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Wyszukujesz frazę "refinement" wg kryterium: Temat


Tytuł:
Adaptive finite elements based on sensitivities fortopological mesh changes
Autorzy:
Friederich, J.
Leugering, G.
Steinmann, P.
Powiązania:
https://bibliotekanauki.pl/articles/205694.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
adaptive mesh refinement
sensitivity-based refinement
topological sensitivity
asymptotic expansion
Opis:
We propose a novel approach to adaptive refinement in FEM based on local sensitivities for node insertion. To this end, we consider refinement as a continuous graph operation, for instance by splitting nodes along edges. Thereby, we introduce the concept of the topological mesh derivative for a given objective function. For its calculation, we rely on the first-order asymptotic expansion of the Galerkin solution of a symmetric linear second-order elliptic PDE. In this work, we apply this concept to the total potential energy, which is related to the approximation error in the energy norm. In fact, our approach yields local sensitivities for minimization of the energy error by refinement. Moreover, we prove that our indicator is equivalent to the classical explicit a posteriori error estimator in a certain sense. Numerical results suggest that our method leads to efficient and competitive adaptive refinement.
Źródło:
Control and Cybernetics; 2014, 43, 2; 279-306
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Refinement of UML collaborations
Autorzy:
Hnatkowska, B.
Huzar, Z.
Tuzinkiewicz, L.
Powiązania:
https://bibliotekanauki.pl/articles/908462.pdf
Data publikacji:
2006
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
UML
współpraca
rafinacja
collaborations
refinement
Opis:
The paper concerns the concept of refinement as a commonly used design practice in the software development process. The refinement relationship is formulated and formally expressed for UML collaborations. Collaborations are suitable for presenting the proposed approach as they represent both static and dynamic aspects of a modeled system or its part, for example, a use case. Our approach to refinement is based on the rule of preserving the observable behavior of a modeled system. The introduced notion of sub-collaborations allows us to refine collaboration diagrams in a systematic way.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2006, 16, 1; 155-164
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structure Refinement of Spring Steel 51CrV4 after Accelerated Spheroidisation
Autorzy:
Hauserova, D.
Dlouhy, J.
Kotous, J.
Powiązania:
https://bibliotekanauki.pl/articles/352039.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
spring steel
Accelerated Spheroidisation
refinement
hardening
Opis:
Material research of the spring steels tries to meet requirements of the industry, which are mainly higher yield and tensile strength. Steel 51CrV4 is widely used for spring production. Optimization of its properties lies in tensile and yield strength enhancement without decrease in ductility in quenched and tempered state. This can be accomplished by structural refinement. One possible way to refine final quenched and tempered structure is refinement of the soft annealed structure before quenching. The article is devoted to accelerated carbide spheroidisation and refinement (ASR) and subsequent hardening of the 51CrV4 spring steel. Samples with different carbide size were prepared by conventional soft annealing in atmosphere furnace and ASR process by induction heating. Influence of the structural refinement on the properties of quenched and tempered state was studied.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 3; 1473-1477
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fading mechanism on grain refinement and modification with Al-B-Sr master alloys in an aluminium-silicon cast alloy
Autorzy:
Muangnoy, Phisith
Eidhed, Krittee
Powiązania:
https://bibliotekanauki.pl/articles/2134110.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aluminium
grain refinement
modification
fading mechanism
Opis:
A fading mechanism during casting of treated Al-B-Sr master alloys in an aluminium-silicon cast alloy was investigated. Two different master alloys, the Al-3%B-3%Sr and Al-4%B-1%Sr were demonstrated for the efficiency test both grain refinement and modification microstructure. From experimental result, the addition of Al-3%B-3%Sr master alloy led to a refined grain size and fully modified eutectic Si. However, smaller grain sizes were found with Al-4%B-1%Sr master alloy addition while eutectic Si had coarser acicular morphology. The formation of high amounts of SrB6 compound in the Al-3%B-3%Sr master alloy resulted to increase of grain size and eutectic Si. In fading mechanism test when holding the melt for prolong time, the agglomeration of the SrB6 and AlSiSr compounds at the bottom of the casting specimen was important factors that decreased both grain refinement and modification efficiency. The stirring of the melt before pouring was found that the grain size and Si morphology were improved.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 3; 1137--1144
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Using Deep Etching in the Study of Eutectic Silicon 3D-Morphology in AlSi7MgTi Cast Alloy
Autorzy:
Kuchariková, L.
Tillová, E.
Bonek, M. S.
Chalupová, M.
Powiązania:
https://bibliotekanauki.pl/articles/356318.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
modification
refinement
eutectic Si morphology
deep etching
Opis:
The effect of combination grain refinement with AlTi5B1 master (55 ppm) and Sr-modification with AlSr5 master (20, 30, 40, 50 and 60 ppm) on the microstructure, tensile and hardness properties of AlSi7MgTi cast alloy were systematically investigated. Eutectic silicon was studied by optical and scanning electron microscopy after standard (0.5% HF) and deep etching (HCl). Morphology of eutectic Si changes from compact plate-like (as-cast state) to fibbers (after modification). Si-fibbers in samples with 50 and 60 ppm Sr coarsen probably as a result of over-modification. The optimum mechanical properties has the experimental material which was grain refined and modified with 40 ppm of Sr (UTS = 220.6 MPa; ductility = 6.1%, and 82.3 HBW 5/250/15).
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 4; 2017-2022
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Anisotropy of mechanical and structural properties in AA 6060 aluminum alloy following hydrostatic extrusion process
Autorzy:
Przybysz, S.
Kulczyk, M.
Pachla, W.
Skiba, J.
Wróblewska, M.
Mizera, J.
Moszczyńska, D.
Powiązania:
https://bibliotekanauki.pl/articles/201595.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
hydrostatic extrusion
anisotropy
mechanical properties
grain refinement
Opis:
The study attempts to investigate the influence of severe plastic deformation (SPD in the hydrostatic extrusion (HE) process on the anisotropy of the structure and mechanical properties of the AA 6060 alloy. Material in isotropic condition was subjected to a single round of hydrostatic extrusion with three different degrees of deformation (ε= 1.23, 1.57, 2.28). They allowed the grain size to be fragmented to the nanocrystalline level. Mechanical properties of the AA 6060 alloy, examined on mini-samples, showed an increase in ultimate tensile strength (UTS) and yield strength (YS) as compared to the initial material. Significant strengthening of the material results from high grain refinement in transverse section, from »220 μm in the initial material to »300 nm following the HE process. The material was characterized by the occurrence of structure anisotropy, which may determine the potential use of the material. Static tensile tests of mini-samples showed »10% anisotropy of properties between longitudinal and transverse cross-sections. In the AA6060 alloy, impact anisotropy was found depending on the direction of its testing. Higher impact toughness was observed in the cross-section parallel to the HE direction. The results obtained allow to analyze the characteristic structure created during the HE process and result in more efficient use of the AA 6060 alloy in applications.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2019, 67, 4; 709-717
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Kierunki zagospodarowania drobnych frakcji z wydobycia i przeróbki surowców mineralnych
Directions of the management of small fraction arising in processing and extraction of mineral raw materials
Autorzy:
Stankiewicz, J.
Powiązania:
https://bibliotekanauki.pl/articles/89140.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Wydział Geoinżynierii, Górnictwa i Geologii. Instytut Górnictwa
Tematy:
kruszywo
drobne frakcje
uszlachetnianie
aggegate
small fractions
refinement
Opis:
Przedstawiono podstawowe kierunki zagospodarowania drobnych frakcji kruszywowych, pochodzących z procesów przeróbczych. Wymagania dotyczące właściwości fizykomechanicznych stanowią podstawowy warunek kwalifikacji kruszywa do odpowiednich zastosowań. Technologiczne możliwości przeróbki i zagospodarowania pozwalają obecnie wykorzystywać większości frakcji, pochodzących zarówno z bieżącej produkcji jak i magazynowanych na składowiskach.
The article describes the basic directions of management of small fractions derived mainly from the processing. The main prerequisite for qualification of aggregates for different applications is its physicomechanical requirements. The technological possibilities of processing and management allow currently for the use of most of fractions derived from current production as well as those stored in landfills.
Źródło:
Mining Science; 2016, 23, Special Issue 1; 155-166
2300-9586
2353-5423
Pojawia się w:
Mining Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Development of a topology-based current-flux characteristic approximation in a Hamiltonian model of a reluctance machine
Autorzy:
Burlikowski, W.
Kowalik, Z.
Powiązania:
https://bibliotekanauki.pl/articles/141438.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Hamiltonian model
simplicial approximation
reluctance machine
triangulation refinement
Opis:
The paper presents an algorithm for the construction of an approximation of a highly nonlinear current-flux characteristic of a synchronous reluctance machine. Such an approximation is required in a Hamiltonian model of an electric machine and the constructed approximation is suited to be used in such a model. It employs a simplicial approximation based on irregular points sets in the spaces of currents and fluxes. The sets are constructed by the iterative insertion of new points. Initially the sets contain an arbitrarily small number of elements. The insertion is based on an approximation error calculation. Based on the sets containing possibly small number of elements, the proposed procedure leads to smooth and precise approximation. Due to the nonlinearity of the approximated characteristics, ambiguities can occur. A method for the triangulation refinement of the sets of currents and fluxes that eliminates them is also presented. In the paper, a reluctance machine model using the constructed approximation is described and compared with a model using the approximation based on regular sets.
Źródło:
Archives of Electrical Engineering; 2015, 64, 2; 277-289
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Insensitive Booster Explosive: DAAF Surface-coated with Viton A
Autorzy:
Li, X.
Wu, B.
Liu, S.
An, C.
Wang, J.
Powiązania:
https://bibliotekanauki.pl/articles/358841.pdf
Data publikacji:
2018
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
DAAF
refinement
surface-coated
thermal analysis
impact sensitivity
Opis:
3,3’-Diamino-4,4’-azoxyfurazan (DAAF) is the principal component of an insensitive booster explosive; refined DAAF and DAAF surface-coated with Viton A were prepared. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and differential scanning calorimetry (DSC) were employed to characterize the morphology, composition, and thermal decomposition of these samples. The impact sensitivity and theoretical detonation velocity of DAAF-based composites were also measured and analyzed. The results showed that DAAF surface-coated with Viton A was successfully obtained, and the impact sensitivity of DAAF/Viton A composites was much lower than that of crude DAAF. In addition, DAAF/Viton A composites exhibited better thermal stability compared to crude DAAF and refined DAAF. The theoretical detonation velocity of DAAF/Viton A composites and TATB/Viton A composites are roughly the same. Therefore, there is still great potential for DAAF to be used as the main explosive component of a booster explosive.
Źródło:
Central European Journal of Energetic Materials; 2018, 15, 3; 445-455
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Alloying Elements on Properties and Structure of High Chromium Cast Irons
Autorzy:
Kaňa, V.
Záděra, A.
Krutiš, V.
Powiązania:
https://bibliotekanauki.pl/articles/351222.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
high chromium cast irons
wear resistance
carbides
refinement
Opis:
The paper deals with hypereutectic high chromium cast irons. The subject of examination was the effect of various alloying elements (Ti, W, Mo, V) on the size of primary carbides and on the resultant material hardness. Using a scanning electron microscope with a wave dispersion analyser, the carbon content in carbides was established. To determine the other elements, an energy dispersion analyser was used. It was found that both the primary and the eutectic carbides were of the M7C3 type and very similar in composition. The carbides always contained Cr and Fe, and also W, Mo, V or Ti, in dependence on the alloying elements used. The structure of materials containing only chromium without any alloying additions exhibited coarse acicular primary carbides. The structure of materials alloyed with another element was always finer. Marked refinement was obtained by Ti alloying.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 2; 609-614
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effect of Rare Earth Addition on Microstructure and Mechanical Properties of the Rapidly Solidified Al-Si and Al-Si-Ni Alloys
Autorzy:
Kapinos, D.
Szymanek, M.
Augustyn, B.
Boczkal, S.
Szymański, W.
Tokarski, T.
Lelito, J.
Powiązania:
https://bibliotekanauki.pl/articles/353569.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aluminium alloy
rapid solidification
grain refinement
ultrafine structure
Opis:
The article presents research aimed at determining the effect of adding rare earth elements to near-eutectic Al-Si and Al-Si-Ni alloys on the microstructure and mechanical properties of the obtained products. Material for the research was prepared using a melt spinner - a device used for rapid crystallization, casting thin ribbons, which were then subjected in subsequent stages to fragmentation, consolidation and plastic working. The ribbons and extruded rods cast were described in terms of their structure and their strength properties were determined at different measurement temperatures. It was shown that the lightweight materials produced from aluminium alloys using the rapid solidification process have an ultra-fine structure and good strength properties. Analysis under a microscope confirmed that the addition of rare earth alloys Al-Si and Al-Si-Ni causes fragmentation of the microstructure in the tapes produced. The presence of rare earth elements in the alloys tested has an impact on the type and the morphology of the particles of the microstructure’s individual components. In addition to the change in particle morphology, the phenomenon of the separation of numerous nanometric particles of intermetallic phases containing rare earth elements was also observed. The change in microstructure caused by the addition of rare earth elements in the form of a mischmetal increases the mechanical properties.
Źródło:
Archives of Metallurgy and Materials; 2020, 65, 1; 185-192
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improving protein structure prediction, refinement and quality assessment techniques
Autorzy:
Leelananda, S. P.
Pawłowski, M.
Faraggi, E.
Kloczkowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/1954426.pdf
Data publikacji:
2014
Wydawca:
Politechnika Gdańska
Tematy:
protein structure prediction
model quality assessment
structure refinement
Opis:
Several novel techniques have been combined to improve protein structure prediction, structural refinement and quality assessment of protein models. We discuss in brief the development of four-body potentials that take into account dense packing and cooperativity of interactions of proteins, and its success. We have developed a method that uses whole protein information filtered through machine learning to score protein models based on their likeness to native structure. Here we consider electrostatic interactions and residue depth, and use these for structure prediction. These potentials were tested to be successful in CASP9 and CASP10. We have also developed a Quality Assessment technique, MQAP single, which is a quasi-single-model MQAP, by combining advantages of both “pure” single-model MQAPs and clustering MQAP s. This technique can be used in ranking and assessing the absolute global quality of single protein models. This model (Pawlowski-Kloczkowski) was ranked 3rd in Model Quality Assessment in CASP 10. Consideration of protein flexibility and its fluctuation dynamics improves protein structure prediction and leads to better refinement of computational models of proteins. Here we also discuss how Anisotropic Network Model (ANM) of protein fluctuation dynamics and Go-like model of energy score can be used for novel protein structure refinement.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2014, 18, 3; 231--243
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effect of Low Deformation Asymmetric Rolling on Microstructure and Texture of the Polycrystalline Copper
Autorzy:
Uniwersał, A.
Wróbel, M.
Wroński, S.
Kalemba-Rec, I.
Wroński, M.
Wierzbanowski, K.
Baczmański, A.
Bacroix, B.
Powiązania:
https://bibliotekanauki.pl/articles/353907.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
asymmetric rolling
polycrystalline copper
microstructure refinement
strip curvature
Opis:
In the most recent years the asymmetric rolling (AR) attracts attention of researchers and technologists. This process can improve some technological parameters (e.g. modification of rolling torque and load, power requirements, etc.) as well as provide the possibility of grain refinement in a relatively inexpensive way. Most of the reports concerning microstructural changes produced by AR refer to high deformations imposed in highly asymmetric conditions. However, such rolling conditions are difficult to control, so there are no prospects to their quick industrial implementation. The present paper refers to relatively low deformation and low asymmetry rate, that is much more interesting for the industry. It was shown that bending of the rolled band (important disadvantage of the AR technology) can be controlled by adjusting of the amount of deformation and asymmetry. It was also shown that ca. 30% reduction in thickness during cold rolling, together with a relatively low asymmetry, reduces significantly the grain size and produces a more fragmented microstructure inside grains of the polycrystalline copper comparing to the symmetric rolling (SR). The material hardness after AR is higher than after the SR. Moreover, the crystallographic texture asymmetry, expressed by its rotation around the transverse direction, is observed in the AR material.
Źródło:
Archives of Metallurgy and Materials; 2016, 61, 4; 2183-2188
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The analysis of the chloride and fluoride influences on the reducer refinement processes (Carbo-N-Ox) aluminum alloys
Autorzy:
Bydałek, A. W.
Schlafka, P.
Biernat, S.
Powiązania:
https://bibliotekanauki.pl/articles/381958.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
refinement
database
copper alloy
rafinacja
baza danych
stop miedzi
Opis:
Slag refining slag with west materials was analysed used the DTA methods. In the paper a method of determining the reduction capability, with the Carbo-N-Ox method, of slag solutions was used. Some relations between the stimulators in the environment - slag - metal system allow to initiate mass exchange reactions in the process of slag refining.The presented in work course of behaviour permits on choice of basic composition of slaglite, the of necessary components stimulating quantities, as well as on accomplishment of opinion of ability refinement. The worked out programme Slag-Prop, after introduction of data with experiment, it allows on next corrections in composition of proposed mixtures also, should be put on properly elaborated factors of multistage reaction with essential usage of suitable stimulators.
Źródło:
Archives of Foundry Engineering; 2013, 13, 3; 9-14
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pearlitic Lamellae Spheroidisation During Austenitization and Subsequent Temperature Hold
Autorzy:
Hauserova, D.
Dlouhy, J.
Kover, M.
Powiązania:
https://bibliotekanauki.pl/articles/354933.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Accelerated Spheroidisation and Refinement
annealing
bearing steel
induction heating
Opis:
Typical processing routes for bearing steels include a soft annealing stage. The purpose of this procedure is to obtain a microstructure containing globular carbides in ferritic matrix. A newly developed process called ASR (Accelerated Spheroidisation and Refinement) cuts the carbide spheroidisation times several fold, producing considerably finer globular carbides than conventional soft annealing. Finer microstructure also leads to more homogeneous and finer structure after final hardening process. The present paper explores process of the accelerated spheroidisation (ASR) in steel 100CrMnSi6-4 with initial pearlitic structure. Cementite lamellae morphology was observed in different stages of austenitization. The heat treatment was performed using induction heating in quenching dilatometer. There was analysed influence of austenitization temperature and austenitization time on spheroidisation. Hardness and carbide morphology was observed. Deep etching was used to reveal evolution of cementitic lamellae fragmentation. It is favourable process especially in induction treatment of small parts.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 1; 201-204
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł

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