biofiltration of air contaminated with odorous volatile organic compounds

2019 ◽  
Vol 100 ◽  
pp. 00021 ◽  
Author(s):  
Milena Gospodarek ◽  
Piotr Rybarczyk ◽  
Anna Brillowska-Dąbrowska ◽  
Jacek Gębicki
Keyword(s):  
Environmental Problem ◽  
Experimental Studies ◽  
Fungal Species ◽  
Biotrickling Filters ◽  
Literature Overview ◽  
Volatile Organic ◽  
Odorous Compounds ◽  
Selection Of Microorganisms ◽  
Selection Of

Air pollution with odorous compounds is a significant social and environmental problem. This paper presents biological deodorization methods. The attention is focused on the application of biotrickling filters for air deodorization. Principles of their operation are discussed, indicating the key role of the selection of microorganisms responsible for the degradation of odorous compounds. A literature overview of the used fungal species is presented and the advantages of using fungi in comparison with bacteria are indicated. The results of experimental studies on the n-butanol removal in biotrickling filter are presented.

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