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Tytuł:
Hybrid texture and gradient modeling for dynamic background subtraction identification systemin tobacco plant using 5G data service
Autorzy:
Gowda Thirthe, M.T.
Chandrika, J.
Powiązania:
https://bibliotekanauki.pl/articles/38699145.pdf
Data publikacji:
2023
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
background subtraction
local binary pattern
tobacco plant
texture
Gaussian mixture model
illumination change
plant disease identification system
usuwanie tła
lokalny wzorzec binarny
tytoń
tekstura
model mieszaniny Gaussa
zmiana oświetlenia
system identyfikacji chorób roślin
Opis:
Background: Detecting the plants as objects of interest in any vision-based input sequence is highly complex due to nonlinear background objects such as rocks, shadows,etc. Therefore, it is a difficult task and an emerging one with the development of precision agriculture systems. The nonlinear variations of pixel intensity with illuminationand other causes such as blurs and poor video quality also make the object detection taskchallenging. To detect the object of interest, background subtraction (BS) is widely usedin many plant disease identification systems, and its detection rate largely depends on thenumber of features used to suppress and isolate the foreground region and its sensitivitytoward image nonlinearity. Methodology: A hybrid invariant texture and color gradient-based approach is proposed to model the background for dynamic BS, and its performance is validated byvarious real-time video captures covering different kinds of complex backgrounds and various illumination changes. Based on the experimental results, a simple multimodal featureattribute, which includes several invariant texture measures and color attributes, yieldsfinite precision accuracy compared with other state-of-art detection methods. Experimental evaluation of two datasets shows that the new model achieves superior performanceover existing results in spectral-domain disease identification model. 5G assistance: After successful identification of tobacco plant and its analysis, the finalresults are stored in a cloud-assisted server as a database that allows all kinds of 5G servicessuch as IoT and edge computing terminals for data access with valid authentication fordetailed analysis and references.
Źródło:
Computer Assisted Methods in Engineering and Science; 2023, 30, 1; 41-54
2299-3649
Pojawia się w:
Computer Assisted Methods in Engineering and Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Component Proportions in Casting Process on Hardness and the Quality of Cast Iron
Autorzy:
Saikaew, Charnnarong
Harnsopa, S.
Powiązania:
https://bibliotekanauki.pl/articles/27314151.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
sand casting
cast hardness
scrap
mixture-design
Monte Carlo simulation
odlew
twardość odlewu
złom
zawartość składników
symulacja Monte Carlo
Opis:
The purposes of this study were to investigate the impact of proportions of cast iron scrap, steel scrap, carbon and ferro silicon on hardness and the quality of cast iron and to obtain an appropriate proportion of the four components in iron casting process using a mixture experimental design, analysis of variance and response surface methodology coupled with desirability function. Monte Carlo simulation was used to demonstrate the impacts of different proportions of the four components by varying the proportions of components within ±5% of the four components. Microstructures of the cast iron sample obtained from a company and the cast iron samples casted with the appropriate proportions of the four components were examined to see the differences of size and spacing of pearlite particle. The results showed that linear mixture components were statistically significant implying a high proportion of total variability for hardness of the cast iron samples explained by the casting mixtures of raw materials. The graphite of the sample casted from the appropriate proportion has shorter length and more uniform distribution than that from the company. When varying percentages of the four components within ±5% of the appropriate proportion, simulated hardness values were in the range of 237 to 256 HB.
Źródło:
Archives of Foundry Engineering; 2023, 23, 2; 35--42
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of the binder on the properties of cold mixtures
Wpływ środka wiążącego na właściwości mieszanek na zimno
Autorzy:
Krasowski, Maciej
Buczyński, Przemysław
Mušuta, Juraj
Powiązania:
https://bibliotekanauki.pl/articles/27322570.pdf
Data publikacji:
2023
Wydawca:
Politechnika Świętokrzyska w Kielcach. Wydawnictwo PŚw
Tematy:
cold mixture
recycling
substructure
foamed asphalt
asphalt emulsion
hydraulic binder
modification
mieszanka na zimno
recykling
podbudowa
asfalt spieniony
emulsja asfaltowa
spoiwo hydrauliczne
modyfikacja
Opis:
The paper aims to present the basic properties of cold mixes in terms of the type of binding agent. In the theoretical part of the article, a description of the technology for producing cold recycled mixtures and the types of road binders used in cold mixtures was presented. The research part presents the experimental design, and gives an overview of the research methodology used to assess the impact of the type of binding agent. Mixes differing in type and binder content were designed. During the laboratory work, mixtures were prepared with cement binder (CBGM), cement-modified polymer binder (CBGM+P), mineral-cement-emulsion modified with polymer binder (BE-RCM+P), and mineral-cement mixtures with foamed bitumen modified with polymer binder (FB-RCM+P). The project aimed to produce cold mixtures with variations in the type and amount of binder used. The mixtures were prepared using cold mix technology. The effect of the binder on the cold mix properties was studied. During the research, the following properties were examined: void content (Vm), indirect tensile strength (ITS), resistance to water damage (TSR), stiffness modulus using the IT-CY method and an axial compressive strength. On the basis of the research carried out, an analysis was made. Among other things, the polymer modification was found to have a positive effect on the void content of the mix. The research carried out in this way made it possible to show the influence of the binder on the properties of cold mixes.
Praca miała na celu przedstawienie podstawowych właściwości mieszanek na zimno w aspekcie rodzaju środka wiążącego. W części teoretycznej artykułu przedstawiono opis technologii wykonywania mieszanek metodą recyklingu głębokiego na zimno oraz rodzaje spoiw drogowych wykorzystywanych w mieszankach na zimno. W części badawczej przedstawiono plan eksperymentu oraz przybliżono metodykę badawczą wykorzystaną w ocenie wpływu rodzaju środka wiążącego. Zaprojektowano mieszanki związane cementem (CBGM), mieszanki związane cementem modyfikowane polimerem (CBGM+P), mieszanki mineralno-cementowo-emulsyjne modyfikowane polimerem (MCE+P) oraz mieszanki mineralno-cementowe z asfaltem spienionym modyfikowane polimerem (MCAS+P). Projekt zakładał wykonanie mieszanek w technologii na zimno, zróżnicowanych pod względem rodzaju oraz ilości zastosowanego spoiw. W ramach badań sprawdzono zawartość wolnych przestrzeni Vm, wytrzymałość na rozciąganie pośrednie ITS, odporność na szkodliwe działanie wody TSR, moduł sztywności według metody IT-CY oraz przeprowadzono badanie wytrzymałości na ściskanie osiowe po 28 dniach pielęgnacji. Na podstawie wykonanych badań dokonano analizy. Tak przeprowadzone badania pozwoliły na ukazanie wpływu spoiwa na właściwości mieszanek na zimno.
Źródło:
Structure and Environment; 2023, 15, 4; 185--195
2081-1500
Pojawia się w:
Structure and Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling the corrosive destruction of underground degassing pipelines
Autorzy:
Yegorchenko, Rostyslav
Yavorskyi, Andrii
Dyachkov, Pavel
Powiązania:
https://bibliotekanauki.pl/articles/27324354.pdf
Data publikacji:
2023
Wydawca:
Instytut Techniki Górniczej KOMAG
Tematy:
degassing
underground vacuum gas pipeline
methane-air mixture
monitoring
corrosion
output
rurociąg gazowy
korozja
Opis:
The general frequency of development of pitting corrosion was established, taking into account the results of the analysis of mine waters and foreign materials, which are favorable conditions for theformation of corrosion of steel degassing pipelines. A base of initial data was created for modeling the corrosion process of a steel degassing gas pipeline at different points in time: the beginning of the corrosion process, its development, and the end of the process. Stress distribution, corrosion potential,as well as anodic and cathodic current densities depending on the size of the corrosion crack and the longitudinal deformation of the rocks of the sole of the production was analysed.Ithas been proven that the high level of corrosion processes of underground pipelines is the result of the interaction of the metal, which acts as an electrode, with groundwater, which acts as anelectrolyte, while the determining factors of the corrosion process are the electrical conductivity of the rocks of the bottom of the mine and the deformation processes in the pipelines. The reason of low service life of underground degassing pipelines, which are constantly exposed to mechanical and electrochemical corrosion, have been established.
Źródło:
Mining Machines; 2023, 41, 4; 220--230
2719-3306
Pojawia się w:
Mining Machines
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Technology of Production of Mold Filling Material for Specific Purposes in the Field of Metallic Foam Casting
Autorzy:
Kroupová, Ivana
Bašistová, Martina
Lichý, Petr
Merta, Václav
Radkovský, Filip
Jezierski, Jan
Powiązania:
https://bibliotekanauki.pl/articles/28099598.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
molding mixture
metallic foams
precursor
abrasion loss
3-point bending strength
Opis:
This paper describes the technology for the production of precursors (space holder material) used to form the complex internal structure of cast metal foam. The precursor material must exhibit sufficient refractoriness, resist contact with liquid metal and at the same time should exhibit good collapsibility after casting. With regard to the greening of foundry production, the focus of this paper was on materials that could exhibit the above properties and at the same time do not have a negative impact on the environment. In this paper, the technology for the production of spherical precursors from a self-hardening mixture with a geopolymer-based binder system is described and verified. The motivation for the choice of material and all the sub-steps of the process - molding into the core box, tumbling, including the necessary accompanying tests of the mechanical properties of the core mixture being verified - are described.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 2; 757--763
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analiza możliwości zasilania certyfikowanych urządzeń gazowych uzdatnionym biogazem rolniczym
Analysis of the possibility of supplying certified gas devices with treated agricultural biogas
Autorzy:
Wojtowicz, Robert
Powiązania:
https://bibliotekanauki.pl/articles/31348164.pdf
Data publikacji:
2022
Wydawca:
Instytut Nafty i Gazu - Państwowy Instytut Badawczy
Tematy:
biogaz
biogaz rolniczy
mieszanina
gaz ziemny
gaz LNG
biogas
agricultural biogas
mixture
natural gas
LNG
Opis:
Głównym celem prowadzonych analiz było sprawdzenie, czy dostępne na rynku certyfikowane urządzenia gazowe użytku domowego i komercyjnego (urządzenia wykorzystywane w zakładach gastronomicznych) można zasilać częściowo oczyszczonym biogazem rolniczym lub mieszaniną takiego biogazu z gazem ziemnym wysokometanowym grupy E lub gazem z regazyfikacji LNG. Aby odpowiedzieć na to pytanie, rozważono sytuację, w której biogaz rolniczy zostanie wstępnie oczyszczony z najbardziej niepożądanych zanieczyszczeń i docelowo będzie gazem składającym się z metanu (CH4), dwutlenku węgla (CO2) i tlenu (O2). Rozpatrywano cztery różne składy biogazu rolniczego, w których zawartość CH4 zmieniała się od 70% do 85%, natomiast CO2 – od 14,8% do 29,8%. Obliczone parametry energetyczne, a w zasadzie liczbę Wobbego tych biogazów, porównywano następnie z wartościami nominalnej liczby Wobbego gazów ziemnych grup Ln, Ls i Lw, podanymi w polskich przepisach prawnych. Innym rozpatrywanym wariantem było mieszanie częściowo oczyszczonego biogazu rolniczego z gazem ziemnym wysokometanowym grupy E lub gazem z regazyfikacji LNG w takich proporcjach, aby powstałe mieszaniny osiągnęły minimalne wymagania energetyczne dla gazów ziemnych grup Ls, Lw i E oraz minimalne i maksymalne wymagania energetyczne dla gazu ziemnego grupy S (gaz zawierający w swoim składzie CO2 rozprowadzany na Węgrzech). Określono proporcje mieszania tych gazów, podano potencjalne składy powstałych mieszanin, ich parametry energetyczne oraz ciśnienia zasilania urządzeń końcowych spalających te mieszaniny. Na podstawie przeprowadzonych obliczeń podano, które kategorie urządzeń można potencjalnie wykorzystać do zasilania ich bądź to częściowo oczyszczonym biogazem, bądź też jego mieszaninami z gazem ziemnym wysokometanowym grupy E lub gazem z regazyfikacji LNG. Opisano również, jakie ewentualne zmiany będą konieczne w takich urządzeniach, aby można je było bezpiecznie użytkować po zmianie gazu.
The main goal of the analyzes was to check whether the certified gas appliances available on the market for domestic and commercial use (catering equipment) can be supplied with partially purified agricultural biogas or mixture of such biogas in combination with group E high-methane natural gas or gas form LNG regasification. To answer this question, a situation in which the agricultural biogas would be pre-treated to remove the most undesirable pollutants and would ultimately be a gas consisting of methane (CH4), carbon dioxide (CO2) and oxygen (O2) was considered. Four different compositions of agricultural biogas were considered in which content of methane varied from 70% to 85% and carbon dioxide from 14.8% to 29.8%. The calculated energy parameters (Wobbe index) of these biogases were then compared with the nominal Wobbe index for natural gases of Ln, Ls and Lw groups set out in Polish legislation. Another option considered was to mix partially purified agricultural biogas with group E high-methane natural gas or gas from LNG regasification, in such proportions that the resulting mixtures would meet the minimum energy requirements for natural gases from the Ls, Lw and E groups as well as the minimum and maximum energy requirements for natural gas S group (a gas containing carbon dioxide distributed in Hungary). The mixing proportions of these gases were determined, the potential compositions of the resulting mixtures, their energy parameters and the supply pressures of the end devices burning these mixtures were given. Based on the calculations performed, the categories of devices that could potentially be supplied with either partially purified biogas or its mixtures with group E high-methane natural gas or gas from LNG regasification were indicated. The article also describes what, if any, modifications will be necessary to such devices to make them safe to use after the gas change.
Źródło:
Nafta-Gaz; 2022, 78, 8; 608-617
0867-8871
Pojawia się w:
Nafta-Gaz
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of advanced technology for combustion of homogeneous fuel mixture
Autorzy:
Puškár, Michal
Lavčák, Matúš
Šoltésová, Marieta
Kopas, Melichar
Powiązania:
https://bibliotekanauki.pl/articles/2203092.pdf
Data publikacji:
2022
Wydawca:
Politechnika Śląska. Wydawnictwo Politechniki Śląskiej
Tematy:
analysis
advanced technology
combustion
fuel mixture
analiza
zaawansowana technologia
spalanie
mieszanka paliwowa
Opis:
The most serious problems to overcome for a successful operation of the HCCI engine are control of the combustion phase, limited operational range, cold start of engine and high noise level during engine operation. This study aims at describing the engine power output characteristics and emission characteristics of HCCI engines under different testing conditions and the various challenges associated with these engines. Furthermore, this study holds a potential guide for overcoming these challenges and improvement of the engine power output as well as the emission characteristics. Thus, it is possible to say, concerning the performed investigation work, that HCCI combustion can be applied in existing conventional engines after their modifications. The most significant result of the HCCI process application is the reduction of NOx emissions and soot emissions, keeping almost the same engine power output as the conventional combustion process.
Źródło:
Zeszyty Naukowe. Transport / Politechnika Śląska; 2022, 117; 211--220
0209-3324
2450-1549
Pojawia się w:
Zeszyty Naukowe. Transport / Politechnika Śląska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Changes in carbohydrate content in mixtures of field pea and spring triticale determining the quality of green fodder
Zmiany zawartości węglowodanów w mieszankach grochu siewnego z pszenżytem jarym decydujące o jakości zielonki
Autorzy:
Górski, R.
Płaza, A.
Rudziński, R.
Powiązania:
https://bibliotekanauki.pl/articles/13925491.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Przyrodniczy w Lublinie. Wydawnictwo Uniwersytetu Przyrodniczego w Lublinie
Tematy:
field pea
spring triticale
mixture
harvest date
carbohydrate
green forage
feed quality
Źródło:
Agronomy Science; 2022, 77, 1; 93-102
2544-4476
2544-798X
Pojawia się w:
Agronomy Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Combined effects of helical force and rotation on stationary convection of a binary ferrofluid in a porous medium
Autorzy:
Kpossa, M.
Monwanou, A. V.
Powiązania:
https://bibliotekanauki.pl/articles/2174187.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
konwekcja
ferrofluid
ośrodek porowaty
helical force
stationary convection
binary mixture of ferrofluid
porous medium
rotation
Opis:
This work studies the simultaneous effects of helical force, rotation and porosity on the appearance of stationary convection in a binary mixture of a ferrofluid and on the size of convection cells. We have determined the analytical expression of the Rayleigh number of the system as a function of the dimensionless parameters. The effect of each parameter on the system is studied. The consideration of the simultaneous effect of the basic characteristics made it possible to determine the evolution of the convection threshold in the ferrofluid and then the size of convection cells. The analyzes of the various results obtained allowed us to deduce whether the convection sets in quickly or with a delay when the various effects taken into account in the study are considered simultaneously.
Źródło:
International Journal of Applied Mechanics and Engineering; 2022, 27, 2; 158--176
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of suction on the mechanical behaviour of unsaturated compacted clay-sand mixtures
Autorzy:
Bouchemella, Salima
Taibi, Said
Powiązania:
https://bibliotekanauki.pl/articles/2172880.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
suction
unsaturated soil
clay-sand mixture
unconfined compression strength
strain secant modulus
wetting-drying path
Opis:
In this work, a series of unconfined compression tests at different water contents were performed to investigate the mechanical behaviour of clay–sand mixtures compacted in standard Proctor conditions. For studying the effect of water content and suction on unconfined compressive strength (UCS) and on strain secant modulus (E50 modulus) of these mixtures, drying–wetting paths were defined by measuring the soil–water characteristic curves (SWCCs) using osmotic and salt solution techniques and filter paper method. The results highlighted that an increase in sand content of the mixture leads to an increase in the maximum dry densities and a decrease in the optimum water content of the materials. However, at the given state, when clay is mixed with 25% of sand, the UCS and E50 modulus increase to 37% and 70%, respectively, compared to those of clayey samples. But when clay is mixed with 50% of sand, the UCS and E50 modulus decrease to 38% and 46%, respectively, compared to those of clayey samples. The results also indicate that the UCS and E50 increase with a decrease in the water content and an increase in suction, irrespective of the sand content.
Źródło:
Studia Geotechnica et Mechanica; 2022, 44, 3; 175--189
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaporation of Zinc in an Argon - Hydrogen Mixture
Autorzy:
Matuła, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/2125530.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
evaporation
gas atmosphere
thermogravimetry
argon-hydrogen mixture
Opis:
Many modern processes for the production and casting of metals and their alloys are carried out in protective gas atmospheres, which protect them, for example, from oxygen pollution. This applies, for example, to titanium, magnesium or aluminum alloys. Most liquid alloys are comprised of constituents that differ in vapor pressures, resulting in harmful phenomenon during melting due to evaporation of some of its components. This harmful process may be limited by the selection of a suitable gas atmosphere in which the liquid metal treatment process is carried out. In the paper, results of study on the impact of the type of gas atmosphere on the rate of evaporation of zinc in argon - hydrogen mixtures are presented. It should be noted that such mixtures are used, for example, in metal welding processes, in which it is also possible to evaporate a component of the so-called liquid metal pool. The research results showed that the rate of zinc evaporation increases with the increase of hydrogen content in the gas atmosphere.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 3; 885--888
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigations of Properties of Soil-Aggregate Mixtures
Autorzy:
Skrzypczak, Izabela
Powiązania:
https://bibliotekanauki.pl/articles/27314805.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
soil-aggregate mixture
strength parameters
grain-size distribution
optimal moisture
mieszanka glebowo-kruszywowa
parametry wytrzymałościowe
rozkład wielkości ziarna
wilgotność optymalna
Opis:
The subject of this paper is the evaluation of the use of waste material, which is the native soil. On the example of the base ground taken from the village of Lipie (Podkarpackie voivodeship), soil-aggregate mixtures were prepared with a different degree of addition of natural aggregate. The study analysed the quantitative and qualitative parameters of the prepared mixtures and assessed their physical and mechanical properties to determine their suitability for the construction of infrastructural facilities. It should be noted that most specifications recommend the use of primarily aggregate mixtures. The paper presents the results of a study analysing the effect of aggregate admixture to the native soil on selected physical and strength properties of the mixtures developed. The obtained results confirmed the validity of research on the use of soil-aggregate mixtures for construction purposes.
Źródło:
Civil and Environmental Engineering Reports; 2022, 32, 3; 116--132
2080-5187
2450-8594
Pojawia się w:
Civil and Environmental Engineering Reports
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigations on Mechanical Properties of Bio-Waste Micro Particles Reinforced Phenol Formaldehyde Composites
Autorzy:
Sujin Jose, A.
Athijayamani, A.
Jani, S. P.
Stalany, Mago V.
Khan, Adam M.
Powiązania:
https://bibliotekanauki.pl/articles/2048760.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
wood sawdust particles
coir pith particles
hybrid composites
mechanical properties
rule of mixture method
Opis:
A characteristic study on the phenol formaldehyde (PF) composite is carried out based on the micro level bio waste particles such as wood sawdust (WSD) and coir pith (CP). Composite is characterized by mechanical properties such as tensile, flexural and impact at different percentages of particles (0-50% by weight) to find out the optimum percentage of particle loading to get the maximum properties. The WSD/CP/PF hybrid composite is also prepared by two different methods i.e., one: one (1:1) ratio and rule of mixture. The first method (1:1) is used to find out the optimum level of hybrid particles loading to get the maximum properties. But, the second method is followed to find out the weight percentages of particles influencing the properties of resulting composite. The results show that the mechanical properties of WSD/PF are higher than CP/PF composite in the entire particle loading. The optimum particle loading to get the maximum properties is 40 wt.% in CP/PF composite, whereas for WSD/PF composite are at 30 wt.%. The hybrid composite (1:1) also gives the maximum properties at 30 wt.%. Moreover, the hybrid composite (20WSD/10CP) prepared by rule of mixture showed the highest mechanical properties compared to the other particle loading. It is identified that the WSD particles are most influencing the properties of PF composites than the CP particles. Fractographic study was performed using scanning electron microscope to examine the failure mechanism of the composite specimens.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 1; 377-384
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Lubricating Properties of Polyester Oils and R404A Refrigerant Mixtures under Starved Lubrication Conditions
Właściwości smarne mieszanin olejów poliestrowych z czynnikiem chłodniczym R404A w waunkach skąpego smarowania
Autorzy:
Górny, Kasper
Stachowiak, Arkadiusz
Tyczewski, Przemysław
Zwierzycki, Wiesław
Powiązania:
https://bibliotekanauki.pl/articles/2171807.pdf
Data publikacji:
2022
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
oil/refrigerant mixture
lubricating properties
starved lubrication
mieszanina olej/czynnik chłodniczy
właściwości smarne
skąpe smarowanie
Opis:
There has been a dynamic shift towards the use of ecological refrigerants in the refrigeration industry. Currently, they must not contain fluorine and chlorine. The substances that deplete the ozone layer have already been withdrawn, and the refrigerants that increase the greenhouse effect are getting restricted. Until recently, R404A was a quite commonly used HFC refrigerant for commercial refrigeration equipment in both small and large systems. Although R404A refrigerant has considerable greenhouse effect potential, it has not been banned from use in existing refrigeration systems. The widespread use of R404A refrigerant requires appropriate compressor lubricants.In refrigeration compressors, the amount of oil in friction pairs in certain situations may be insufficient. In that event, poor lubrication conditions may occur. There may also be a situation in which the areas of friction lack lubricant and friction pairs are lubricated only by the refrigerant.The article contains a methodical selection of test parameters for polyester oils, allowing one to assess the lubricating properties of the mixtures of oils for refrigeration compressors and refrigerants under poor lubrication conditions. The article also includes the results of wear tests which allow one to evaluate the lubricating properties of oil-refrigerant mixtures under starved lubrication conditions for R404A refrigerant and polyester oils.
Obecnie w chłodnictwie następuje dynamiczny zwrot w kierunku stosowania ekologicznych czynników chłodniczych. Dość powszechnie stosowanym czynnikiem chłodniczym z grupy HFC dla komercyjnych urządzeń chłodniczych zarówno w małych jak i dużych instalacjach był do niedawna R404A, co wiąże się z potrzebą doboru odpowiednich sprężarkowych środków smarnych. W sprężarkach chłodniczych może wystąpić sytuacja, w której ilość oleju w węzłach tarcia jest niewystarczająca. Wówczas mogą wystąpić skąpe warunki smarowania lub smarowanie tylko przez czynnik chłodniczy. W artykule przedstawiono metodyczny dobór parametrów badań pozwalających na ocenę właściwości smarnych olejów do sprężarek chłodniczych w mieszaninie z czynnikiem chłodniczym w warunkach skąpego smarowania dla olejów poliestrowych. Umieszczono również wyniki badań zużyciowych pozwalających na ocenę właściwości smarnych mieszanin olej – czynnik chłodniczy w warunkach skąpego smarowania uzyskanych dla czynnika chłodniczego R404A z olejami poliestrowymi.
Źródło:
Tribologia; 2022, 3; 9--15
0208-7774
Pojawia się w:
Tribologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mathematical modelling of the process of pipeline deformation through which gas-liquid mixtures with aggressive components are transported
Autorzy:
Oliynyk, A. P.
Feshanych, L. I.
Grygorchuk, G. V.
Powiązania:
https://bibliotekanauki.pl/articles/2172155.pdf
Data publikacji:
2022
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
tense state
pipeline
viscous fluid flow
dynamic viscosity
Navier-Stokes equations
gas mixture
rurociąg
lepkość dynamiczna
równania Naviera-Stokesa
mieszanka gazowa
Opis:
Purpose Mathematical modelling of the process of deformation of pipeline, transporting gas-liquid mixtures with aggressive components and a comparative analysis of the value of the specified velocity depending on the dynamic viscosity of the multicomponent gas mixture is conducted. Design/methodology/approach A mathematical model of the process of leakage of the transported product due to the loss of tightness of the pipe based on the system of Navier-Stokes equations with boundary conditions with considering the geometry of the leakage zones and the value of the leakage rate is implemented. Findings Models of the process of deformation of the pipeline due to displacements of a certain set of surface points by specifying different types of functions, describing the geometry of deformed sections are constructed. The method of calculating the tensely deformed state based on the data on the movement of surface points by comparing different ways of setting functions, taking into account the actual configuration of sections and axes is improved. The change of flow characteristics in the pipeline when changing the structure of the mix, transported by studying of influence of change of dynamic viscosity is investigated; The method of calculating the rate of leakage of the mixture in case of loss of tightness due to the occurrence of critical stresses in the pipe material is improved. Research limitations/implications Building a model of the deformation process, information about the nature, duration of forces and loads affecting the pipeline is not used. The law of the pipeline movement was constructed having taken into account the deformation of the sections in three directions. The necessity to take wind loads into account, estimating the real tensely deformed state was displayed. Practical implications Using the method of calculating the tensely deformed state based on the data on the movement of surface points by comparing different ways of setting functions, taking into account the actual configuration of sections and axes. Originality/value According to the computational algorithms created on the basis of the specified models, the calculations of the tense state of the pipelines and the flow rate of the mixture depending on its composition were performed. An analysis of the results of calculations - tense intensity and flow rate depending on the dynamic viscosity of the mixture is performed. The influence on the flow parameters - the flow rate of the mixture and the force of hydraulic resistance - changes in the dynamic viscosity of the mixture is analyzed.
Źródło:
Journal of Achievements in Materials and Manufacturing Engineering; 2022, 111, 2; 57--63
1734-8412
Pojawia się w:
Journal of Achievements in Materials and Manufacturing Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 500

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