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Wyszukujesz frazę "Sikorski, A." wg kryterium: Autor


Tytuł:
Properties of Confined Polymer Melts
Autorzy:
Sikorski, A.
Powiązania:
https://bibliotekanauki.pl/articles/2041818.pdf
Data publikacji:
2005-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
02.50.Ng
36.20.Ey
61.25.Hq
Opis:
Properties of simple models of confined linear polymer chains were studied by means of the Monte Carlo method. Model chains were built of united atoms (statistical segments) and embedded to a simple cubic lattice. Then polymers were put into a slit formed by two parallel impenetrable surfaces. Chain lengths were varied up to 800 segments and the density of the polymer melt was changed up to 0.5. A Metropolis-like sampling Monte Carlo algorithm was used to determine the static properties of this model. The influence of the size of the confinement, the polymer melt concentration and the chain length on the chain's size and the structure was studied. The universal behavior of all confined polymer linear chains under consideration was found and discussed.
Źródło:
Acta Physica Polonica A; 2005, 107, 3; 443-450
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
FACET5 in the recruitment and managing process as regards production personnel – case study
Autorzy:
Sikorski, A.
Powiązania:
https://bibliotekanauki.pl/articles/111787.pdf
Data publikacji:
2017
Wydawca:
Stowarzyszenie Menedżerów Jakości i Produkcji
Tematy:
Facet5
competences
measuring employees’ potential
recruitment
managing talents
rekrutacja personelu
zarządzanie personelem
kompetencje
Opis:
The hereby article describes the study of two cases, the recruitment process as regards a newly created position and the decision concerning promotion to a managerial position. In both cases tool called Facet5 (used for measuring employees' potential) was applied to support decisions connected with human resources. As far as the first case is concerned, the profile of an ideal candidate was established. Then the profiles of three candidates selected based on content were compared to the aforementioned profile of an ideal candidate. As regards the second case, the analysis of the strengths and weaknesses in the employee profile and comparing the benchmarks concerning the particular position confirmed the subjective assessments of the supervisors and contributed to making the right decision. The issues connected to the increasing significance of soft competences, talent management in organization and organizational culture in terms of employee effectiveness and corporate competitive were discussed as well. Analyzed situations indicate the potential value resulting from the usage of tools for researching employees’ potential.
Źródło:
Production Engineering Archives; 2017, 15; 36-40
2353-5156
2353-7779
Pojawia się w:
Production Engineering Archives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Shape of Confined Polymer Chains
Autorzy:
Sikorski, A.
Powiązania:
https://bibliotekanauki.pl/articles/2035734.pdf
Data publikacji:
2003-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
02.50.Ng
05.10.Ln
61.25.Hq
Opis:
The linear polymer chains were modeled on a simple cubic lattice. The excluded volume was included into the model while the system remained athermal (no attractive interactions) which simulated the good solvent conditions. The polymer chain was located between two parallel impenetrable walls and the distance between the walls was changing. No interaction between walls and polymer segments was assumed. These models of polymer chains were simulated by the means of the Monte Carlo method. In the sampling algorithm we used the micromodifications of chain's conformations to sample efficiently the conformational space. The size of the chain did not change monotonically for all lengths under consideration (up to 800 statistical segments). For distances between the plates close to the double value of chain's radius of gyration the size of the chain approached its minimum value. It was shown that scaling of chain dimensions with its length changed from N$\text{}^{1.18}$ to N$\text{}^{1.5}$ while the distance between the walls was decreasing. The behavior of the asymmetry of the chain was found to be analogous to that of the radius of gyration.zapisz i p
Źródło:
Acta Physica Polonica A; 2003, 103, 4; 339-347
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structure of Dense Polymer Systems Confined to a Slit
Autorzy:
Sikorski, A
Powiązania:
https://bibliotekanauki.pl/articles/2044630.pdf
Data publikacji:
2006-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
02.50.Ng
05.10.Ln
61.25.Hq
Opis:
The linear polymer chains were approximated as series of identical segments on a simple cubic lattice. The excluded volume was included into the model with no attractive interactions which corresponded to the good solvent conditions. The polymer chains were put into a slit formed by a pair of parallel surfaces. These walls were impenetrable for polymer segments and no other interactions between walls and chains were assumed. The models chains were studied by the means of the Monte Carlo method. The sampling algorithm was Metropolis-type and employing micromodifications of chain's conformation to sample efficiently the conformational space. The influence of the chain length, density of the polymer system, and the distance between the surfaces on the shape of macromolecules was studied. It was found that the decrease in the size of the slit and the decrease in the polymer density led to the formation of more spherical macromolecules. This is partially caused by the interpenetration of polymer chains.
Źródło:
Acta Physica Polonica A; 2006, 109, 2; 133-141
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fiber Processing of Queries on Hierarchical Data
Włókniste przetwarzanie zapytań w hierarchicznych strukturach danych
Autorzy:
Sikorski, A.
Powiązania:
https://bibliotekanauki.pl/articles/282124.pdf
Data publikacji:
2012
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
włókna
zapytanie ścieżkowe
złączenie strukturalne
fiber processing
path query
structural join
Opis:
This paper is dealing with fiber processing of XPath queries. We make use of the Structural Join (SJ) method that we modify so as to achieve an improved number of page fetches containing input data. The fiber aggregation based composition, defined in this paper, allows local optimization of individual search steps taking advantage either of input Iow cardinality or high selectiveness of parent-child join.
W pracy omówiono wykorzystanie włókien - pewnej odmiany wątku - do celów efektywnego przetwarzania zapytań XPath. Zmodyfikowano standardowy algorytm złączenia strukturalnego w celu zmniejszenia liczby operacji 10. Zaproponowana metoda agregacji włókien pozwala na lokalną optymalizację składowych zapytania hierarchicznego. Optymalizacja wykorzystuje zarówno informacje o rozmiarze zbioru wejściowego jak i wysoką selektywność typową dla złączenia rodzic-dziecko (w przeciwieństwie do mniej selektywnych złączeń przodek-potomek).
Źródło:
Automatyka / Automatics; 2012, 16, 2; 165-173
1429-3447
2353-0952
Pojawia się w:
Automatyka / Automatics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Predictive current control of three-phase matrix converter with GaN HEMT bidirectional switches
Autorzy:
Nowaszewski, K.
Sikorski, A.
Powiązania:
https://bibliotekanauki.pl/articles/202007.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
predictive control
matrix converter
GaN HEMT
LC filter
bidirectional switch
Opis:
This paper presents an analysis and simulation studies of three-phase matrix converter with GaN HEMT bidirectional switches with predictive control of grid currents and converter output currents. Two methods of grid currents shaping are described and compared. The first method is based on calculations of instantaneous grid reactive power and the second one uses the active power of the load. The analyzed converter works with the resistive-inductive load, and from the grid side the LC filter with damping resistor has been used.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2020, 68, 5; 1077-1085
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Monte Carlo Study of Chain Entanglements in Polymer MeltDOI
Autorzy:
Sikorski, A.
Romiszowski, P.
Powiązania:
https://bibliotekanauki.pl/articles/2028878.pdf
Data publikacji:
2001-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
02.50.Ng
61.25.Hq
Opis:
The new multibond algorithm for the Monte Carlo simulations of polymers developed for an isolated chain was extended for the case of dense polymer melts. Polymer chains were confined to a simple cubic lattice with excluded volume and no attractive interactions (good solvent conditions). The simulations were carried out by the means of the classical Metropolis scheme. The algorithm was verified by the analysis of static and dynamic properties of polymer melts. The dependence of the longest relaxation time and the self-diffusion coefficient on the chain length and the polymer concentration was discussed and the proper scaling laws were formulated. The number of entanglements, their distribution, and lifetimes were determined for different chain lengths and melt concentrations using the new algorithm.
Źródło:
Acta Physica Polonica A; 2001, 100, 4; 477-484
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New Multi-Bond Algorithm for Monte Carlo Simulation of Lattice Chains
Autorzy:
Romiszowski, P.
Sikorski, A.
Powiązania:
https://bibliotekanauki.pl/articles/2011150.pdf
Data publikacji:
1999-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
02.50.Ng
61.25.Hq
Opis:
The new algorithm for the Monte Carlo simulations of polymer lattice chains was developed. The model chains were constructed on a simple cubic lattice. The simulations were carried out on chains with and without excluded volume effect using the Metropolis scheme. The basic concept of the new algorithm is the multi-bond modification of the chain conformation instead of applying the classical set of elementary micromodifications. The correctness of the algorithm was verified by studying both static and dynamic properties of the chains. The new algorithm was found to be 3 to 8 times faster than the classical one.
Źródło:
Acta Physica Polonica A; 1999, 96, 6; 691-697
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Efficiency improvement due to direct torque and flux three levels three areas control method applied to small hydroelectric power plant
Autorzy:
Kulikowski, K.
Sikorski, A.
Powiązania:
https://bibliotekanauki.pl/articles/200033.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
asynchronous machine
AC/DC/AC converter
DC/AC converter
DTC
flux control
Opis:
The paper presents a description of a new DTFC3L3A (direct torque and flux control three levels three areas) control method of induction machine as well as its comparison with the DTC method. The basis for the comparison is the switching frequency of described methods. The proposed method is optimized to reduce number of switchings (which is proportional to switching power losses) in static state, as well as it takes into account the angle which makes it possible to obtain a sinusoidal shape of flux within range of low angular frequencies of an asynchronous machine. The paper includes the results of experiments performed on a three level DC/AC inverter for both control methods.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2011, 59, 4; 569-574
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
AC/DC/AC converter in a small hydroelectric power plant
Autorzy:
Sikorski, A.
Korzeniowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/200049.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
induction generator
AC/DC/AC converter
hydroelectric power plant
Opis:
The article discusses application of AC/DC/AC converter cooperating with an induction generator in small hydroelectric power plants. The induction generator works with power grid or a separated group of receivers, enabling to generate power even at low speeds of the turbine. The article provides also results of the investigation concerning the functioning of the generator coupled with AC/DC/AC converter in steady and transient states during start-up and voltage decay.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2011, 59, 4; 507-511
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Collapse of Semiflexible Polymers in Two Dimensions. Monte Carlo Simulations
Autorzy:
Koliński, A.
Vieth, M.
Sikorski, A.
Powiązania:
https://bibliotekanauki.pl/articles/1887460.pdf
Data publikacji:
1991-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
02.60.+y
82.35.+t
Opis:
We present Monte Carlo simulations of a two-dimensional square lattice semi-flexible polymer model. Short-range repulsive potential (excluded volume) and long-range attractive (segment-segment) potential are included. Particular attention was paid to a phase transition of a model polymer chain from a random coil state to a dense globule. The transition temperature increases with the chain length and decreases with the stiffness of the model chain. The cooperativity of the transition increases with the polymer stiffness.
Źródło:
Acta Physica Polonica A; 1991, 79, 5; 601-612
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Frequency based islanding detection methods in power electronic converters
Autorzy:
Dmitruk, K.
Korzeniewski, M.
Sikorski, A.
Powiązania:
https://bibliotekanauki.pl/articles/1193396.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
anti-islanding protection
active frequency drift
grid converter
Opis:
Frequency based methods developed to detect an islanding condition in modern power grid structures have been discussed. The condition may occur in power grid lines to which additional energy sources with power electronic converters have been connected such as solar panels or wind turbines. It is a hazardous operating state for grid workers and devices connected to the islanded part of the grid. Such a state results from the inability to control amplitude and frequency of basic harmonic of the grid voltage. An islanding problem in a power grid with additional small energy sources has been discussed. A basic passive and active islanding detection method have been presented and compared with known frequency based algorithms, namely active frequency drift and active frequency drift with a positive feedback algorithm. Finally, a laboratory test of the proposed islanding detection methods in a three-phase grid with an AC-DC converter has been conducted. To demonstrate differences between the tested methods, total harmonic distortion injected into the output converter current and detection time of islanding state have been measured.
Źródło:
Power Electronics and Drives; 2017, 2, 37/1; 27-41
2451-0262
2543-4292
Pojawia się w:
Power Electronics and Drives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modern Direct Torque and Flux Control methods of an induction machine supplied by three-level inverter
Autorzy:
Sikorski, A.
Kulikowski, K.
Korzeniewski, M.
Powiązania:
https://bibliotekanauki.pl/articles/201199.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
asynchronous machine
DC/AC inverter
DTC
flux and torque control
3-level DC/AC inverter
Opis:
This paper describes two modern direct torque and flux control methods of an induction machine supplied by a three-level inverter. Additionally, it presents a comparison of the methods both in static and dynamic states. The methods, in a specific way, make use of an increased number of active vectors of the three-level inverter in order to improve control quality and reduce switching frequency. The two methods modify the DTC method by using its advantages and eliminating, at the same time its drawbacks. In static states the comparison was based on the results of investigations performed for two different load values and three set values of angular speed, whereas in dynamic states the comparison was focused on the behavior of the machine at startup. The results of the investigations have shown that both methods give very good performance. They are characterized by both sinusoidal shape of flux and low current deformations even at low angular speeds i.e. less than 10% of the nominal value. The presented methods also allow to generate nominal flux for set zero angular speed in order to achieve excitation of the induction machine. The switching frequencies for both methods are very similar in almost the whole range of control but the methods have shown some differences in control quality, particularly for higher torque values.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2013, 61, 4; 771-778
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Properties of active rectifier with LCL filter in the selection process of the weighting factors in finite control set-MPC
Autorzy:
Falkowski, P.
Sikorski, A.
Kulikowski, K.
Korzeniewski, M.
Powiązania:
https://bibliotekanauki.pl/articles/200718.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
model predictive control (MPC)
active front end converters
inductive-capacitive-inductive (LCL) filter
weighting factors selection
Opis:
One of the main problems of multivariable cost functions in model predictive control is the choice of weighting factors. Two finite control set model predictive control algorithms, applied to the three-phase active rectifier with an LCL filter, are described in the paper. The investigated algorithms, i.e. PCicuc and PCigicuc, implement multivariable approaches applying line (grid) current, capacitor voltage and converter current. The main problem dealt with in the paper is the choice of optimum values of the cost function weighting factors. The values of the factors calculated using the method proposed in the paper are very close to the values represented by the lowest THDi of the line current. Moreover, simulations verifying the equations used in the prediction of controlled values, i.e. line current, capacitor voltage and converter current, are presented. Both simulation and experimental results are presented to verify effectiveness of the investigated control strategies under change of the load (P = 5 kW and 2.5 kW), during transient states, under unbalanced and balanced line voltage.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2020, 68, 1; 51-60
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The prevalence and distribution of Dirofilaria repens in dogs in the Mazovian Province of Central-Eastern Poland
Autorzy:
Demiaszkiewicz, A.W.
Polanczyk, G.
Osinska, B.
Pyziel, A.M.
Kuligowska, I.
Lachowicz, J.
Sikorski, A.
Powiązania:
https://bibliotekanauki.pl/articles/51836.pdf
Data publikacji:
2014
Wydawca:
Instytut Medycyny Wsi
Źródło:
Annals of Agricultural and Environmental Medicine; 2014, 21, 4
1232-1966
Pojawia się w:
Annals of Agricultural and Environmental Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł

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