Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Centralna Biblioteka Wojskowa Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaCentralna Biblioteka Wojskowa

Wyszukujesz frazę "gas resistance" wg kryterium: Wszystkie pola

  Lista filtrów
Wyrównaj
Wyświetlanie 1-15 z 28
Tytuł:
Comparison of the results for calculation of vortex currents after sudden expansion of the pipe with different diameters
Autorzy:
Kholboev, B. M.
Navruzov, D. P.
Asrakulova, D. S.
Engalicheva, N. R.
Turemuratova, A. A.
Powiązania:
https://bibliotekanauki.pl/articles/2174200.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
fluktuacja prędkości
prąd wirowy
anizotropia turbulencji
two-fluid turbulence model
sudden expansion
velocity fluctuation
intensity of fluctuations
gas resistance
quasi-periodic regime
Opis:
In this work, a numerical study of a sharply expanding highly swirling flow is carried out using v2-f models based on the Comsol Multiphysics 5.6 software package and a two-fluid turbulence model. The results obtained are compared with known experimental data with different pipe diameters. The purpose of this work is to test the ability of models to describe anisotropic turbulence. It is shown that the two-fluid model is more suitable for studying such flows.
Źródło:
International Journal of Applied Mechanics and Engineering; 2022, 27, 2; 115--123
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Layered thin film nanostructures of Pd/WO3-x as resistance gas sensors
Autorzy:
Urbańczyk, M.
Maciak, E.
Gut, K.
Pustelny, T.
Jakubik, W.
Powiązania:
https://bibliotekanauki.pl/articles/200121.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
tungsten trioxide
palladium
layered nanostructure
resistance sensor
nitrogen dioxide
ammonia
Opis:
Layered nanostructures of tungsten trioxide WO3-x about 62 nm thick, with a very thin film of palladium (about 3.3 nm) on the top, have been studied for gas-sensing application at temperatures 50.C and 120.130.C and low NO2 and NH3 concentrations in 6%, 30% or 45% relative humidity in the air. Thin film WO3-x nanostructures were obtained by vacuum deposition on a common Si-SiO2 substrate at room temperature and 120.C. The palladium was coated by vacuum evaporation at room temperature and 4 �E 10.6 mbar on WO3-x layers obtained at two different substrate temperatures. The average rate of growth of the films, controlled by a QCM, was 0.1.0.2 nm/s. A multi-channel (four-channel interdigital gold electrodes) planar resistance gas sensor structure was used in the experiments. The surface of the nanostructures was characterized by means of the AFM method. Good sensor results have been observed at these layered nanostructures with an increasing resistance for NO2 molecules and decreasing resistance for NH3 molecules in a humid air atmosphere. The interaction and recovery speed were higher in the case of the nanostructure obtained at room temperature.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2011, 59, 4; 401-407
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nitrate reduction and nitrogen fixation in symbiotic association Rhizobium - legumes.
Autorzy:
Luciński, Robert
Polcyn, Władysław
Ratajczak, Lech
Powiązania:
https://bibliotekanauki.pl/articles/1043794.pdf
Data publikacji:
2002
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
root nodules
nitrate reductase (NR)
dissimilatory nitrate reduction
nitrogenase
bacteroids
gas diffusion resistance
Opis:
The inhibitory effect of nitrate on nitrogenase activity in root nodules of legume plants has been known for a long time. The major factor inducing changes in nitrogenase activity is the concentration of free oxygen inside nodules. Oxygen availability in the infected zone of nodule is limited, among others, by the gas diffusion resistance in nodule cortex. The presence of nitrate may cause changes in the resistance to O2 diffusion. The aim of this paper is to review literature data concerning the effect of nitrate on the symbiotic association between rhizobia and legume plants, with special emphasis on nitrogenase activity. Recent advances indicate that symbiotic associations of Rhizobium strains characterized by a high nitrate reductase activity are less susceptible to inhibition by nitrate. A thesis may be put forward that dissimilatory nitrate reduction, catalyzed by bacteroid nitrate reductase, significantly facilitates the symbiotic function of bacteroids.
Źródło:
Acta Biochimica Polonica; 2002, 49, 2; 537-546
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination Of Gas Mixture Components Using Fluctuation Enhanced Sensing And The LS-SVM Regression Algorithm
Autorzy:
Lentka, Ł.
Smulko, J. M.
Ionescu, R.
Granqvist, C. G.
Kish, L. B.
Powiązania:
https://bibliotekanauki.pl/articles/221708.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
LS-SVM algorithm
resistance gas sensor
fluctuation enhanced sensing
gas detection
Opis:
This paper analyses the effectiveness of determining gas concentrations by using a prototype WO3 resistive gas sensor together with fluctuation enhanced sensing. We have earlier demonstrated that this method can determine the composition of a gas mixture by using only a single sensor. In the present study, we apply Least-Squares Support-Vector-Machine-based (LS-SVM-based) nonlinear regression to determine the gas concentration of each constituent in a mixture. We confirmed that the accuracy of the estimated gas concentration could be significantly improved by applying temperature change and ultraviolet irradiation of the WO3 layer. Fluctuation-enhanced sensing allowed us to predict the concentration of both component gases.
Źródło:
Metrology and Measurement Systems; 2015, 22, 3; 341-350
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Portable exhaled breath analyzer employing fluctuation-enhanced gas sensing method in resistive gas sensors
Autorzy:
Kwiatkowski, A.
Chludziński, T.
Smulko, J.
Powiązania:
https://bibliotekanauki.pl/articles/220591.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
resistance gas sensor
fluctuation enhanced sensing
flicker noise
gas detection
breath sample collection
Opis:
This paper presents a portable exhaled breath analyser, developed to detect selected diseases. The set-up employs resistive gas sensors: commercial MEMS sensors and prototype gas sensors made of WO3 gas sensing layers doped with various metal ingredients. The set-up can modulate the gas sensors by applying UV light to induce physical changes of the gas sensing layers. The sensors are placed in a tiny gas chamber of a volume of about 22 ml. Breath samples can be either injected or blown into the gas chamber when an additional pump is used to select the last breath phase. DC resistance and resistance fluctuations of selected sensors using separate channels are recorded by an external data acquisition board. Low-noise amplifiers with a selected gain were used together with a necessary bias circuit. The set-up monitors other atmospheric parameters interacting with the responses of resistive gas sensors (humidity, temperature, atmospheric pressure). The recorded data may be further analysed to determine optimal detection methods.
Źródło:
Metrology and Measurement Systems; 2018, 25, 3; 551-560
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Study of the Nonsteady-State Filtration Process in a Fibrous Material in Conditions of Real Dust Loading
Autorzy:
Majchrzycka, K.
Powiązania:
https://bibliotekanauki.pl/articles/90344.pdf
Data publikacji:
2000
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
air filtration
fibrous filtering material
particular deposition
filtration efficiency
clogging test
gas flow resistance
model of nonsteady-state filtration
filtracja powietrza
materiał filtracyjny
skuteczność filtracji
opór przepływu gazu
Opis:
The study concerns ways to describe filtration efficiency and gas flow resistance while particles are deposited in fibrous respiratory protective filters under conditions characteristic for their use. The performance of fibrous filter materials of varied structure and electrostatic properties was studied, using polydisperse coarse-grained aerosols and submicron aerosols of sodium chloride. Evidence was found that changes in airflow resistance depended to a large extent on air humidity and the concentration of the aerosol. A relationship was also found between the electrostatic properties of filter media and their decreasing efficiency with time. A numerical model was developed to simulate the phenomenon of nonsteady-state filtration for 2 mechanisms of deposition, which permitted assessment of the filtration characteristics of filter media of any design and in any conditions.
Źródło:
International Journal of Occupational Safety and Ergonomics; 2000, Zeszyt Specjalny; 45-58
1080-3548
Pojawia się w:
International Journal of Occupational Safety and Ergonomics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sustainability in the Supply Chain: reducing supply-chain greenhouse gas emissions in medium-sized businesses
Autorzy:
Stepan, John
Powiązania:
https://bibliotekanauki.pl/articles/529782.pdf
Data publikacji:
2013
Wydawca:
Wyższa Szkoła Bankowa we Wrocławiu
Tematy:
Medium Sized Businesses) greenhouse gas emission reduction resistance to sustainability issues
supply-chain / business operations improvement
role of higher education establishments
Opis:
Medium Sized Businesses (MSB’s) form a sizable part of the Polish and EU Business Environment with many of these companies operating in industrial / commercial sectors. Their aggregate Green-House Gas (GHG) impact is therefore significant. However, within MSB’s, there is a significant resistance to GHG / Sustainability issues. This paper presents ways in which MSB’s can be convinced that positive responses on GHG / Sustainability issues can provide sustained Business Benefits. It goes on to describe how the Academic Community can contribute to this process by assisting MSB’s to operate in a more environmentally sustained manner whilst at the same time gaining the advantages of concrete Business and Financial Operation benefits.
Źródło:
Central and Eastern European Journal of Management and Economics (CEEJME); 2013, 1, 1; 47-68
2353-9119
Pojawia się w:
Central and Eastern European Journal of Management and Economics (CEEJME)
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mathematical Model of Gas, Powder and Bed Flow in Metallurgical Shaft Furnaces
Autorzy:
Panic, B.
Powiązania:
https://bibliotekanauki.pl/articles/353174.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
mathematical modeling
metallurgical shaft furnace
system: descending packed bed - gas - powder
resistance of gas flow
bed suspension
Opis:
This paper presents the second phase of model investigations. In the first phase research into flow for the system “gas transporting powder - moving packed bed” was conducted in the physical modeling. The influence of bed, powder and gas parameters on values of interaction forces and phenomena occurring in investigated system was defined. The article discusses the successive stage of investigations into gas flow carrying the powder through the descending packed bed. The research was performed with the application of mathematical modeling after tests with a physical model in use had been accomplished. The elaborated mathematical model was used to calculate resistance values of gas flow carrying the powder through the descending packed bed, masses of ‘static’ and ‘dynamic’ powders as well as total mass of powder holdup in the bed. Then the verification of the model was done comparing the obtained results with those from the physical model.
Źródło:
Archives of Metallurgy and Materials; 2016, 61, 1; 227-232
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fretting Corrosion Effect on Fatigue Resistance of Gas Turbine Engine Part Material
Wpływ korozji ciernej na wytrzymałość zmęczeniową materiału części silnika turbiny gazowej
Autorzy:
Bezyazychny, Vyacheslav F.
Szczerek, Marian
Timofeev, Mikhail V.
Lyubimov, Roman V.
Powiązania:
https://bibliotekanauki.pl/articles/188196.pdf
Data publikacji:
2020
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
fretting corrosion
material fatigue
high-cycle
low-cycle
fatigue enhancement
surface plastic deformation methods
korozja cierna
zmęczenie materiału
wysoka częstotliwość
niska częstotliwość
zwiększanie odporności na zmęczenie
metody odkształcania plastycznego powierzchni
Opis:
The paper presents the results of a study on the fretting corrosion effect on strength as per the diagrams of material fatigue of low-cycle and high-cycle loading. An experimental study of the effect of fretting corrosion on fatigue of a titanium alloy VT3-1 showed that, when choosing a particular technological method to increase fatigue resistance of gas turbine engine parts operating under fretting corrosion conditions, it is necessary to take into account the fact that fretting itself is intensive strengthening and at the same time a softening factor affecting the surface layers of the material. Technological methods of surface plastic deformation treatment result in a significant change in the parameters of metal surface layer state, which depends on both the type and duration of treatment. If the power and time parameters of processing are too high, the surface may be re-cold worked and the surface layer of the material almost completely exhausts the reserve of plasticity, as a result dangerous microcracks occur, and the formation of particles of flaking metal emerge. Possible ways using technological methods have been suggested by the authors to improve fretting strength of part surfaces operating under fretting corrosion conditions.
W artykule przedstawiono wyniki badań wpływu korozji ciernej na wytrzymałość zmęczeniową przy niskiej i wysokiej częstotliwości obciążania. Eksperymentalne badania wpływu korozji ciernej na zmęczenie stopu tytanu VT3-1 wykazały, że wybierając metodę technologicznego zwiększania odporności zmęczeniowej części silników turbogazowych pracujących w warunkach korozji ciernej, należy wziąć pod uwagę fakt, że sam fretting jest czynnikiem wzmacniającym i jednocześnie osłabiającym warstwy wierzchnie materiału. Technologiczne metody powierzchniowej obróbki plastycznej powodują istotną zmianę parametrów stanu warstwy metalu w zależności zarówno od rodzaju, jak i czasu trwania obróbki. Gdy parametry obróbki (moc i czas) są zbyt duże, powierzchnia zostaje poddana obróbce na zimno, warstwa wierzchnia materiału nie jest podatna na odkształcenie plastyczne, wobec czego powstają niebezpieczne mikropęknięcia oraz tworzą się odpryski. Wskazano potencjalne zabiegi technologiczne rekomendowane do zwiększenia odporności elementów maszyn pracujących w warunkach występowania korozji ciernej.
Źródło:
Tribologia; 2020, 290, 2; 7-14
0208-7774
Pojawia się w:
Tribologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studies of changes in electrical resistance of zinc oxide nanostructures under the influence of variable gaseous environments
Autorzy:
Procek, M.
Pustelny, T.
Stolarczyk, A.
Maciak, E.
Powiązania:
https://bibliotekanauki.pl/articles/201073.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
zinc oxide
ZnO
flower-like nanostructures
gas sensor
wide gap semiconductors
electric properties of semiconductors
tlenek cynku
kwiatopodobne nanostruktury
czujnik gazu
właściwości elektryczne półprzewodników
Opis:
The paper deals with the investigations concerning the influence of the changing gas environment on electrical resistance of zinc oxide (ZnO) nanostructures. The investigated structures are wide-gap semiconductors with the morphology of ZnO flower-shaped agglomerates of nanostructures. The resistance changes of these nanostructures were tested under the influence of various gases such as nitrogen dioxide (NO2), hydrogen (H2), ammonia (NH3) and also of humidity changes of carrier gases. To clarify the mechanisms of physicochemical processes in ZnO nanostructures during their interaction with gaseous environments, investigations were performed in two different carrier gases, viz. in synthetic air and in nitrogen. The study was carried out at a structure temperature of 200◦C.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2014, 62, 4; 635-639
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of the Bed Type on the Flow Resistance Change During the Two-Phase (Gas + Powder) Flow through the Descending Packed Bed
Wpływ rodzaju złoża na zmianę oporów przepływu podczas dwufazowego (gaz+pył) przepływu przez schodzące złoże kawałkowe
Autorzy:
Panic, B.
Powiązania:
https://bibliotekanauki.pl/articles/351216.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
descending packed bed
gas-powder flow
powder holdup
bed suspension
złoże schodzące
przepływ pyłu w gazie
zator gazowy
zawieszenie schodzącego złoża
Opis:
The flow of gases with powder in the countercurrent to the charge materials occurs in many chemical processes. In the shaft metallurgical devices, the physical and chemical processes take place also in the countercurrent system. An important issue is that there are no disruptions of the flow in this multiphase system. Under real operating conditions of the device, the powder is generated within the process and its source is the charge or it is inserted to the device within the process procedure. In this system, a problem of bed particle suspension appears. That is why the author undertook investigations on the gas - powder flow in the descending bed. A physical model of this system was constructed. The experiments were performed and the influence of gas velocity, a type and size of the bed and powder particles as well as the powder concentration in the gas was established. Conditions when the descending bed suspension occurs were defined. In the case of physical model with glass materials, the suspension of bed did not occur. Therefore, investigations using beds of high alumina materials, blast furnace pellets and iron powder were performed. The results are presented below. When the bed of glass spheres was replaced with the bed of alumina spheres, a considerable increase in the volume of powder held up in the bed the gas flow resistance were observed. The surface properties of bed particles changed and better conditions for powder holdup were created. The actual gas velocity in the bed increased due to void fraction reduction. Replacement of the glass powder with the iron powder caused a change in the powder density, its surface properties and the shape factor. Greater amounts of the iron powder were held up in the bed and the gas flow resistance increased. Comparing the alumina particle bed - iron powder system to the blast furnace pellet bed - iron powder system, changes in the surface properties of bed particles and the void fraction of bed changed. The study results were the basis for defining conditions of the descending bed suspension.
Przepływ gazów z pyłem w przeciwprądzie do materiałów wsadowych występuje w wielu procesach chemicznych. W szybowych agregatach metalurgicznych procesy fizykochemiczne zachodzą także w układzie przeciwprądowym Istotnym jest by w tym wielofazowym układzie nie dochodziło do zakłóceń przepływu. W warunkach rzeczywistych pracy agregatów pył jest generowany podczas przebiegu procesu a jego źródłem są materiały wsadowe lub jest wprowadzany do agregatu w ramach procedury procesowej. W układzie takim pojawia się problem zawieszania cząstek złoża. Stąd autor podjął badania przepływu gaz + pył w złożu schodzącym. Skonstruowano model fizyczny układu. Przeprowadzono badania z analizą wpływ u prędkości gazu. rodzaju i wielkości kawałków złoża, cząstek pyłu, ilości pyłu w gazie. Określono warunki, w których dochodzi do zawieszania schodzącego złoża. W przypadku modelu z materiałów szklanych do zawieszania złoża nie doszło. W związku z tym podjęto badania na złożach z tworzyw wysokoglinowych na bazie AI2O3 i grudek wielkopiecowych oraz pyle żelaza. Otrzymane wyniki przedstawiono w niniejszej publikacji. Zamieniając złoże z kul szklanych na złoże z kul wysokoglinowych stwierdza się wyraźny wzrost ilości zatrzymanego w złożu pyłu i oporów przepływu gazu. Zmianie uległy własności powierzchniowe cząstek złoża, powstały korzystne warunki do odkładania pyłu, wzrosła prędkość rzeczywista gazu w wyniku zmniejszenia wolnych przestrzeni. Zastąpienie pyłu szklanego pyłem żelaza spowodowało że zmianie uległa gęstość pyłu, jego własności powierzchniowe, współczynnik kształtu. Pył żelaza został zatrzymany w złożu w większej ilości, wzrosły też opory przepływu gazu. Przy porównaniu układów złoże z kul wysokoglinowych - pył żelaza i złoże z grudek wielkopiecowych - pył żelaza, stwierdzono zmianę nie tylko własności powierzchniowych złoża ale również średnicy cząstek złoża a co za tym idzie wskaźnika początkowych wolnych przestrzeni. Uzyskane wyniki badań były podstawą do określenia warunków, w których dochodzi do zawieszania schodzącego złoża.
Źródło:
Archives of Metallurgy and Materials; 2014, 59, 2; 795-800
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The thermoelastic state of a bi-material with an open gas-filled interface crack
Autorzy:
Serednytska, Khristina
Martynyak, Rostyslav
Chumak, Kostyantyn
Powiązania:
https://bibliotekanauki.pl/articles/280179.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
bi-material
interface crack
ideal gas
pressure
thermal resistance
Opis:
The thermoelastic behavior of a bi-material with a gas-filled interface crack is investigated. The bi-material is subjected to a uniform tensile load and a uniform heat flow. The gas exerts pressure on the crack surfaces and offers thermal resistance proportional to the crack opening. The gas state is assumed to be described by the ideal gas law. The effects of gas mass, gas thermal conductivity and heat flux on the crack opening, interface temperature jump, gas pressure and stress intensity factors are analyzed. It is revealed that a bi-material with a heat-conducting crack exhibits the heat flow directional effect.
Źródło:
Journal of Theoretical and Applied Mechanics; 2019, 57, 2; 331-341
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tribological Characteristic of Titanium Alloy Surface Layers Produced by Diode Laser Gas Nitriding
Autorzy:
Lisiecki, A.
Piwnik, J.
Powiązania:
https://bibliotekanauki.pl/articles/351668.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
titanium alloys
laser gas nitriding
surface layer
wear resistance
ball-on-disk
Opis:
In order to improve the tribological properties of titanium alloy Ti6Al4V composite surface layers Ti/TiN were produced during laser surface gas nitriding by means of a novel high power direct diode laser with unique characteristics of the laser beam and a rectangular beam spot. Microstructure, surface topography and microhardness distribution across the surface layers were analyzed. Ball-on-disk tests were performed to evaluate and compare the wear and friction characteristics of surface layers nitrided at different process parameters, base metal of titanium alloy Ti6Al4V and also the commercially pure titanium. Results showed that under dry sliding condition the commercially pure titanium samples have the highest coefficient of friction about 0.45, compared to 0.36 of titanium alloy Ti6Al4V and 0.1-0.13 in a case of the laser gas nitrided surface layers. The volume loss of Ti6Al4V samples under such conditions is twice lower than in a case of pure titanium. On the other hand the composite surface layer characterized by the highest wear resistance showed almost 21 times lower volume loss during the ball-on-disk test, compared to Ti6Al4V samples.
Źródło:
Archives of Metallurgy and Materials; 2016, 61, 2A; 543-552
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Resistance of WE43 and ZRE1 Magnesium Alloys to Gas Corrosion
Autorzy:
Przeliorz, R.
Piątkowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/379573.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
wear resistant alloys
magnesium alloys
oxidation resistance
stopy odporne na zużycie
stopy magnezu
odporność na utlenianie
Opis:
In spite of the fact that in most applications, magnesium alloys are intended for operation in environments with room temperature, these alloys are subject to elevated temperature and oxidizing atmosphere in various stages of preparation (casting, welding, thermal treatment). At present, the studies focus on development of alloys with magnesium matrix, intended for plastic forming. The paper presents results of studies on oxidation rate of WE43 and ZRE1 magnesium foundry alloys in dry and humidified atmosphere of N2+1%O2. Measurements of the oxidation rate were carried out using a Setaram thermobalance in the temperature range of 350-480°C. Corrosion products were analyzed by SEM-SEI, BSE and EDS. It was found that the oxide layer on the WE43 alloy has a very good resistance to oxidation. The high protective properties of the layer should be attributed to the presence of yttrium in this alloy. On the other hand, a porous, two-layer scale with a low adhesion to the substrate forms on the ZRE1 alloy. The increase in the sample mass in dry gas is lower than that in humidified gas.
Źródło:
Archives of Foundry Engineering; 2017, 17, 2; 217-221
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Calculation of Hydrodynamic Characteristics of Apparatus with Regular Tubular Packing
Autorzy:
Issayeva, Aikerim Nurlankyzy
Korganbayev, Bayrzhan Nogaybaevich
Volnenko, Alexandr Anatolevich
Zhumadullayev, Daulet Koshkarovich
Jumadillayeva, Gulzhamal Nurtazaevna
Powiązania:
https://bibliotekanauki.pl/articles/2069897.pdf
Data publikacji:
2021
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
regular tubular packing
vortex interaction
local resistance
roughness
hydraulic resistance
retained liquid amount
gas content
Opis:
Among the apparatuses with a regular arrangement of packing elements creating an in-phase mode of vortex interaction, which ensures high efficiency of the processes, it is interesting to use a standard tubular packing. Such packing allows additional advantages associated with heat supply or extraction directly in the contact zone of the interacting phases, which is very important for conducting some chemisorption processes. The research covers such hydrodynamic regularities as hydraulic resistance during a heat carrier movement in pipes and during external flow around a tubular beam, retained liquid amount and gas content of layer in the external flow around the tubular beam with liquid and gas flows. The research was carried out using an experimental setup with a heat and mass transfer apparatus with regular tubular packing. The medium used during experiments is water-air. The research methodology included standard methods for determining hydraulic resistance and retained liquid amount and visual observation and photographing of gas-liquid flows. The novelty of the research was equations – one for calculating the hydraulic resistance in pipes, taking into account local resistances and pipe roughness. The other ones for determining the pressure losses during the external flow around the tubular beam, the retained liquid amount, and the gas content of the layer, taking into account the vortex interaction of gas and liquid flows. Graphical and calculated dependences of the investigated hydrodynamic characteristics were obtained as a result of the conducted research of the hydraulic resistance during the heat carrier movement in the pipes, as well as the hydraulic resistance and the retained liquid amount during the external flow around the tubular beam with a change in the gas velocity and irrigation density. When the heat carrier flows in the pipes, the numerical values of the hydraulic resistance in the transient mode do not exceed 1.5 kPa, in the developed turbulence mode in the range of the Reynolds number from 1·104 to 6·104 ΔР varies from 1.5 to 53 kPa. With the external flow around the tubular beam, in the developed turbulence mode wg = 4 m/s and L = 25 m3/m2h, the hydraulic resistance is 85 Pa, the retained liquid amount is 4.5·10-3 m. The change in the irrigation density in this mode (developed turbulence) in the L range from 10 to 100 m3/m2h leads to an increase in the hydraulic resistance from 65 to 160 Pa, the retained liquid amount from 2.16·10-3 to 13.6·10-3 m. The calculated dependencies are the basis of the method for calculating the hydrodynamic characteristics of the apparatus with the regular tubular packing, which can be used to calculate industrial devices.
Źródło:
Rocznik Ochrona Środowiska; 2021, 23; 868--882
1506-218X
Pojawia się w:
Rocznik Ochrona Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 28

Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies