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Tytuł:
The role of stray currents in the evolution of damage in transport systems
Autorzy:
Kałkowska, E
Powiązania:
https://bibliotekanauki.pl/articles/135114.pdf
Data publikacji:
2016
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
stray currents
electric currents
catenary
circuit
corrosion
erosion
resistance
Opis:
The aim of the present work is the influence of stray currents on transport systems, especially rail and city systems. Therefore, a study was conducted that simulated flow of stray currents on elements of the transportation system. Steel DOMEX, which has enhanced resistance to corrosion, was used as research material. It is rarely understood that transport systems can have reciprocal negative effects on each other. For example, the urban and long-distance rail transport systems influence the transmission systems (gas pipelines, information systems). A side effect of the functioning of railways is the formation of stray currents, which cause electrochemical corrosion in all undergrounded metal components. It has been demonstrated that the impact of stray currents on the metal parts is of corrosive nature, and their effects can be presented graphically and numerically. It has also been proven that the anodic potential causes a greater loss than the cathodic potential. Furthermore, the exposure to the elements, both in the process of corrosion and erosion, accelerates the destruction of the material.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2016, 48 (120); 134-137
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stanowisko do diagnostyki zabezpieczeń różnicowoprądowych
The laboratory stand for testing of residual current devices
Autorzy:
Czapp, S.
Świsulski, D.
Powiązania:
https://bibliotekanauki.pl/articles/267978.pdf
Data publikacji:
2008
Wydawca:
Politechnika Gdańska. Wydział Elektrotechniki i Automatyki
Tematy:
prądy różnicowe
prądy upływowe
zabezpieczenia różnicowoprądowe
residual currents
leakage currents
residual current devices
Opis:
W obwodach z urządzeniami elektronicznymi, a w szczególności przekształtnikami, należy się liczyć z odkształconymi prądami ziemnozwarciowymi. Może też występować znaczny przejściowy i/lub ustalony prąd upływowy. Ma to istotne znaczenie dla skuteczności ochrony przeciwporażeniowej i niezawodności zasilania, jeżeli zastosowano zabezpieczenia różnicowoprądowe. W skrajnych przypadkach zabezpieczenia te mogą w ogóle nie reagować na silnie odkształcony prąd różnicowy, natomiast mogą zbędnie wyzwalać, przy braku zagrożenia porażeniowego, jeżeli załączeniu urządzenia towarzyszy znaczny przejściowy prąd upływowy. W pracy przedstawiono stanowisko laboratoryjne, które umożliwia badanie zabezpieczeń różnicowoprądowych przy wybranych prądach różnicowych przewidzianych przez normy przedmiotowe oraz dodatkowo przy różnych przebiegach prądów spotykanych w praktyce, a nie przewidzianych przez normy przedmiotowe. Stanowisko umożliwia generowanie ustalonych prądów różnicowych oraz różnego typu prądów przejściowych. Zasadniczym elementem stanowiska jest generator, którego programowanie wykonuje się za pomocą dedykowanych aplikacji, a także środowiska LabVIEW. W pracy zaprezentowano również wyniki przykładowych badań.
In circuits with electronic equipment, especially with frequency converters distorted eartb. fault current may occur. That circuits are also characterised by transient and/or steady state leakage currents. Harmonics in the earth fault current have negative effect on tripping of residual current devices. In some cases sensitivity of residual current devices rapidly decreases and protection against electric shock is not effective. Transient and steady state leakage current may cause residual current devices nuisance tripping. In the paper a laboratory stand for residual current devices testing is presented. This stand enables to generate distorted residual currents whose shape are not covered by international standards but may occur in practice. The main element of the stand is a programmed generator. For programming the generator dedicated software is used. Also special application in LabVIEW enviroment was carried out. In the paper the example results of the laboratory testing of residual current devices are described as well.
Źródło:
Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej; 2008, 25; 29-32
1425-5766
2353-1290
Pojawia się w:
Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Use of random walk in two-dimensional lattice graphs to describe influence of wind and sea currents on oil slick movement
Autorzy:
Guze, S.
Mazurek, J.
Smolarek, L.
Powiązania:
https://bibliotekanauki.pl/articles/244325.pdf
Data publikacji:
2016
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
random walk
oil spill
currents
Opis:
The concept of oil slick movement being influenced by wind and sea currents is elementary for the decision model of the distribution of large oil spill emergency control means at sea. The analysis of water area conditions such as wind and sea currents is elementary for the concept of oil slick movement. The article presents the model of oil slick movement under the influence of wind and sea currents. In building the model, random walk in two-dimensional lattice graphs has been used. The movement of oil slick is analysed in two ways. In the paper, the movement of the oil slick is analysed in two ways without wind and focus on surface sea currents and with wind and currents. Case one assumes no wind and focuses on surface sea currents only using random walk in a two-dimensional square grid graph. Case two assumes that wind is in place, so oil slick is moving due to surface sea currents and wind currents. The description of movement in case two is based on a two-dimensional lattice graph, which is a combination of a triangular grid graph and a hexagonal grid graph. The article also describes the basic assumptions of oil slick model: the definition of water area, oil slick and algorithm for rescue action to contain the oil spill. Oil slick movement concept is elementary for the decision model of oil spill control at sea. The model allows estimating the distance of oil slick from coastal areas.
Źródło:
Journal of KONES; 2016, 23, 2; 147-153
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Singular holomorphic functions for which all fibre-integrals are smooth
Autorzy:
Barlet, D.
Maire, H.
Powiązania:
https://bibliotekanauki.pl/articles/1207964.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
singularities
fibre-integrals
Mellin transform
currents
Opis:
For a germ (X,0) of normal complex space of dimension n + 1 with an isolated singularity at 0 and a germ f: (X,0) → (ℂ,0) of holomorphic function with df(x) ≤ 0 for x ≤ 0, the fibre-integrals
    $s ↦ ∫_{f=s} ϱ ω' ⋀ \bar{ω''}, ϱ ∈ C^{∞}_{c}(X), ω', ω'' ∈ Ω_{X}^{n}$,
are $C^{∞}$ on ℂ* and have an asymptotic expansion at 0. Even when f is singular, it may happen that all these fibre-integrals are $C^{∞}$. We study such maps and build a family of examples where also fibre-integrals for $ω',ω'' ∈ ⍹_{X}$, the Grothendieck sheaf, are $C^{∞}$.
Źródło:
Annales Polonici Mathematici; 2000, 74, 1; 65-77
0066-2216
Pojawia się w:
Annales Polonici Mathematici
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Elektrochemiczne zużycie szyn w torowiskach tramwajowych
Electrochemical wear of rails in tram trackway
Autorzy:
Dąbrowski, J.
Szostak, P.
Szyszko, R.
Powiązania:
https://bibliotekanauki.pl/articles/159142.pdf
Data publikacji:
2018
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Elektrotechniki
Tematy:
prądy błądzące
torowiska
stray currents
trackway
Opis:
Mechaniczne zużycie szyn jest zjawiskiem znanym i opisywanym w literaturze, a także widocznym w torowisku dla postronnego obserwatora. Zelektryfikowanie prądem stałym transportu szynowego wywołuje w torowisku dodatkowe zagrożenia w stosunku do szyn. W literaturze technicznej istnieje wiele pozycji dotyczących oddziaływania prądów błądzących na podziemną metalową infrastrukturę oraz sposobom ochrony tych konstrukcji. W niniejszym artykule zwrócono uwagę na fakt, że prądy błądzące przyczyniają się również do zużycia – zmiany geometrii szyn – w miejscach innych niż główka szyny. Podano przykłady takiego zużycia oraz warunki jakie muszą wystąpić, aby skutki zjawiska prądów błądzących mogły się uwidocznić.
Mechanical wear of rails is a phenomenon known and described in the literature and also visible in the track for an outside observer. The electrification by direct current of rail transport causes additional hazards in the track in relation to the rails. In the technical literature, there are many items regarding the impact of currents straying on underground metal infrastructure and ways to protect these structures. In this work, attention is paid to the fact that stray currents also contribute to wear – changes in the geometry of rails – in places other than the rail head. Examples of such wear are given to the conditions that must occur in order for the effects of stray currents to become visible.
Źródło:
Prace Instytutu Elektrotechniki; 2018, 278; 21-52
0032-6216
Pojawia się w:
Prace Instytutu Elektrotechniki
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Convergence of holomorphic chains
Autorzy:
Rams, Sławomir
Powiązania:
https://bibliotekanauki.pl/articles/1310622.pdf
Data publikacji:
1997
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
holomorphic chains
currents
convergence of chains
Opis:
We endow the module of analytic p-chains with the structure of a second-countable metrizable topological space.
Źródło:
Annales Polonici Mathematici; 1996-1997, 65, 3; 227-234
0066-2216
Pojawia się w:
Annales Polonici Mathematici
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new division formula for complete intersections
Autorzy:
Passare, Mikael
Powiązania:
https://bibliotekanauki.pl/articles/1312650.pdf
Data publikacji:
1991
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
complete intersections
residue currents
integral representations
Opis:
We provide a new division formula for holomorphic mappings. It is given in terms of residue currents and has the advantage of being more explicit and simpler to prove than the previously known formulas.
Źródło:
Annales Polonici Mathematici; 1991, 55, 1; 283-286
0066-2216
Pojawia się w:
Annales Polonici Mathematici
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Currents physical components (CPC) in circuits with nonsinusoidal voltages and currents. Part 1, Single-phase linear circuits
Autorzy:
Czarnecki, L. S.
Powiązania:
https://bibliotekanauki.pl/articles/262747.pdf
Data publikacji:
2005
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie
Tematy:
nonsinusoidal voltages and currents
harmonics
power definitions
power phenomena
apparent
reactive
scattered
unbalanced currents or powers
Opis:
The paper summarizes the present state of discussions on power phenomena, power definitions and compensation in single-phase linear circuits. The main concepts developed over several decades on how various non-active powers in circuits with nonsinusoidal voltages and currents should be defined and compensated are presented along with a detailed discussion of these concepts. The paper presents also the concept of the single-phase load current decomposition into Currents' Physical Components (CPC) and its application for power definitions and compensation in such circuits. The paper is not addressed to scientists and experts on powers, but rather to common electrical engineers that sometimes face power related problems in nonsinusoidal systems.
Źródło:
Electrical Power Quality and Utilisation. Journal; 2005, 11, 2; 3-14
1896-4672
Pojawia się w:
Electrical Power Quality and Utilisation. Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Identification of the reinforcement bars in concrete samples using eddy currents thermography
Autorzy:
Różański, Leszek
Ziopaja, Krzysztof
Powiązania:
https://bibliotekanauki.pl/articles/114038.pdf
Data publikacji:
2019
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
active IR thermography
eddy currents
reinforcement bars
Opis:
It is known that sub-surface discontinuities of matter, internal voids, inclusions of other materials or delaminations of the structure can be revealed on the surface temperature distribution. An important element of IR thermography investigations is the application of an appropriate heat source to heat the examined object. This article discusses the use of eddy currents for identification of reinforcing bars in concrete samples. The experiments have the laboratory character and are used primarily for qualitative assessment of the influence of bar diameter and concrete cover thickness on the identification of reinforcement in concrete elements. In order to induce a transient heat flow in tested samples, the eddy currents (EC) generator from IFF GmbH was used. After the pulse was completed, the surface temperature distribution was recorded using FLIR T620 infrared camera. The following experimental studies validate the practical application of active IR with EC to locate and assess the technical condition of reinforcing bars in reinforced concrete structures in buildings and civil engineering structures.
Źródło:
Measurement Automation Monitoring; 2019, 65, 2; 55-59
2450-2855
Pojawia się w:
Measurement Automation Monitoring
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Time-Domain CPC Decomposition: Answers to Comments on “Physical Interpretation of the Reactive Power in Terms of CPC Power Theory Revisited”
Autorzy:
Jeltsema, D.
van der Woude, J.
Powiązania:
https://bibliotekanauki.pl/articles/262614.pdf
Data publikacji:
2014
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie
Tematy:
power theory
reactive power
currents' physical components
Opis:
This note addresses some issues raised in [4] and refines some assertions made in our previous work on the time-domain Currents’ Physical Components (CPC) decomposition in [10].
Źródło:
Electrical Power Quality and Utilisation. Journal; 2014, 17, 1; 13-20
1896-4672
Pojawia się w:
Electrical Power Quality and Utilisation. Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Models of traction stray currents interaction with the earth return circuits
Autorzy:
Budnik, K.
Machczyński, W.
Szymenderski, J.
Powiązania:
https://bibliotekanauki.pl/articles/377830.pdf
Data publikacji:
2018
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
stray currents
earth return circuits
interaction
simulation
Opis:
The paper presents methods for analyzing the impact of stray currents generated by DC electric traction on nearby earth-return circuits (pipelines). Various simulation models were developed and compared. First the current and potential of the rail were determined using two models. A model with distributed parameters and a model with lumped parameters consisting of chain-connected two-ports of the π type, for which the potential values in the nodes and currents in the branches were determined using the node potential method. The results obtained were used to further analyze the interaction between the railway rail and the pipeline. The pipeline model is presented in the form of a chain connection of π type two-ports. To determine the impact of stray currents on the pipeline, an analysis of the electric field in its vicinity was carried out. For this purpose, two methods have been developed. First, the analysis of the distribution of the scalar potential in the ground for a rail section of finite length was performed. Second method required taking into account the mutual conductivity of the two circuits (rail and pipeline), which in connection with the knowledge of the leakage current from the rail made it possible to determine the potential of the tested pipeline (using controlled voltage sources). The paper presents the implementation of methods and a comparison of the results obtained. The usefulness and applicability of the developed models for the analysis of the impact of stray currents from DC electric traction on earth-return circuits were also assessed.
Źródło:
Poznan University of Technology Academic Journals. Electrical Engineering; 2018, 93; 227-239
1897-0737
Pojawia się w:
Poznan University of Technology Academic Journals. Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Variability of Hydrodynamic and Lithodynamic Coastal Processes in the East Part of the Gulf of Gdańsk
Autorzy:
Ostrowski, R.
Pruszak, Z.
Skaja, M.
Szmytkiewicz, M.
Powiązania:
https://bibliotekanauki.pl/articles/241442.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
sediment transport
waves
currents
deep-water climate
Opis:
The paper presents new findings concerning motion of water and sediment in the coastal zone of the east part of the Gulf of Gdańsk, from the Vistula River mouth at Świbno (Poland) to Cape Taran (Russia, Kaliningrad Oblast). The presented study deals with spatial variability of parameters of hydrodynamic and lithodynamic processes which have been subject to theoretical modelling. For the considered coastal segment, deep-water wave conditions reconstructed for a 44-year period have been analysed and transformed to the nearshore zone. Next, velocities of wave-driven longshore currents for the mean statistical year have been calculated, along with the longshore sediment transport rates. Regarding the net longshore sand motion, its detected direction is from Cape Taran towards the Vistula Spit. Very high annual rates of longshore sediment transport have been obtained for the coastal segment at Sambian Peninsula. These rates decrease considerably along the Vistula Spit, reaching zero at a distance of about one third of the Polish part of the Spit, measured from its root. At this location, the net longshore sediment transport (resulting from net longshore wave-current impact) reverses from westward to eastward.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2010, 57, 2; 139-153
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Maksymalne wartości prądów obciążeń trakcyjnych dla rzeczywistej trasy kolejowej w odniesieniu do bezpiecznej eksploatacji wyłączników szybkich
The maximum values of traction currents for the real railway line with reference to the safe use of fast switches
Autorzy:
Bartkiewicz, P.
Chrabąszcz, I.
Prusak, J.
Powiązania:
https://bibliotekanauki.pl/articles/249723.pdf
Data publikacji:
2012
Wydawca:
Instytut Naukowo-Wydawniczy TTS
Tematy:
bezpieczeństwo eksploatacyjne
obciążenie
obciążenie trakcyjne
traction currents
Opis:
Bezpieczeństwo eksploatacyjne kolejowych sieci trakcyjnych prądu stałego zależy od prawidłowego działania wszystkich elementów układu zasilania. Szczególną rolę na podstacjach trakcyjnych i w kabinach sekcyjnych odgrywają wyłączniki szybkie (WS) prądu stałego. Urządzenia te montowane są w obwodach bezpośrednio zasilających sieć jezdną o potencjale 3 kV DC, a ich zadaniem jest wyłączanie prądów roboczych, przeciążeniowych i zwarciowych. Poprawne i skuteczne działanie WS jest bardzo ważne dla aparatury trakcyjnej i może również decydować o zdrowiu a nawet życiu ludzkim.
Źródło:
TTS Technika Transportu Szynowego; 2012, 5-6; 49-53
1232-3829
2543-5728
Pojawia się w:
TTS Technika Transportu Szynowego
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quasi-instantaneous generation of reference signals for hybrid compensator control
Autorzy:
Czarnecki, L. S.
Powiązania:
https://bibliotekanauki.pl/articles/262594.pdf
Data publikacji:
2007
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie
Tematy:
compensator control
CPC
harmonic filters
hybrid compensators
power variation
power theory
non-periodic currents
semi-periodic currents
harmonics
Opis:
Power variation of a customer load can disturb other loads in distribution systems and compensators for such loads are sometimes needed. Voltages and currents in systems with such loads can be asymmetrical, nonperiodic, distorted and even unpredictable. Consequently, reference signals for the compensator control have to be generated in a situation where the power properties of the load are not well specified. Voltages and currents in systems with time-varying loads, although nonperiodic, can be treated as quantities with a disturbed periodicity. These are referred to as semi-periodic quantities. Under such an assumption, the Current Physical Components (CPC) power theory can by used for estimation of the power properties of such loads. In such a case, the CPC power theory provides fundamentals for a quasi-instantaneous generation of reference signals for the compensator control, based both on the frequency- and on the time-domain approach. The paper presents fundamentals of generation of reference signals for unbalanced loads with semi-periodic voltages and currents.
Źródło:
Electrical Power Quality and Utilisation. Journal; 2007, 13, 2; 3-8
1896-4672
Pojawia się w:
Electrical Power Quality and Utilisation. Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Validation of finite element solutions of nonlinear, periodic eddy current problems
Autorzy:
Plasser, R.
Bíró, O.
Powiązania:
https://bibliotekanauki.pl/articles/140778.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
eddy currents
nonlinear magnetic
finite elements
3-dimensional
Opis:
An industrial application is presented to validate a finite element analysis of 3-dimensional, nonlinear eddy-current problems with periodic excitation. The harmonicbalance method and the fixed-point technique are applied to get the steady state solution using the finite element method. The losses occurring in steel reinforcements underneath a reactor due to induced eddy-currents are computed and compared to measurements.
Źródło:
Archives of Electrical Engineering; 2014, 63, 4; 591-600
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heat generation by eddy currents in a shell of superconducting bus-bars for SIS100 particle accelerator at FAIR
Autorzy:
Tomków, Ł.
Trojanowski, S.
Ciszek, M.
Chorowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/141177.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
superconductors
eddy currents
electromagnetic heat generation
particle accelerators
Opis:
Superconducting magnets in the SIS100 particle accelerator require the supply of liquid helium and electric current. Both are transported with by-pass lines designed at Wrocław University of Technology. Bus-bars used to transfer an electric current between the sections of the accelerator will be encased in a steel shell. Eddy currents are expected to appear in the shell during fast-ramp operation of magnets. Heat generation, which should be limited in any cryogenic system, will appear in the shell. In this work the amount of heat generated is assessed depending on the geometry of an assembly of the bus-bars and the shell. Numerical and analytical calculations are described. It was found that heat generation in the shell is relatively small when compared to other sources present in the accelerator and its value strongly depends on the geometry of the shell. The distribution of eddy currents and generated heat for different geometrical options are presented. Based on the results of the calculations the optimal design is proposed.
Źródło:
Archives of Electrical Engineering; 2017, 66, 4; 705-715
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wykrywanie pęknięć w połączeniach nitowanych elementów lotniczych z wykorzystaniem technologii EC Array
Detection of cracks in connections of riveted aircraft elements using EC Array technology
Autorzy:
Synaszko, P.
Zając, B.
Powiązania:
https://bibliotekanauki.pl/articles/107836.pdf
Data publikacji:
2018
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
lotnictwo
prądy wirowe
EC Array
aviation
eddy currents
Opis:
Autorzy zaprezentowali wynik badań fragmentów konstrukcji lotniczej z uszkodzeniami znajdującymi się poniżej pierwszej warstwy materiału. Do badań wykorzystano zestaw firmy OLYMPUS oparty na systemie OMNISCAN MX2 i głowicy EC ARRAY oraz porównawczo, zestaw MAUS V. Wyniki, w obu przypadkach przedstawiono za pomocą zobrazowania typu C. Interpretacja sygnałów pochodzących z wewnętrznych warstw konstrukcji przy zastosowaniu tradycyjnego zobrazowania typu A jest utrudniona, co wpływa zarówno na czas realizacji jak i wiarygodność otrzymanych wyników. Zastosowanie zobrazowania typu C ułatwia interpretację i raportowanie uszkodzeń. Ponadto głowica EC Array ze względu na dużą powierzchnię skanowania znacząco skraca czas realizacji badań. Istotnym elementem artykułu jest przedstawienie metodologii doboru parametrów do badań konstrukcji wielowarstwowych.
The authors presented the results of tests of fragments of the aircraft structure with damage below the first layer of material. The OLYMPUS set based on the MX2 OMV and EC ARRAY head and comparative MAUS V kit were used for the research. The results, in both cases, are represented by C-type imaging. Interpretation of signals from the internal layers of the structure using traditional A-type imaging is difficult, which affects both for the duration of the implementation and the reliability of the results obtained. The use of C-type imaging makes it easier to interpret and report damage. In addition, the EC Array head, due to its large scanning area, significantly shortens the time of testing. An important element of the article is the presentation of the methodology for the selection of parameters for testing multilayer structures.
Źródło:
Badania Nieniszczące i Diagnostyka; 2018, 4; 77-79
2451-4462
2543-7755
Pojawia się w:
Badania Nieniszczące i Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Physical Interpretation of the Reactive Power in Terms of CPC Power Theory Revisited
Autorzy:
Jeltsema, D.
van der Woude, J.
Powiązania:
https://bibliotekanauki.pl/articles/262600.pdf
Data publikacji:
2013
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie
Tematy:
power theory
reactive power
current’s physical
components
Opis:
Recently the authors have developed a time-domain representation of the Currents’ Physical Components (CPC) power theory. Consequently, piece-wise continuous currents and voltages, such as square waves and sawtooth signals, can naturally be taken into account without approximating them by a finite number of harmonics. Based on the time-domain CPC approach, this paper refines and corrects some of the assertions made by Czarnecki in his paper ‘Physical Interpretation of the Reactive Power in Terms of CPC Power Theory’.
Źródło:
Electrical Power Quality and Utilisation. Journal; 2013, 16, 2; 1-6
1896-4672
Pojawia się w:
Electrical Power Quality and Utilisation. Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wind influence on the formation of nearshore currents in the southern Baltic: mumerical modelling results
Autorzy:
Sokolov, A.
Chubarenko, B.
Powiązania:
https://bibliotekanauki.pl/articles/241238.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
currents
waves
numerical modelling
coastal zone
Baltic Sea
Opis:
A two-dimensional numerical model was used for a simulation of vertical average longshore currents generated by both wind friction and wind-wave action in the nearshore zone. The modelling domain includes the southern part of the Baltic Proper (all boundaries were closed). Wind, uniform in space and varying in time, was the only forcing in the model. The correlation coefficient higher than 0.8 was obtained by model calibration versus the field measurements of currents conducted at the Lubiatowo field station (southern Baltic) during about 1.5 months in 2006. Comparative simulations of total currents including both wind-induced drift and wave components, and of total currents including only a wind-induced drift component, showed that the input of the drift component into currents in the nearshore zone is greater than commonly believed. Wind-induced drift strongly dominates outside the zone of wave transformation, and its input into the total resulting currents remains noticeable even in a zone between the shoreline and the depth of the first wave breaking. Thus, wind-induced drift constitutes up to 50% of the resulting longshore currents for longshore winds and no less than 20% of the longshore component of currents for winds at 45 degrees to the longshore direction.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2012, 59, 1-2; 37-48
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Storm deposits: evidence of event sedimentation in the Bajocian of the Central High Atlas, Morocco
Autorzy:
Alt Addi, A.
Powiązania:
https://bibliotekanauki.pl/articles/2061350.pdf
Data publikacji:
2008
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Bajocian
High Atlas
Morocco
oscillatory currents
resedimentation
storm deposits
Opis:
Storm beds interbedded with marls, claystones and beds of nodular to undulose bioclastic limestones have been recognized in the Central High Atlas of Morocco. These provide the first evidence of event sedimentation in the Bajocian of the area. The outcrops studied are included in the Agoudim and Tazigzaout formations in the center of the basin, and are parts of the Bin El Ouidane Group at the margins of the basin. The storm deposits comprise calcarenites and bioclastic packstones-grainstones. These beds have symmetrical wave-ripples at their tops and an internal structure of hummocky cross-stratification. They are considered to have been formed by tropical storms and hurricanes. Multiple reworking and winnowing of siliciclastic or bioclastic material by oscillatory currents related to storm and to currents resulting from storm/tide interactions is inferred. Bed features are the most important evidence in favour of a palaeobathymetric interpretation of related pelagic sediments, with calcareous tempestites representing episodic resedimentation, mainly coincident with relative sea-level falls during which major storm waves affected the sea bottom. This interpretation is in agreement with the regional palaeogeography and is further supported by evidence of Jurassic storm-controlled sedimentation in adjacent Mediterranean basins.
Źródło:
Volumina Jurassica; 2008, 6, 1; 23-32
1896-7876
1731-3708
Pojawia się w:
Volumina Jurassica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of Physiotherapeutic Procedures on the Treatment of Damaged Rotator Cuff Muscules of the Shoulder Girdle
Autorzy:
Bolach, Bartosz
Walowska, Jagoda
Bolach, Eugeniusz
Powiązania:
https://bibliotekanauki.pl/articles/1030752.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Szczeciński. Wydawnictwo Naukowe Uniwersytetu Szczecińskiego
Tematy:
Lovett scale
VAS scale
kinesiotherapy
rotator cuff
tens currents
Opis:
Damage to the rotator cuffs within the shoulder girdle is one of the many causes of the painful shoulder syndrome. The main symptom is the accompanying pain limiting partial or complete mobility in the shoulder joint. Weakness and atrophy of the deltoid and supraspinous muscles of the shoulder are secondary symptoms caused by immobilization of the upper limb. The aim of the study was to evaluate the effects of the use of physical therapy in women with damaged rotator cuff muscles of the shoulder girdle. The study involved 30 women aged 45–70, who were divided into two groups: professionally active (n = 15) and professionally inactive (n = 15). The muscle strength of the shoulder joint rim, strength of the hand grip and pain assessment according to the VAS scale were analyzed. The assessment of upper limb fitness was assessed before and after 20 physiotherapy procedures. Professionally active women returned to physical fitness faster, gaining greater strength of the shoulder girdle, strength of the hand grip and reduction of perceptible pain.
Źródło:
Central European Journal of Sport Sciences and Medicine; 2019, 27, 3; 17-23
2300-9705
2353-2807
Pojawia się w:
Central European Journal of Sport Sciences and Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Confronting theoretical predictions with experimental data; A fitting strategy for multi-dimensional distributions
Autorzy:
Przedziński, T.
Roig, P.
Shekhovtsova, O.
Wąs, Z.
Zaremba, J.
Powiązania:
https://bibliotekanauki.pl/articles/305752.pdf
Data publikacji:
2015
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
RChL
TAUOLA
hadronic currents
fitting strategies
multi-dimensional fits
Opis:
After developing a Resonance Chiral Lagrangian (R χ L) model to describe hadronic τ lepton decays, the model was confronted with experimental data. This was accomplished by using a fitting framework that was developed to take into account the complexity of the model and to ensure numerical stability for the algorithms used in the fitting. Since the model used in the fit contained 15 parameters and there were only three one-dimensional distributions available, we could expect multiple local minima or even whole regions of equal potential to appear. Our methods had to thoroughly explore the whole parameter space and ensure (as well as possible) that the result is a global minimum. This paper is focused on the technical aspects of the fitting strategy used. The first approach was based on a re-weighting algorithm published in article Shekhovtsova et al. and produced results in about two weeks. A later approach, with an improved theoretical model and a simple parallelization algorithm based on Inter-Process Communication (IPC) methods of UNIX system, reduced computation time down to 2–3 days. Additional approximations were introduced to the model, decreasing the necessary time to obtain the preliminary results down to 8 hours. This allowed us to better validate the results, leading to a more robust analysis published in article Nugent et al.
Źródło:
Computer Science; 2015, 16 (1); 17-38
1508-2806
2300-7036
Pojawia się w:
Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Coupled wave-equation and eddy-current model for modelling and measuring propagating stress-waves
Autorzy:
Peussa, T.
Belahcen, A.
Powiązania:
https://bibliotekanauki.pl/articles/140923.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
coupled model
eddy currents
finite element method
magnetostriction
stress wave
Opis:
The coupling of the propagating stress wave with the eddy current model is presented. The applied stress produces magnetization in the sample that can be measured outside the sample by measuring the resulting magnetic flux density. The stress and flux density measurements are made on a mechanically excited steel bar. The problem is modelled with the finite element method for both the propagating wave and the eddy current. Three aspects are considered: eddy current model using magnetization from the measurements, coupled wave and eddy current models, and coupled different dimensions in the wave model. The measured stress can be reproduced from the measured flux density by modelling. The coupled models work both for stress and flux couplings as well as for the different dimensionality couplings.
Źródło:
Archives of Electrical Engineering; 2015, 64, 2; 215-226
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of end-winding proximity losses in a high-speed PM machine
Autorzy:
Mlot, A.
Lukaniszyn, M.
Korkosz, M.
Powiązania:
https://bibliotekanauki.pl/articles/141443.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
end-winding
permanent magnet motor
eddy-currents losses
proximity losses
Opis:
This paper presents a finite element investigation into the proximity losses in a high-speed permanent magnet (PM) machine for traction applications. A three-dimensional (3D) finite element analysis (FEA) is employed to evaluate and identify the endwinding contribution into the overall winding power loss generated. The study is focused on the end-winding effects that have not been widely reported in the literature. The calculated results confirm that the end-winding copper loss can significantly affect the eddycurrent loss within copper and it should be taken into account to provide reasonable prediction of total losses. Several structures of the end-winding are analyzed and compared in respect to the loss and AC resistance. The results clearly demonstrate that the size of the end-winding has a significant impact on the power loss. The calculated results are validated experimentally on the high-speed permanent magnet synchronous machine (PMSM) prototype for selected various winding arrangements.
Źródło:
Archives of Electrical Engineering; 2016, 65, 2; 249-261
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental results of parallel connected inverters feeding medium voltage transformer
Autorzy:
Kozak, M.
Powiązania:
https://bibliotekanauki.pl/articles/377860.pdf
Data publikacji:
2017
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
electrical transformer
line side inverter
inrush currents
inverter parallel operation
Opis:
Development of medium voltage, high power ship electrical installations on board of special purpose vessels, has led to use of grid side inverters along with step-up grid transformers. In this paper there is presented theoretical background and experimental results of two inverters in parallel connection feeding one 0,4/15 kV transformer.
Źródło:
Poznan University of Technology Academic Journals. Electrical Engineering; 2017, 90; 359-368
1897-0737
Pojawia się w:
Poznan University of Technology Academic Journals. Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-25 z 137

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