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Tytuł:
Austenitization of FerriticDuctile Iron
Autorzy:
Krzyńska, A.
Kochański, A.
Powiązania:
https://bibliotekanauki.pl/articles/379464.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
austenitization
ductile iron
ferritic matrix
matrix structure
ADI
austenityzacja
żeliwo sferoidalne
Opis:
Austenitization is the first step of heat treatment preceding the isothermal quenching of ductile iron in austempered ductile iron (ADI) manufacturing. Usually, the starting material for the ADI production is ductile iron with more convenient pearlitic matrix. In this paper we present the results of research concerning the austenitizing of ductile iron with ferritic matrix, where all carbon dissolved in austenite must come from graphite nodules. The scope of research included carrying out the process of austenitization at 900oC using a variable times ranging from 5 to 240 minutes,and then observations of the microstructure of the samples after different austenitizing times. These were supplemented with micro-hardness testing. The research showed that the process of saturating austenite with carbon is limited by the rate of dissolution of carbon from nodular graphite precipitates.
Źródło:
Archives of Foundry Engineering; 2014, 14, 4; 49-54
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Bayesian Approach to Matrix Balancing: Transformation of Industry-Level Data under NACE Revision
Autorzy:
Boratyński, Jakub
Powiązania:
https://bibliotekanauki.pl/articles/2076451.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
matrix balancing
Bayesian inference
NACE revision
transformation matrix
multi-sector modelling
Opis:
We apply Bayesian inference to estimate transformation matrix that converts vector of industry outputs from NACE Rev. 1.1 to NACE Rev. 2 classification. In formal terms, the studied issue is a representative of the class of matrix balancing (updating, disaggregation) problems, often arising in the field of multi- sector economic modelling. These problems are characterised by availability of only partial, limited data and a strong role for prior assumptions, and are typically solved using bi-proportional balancing or cross-entropy minimisation methods. Building on Bayesian highest posterior density formulation for a similarly structured case, we extend the model with specification of prior information based on Dirichlet distribution, as well as employ MCMC sampling. The model features a specific likelihood, representing accounting restrictions in the form of an underdetermined system of equations. The primary contribution, compared to the alternative, widespread approaches, is in providing a clear account of uncertainty.
Źródło:
Central European Journal of Economic Modelling and Econometrics; 2016, 4; 219-239
2080-0886
2080-119X
Pojawia się w:
Central European Journal of Economic Modelling and Econometrics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Microstructure of WE43 MMC Reinforced with SiC Particles
Autorzy:
Dybowski, B.
Rzychoń, T.
Chmiela, B.
Gryc, A.
Powiązania:
https://bibliotekanauki.pl/articles/356597.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
metal matrix composite
WE43 matrix
SiC Reinforcement
microstructure
interface
mechanical properties
Opis:
It is well known that the properties of a metal matrix composites depend upon the properties of the reinforcement phase, of the matrix and of the interface. A strong interface bonding without any degradation of the reinforcing phase is one of the prime objectives in the development of the metal matrix composites. Therefore, the objective of this work is to characterize the interface structure of WE43/SiC particles composite. Magnesium alloys containing yttrium and neodymium are known to have high specific strength, good creep and corrosion resistance up to 250°C. The addition of SiC ceramic particles strengthens the metal matrix composite resulting in better wear and creep resistance while maintaining good machinability. In the present study, WE43 magnesium matrix composite reinforced with SiC particulates was fabricated by stir casting. The SiC particles with 15 μm, 45 μm and 250 μm diameter were added to the WE43 alloy. The microstructure of the composite was investigated by optical microscopy, scanning electron microscopy, scanning transmission electron microscopy and XRD analysis. YSi and Y2Si reaction products are observed at the interfaces between SiC particles and WE43 matrix in the composite stirred at 780°C. Microstructure characterization of WE43 MMC with the 45 μm, stirred at 720°C showed relative uniform reinforcement distribution. Moreover, the Zr-rich particles at particle/matrix interface were visible instead of Y-Si phases. In the case of composite with 15 μm particles the numerous agglomerates and reaction products between SiC particles and alloying elements were observed. The presence of SiC particles assisted in improving hardness and decreasing the tensile strength and plastic properties.
Źródło:
Archives of Metallurgy and Materials; 2016, 61, 1; 393-398
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A key metric and its calculation models for a continuous diagnosis capability based on a dependency matrix
Autorzy:
Shi, J.-Y.
Lin, X.-G.
Shi, M.
Powiązania:
https://bibliotekanauki.pl/articles/221741.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
fault diagnosis
dependency matrix
measurement
Opis:
This paper is devoted to measuring the continuous diagnosis capability of a system. A key metric and its calculation models are proposed enabling us to measure the continuous diagnosis capability of a system directly without establishing and searching the sequential fault tree (SFT) of the system. At first a description of a D matrix is given and its metric is defined to determine the weakness of a continuous diagnosis. Then based on the definition of a sequential fault combination, a sequential fault tree (SFT) is defined with its establishment process summarized. A key SFT metric is established to measure the continuous diagnosis capability of a system. Two basic types of dependency graphical models (DGMs) and one combination type of DGM are selected for characteristics analysis and establishment of metric calculation models. Finally, both the SFT searching method and direct calculation method are applied to two designs of one type of an auxiliary navigation equipment, which shows the high efficiency of the direct calculation method.
Źródło:
Metrology and Measurement Systems; 2012, 19, 3; 509-520
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling of electric current flow in 1D Pd-C nanostructure: comparison with experiment
Autorzy:
Bielski, W.
Kowalczyk, P.
Czerwosz, E.
Idzik, A.
Rymarczyk, J.
Powiązania:
https://bibliotekanauki.pl/articles/200117.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
nanocomposites
palladium
carbonaceous matrix
homogenization
Opis:
In this paper we propose a model of electric current flow through one-dimensional palladium-carbon nanostructure (nanowire) and compare the results of numerical computations with the experimental data. We focus on two aspects: 1) calculation of the current flow through the nanowire model, 2) determination of the macroscopic parameters in the nanocomposite in our model. Because of a complex micro-geometry of a nanowire, we apply the homogenization method to perform the numerical computations.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2014, 62, 3; 465-469
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The K4 graph and the inertia of the adjacency matrix for a connected planar graph
Autorzy:
Taliceo, Nicholas P.
Griffith, Daniel A.
Powiązania:
https://bibliotekanauki.pl/articles/2021553.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
K4 graph
planar graph
matrix inertia
adjacency matrix
Jacobian term
Nauki Humanistyczne i Społeczne
Źródło:
Studia komitetu przestrzennego zagospodarowania kraju PAN; 2018, 183; 185-209
0079-3507
Pojawia się w:
Studia komitetu przestrzennego zagospodarowania kraju PAN
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of the thermodynamics of a four level system using canonical density matrix method
Autorzy:
Awoga, O.
Ikot, A.
Ituen, E.
Akpabio, L.
Powiązania:
https://bibliotekanauki.pl/articles/240775.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
entropia
Iloczynem Kroneckera
macierz gęstości
redukcja
Canonical density matrix
entropy
Kronecker product
Reduced density matrix
Opis:
We consider a four-level system with two subsystems coupled by weak interaction. The system is in thermal equilibrium. The thermodynamics of the system, namely internal energy, free energy, entropy and heat capacity, are evaluated using the canonical density matrix by two methods. First by Kronecker product method and later by treating the subsystems separately and then adding the evaluated thermodynamic properties of each subsystem. It is discovered that both methods yield the same result, the results obey the laws of thermodynamics and are the same as earlier obtained results. The results also show that each level of the subsystems introduces a new degree of freedom and increases the entropy of the entire system. We also found that the four-level system predicts a linear relationship between heat capacity and temperature at very low temperatures just as in metals. Our numerical results show the same trend.
Źródło:
Archives of Thermodynamics; 2012, 33, 4; 91-107
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Three-phase hybrid transformer using matrix-chopper as an interface between two AC voltage sources
Autorzy:
Kaniewski, J.
Fedyczak, Z.
Szcześniak, P.
Powiązania:
https://bibliotekanauki.pl/articles/950668.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
hybrid transformer
power system
matrix chopper
Opis:
This paper deals with a three-phase power system with hybrid transformer (HT) installed between two AC sources. The main aim of this paper is analyze the basic properties of HT with active load and ability to bidirectional energy flow. The HT contains two main units – a conventional transformer with electromagnetic coupling and PWM AC line chopper connected with secondary windings with electric coupling. The HT is located between the distribution system and a Local Balancing Area (LBA) with low power local energy sources. After describing the HT circuit and three-phase, twosources power system, the mathematical and circuit models of the AC source with HT are presented. These models are verified by means of the simulation and experimental test results obtained for a three-phase HT of about 3 kVA rated power.
Źródło:
Archives of Electrical Engineering; 2014, 63, 2; 197-210
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Processing and Characterization of Fe-Cu-Ni Sinters Prepared by Ball Milling and Hot Pressing
Autorzy:
Borowiecka-Jamrozek, J.
Powiązania:
https://bibliotekanauki.pl/articles/354394.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
matrix
diamond
hot pressing
diamond tools
Opis:
The main objective of the present work was to determine the effect of powder composition on microstructure and properties of iron-base materials used as matrices in diamond impregnated tools. The Fe-Cu-Ni powders premixed and ball-milled for 30 hours, were used for the experiments. The influence of manufacturing process parameters on microstructure and mechanical properties of produced sinters was investigated. Sintering was done by hot-pressing technique in graphite mould. The powders were consolidated to a virtually pore-free condition during 3 minutes hold at 35 MPa and 900°C. Investigations of the sintered materials included: density, hardness, static tensile test and X-ray diffraction (XRD) analysis. Microstructural and fractographic observations were also made with a scanning electron microscope (SEM). The obtained results indicate that the sintered parts have a high density, close to the theoretical value, good plasticity, relatively high hardness and yield strength, and are characterized by a coarse-grained microstructure.
Źródło:
Archives of Metallurgy and Materials; 2020, 65, 3; 1157-1161
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Lyapunov matrices approach to the parametric optimization of a neutral system
Autorzy:
Duda, J.
Powiązania:
https://bibliotekanauki.pl/articles/229256.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
neutral system
Lyapunov matrix
Lyapunov functional
Opis:
In the paper a Lyapunov matrices approach to the parametric optimization problem of a neutral system with a P-controller is presented. The value of integral quadratic performance index of quality is equal to the value of Lyapunov functional for the initial function of the neutral system. The Lyapunov functional is determined by means of the Lyapunov matrix.
Źródło:
Archives of Control Sciences; 2016, 26, 1; 81-93
1230-2384
Pojawia się w:
Archives of Control Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Lyapunov matrices approach to the parametric optimization of a system with two delays and a PD-controller
Autorzy:
Duda, J.
Powiązania:
https://bibliotekanauki.pl/articles/229274.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
neutral system
Lyapunov matrix
Lyapunov functional
Opis:
In the paper the parametric optimization problem for a linear system with two delays and a PD-controller is presented. In the parametric optimization problem the quadratic performance index is considered. The value of the quadratic index of quality is calculated due to the Lyapunov functional and is equal to the value of that functional for the initial function of the neutral system with two delays. The Lyapunov functional is determined by means of the Lyapunov matrix.
Źródło:
Archives of Control Sciences; 2018, 28, 4; 585-600
1230-2384
Pojawia się w:
Archives of Control Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of the matrix converter to power flow control
Autorzy:
Szcześniak, P.
Fedyczak, Z.
Powiązania:
https://bibliotekanauki.pl/articles/141546.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
matrix converter
AC systems
power flow
Opis:
Advanced power electronic converters can provide the means to control power flow and ensure proper and secure operation of the future power grid. The small electrical energy sources dispersed in electrical power systems referred to as distributed generation are one of the most significant parts of future grids - Smart Grids. The threephase, direct matrix converter is an alternative solution to the conventional AC-DC-AC converter for interfacing two AC systems in distributed power generation with different voltage and/or frequency parameters. This paper presents a control analysis of a threephase matrix converter employed as a power interface of future electrical grids. The proposed system has been successfully tested for bidirectional power flow operation with different grid operating conditions, such as, frequency and voltage variation.
Źródło:
Archives of Electrical Engineering; 2014, 63, 3; 409-422
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Common Trends and Common Cycles - Bayesian Approach
Autorzy:
Wróblewska, Justyna
Powiązania:
https://bibliotekanauki.pl/articles/2076539.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
cointegration
Bayesian analysis
common cyclical features
matrix Bingham-von Mises-Fisher distribution
matrix Langevin-Bingham distribution
Opis:
In 1993 Engle and Kozicki proposed the notion of common features of which one example is a serial correlation common feature. We say that stationary, noninnovation processes exhibit common serial correlation when there exists at least one linear combination of them which is an innovation. Later on in 1993 Vahid and Engle combined the notions of cointegration among I(1) processes with common serial correlation within their first differences. It is commonly known that cointegrated time series have vector error correction (VEC) representation. The existence of common serial correlation leads to an additional reduced rank restriction imposed on the VEC model’s parameters. This type of restriction was later termed a strong form (SF) reduced rank structure, as opposed to a weak one introduced in 2006 by Hecq, Palm and Urbain. The main aim of the present paper is to construct the Bayesian vector error correction model with these additional strong form restrictions. The empirical validity of investigating both the short- and long-run comovements between macroeconomic time series will be illustrated by the analysis of the price-wage nexus in the Polish economy.
Źródło:
Central European Journal of Economic Modelling and Econometrics; 2015, 2; 91-110
2080-0886
2080-119X
Pojawia się w:
Central European Journal of Economic Modelling and Econometrics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Inter-frame Prediction with Fast Weighted Low-rank Matrix Approximation
Autorzy:
Huang, Z. L.
Hsiao, H. F.
Powiązania:
https://bibliotekanauki.pl/articles/227337.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
inter-frame prediction
template matching
block matching
low-rank matrix approximation
weighted low rank
matrix approximation
Opis:
In the field of video coding, inter-frame prediction plays an important role in improving compression efficiency. The improved efficiency is achieved by finding predictors for video blocks such that the residual data can be close to zero as much as possible. For recent video coding standards, motion vectors are required for a decoder to locate the predictors during video reconstruction. Block matching algorithms are usually utilized in the stage of motion estimation to find such motion vectors. For decoder-side motion derivation, proper templates are defined and template matching algorithms are used to produce a predictor for each block such that the overhead of embedding coded motion vectors in bit-stream can be avoided. However, the conventional criteria of either block matching or template matching algorithms may lead to the generation of worse predictors. To enhance coding efficiency, a fast weighted low-rank matrix approximation approach to deriving decoder-side motion vectors for inter frame video coding is proposed in this paper. The proposed method first finds the dominating block candidates and their corresponding importance factors. Then, finding a predictor for each block is treated as a weighted low-rank matrix approximation problem, which is solved by the proposed column-repetition approach. Together with mode decision, the coder can switch to a better mode between the motion compensation by using either block matching or the proposed template matching scheme.
Źródło:
International Journal of Electronics and Telecommunications; 2013, 59, 1; 9-16
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Matrix black box algorithms - a survey
Autorzy:
Respondek, Jerzy
Powiązania:
https://bibliotekanauki.pl/articles/2173638.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
matrix algebra
matrix multiplication algorithm
numerical recipes
recursion
algebra macierzowa
algorytm mnożenia macierzy
receptury numeryczne
rekurencja
Opis:
The implementations of matrix multiplication on contemporary, vector-oriented, and multicore-oriented computer hardware are very carefully designed and optimized with respect to their efficiency, due to the essential significance of that operation in other science and engineering domains. Consequently, the available implementations are very fast and it is a natural desire to take advantage of the efficiency of those implementations in other problems, both matrix and nonmatrix. Such an approach is often called a black box matrix computation paradigm in the literature on the subject. In this article, we gathered a broad series of algorithms taking advantage of the efficiency of fast matrix multiplication algorithms in other mathematical and computer science operations.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2022, 70, 2; art. no. e140535
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł

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