scholarly journals Experimental studies of the operation of a frameless building made of thin-gauge structural sections

2021 ◽  
Vol 31 (4) ◽  
pp. 110-119
Author(s):  
I. I. Vedyakov ◽  
D. V. Solovyev ◽  
A. V. Smagin
Keyword(s):  
Comparative Analysis ◽  
Construction Industry ◽  
Experimental Studies ◽  
Numerical Data ◽  
Light Metal ◽  
Operating Conditions ◽  
Shell Structures ◽  
Metal Structures ◽  
Promising Direction ◽  
Operational Scheme

Light metal structures (LMS) are widely spread in domestic construction industry. A promising direction for the development of LMS includes prefabricated shell structures made of thin-gauge structural sections. The scope and operating conditions of such structures are quite extensive. In this regard, the development of a competent engineering methodology for calculating buildings using thin-gauge structural sections is required. The present paper describes a method for a full-scale testing of a shell building fragment and provides the results of forces and deformations calculated using the experimental model. In addition, an approach to modeling and dimensioning of finite elements for the profiles under consideration is described. The comparative analysis of numerical data and experimental results is performed. The results of the study can be used both for developing recommendations and engineering methods for calculating similar shell buildings and for determining the actual operational scheme for units and elements of the considered structure.

scholarly journals ДОСЛІДЖЕННЯ ГІГІЄНІЧНИХ ВЛАСТИВОСТЕЙ МАТЕРІАЛІВ НАТІЛЬНОЇ ЛІКАРНЯНОЇ БІЛИЗНИ

2020 ◽  
Vol 140 (6) ◽  
pp. 38-47
Author(s):  
І. О. Іванов ◽  
Н. П. Супрун ◽  
Ю. О. Ващенко
Keyword(s):  
Comparative Analysis ◽  
Materials Science ◽  
Experimental Studies ◽  
Operating Conditions ◽  
Raw Material ◽  
Experimental Investigations ◽  
Textile Materials ◽  
Composition And Structure ◽  
Innovative Materials ◽  
Basic Functions

Investigation of the influence of the peculiarities of raw material composition and structure of traditional and innovative linen textile materials on their hygienic properties. Theoretical and experimental investigations are based on the main positions of textile materials science. In experimental studies, modern standardized methods for determining the hygienic properties of textile materials were used, as well as techniques specially developed taking into account the peculiarities of the operating conditions of underwear. The peculiarities of the operating conditions and the basic functions of hospital underwear were determined. The comparative analysis of hygienic properties of traditional and modern fabrics for underwear was carried out. Using the standardized and the developed methods, adapted to the peculiarities of the conditions of use of the products, the indicators characterizing the processes of water absorption of the materials were experimentally determined. On the basis of the obtained values of quality indicators, a comprehensive assessment of the ability of materials to transfer moisture and air, with the calculation of the arithmetic complex quality index was done. This allowed to determine the material that is optimal in properties, which provides thermophysiological comfort when operating hospital underwear. Using the developed methods, which take into account the specifics of the operating conditions, a comparative analysis of the hygienic properties of traditional and innovative materials for underwear was carried out. A new range of textile materials for underwear has been proposed, taking into account the peculiarities of the operational situation of consumption.

scholarly journals ADDITIONAL CHARACTERISTICS OF HYBRID COMPOSITES FOR FILLING TEETH UNDER LOCAL MOUNTING CLOCKS

2021 ◽  
pp. 29-36
Author(s):  
V.F. Makeev ◽  
V.S. Kukhta ◽  
O.S. Kyrmanov ◽  
V.R. Skalsky
Keyword(s):  
Tensile Strength ◽  
Comparative Analysis ◽  
Oral Cavity ◽  
Air Temperature ◽  
Hybrid Composites ◽  
Experimental Studies ◽  
Operating Conditions ◽  
Dental Composites ◽  
Local Loading ◽  
Ball Diameter

For the rational use of materials, it is necessary to have data on their ability to resist deformation and destruction. In particular, in each case it is necessary to have information on the stiffness, strength and resistance to destruction of materials in the specified operating conditions of the elements. To determine such strength characteristics of the material, certain studies are carried out. According to the analysis of literature sources in the study of dental composites mainly determine the tensile strength (bending) and compression [2-10], because it is subjected to restore materials during their operation in the oral cavity. The purpose of the study is to conduct a comparative analysis of the strength of hybrid composites of domestic and imported production during their local loading: Latelux (Latus, Ukraine), TETRIC N-CERAM (Ivoclar Vivadent, Liechtenstein), CHARISMA CLASSIC (Kulzer, Germany). To conduct research, 10 samples of each dental polymer composite were made. Packaging and molding of the material into a specially designed form was performed in laboratory conditions at an air temperature of 18 210 C with their subsequent polymerization with a LED photopolymer lamp Bluephase 20i (G2) (Ivoclar Vivadent). Before the test, the samples were kept for 24 hours at a temperature of 370 C in saline. The samples were loaded on the SVR-5 installation using a ball indenter (ball diameter mm steel SHX15, modulus of elasticity GPa, Poisson's ratio) with a speed of 0.002 mm/s. The purpose of the study is to conduct a comparative analysis of the strength of hybrid composites of domestic and imported production during their local loading. According to the results of experimental studies on the load of PB fracture, the Charisma Classic composite (5.72 ± 0.16 kN) has the highest strength, Latelux (4.23 ± 0.53 kN) the lowest, and Tetric N-Ceram (5, 03 ± 0.71 kN) occupies an intermediate position. To move the indenter, we obtained the following order of materials (in ascending order): Latelux (0.94 ± 0.11 mm); Charisma Classic (1.02 ± 0.04 mm); Tetric N-Ceram (1.03 ± 0.17 mm).

RECLAMATION AND CULVERT CROSSINGS MADE OF CORRUGATED PIPES ON SPAWNING STREAMS

2020 ◽  
pp. 68-77
Author(s):  
O.N. CHERNYKH ◽  
◽  
A.V. RBURLACHENKO
Keyword(s):  
Single Point ◽  
Experimental Studies ◽  
Fish Passage ◽  
Future Research ◽  
Fish Stocks ◽  
Metal Structures ◽  
Natural Reproduction ◽  
Spiral Shape ◽  
Corrugated Metal ◽  
Spawning Streams

Recommendations are presented for solving issues that arise in the design and operation of tubular transport crossings of corrugated metal structures through spawning streams while ensuring the safety and natural reproduction of fish stocks. There are discussed the results of experimental studies of culverts made of metal corrugated pipes with a normal and spiral shape of corrugation the bottom of which is buried and filled with suitable granular material to the level of the natural channel of a small watercourse. It is established that when 10% of the area of the corrugated pipe is occupied by stone filling, its throughput is reduced by about 10-12%. Based on the review of the existing literature and the results of laboratory experiments, data is provided to estimate the values of the roughness coefficients of the composite cross-section of a single-point junction and directions for future research on culvert reclamation are outlined. Studying of the structure of the velocity distribution in culverts can lead to the improved conditions for fish passage without installing special structural elements in the transit path of the fish passage structure.

scholarly journals Ethanol/Gasoline Blends as Alternative Fuel in Last Generation Spark-Ignition Engines: A Review on CO and HC Engine Out Emissions

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 4034
Author(s):  
Paolo Iodice ◽  
Massimo Cardone
Keyword(s):  
Physicochemical Properties ◽  
Alternative Fuels ◽  
Experimental Studies ◽  
Alternative Fuel ◽  
Exhaust Emissions ◽  
Spark Ignition ◽  
Operating Conditions ◽  
Spark Ignition Engine ◽  
Spark Ignition Engines ◽  
The Impact

Among the alternative fuels existing for spark-ignition engines, ethanol is considered worldwide as an important renewable fuel when mixed with pure gasoline because of its favorable physicochemical properties. An in-depth and updated investigation on the issue of CO and HC engine out emissions related to use of ethanol/gasoline fuels in spark-ignition engines is therefore necessary. Starting from our experimental studies on engine out emissions of a last generation spark-ignition engine fueled with ethanol/gasoline fuels, the aim of this new investigation is to offer a complete literature review on the present state of ethanol combustion in last generation spark-ignition engines under real working conditions to clarify the possible change in CO and HC emissions. In the first section of this paper, a comparison between physicochemical properties of ethanol and gasoline is examined to assess the practicability of using ethanol as an alternative fuel for spark-ignition engines and to investigate the effect on engine out emissions and combustion efficiency. In the next section, this article focuses on the impact of ethanol/gasoline fuels on CO and HC formation. Many studies related to combustion characteristics and exhaust emissions in spark-ignition engines fueled with ethanol/gasoline fuels are thus discussed in detail. Most of these experimental investigations conclude that the addition of ethanol with gasoline fuel mixtures can really decrease the CO and HC exhaust emissions of last generation spark-ignition engines in several operating conditions.

Numerical Modeling and Experimental Studies of the Operational Parameters of the Earth-To-Air Heat Exchanger of the Geothermal Ventilation System

2021 ◽  
Vol 23 ◽  
pp. 42-64
Author(s):  
Boris Basok ◽  
Ihor Bozhko ◽  
Maryna Novitska ◽  
Aleksandr Nedbailo ◽  
Myroslav Tkachenko
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Ventilation System ◽  
Experimental Studies ◽  
Operating Conditions ◽  
Operational Parameters ◽  
Cross Sectional ◽  
Distinctive Features ◽  
Sectional Shape ◽  
Experimental Bench

This article is devoted to the analysis of the heat engineering characteristics of the operation of an Earth-to-Air Heat Exchanger, EAHE, with a circular cross-sectional shape, which is a component of the geothermal ventilation system. The authors analyzed literature sources devoted to the research of heat exchangers of the soil-air type of various designs and for working conditions in various soils. Much attention is paid to the issues of modeling the operation of such heat exchangers and the distinctive features of each of these models. Also important are the results of experimental studies carried out on our own experimental bench and with the help of which the numerical model was validated. The results of these studies are the basis for the development of a method for determining the optimal diameter of an EAHE under operating conditions for soil in Kyiv, Ukraine.

scholarly journals IMPROVING DYNAMIC REGIME OF ROLLING FOR INCREASING DURABILITY OF BALL-ROLLING MILL ROLLS

2019 ◽  
Vol 61 (12) ◽  
pp. 927-932 ◽  
Author(s):  
V. Yu. Rubtsov ◽  
O. I. Shevchenko ◽  
M. V. Mironova
Keyword(s):  
Contact Pressure ◽  
Rotational Speed ◽  
Rolling Mill ◽  
Experimental Studies ◽  
Rolling Process ◽  
Operating Conditions ◽  
Frequency Method ◽  
Rolling Mills ◽  
Ball Rolling ◽  
Progressive Technology

One  of  the  important  reasons  for  the  downtime  of  ball  rolling  mills  is  replacement  of  rolls  due  to  their  wear  and  tear.  The  degree  and  zones  of  critical  wear  of  ball  rolling  rolls  are  investigated  in  the  article, where the greatest wear is observed over the flanges in zone of billet  capture.  Conditions  necessary  to  capture  the  blank  and  to  perform  rolling  process  are  analytically  determined.  Variable  frequency  method  of  roll  rotations  is  proposed  as  a  progressive  technology  for  blank supply. The results of tests for its variations in accordance with  linear  and  quadratic  law  are  presented.  Known  formulas  determining  average  strain  rate  at  rolls  rotational  speed  change  are  converted  for  linear and quadratic dependences. Experimental studies have been carried  out  in  conditions  of  EVRAZ  Nizhnetagilsky  Metallurgical  Plant  ball rolling mills during rolling of 60mm ball made of Sh-3G steel. Experiments  were  performed  for  given  parameters  of  manual  change  in  rolls rotation speed at blank capture by rollers. The results have shown  a  significant  effect  of  change  in  rotational  speed  on  average  specific  pressure during blank capture. Evaluation of torque-time and average  contact  pressure  for  calculated  and  experimental  data  are  presented.  Empirical characteristics are also described at variable rotational speed  of rolls according to linear and quadratic law. Acceptable convergence  of results of calculated and empirical characteristics is determined. Engineering solution has been proposed for that task. It consists in installation of a thyristor converter. This solution allows reduction of rolls  speed before blank capture. Also, this solution will increase frequency  to  the  nominal  value  according  to  the  given  law  after  blank  capture.  As an obtained result, there is uniform distribution of average contact  pressure over the entire length of the roll under different operating conditions  of  mill  in  automatic  mode. Application  of  this  technique  will  reduce wear degree of the rolling tool. At the same time, productivity  of ball rolling mill will be maintained. Rolls consumption and number  of rolls change will decrease due to rolls wear.

scholarly journals The Business Service Sector in India, Ireland and Poland. A Comparative Analysis

2019 ◽  
Vol 22 (2) ◽  
pp. 159-172
Author(s):  
Arkadiusz Mroczek
Keyword(s):  
Comparative Analysis ◽  
Service Sector ◽  
Operating Conditions ◽  
Business Service ◽  
Literature Study ◽  
Location Factors ◽  
Current Growth ◽  
Characteristic Features ◽  
Selection Of ◽  
Made In

The fast growth of the service sector is one of the characteristic features of the contemporary economy. Amongst other CEE countries, Poland is one of the emerging locations for this sector. The aim of the paper is to examine and compare the business service sector in India, Ireland and Poland. Both India and Ireland are exceptional locations for this industry, so comparing the state and operating conditions in Poland with those countries can be insightful. A literature study is used to determine the motives of companies undertaking offshore investments, upon which a selection of location factors is made. In the empirical part, those factors are analyzed in a descriptive way. This allows us to draw conclusions concerning this sector in Poland. This country, to some extent, possesses selected positive features of both India and Ireland, which explains the current growth of the sector.

scholarly journals Low Speed Estimation of Sensorless DTC Induction Motor Drive Using MRAS with Neuro Fuzzy Adaptive Controller

2018 ◽  
Vol 8 (5) ◽  
pp. 2691
Author(s):  
Mini R ◽  
Shabana Backer P. ◽  
B. Hariram Satheesh ◽  
Dinesh M. N
Keyword(s):  
Comparative Analysis ◽  
Induction Motor ◽  
Reactive Power ◽  
Adaptive Controller ◽  
Operating Conditions ◽  
Estimation Methods ◽  
Speed Estimation ◽  
Loop Model ◽  
Low Speed ◽  
Rotor Flux

<p>This paper presents a closed loop Model Reference Adaptive system (MRAS) observer with artificial intelligent Nuero fuzzy controller (NFC) as the adaptation technique to mitigate the low speed estimation issues and to improvise the performance of the Sensorless Direct Torque Controlled (DTC) Induction Motor Drives (IMD). Rotor flux MRAS and reactive power MRAS with NFC is explored and detailed analysis is carried out for low speed estimation. Comparative analysis between rotor flux MRAS and reactive power MRAS with PI as well as NFC as adaptive controller is performed and results are presented in this paper. The comparative analysis among these four speed estimation methods shows that reactive power MRAS with NFC as adaptation mechanism shows reduced speed estimation error and actual speed error at steady state operating conditions when the drive is subjected to low speed operation. Simulation carried out using MATLAB-Simulink software to validate the performance of the drive especially at low speeds with rated and variable load conditions.</p>

scholarly journals Simulation Study of the Process of Friction in the Working Elements of a Car Braking System at Different Degrees of Wear

2018 ◽  
Vol 12 (3) ◽  
pp. 221-226 ◽  
Author(s):  
Andrzej Borawski
Keyword(s):  
Simulation Study ◽  
Friction Pair ◽  
Experimental Studies ◽  
Real Life ◽  
Operating Conditions ◽  
Heating Process ◽  
Passenger Cars ◽  
The Road ◽  
Emergency Braking ◽  
Braking System

Abstract Among the many elements of a modern vehicle, the braking system is definitely among the most important ones. Health, and, frequently, life, may rest upon the design and reliability of brakes. The most common friction pair used in passenger cars today is a disc which rotates with the road wheel and a cooperating pair of brake pads. The composite material of the pad results in changing tribological properties as the pad wears, which was demonstrated in experimental studies. The change is also facilitated by the harsh operating conditions of brakes (high and rapid temperature changes, water, etc.). This paper looks into how changing tribology reflects on the heating process of disc and pads during braking. And so a simulation study was conducted, as this method makes it possible to measure temperature in any given point and at any time, which is either impossible or extremely difficult in real life conditions. Finite element method analyses were performed for emergency braking events at various initial speeds of the vehicle reflecting the current road speed limits.

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