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Wyszukujesz frazę "cryogenic" wg kryterium: Temat


Tytuł:
Experimental investigation of cryogenically treated HSS tool in turning on AISI1045 using fuzzy logic – Taguchi approach
Autorzy:
Raja, P.
Malayalamurthi, R.
Sakthivel, M.
Powiązania:
https://bibliotekanauki.pl/articles/202147.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
cryogenic
fuzzy
roughness
Taguchi
temperature
turning
Opis:
This work depicts the effects of deep cryogenically treated high-speed steel on machining. In recent research, cryogenic treatment has been acknowledged for improving the life or performance of tool materials. Hence, tool materials such as the molybdenum-based high-speed tool steel are frequently used in the industry at present. Therefore, it is necessary to observe the tool performance in machining; the present research used medium carbon steel (AISI 1045) under dry turning based on the L9 orthogonal array. The effect of untreated and deep cryogenically treated tools on the turning of medium carbon steel is analyzed using the multi-input-multi-output fuzzy inference system with the Taguchi approach. The cutting speed, feed rate and depth of cut were the selected process parameters with an effect on surface roughness and the cutting tool edge temperature was also observed. The results reveal that surface roughness decreases and cutting tool edge temperature increases on increasing the cutting speed. This is followed by the feed rate and depth of cut. The deep cryogenically treated tool caused a reduction in surface roughness of about 11% while the cutting tool edge temperature reduction was about 23.76% higher than for an untreated tool. It was thus proved that the deep cryogenically treated tool achieved better performance on selected levels of the turning parameters.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2019, 67, 4; 687-696
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theoretical analysis of LNG regasifier supplementing gas turbine cycle
Autorzy:
Szczygieł, Ireneusz
Rutczyk, Bartłomiej
Powiązania:
https://bibliotekanauki.pl/articles/1955037.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
LNG
gas turbine
cryogenic exergy
energy recovery
Opis:
Liquefied natural gas (LNG) is transported by the sea-ships with relatively low pressure (0.13–0.14 MPa) and very low temperature (about 100 K) in cryo-containers. Liquid phase, and the low temperature of the medium is connected with its high exergy. LNG receives this exergy during the liquefaction and is related with energy consumption in this process. When the LNG is evaporated in atmospheric regasifiers (what takes place in many on-shore terminals as well as in local regasifier stations) the cryogenic exergy is totally lost. fortunately, there are a lot of installations dedicated for exergy recovery during LNG regasification. These are mainly used for the production of electricity, but there are also rare examples of utilization of the LNG cryogenic exergy for other tasks, for example it is utilized in the fruit lyophilization process. In the paper installations based on the Brayton cycle gas turbine are investigated, in the form of systems with inlet air cooling, liquid phase injection, exhaust gas based LNG evaporation and mirror gas turbine systems. The mirror gas turbine system are found most exegetically effective, while the exhaust gas heated systems the most practical in terms of own LNG consumption.
Źródło:
Archives of Thermodynamics; 2021, 42, 4; 47-67
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
“Ghost structures” in alkaline fen microrelief as a consequence of Late Glacial periglacial activity in chalklands : a case study from the Chełm Hills (East Poland)
Autorzy:
Dobrowolski, Radosław
Powiązania:
https://bibliotekanauki.pl/articles/2055867.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Geologiczne
Tematy:
alkaline peatlands
solifluction structures
relict cryogenic mounds
LiDAR
Opis:
On the basis of high-resolution LiDAR data, collected at the surface of alkaline fens in the Chełm Hills area (Lublin chalkland, East Poland), structures deviating from the natural paludification processes related to the development of fens (“ghost structures”) were identified. At each of the sites analysed, field verification by means of drillhole cores indicates an indirect relationship between the modern topography of the peatlands and the morphology of their substratum, related to periglacial processes. Three categories of periglacial structure were recognized in the chalk bedrock: (1) solifluction sheets, lobes and terraces; (2) pingo-type structures (ramparted depressions, lithalsas); and (3) relict cryogenic mounds. A conceptual model of the development of slope and peatland relief in the Lublin chalkland during the Late Glacial and Holocene was prepared on the basis of the results obtained. The results indicate the role of the periglacially transformed chalk substratum in the development of alkaline fens in the chalklands, which rarely was considered in previous studies.
Źródło:
Annales Societatis Geologorum Poloniae; 2021, 91, 4; 347--362
0208-9068
Pojawia się w:
Annales Societatis Geologorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Epileptic burst measurement using microelectrodes equipped on a cryogenic microprobe for minimally invasive brain surgery of intractable epilepsy treatment
Autorzy:
Yamakawa, T.
Ishizuka, S.
Grigorievich, Z. L.
Suzuki, M.
Fujii, M.
Powiązania:
https://bibliotekanauki.pl/articles/385222.pdf
Data publikacji:
2009
Wydawca:
Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Tematy:
epilepsy
cryogenic surgery
minimally invasive
microelectrodes
CMOS IC
Opis:
A microprobing system, which has the functions of measuring the intracranial EEG(IC-EEG) and freezing brain tissue, is proposed for the minimally invasive brain cryogenic surgery of intractable epilepsy treatment. Two fi76 µm platinum electrodes were equipped on a fi0.8 mm cryogenic probe. Epileptic burst, which was evoked on a brain sample of a rat, was measured by the electrodes. The freezing function was confirmed with the experiments with sliced hippocampus samples of a rat.
Źródło:
Journal of Automation Mobile Robotics and Intelligent Systems; 2009, 3, 4; 76-79
1897-8649
2080-2145
Pojawia się w:
Journal of Automation Mobile Robotics and Intelligent Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transport and storage of LNG in container tanks
Autorzy:
Lisowski, E.
Czyżycki, W.
Powiązania:
https://bibliotekanauki.pl/articles/245524.pdf
Data publikacji:
2011
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
LNG
transport
container tank
stationery tank
cryogenic tank
simulation
Opis:
The work presents issues with the structure and thermal calculations of mobile tank for transport and storage of LNG. A modern design of cryogenic tank container and stationery cryogenic tank is presented in the paper. Mobile cryogenics container tank has been designed for transportation of LNG as well as other liquefied cryogenic gases with the temperature down to -196 centigrade. The analysis included two types of logistics solutions: one involving the transport full container, which is removable from the vehicle and left in the workplace, and the second solution with reloading from mobile tank into simplified container tank or other mobile tank located in the workplace. Simplified container tank and mobile tank have been designed to storage some cryogenics gases as well as mobile container but without transportation of them. Modern and effective insulation materials were applied in the tank structure. Therefore, the liquefied cryogenic gases can be stored for a long time periods. Presented are selected depending on the extent of heat exchange in cryogenic conditions, as well as a model for FEM calculations of thermal insulation inside the tank and supports. Simulation results show the long storage times obtained for a simplified container which are close to the times obtained by stationary tanks, however a lot easier to transport without charge. Presented solutions and results of simulations may indicate, that depending on the requirements and considering manufacturing costs and operational conditions, the proper variant of the tank can be chosen.
Źródło:
Journal of KONES; 2011, 18, 3; 193-201
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of single whole body cryostimulation treatment on the dynamics and the level of maximal anaerobic power
Autorzy:
Klimek, Andrzej T.
Lubkowska, Anna
Szyguła, Zbigniew
Frączek, Barbara
Chudecka, Monika
Powiązania:
https://bibliotekanauki.pl/articles/2185364.pdf
Data publikacji:
2011-06-01
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
cryostimulation
cryogenic temperature
hypothermia
maximal anaerobic power
anaerobic capacity
Opis:
Objectives: The objective of this work was to determine the dynamics of maximal anaerobic power (MAP) of the lower limbs, following a single whole body cryostimulation treatment (WBC), in relation to the temperature of thigh muscles. Materials and Methods: The subjects included 15 men and 15 women with an average age (±SD) of 21.6±1.2 years. To evaluate the level of anaerobic power, the Wingate test was applied. The subjects were submitted to 6 WBC treatments at -130°C once a day. After each session they performed a single Wingate test in the 15, 30, 45, 60, 75 and 90th min after leaving the cryogenic chamber. The order of the test was randomized. All Wingate tests were preceded by an evaluation of thigh surface temperature with the use of a thermovisual camera. Results: The average thigh surface temperature $(\text{T}_\text{av})$ in both men and women dropped significantly after the whole body cryostimulation treatment, and next increased gradually. In women $\text{T}_\text{av}$ remained decreased for 75 min, whereas in men it did not return to the basal level until 90th min. A statistically insignificant decrease in MAP was observed in women after WBC. On the contrary, a non-significant increase in MAP was observed in men. The course of changes in MAP following the treatment was similar in both sexes to the changes in thigh surface temperature, with the exception of the period between 15th and 30th min. The shorter time to obtain MAP was observed in women till 90th min and in men till 45 min after WBC compared to the initial level. Conclusions: A single whole body cryostimulation may have a minor influence on short-term physical performance of supramaximal intensity, but it leads to improvement of velocity during the start as evidenced by shorter time required to obtain MAP.
Źródło:
International Journal of Occupational Medicine and Environmental Health; 2011, 24, 2; 184-191
1232-1087
1896-494X
Pojawia się w:
International Journal of Occupational Medicine and Environmental Health
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimization of cutting parameters in pocket milling of tempered and cryogenically treated 5754 aluminum alloy
Autorzy:
Samtas, G.
Korucu, S.
Powiązania:
https://bibliotekanauki.pl/articles/200335.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aluminum alloys
cryogenic treatment
surface roughness
Taguchi technique
optimization
Opis:
Aluminum alloys are widely used today in plastic injection molds in the automotive and aerospace industries due to their high strength and weight ratio, good corrosion and fatigue resistance as well as high feed rates. The 5754 aluminum alloy has high corrosion resistance and a structure suitable for cold forming. In this study, an AA 5754-H111 tempered aluminum alloy with the dimensions of 80£80£30 mm was used, and some of the materials were cryogenically heat treated. For the milling operations, φ12 mm diameter 76 mm height uncoated as well as TiCN and TiAlN coated end mills were used. Different levels of cutting depth (1.25, 2.0, 2.5 mm), cutting speed (50, 80, 100 m/ min), feed rate (265, 425, 530 m/ min) and machining pattern (concentric, back and forth and inward helical) were used. The number of experiments was reduced from 486 to 54 using the Taguchi L54 orthogonal array. The values obtained at the end of the experiments were evaluated using the signal-to-noise ratio, ANOVA, three-dimensional graphs and the regression method. Based on the result of the verification experiments, the processing accuracy for surface roughness was improved from 3.20 μm to 0.90 μm, with performance increase of 71.88%.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2019, 67, 4; 697-707
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ecosystem services of the cryogenic environments: identification, evaluation and monetisation - A review
Autorzy:
Abakumov, Evgeny
Suleymanov, Azamat
Guzov, Yuriy
Titov, Victor
Vashuk, Angelina
Shestakova, Elena
Fedorova, Irina
Powiązania:
https://bibliotekanauki.pl/articles/2073732.pdf
Data publikacji:
2022
Wydawca:
Instytut Technologiczno-Przyrodniczy
Tematy:
amenability
Arctic
cryogenic environment
economic assessment
ecosystem services
monetisation
Opis:
The article discusses the valuation of ecosystem services in connection with the economic activity of the Russian Federation in the Arctic zone. It also considers the categories of ecosystem services in general and the assessment of ecosystem services in the Arctic in particular. The article also considers types of negative impacts on the Arctic ecosystems, their assessment, and investment risks existing in ecosystem services. It is shown that the application of the methodology and ecosystem services contributes to the adequate assessment and creation of a hierarchical classification of “usefulness” and “benefits” for society derived from the existence, use, and non-use of ecosystems. The concept of Arctic ecosystem services consists of three components: identification, monetisation, and ecological risk assessment. Identification, classification, and initial assessment, mainly at the qualitative level, allow us to determine and classify services for further improvement of life quality and regulation of socio-economic effects of environmental changes. Quantitative assessment is related to the identification of the degree of ecosystem service amenability. The example of the Arctic ecosystems shows that the possibility to assess and the accuracy of the assessment can be quite different and largely depends on the type of service. The analysis of possible ecosystem services and their relationship with the quality of life in the Russian Arctic indicates significant investment risks.
Źródło:
Journal of Water and Land Development; 2022, 52; 1--8
1429-7426
2083-4535
Pojawia się w:
Journal of Water and Land Development
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Deep Cryogenic Treatment and Tempering at Different Temperatures of HS6-5-2 High Speed Steel
Autorzy:
Ciski, A.
Powiązania:
https://bibliotekanauki.pl/articles/352505.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
deep cryogenic treatment
high speed steel
tempering
hardness
microstructure
Opis:
The paper presents properties of HS6-5-2 high speed steel subjected to deep cryogenic treatment (DCT) and subsequent tempering at different temperatures. DCT process of HS6-5-2 steel leads to shifting of maximum hardness peak to the lower temperature and the reduction of the obtained maximum hardness by about 1 HRC. These changes in hardness may be due to the shifting of the stage of nucleation and growth of carbide phases to lower temperatures or the changes taking place in the matrix, connected with the additional transformation of the martensite proceeding during the isothermal martensitic transformation occurring at cryogenic temperatures and more extensively occurring precipitation processes, lowering the content of the carbon in the martensite, determining thereby its lower hardness.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 2; 929-934
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of deep cryogenic treatment on transformations during tempering of quenched D2 steel studies of XRD, structures, DSC, dilatometry, hardness and impact energy
Wpływ niskotemperaturowej obróbki kriogenicznej na przemiany podczas odpuszczania zahartowanej stali D2. Badania rentgenowskie, struktury, DSC, dylatometryczne, twardości i energii łamania
Autorzy:
Wierszyłłowski, I.
Samolczyk, J.
Wieczorek, S.
Andrzejewska, E.
Niemczyk, W.
Powiązania:
https://bibliotekanauki.pl/articles/211584.pdf
Data publikacji:
2008
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Obróbki Plastycznej
Tematy:
obróbka kriogeniczna
przesycanie
dylatometria
cryogenic processing
supersaturation
dilatometry
DSC
tempering
Opis:
The study analyses the influence of cryogenic treatment on the resultant structures, the development of changes during tempering and the properties obtained. It was observed that cryo treatment affects the properties through: a significant reduction in retained austenite content, gradual reduction in value of martensite tetragonality and an increase in the number of carbon atoms participating in transformations during tempering. The consequence of the transformations taking place during cryogenic treatment is precipitation of ?-carbide instead of ?-carbide during low tempering. The number of ?-carbides precipitated is higher than that of ?-carbide. This affects the functional characteristics of steel.
Podczas badań analizowano wpływ obróbki kriogenicznej na uzyskane struktury, przemiany podczas odpuszczania i uzyskiwane właściwości. Stwierdzono, że obróbka kriogeniczna wpływa na właściwości wskutek znacznego zmniejszenia zawartości austenitu szczątkowego, stopniowego obniżenia tetragonalności martenzytu i zwiększenia liczby atomów węgla biorących udział w przemianach podczas odpuszczania. W wyniku przemian zachodzących podczas obróbki kriogenicznej podczas odpuszczania wydziela się węglik ? zamiast węglika ?. Liczba węglików ? wydzielających się podczas odpuszczania jest większa niż liczba wydzielających się podczas obróbki konwencjonalnej węglików ? . Zmiany te mają wpływ na właściwości użytkowe stali.
Źródło:
Obróbka Plastyczna Metali; 2008, 19, 2; 53-59
0867-2628
Pojawia się w:
Obróbka Plastyczna Metali
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studies of Plasma-Focus discharges within the PF-360 facility equipped with a planar D2O-ice target
Autorzy:
Zebrowski, J.
Baranowski, J.
Jakubowski, L.
Sadowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/147057.pdf
Data publikacji:
2001
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
cryogenic target
ion beams
neutron yield
plasma focus
X-rays
Opis:
The paper reports on investigations of dense magnetized plasmas produced within a modernized PF-360 facility, which was operated with an additional planar cryogenic target placed in the front of the electrode outlet and covered with D2O-ice layers. The main aim of these studies was to overcome the neutron saturation effect and to increase the maximum neutron yield from PF discharges by using fast deuteron beams. Such beams are usually emitted from a pinch region and can produce fast neutrons from D-D reactions during their interactions with the additional target.
Źródło:
Nukleonika; 2001, 46, suppl. 1; 65-68
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cryogenic carbonates and cryogenic speleothem damage in the Za Hájovnou Cave (Javoříčko Karst, Czech Republic)
Autorzy:
Žak, K.
Lipták, V.
Filippi, M.
Orvošová, M.
Hercman, H.
Matouškova, Š.
Powiązania:
https://bibliotekanauki.pl/articles/2060084.pdf
Data publikacji:
2018
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
cryogenic cave carbonates
speleothem damage
Javoříčko Karst
U-series dating
Opis:
A new locality of coarse-grained cryogenic cave carbonates has been found in the Za Hájovnou Cave in Javoříčko Karst in Central Moravia, Czech Republic. Crystals and crystal aggregates, usually up to 15 mm in size, form typical loose accumulations on the surface of large fallen limestone blocks and clays covering the bottoms of several cave chambers distant from the cave entrance. The cryogenic origin of the carbonates is supported by their mode of occurrence, specific crystal and aggregate morphology, and C and O stable isotope data. U-series dating of one sample of cryogenic carbonate (age 29.5 ±0.1 ka) indicated that a period of karst water freezing occurred in marine isotope stage (MIS) 3, within the Weichselian. The cave also hosts numerous examples of speleothem damage. As shown in this paper, some of these are clearly connected with freezing conditions and cave ice action.
Źródło:
Geological Quarterly; 2018, 62, 4; 829--839
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studies of Plasma-Focus discharges within the PF-360 facility equipped with needle D2O-ice target
Autorzy:
Baranowski, J.
Jakubowski, L.
Sadowski, M.
Zebrowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/147583.pdf
Data publikacji:
2001
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
cryogenic target
current sheath
neutrons yield
plasma focus
X-ray
Opis:
The paper describes a new technique which has been investigated in order to overcome the neutron saturation effect and to increase the neutron yield from the plasma-focus (PF) discharges [1]. The PF-360 experimental facility was constructed at the Andrzej Soltan Institute for Nuclear Studies (IPJ) in Swierk, Poland in the late 70s [4, 5]. Recently in order to improve the neutron yield from the PF-360 machine, it was proposed to use a cryogenic deuterium target, which might be placed within the plasma-focus region. For this purpose, we have been made a needle-like cryogenic target covered with a thin „heavy-ice“ layer. A considerable increase in the average neutron yield (from 1.7×1010 to about 2.2×1010 neutrons/shot) has been achieved for 122 kJ PF discharges when the needle target top was placed at a distance of about 100 mm from the electrode ends.
Źródło:
Nukleonika; 2001, 46, suppl. 1; 69-71
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Terapeutyczne oddziaływanie kriostymulacji ogólnoustrojowej
Autorzy:
Gmernicka, Katarzyna
Powiązania:
https://bibliotekanauki.pl/articles/2097366.pdf
Data publikacji:
2017-12-28
Wydawca:
Państwowa Wyższa Szkoła Zawodowa w Tarnowie
Tematy:
krioterapia
terapia zimnem
kriokomora ogólnoustrojowa
cryotherapy
cold therapy
cryogenic chamber
Opis:
Krioterapia ogólnoustrojowa polega na oddziaływaniu niskiej temperatury (poniżej -100 stopni Celsjusza) przez okres od 1,5 do 3 minut na cały organizm. Leczenie jest bezbolesne i ma na celu wyzwolenie reakcji fizjologicznych, które są korzystne z medycznego punktu widzenia. Zabieg ma działanie przeciwzapalne, zmniejsza bolesność mięśni, poprawia ich siłę, funkcję stawów oraz zwiększa krążenie krwi. Wywołuje również reakcję hormonalną, powodując wzrost ACTH, kortyzolu, beta-endorfin a u mężczyzn testosteronu. Krioterapia jest wykorzystywana nie tylko jako sposób leczenia, ale również jako część odnowy biologicznej oraz wspomaganie treningu sporto wego. Stosuje się ją profilaktycznie w celu poprawy komfortu fizycznego oraz zdrowia psychicznego. Aby osiągnąć pożądane efekty, konieczne jest zastosowanie po zabiegu w kriokomorze ogólnoustrojowej zestawu 20-minutowych ćwiczeń, wykonywanych pod nadzorem fizjoterapeuty.
Whole body cryotherapy (WBC) involves exposing individuals to extremely cold dry air (under -100 °C) for a period ranging from 1.5 to 3 minutes. The treatment is painless and is intended to produce and use physiological reaction, which is medically beneficial and effective in restoring normal body functions. Whole body cryotherapy provides various benefits such as: analgesic and anti-inflammatory effects, decreases muscle soreness, improves muscle strength and joint function, boosts blood circulation. It also causes a hormonal reaction, growth of ACTH, cortisol, beta-endorphin and testosterone. Cryotherapy is not only used as a way of treatment but also as a part of wellness and spa. WBC is used prophylactically to improve physical comfort and mental health. It is necessary to use kinesis immediately after cryotherapy to achieve its desirable affects. Kinesitherapy is a 20 minutes set of exercises performed on machines under the guidance of a physiotherapist. The purpose of kinesitherapy is the restoration of normal motion stereotypes, which will prevent overloads.
Źródło:
Health Promotion & Physical Activity; 2017, 1, 1; 19-22
2544-9117
Pojawia się w:
Health Promotion & Physical Activity
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Constitutive model of plastic strain induced phenomena at cryogenic temperatures
Opis konstytutywny zjawisk wywołanych odkształceniami plastycznymi w temperaturach kriogenicznych
Autorzy:
Skoczeń, B.
Powiązania:
https://bibliotekanauki.pl/articles/280706.pdf
Data publikacji:
2008
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
constitutive behaviour
yield condition
phase transformation
voids and inclusions
cryogenic temperature
Opis:
FCC metals and alloys are frequently used in cryogenic applications, nearly down to the temperature of absolute zero, because of their excellent physical and mechanical properties, including ductility. These materials, often characterized by the Low Stacking Fault Energy (LSFE), undergo at low temperatures three distinct phenomena: Dynamic Strain Ageing (DSA), plastic strain induced transformation from the parent phase to the secondary phase _ and evolution of micro-damage. As all three phenomena lead to irreversible degradation of lattice and can accelerate the process of material failure, a combined constitutive description appears to be fundamental for the correct analysis of structures applied at very low temperatures. The constitutive model presented in the paper takes into account all the three phenomena as well as the relevant thermodynamic background.
Materiały konstrukcyjne (metale lub ich stopy) o sieci krystalicznej regularnej ściennie centrowanej są często stosowane w temperaturach kriogenicznych (także w temperaturach bliskich absolutnego zera) z uwagi na bardzo dobre własności fizyczne i mechaniczne, a w szczególności wysoką plastyczność. Materiały te, charakteryzujące się z reguły niską energią błędu ułożenia, podlegają w niskich temperaturach trzem procesom: dynamicznemu starzeniu odkształceniowemu (które generuje nieciągłe płynięcie plastyczne), przemianie fazowej od struktury regularnej ściennie centrowanej do struktury regularnej przestrzennie centrowanej oraz ewolucji mikrouszkodzeń. Wszystkie te zjawiska prowadzą do nieodwracalnej degradacji sieci krystalicznej i szybszego zniszczenia materiału, dlatego budowa modelu konstytutywnego staje się nieodzownym elementem projektowania konstrukcji pracujących w temperaturach kriogenicznych. Model konstytutywny przedstawiony w artykule ujmuje wszystkie wyżej wymienione zjawiska, jak również termodynamikę procesów zacho- dzących w sieci krystalicznej w niskich temperaturach.
Źródło:
Journal of Theoretical and Applied Mechanics; 2008, 46, 4; 949-971
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł

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