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Tytuł:
CFD-predicted rotordynamic characteristics of a high temperature sodium liquid seal
Autorzy:
Wang, Tong
Chen, Pingwei
Ma, Wensheng
Yu, Guangbin
Powiązania:
https://bibliotekanauki.pl/articles/2086978.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
sodium liquid seal
multi-frequency whirling model
rotordynamic characteristics
CFD
Opis:
Rotordynamic characteristics of a high temperature sodium liquid (HTSL) seal were studied in this paper by using CFD software. Compared with the water liquid seal, the HTSL seal has a larger leakage flow rate and a lower drag power loss. The HTSL seal has a larger direct stiffness coefficient and the effective stiffness coefficient Keff is also larger than the water liquid seal, which means the HTSL seal has a better stiffness capacity. The HTSL seal possesses a positive effective damping coefficient Ceff in the whole whirling frequency range, which means better stability for the rotor system especially in high rotor speeds.
Źródło:
Journal of Theoretical and Applied Mechanics; 2022, 60, 3; 347--360
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Model Tests of Under Frequency Load Shedding (UFLS) for Connected Systems of Continental Europe
Badania modelowe działania SCO w połączonych systemach krajów Europy kontynentalnej
Autorzy:
Głaz, M.
Trębski, R.
Powiązania:
https://bibliotekanauki.pl/articles/397378.pdf
Data publikacji:
2016
Wydawca:
ENERGA
Tematy:
frequency model
study the impact of dispersed generation
UFLS optimization settings
ENTSO-E guidelines
model częstotliwościowy
badania wpływu generacji rozproszonej
optymalizacja nastaw SCO
wytyczne ENTSO-E
Opis:
The task force set up by working group System Protection and Dynamics within ENTSO-E model tests of Under Frequency Load Shedding (UFLS) for connected systems of continental Europe were carried out. Over 360 simulation scenarios were performed including 16 strategies UFLS, 2 variants of load, 6 types of contingency, with and without considering the impact of dispersed generation. On the basis of calculation results conditions for improving the effectiveness of the UFLS were specified,, including recommended changes of UFLS settings, necessary to achieve this aim. The following report contains a summary description of the test method together with the presentation of selected results of summary calculations and conclusions of the study.
Zespół zadaniowy powołany przez grupę roboczą System Protection and Dynamics przy ENTSO-E przeprowadził badania modelowe działania SCO w połączonych systemach krajów Europy kontynentalnej. Wykonano ponad 360 symulacji obejmujących 16 scenariuszy nastaw SCO, 2 warianty zapotrzebowania, 6 wariantów zakłóceń oraz z uwzględnieniem i bez wpływu generacji rozproszonej. Na podstawie otrzymanych wyników obliczeń określono uwarunkowania poprawy skuteczności działania SCO, w tym zarekomendowano propozycje zmian w nastawach SCO, potrzebnych do osiągnięcia tego celu. Poniższy referat zawiera skrócony opis metody badawczej wraz z prezentacją wybranych wyników obliczeń i wniosków podsumowujących badania.
Źródło:
Acta Energetica; 2016, 3; 59-64
2300-3022
Pojawia się w:
Acta Energetica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Binaural speech segregation system on single board computer
Autorzy:
Usagawa, Tsuyoshi
Irwansyah, Irwansyah
Powiązania:
https://bibliotekanauki.pl/articles/950427.pdf
Data publikacji:
2019
Wydawca:
Politechnika Poznańska. Instytut Mechaniki Stosowanej
Tematy:
frequency domain binaural model
single-board computer
hearing assistance
open-source software
komputer jednopłytkowy
wsparcie słuchu
oprogramowanie otwarte
Opis:
A pocket-size binaural speech segregation system has been developed and assembled with available consumer hardware. It can enhance a target speech in a certain direction while attenuating interfering sounds from other directions. This system is based on the frequency domain binaural model (FDBM) and it segregates multiple speeches based on the directivity. This real-time system is implemented on a low-cost single board computer which might be used as a hearing assistance device. Performance of the system is evaluated in a normal laboratory room as well as anechoic chamber. Even in a room with reverberation, the system works well and show the almost same performance obtained in anechoic chamber.
Źródło:
Vibrations in Physical Systems; 2019, 30, 1; 1-9
0860-6897
Pojawia się w:
Vibrations in Physical Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Large-Signal RF Modeling with the EKV3 MOSFET Model
Autorzy:
Chalkiadaki, M. A.
Buchar, M.
Powiązania:
https://bibliotekanauki.pl/articles/308061.pdf
Data publikacji:
2010
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
compact model
EKV3 model
large-signal
load-pull
MOSFET model
radio frequency
Opis:
This paper presents a validation of the EKV3 MOSFET model under load-pull conditions with high input power at 5.8 GHz, as well as S-parameter measurements with low input power up to 20 GHz. The EKV3 model is able to represent coherently the large- and small-signal RF characteristics in advanced 90 nm CMOS technology. Multifinger devices with nominal drawn gate length of 70 nm are used.
Źródło:
Journal of Telecommunications and Information Technology; 2010, 1; 29-33
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Criteria for identifying maximum rainfall determined by the peaks-over-threshold (POT) method under the Polish Atlas of Rainfall Intensities (PANDa) project
Autorzy:
Burszta-Adamiak, Ewa
Licznar, Paweł
Zaleski, Janusz
Powiązania:
https://bibliotekanauki.pl/articles/108607.pdf
Data publikacji:
2019
Wydawca:
Instytut Meteorologii i Gospodarki Wodnej - Państwowy Instytut Badawczy
Tematy:
rainfall model
Intensity-Duration-Frequency
IDF
Depth-Duration-Frequency
DDF
extreme value theory
EVT
Opis:
Determination of rainfall maxima from long-term series is one of the more important tasks in urban hydrology. These maxima are useful both in designing land drainage systems and for flood protection in a catchment. The identification of rainfall maxima for the hierarchy of rainfall durations from 5 min to 4 320 min is a fundamental stage of the creation of the first version of the Polish Atlas of Rainfall Intensities (PANDa), which will ultimately be a source of updated and reliable information on design rainfall intensities for designing and modeling rainwater drainage and retention systems in Poland. One of the methods for identifying extreme rainfall events is to use criteria for selecting rainfall based on their depth for a given rainfall frequency and duration. Existing national experience in this respect is based on the results of analyses usually conducted with regard to records from single weather stations. This article presents the results of a study designed to verify the usefulness of the literature-based criteria for identifying rainfall maxima using the peaks-over-threshold (POT) method at a much broader nationwide scale. The study analyzed data from a previously created digital database of rainfall series, which includes 3 000 stationyears (consisting of a 30-year measurement series from 100 weather stations of the Institute of Meteorology and the Water Management - National Research Institute (IMGW-PIB). The study results show that as far as the investigated measurement series are concerned, the criteria based on the literature sources have limited application and can only be used for identifying the largest short-duration rainfall events. To determine rainfall maxima for all of the time intervals analyzed (from 5 minutes to 3 days), it was necessary to develop our own criteria that would allow the methodology for identifying extreme rainfall events to be standardized for all 100 stations.
Źródło:
Meteorology Hydrology and Water Management. Research and Operational Applications; 2019, 7, 1; 3-13
2299-3835
2353-5652
Pojawia się w:
Meteorology Hydrology and Water Management. Research and Operational Applications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of acoustical and optical zooplankton measurements using an acoustic scattering model: A case study from the Arctic frontal zone
Autorzy:
Szczucka, Joanna
Błachowiak-Samołyk, Katarzyna
Trudnowska, Emilia
Hoppe, Łukasz
Powiązania:
https://bibliotekanauki.pl/articles/2046858.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Arctic
Svalbard
zooplankton
high−frequency echosounding
sound scattering model
Źródło:
Polish Polar Research; 2016, 37, 1; 67-88
0138-0338
2081-8262
Pojawia się w:
Polish Polar Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Computer modeling in the diagnostics of transformers’ windings deformations
Autorzy:
Banaszak, S.
Gawrylczyk, K. M.
Powiązania:
https://bibliotekanauki.pl/articles/97341.pdf
Data publikacji:
2010
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
transformer
computer model
winding of the transformer
frequency response
Opis:
The diagnostics of power transformers is very important in order to plan repairs and replacements of aged population of transformers operated in Poland and Europe. One of these methods is Frequency Response Analysis - FRA. It can detect any mechanical changes in active part of transformer, which may even lead to serious faults of units in service. As the method is based on comparison of measured curves, which are not always available from previous measurements the computer modeling was applied to create models of windings’ response. The paper presents examples of models created for simple windings and also for real transformer with some deformations of windings simulated.
Źródło:
Computer Applications in Electrical Engineering; 2010, 8; 132-140
1508-4248
Pojawia się w:
Computer Applications in Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dehydration of no flotation size coal's slimes on the deck of high-frequency screen with multislopes area's working surface
Оbezvozhivanie ugolnogo shlama na site vysokochastotnogo vibracionnogo grokhota s raznonaklonnymi uchastkami rabochejj poverkhnosti
Autorzy:
Eremejev, I.
Polulyakh, A.
Polulyakh, D.
Grachyov, O.
Powiązania:
https://bibliotekanauki.pl/articles/791890.pdf
Data publikacji:
2014
Wydawca:
Komisja Motoryzacji i Energetyki Rolnictwa
Tematy:
coal
dehydration
physical model
working surface
high-frequency screen
Źródło:
Teka Komisji Motoryzacji i Energetyki Rolnictwa; 2014, 14, 2
1641-7739
Pojawia się w:
Teka Komisji Motoryzacji i Energetyki Rolnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Model i badania czujnika wiroprądowego
Eddy current sensor - model and sensitivity analysis
Autorzy:
Stencel, M.
Piwowar, P.
Powiązania:
https://bibliotekanauki.pl/articles/157552.pdf
Data publikacji:
2010
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
czujnik wiroprądowy
charakterystyki częstotliwościowe
czułość czujnika
model nieliniowy
optymalna częstotliwość pracy
eddy current sensor
frequency characteristic
sensor sensitivity
nonlinear model
optimal frequency
Opis:
Praca przedstawia eksperymentalny model czujnika wiroprądowego oraz wskazuje częstotliwości pracy pozwalającej uzyskać maksymalną jego czułość. Badany czujnik przeznaczony jest do pracy w systemach obrazowania 2-D obiektów metalowych, a przeprowadzone badania mają na celu wskazanie warunków pracy pozwalających osiągnąć maksymalną strefę detekcji zależną od jego czułości.
The paper presents the principle of operation and experimental model of an eddy current sensor. The investigated sensor will work in systems of 2D visualization of metal objects. The aim of measurement experiments was to reach operation frequencies at which the sensor sensitivity is maximum, and to determine such conditions of work which allow getting the maximal detection zone of the sensor dependent on its sensitivity. In the preliminary research a circuit model of the sensor was formulated. It was pointed out that such a model has to be nonlinear in order to obtain consistence with verification measurements. The investigation results show that there are four resonances on the frequency characteristics. These points of characteristics are also points of the maximum sensor sensitivity. The maximum value of the amplitude-frequency characteristic resonance was at about 147 kHz which was the lowest resonance frequency and was chosen as a work frequency for scanning process. The final investigations deal with observation of the influence of the type of object on the sensor sensitivity. They show that the sensor sensitivity is higher under influence of nonferromagnetic materials.
Źródło:
Pomiary Automatyka Kontrola; 2010, R. 56, nr 9, 9; 1092-1095
0032-4140
Pojawia się w:
Pomiary Automatyka Kontrola
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the optimum absorber parameters: revising the classical results
Autorzy:
Puzyrov, V.
Awrejcewicz, J.
Powiązania:
https://bibliotekanauki.pl/articles/281548.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
dynamic vibration absorber
Den Hartog’s model
frequency-amplitude curve
optimization
Opis:
The dynamic vibration absorber is a kind of mechanical device with inertia, stiffness, and damping. Once connected to a given structure or machine, it is capable of absorbing vibratory energy. As a result, the primary system can be protected from excessively high vibration levels. In this paper, we deal with classical Den Hartog’s model to clarify the known results and improve the mathematical component of this approach. We suggest the optimal choice of absorber parameters, which is slightly different and more general analytical approach. The comparison of two methods of optimization is carried out, and the corresponding error of calculus is estimated.
Źródło:
Journal of Theoretical and Applied Mechanics; 2017, 55, 3; 1081-1089
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Model flickermetru dla modulacji częstotliwości napięcia wejściowego
A model of the flickermeter for frequency modulation of input voltage
Autorzy:
Wiczyński, G.
Powiązania:
https://bibliotekanauki.pl/articles/153232.pdf
Data publikacji:
2007
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
flickermetr
model
wskaźnik Pst
modulacja FM
flickermeter
Ps
indicator
frequency modulation
Opis:
Flickermetr jest potoczną nazwą układu do pomiaru uciążliwości odczuwania migotania światła wywołanego wahaniami napięcia. Przetwarzanie toru sygnałowego tego układu jest na tyle złożone, że analityczne wyznaczenie wartości wyjściowych nie jest proste. Założonym celem prac opisanych w artykule jest budowa prostego modelu dla modulacji częstotliwości FM sygnału wejściowego. Obecnie brak specyfikacji normatywnej flickermetru do modulacji FM. W artykule zaproponowano model flickermetru dla modulacji FM sygnałami wolnozmiennymi i w zakresie od 1Hz do 100 Hz. Dokonano ocenę prawidłowości aproksymacji charakterystyk dla modulacji FM przebiegami harmonicznym i prostokątnym, bazując na wynikach symulacji numerycznych. Prezentowany model ułatwia zrozumienie działania badanego toru sygnałowego flickermetru i weryfikację prawidłowości działania rzeczywistych układów pomiarowych w rozpatrywanym zakresie częstotliwości sygnału modulującego FM.
The aim of studies presented in the paper is a structure of the simple model for FM frequency modulation of the input signal. There is a lack of the flickermeter standard specification in this subject. Based on results of numerical simulations, evaluation of approximation correctness of characteristics for FM modulation with harmonic as well as rectangular waveforms has been made. The equations for FM modulation using slowly varying signals and signals in the frequency range from 1 Hz to 100 Hz are proposed. The presented model facilitates understanding the operation of the tested flickermeter signal chain and verification of the operation correctness of real measuring systems in the considered frequency range.
Źródło:
Pomiary Automatyka Kontrola; 2007, R. 53, nr 9 bis, 9 bis; 633-636
0032-4140
Pojawia się w:
Pomiary Automatyka Kontrola
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of shock absorber characteristics’ nonlinearities on suspension Frequency Response Function estimation and possibilities of simplified characteristics modelling
Autorzy:
Ślaski, Grzegorz
Klockiewicz, Zbyszko
Powiązania:
https://bibliotekanauki.pl/articles/2124767.pdf
Data publikacji:
2022
Wydawca:
Sieć Badawcza Łukasiewicz. Przemysłowy Instytut Motoryzacji
Tematy:
shock absorber
damper
frequency response function
estimation
nonlinear
damper model
bilinear
Opis:
The paper shortly presents shock absorber design evolution and resulting achieved characteristics. The way in which suspension performance is evaluated is described giving information about models used for suspension parameter tuning during simulation testing of suspension transmissibility (FRF - Frequency Response Function) for most important suspension assessment criteria. More detailed information about models of shock absorber (damper) nonlinearities of characteristics allows for description of methods of linear and nonlinear suspension models FRF estimation. Testing linear suspension model is possible with the use of analytical transfer function formulas which were used to verify methods for estimation FRF using estimated power spectral density functions of excitation and response signals. Designing appropriate input signal allowing to get useful response signals was necessary to for the success of this research. Proposed FRF estimation method was used for linear estimation of nonlinear suspension for a given range of working condition. It was demonstrated that there is no single value of a damping coefficient which would make the linear model responses similar to the responses of the nonlinear one. Then the bilinear model was proposed, giving good damper static nonlinear characteristic.
Źródło:
Archiwum Motoryzacji; 2022, 96, 2; 77--95
1234-754X
2084-476X
Pojawia się w:
Archiwum Motoryzacji
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multivariable predictive control considering time delay for load-frequency control in multi-area power systems
Autorzy:
Daniar, S.
Shiroei, M.
Aazami, R.
Powiązania:
https://bibliotekanauki.pl/articles/229223.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
load frequency control
model predictive control
time delay
generation rate constraint
Opis:
In this paper, a multivariable model based predictive control (MPC) is proposed for the solution of load frequency control (LFC) in a multi-area interconnected power system. The proposed controller is designed to consider time delay, generation rate constraint and multivariable nature of the LFC system, simultaneously. A new formulation of the MPC is presented to compensate time delay. The generation rate constraint is considered by employing a constrained MPC and economic allocation of the generation is further guaranteed by an innovative modification in the predictive control objective function. The effectiveness of proposed scheme is verified through time-based simulations on the standard 39-bus test system and the responses are then compared with the proportional-integral controller. The evaluation of the results reveals that the proposed control scheme offers satisfactory performance with fast responses.
Źródło:
Archives of Control Sciences; 2016, 26, 4; 527-549
1230-2384
Pojawia się w:
Archives of Control Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamic and mathematical models of the hydroimpulsive vibro-cutting device with a pressure pulse generator bult into the ring spring
Modele dynamiczne i matematyczne hydraulicznego urządzenia impulsowego do cięcia wibracyjnego z generatorem impulsów wbudowanym wsprężynę pierścieniową
Autorzy:
Obertyukh, Roman
Slabkyі, Andrii
Polishchuk, Leonid
Povstianoi, Oleksandr
Kumargazhanova, Saule
Satymbekov, Maxatbek
Powiązania:
https://bibliotekanauki.pl/articles/2174711.pdf
Data publikacji:
2022
Wydawca:
Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Tematy:
mathematical model
dynamic model
hydropulper device
ring spring
frequency
amplitude
model matematyczny
model dynamiczny
hydrauliczne urządzenie impulsowe
sprężyna pierścieniowa
częstotliwość
amplituda
Opis:
Structural calculation scheme of the hydropulse device for vibration cutting with built-in ring with pressure pulse generator (PPG) is considered. On the basis of the structural scheme and cyclogram of the working cycle of the device, its dynamic and mathematical models were developed, in whichthe hydraulic link is represented by a visco-elastic model of the working fluid (energy carrier) composed of the inertial elastic and dissipative elements (Kelvin-Foyga's body).
Rozważa się schemat konstrukcyjny i projektowy hydraulicznego urządzenia impulsowego do cięcia wibracyjnego z wbudowanym generatorem impulsów ciśnieniowych ze sprężyną pierścieniową (PPG). Na podstawie schematu strukturalnego i cyklu pracy urządzenia opracowano jego modele dynamiczne i matematyczne, w których ogniwo hydrauliczne reprezentowane jest przez lepkosprężysty model cieczy roboczej (nośnika energii), złożony z bezwładnych elementów sprężystych i dyssypacyjnych (ciał Kelvina-Foiga).
Źródło:
Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska; 2022, 12, 3; 54--58
2083-0157
2391-6761
Pojawia się w:
Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fatigue Behavior and Mechanism of FV520B-I Owing to the Effect of Loading Frequency on the Fatigue Property in HCF and VHCF Regime
Autorzy:
Wang, J.
Zhang, Y.
Shi, B.
Zhao, Q.
Sun, Q.
Zhang, Z.
Lu, H.
Powiązania:
https://bibliotekanauki.pl/articles/353784.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ultrahigh loading frequency
FV520B-I
fatigue strength
fatigue conversion model
Opis:
Fatigue property of FV520B-I is affected by the ultrahigh loading frequency significantly, and the ultrasonic fatigue experimental data can’t be employed directly to analyze the fatigue failure in the actual remanufacturing engineering. However few theories about the effect of loading frequency on the fatigue property of FV520B-I has ever been proposed. In this paper, both ultrasonic experiment and conventional experiment are conducted out to obtain the fatigue data. The effect of loading frequency on the fatigue data distribution is discussed firstly, its fatigue limit declines with the increase of the loading frequency. Then the fracture surface observations are captured, the fatigue property and fatigue behavior mechanism of FV520B-I is examined by analyzing the fracture surface features, crack initiation and failure observations. A new material frequency correction factor is proposed and introduced to eliminate the influence of the loading frequency on the FV520B-I fatigue property. FV520B-I empirical fatigue life conversion model and fatigue strength conversion model are established with comprehensive use of a fitting algorithm based on the combination of experimental data and classic formula. A clear understand of the effect of loading frequency on the fatigue property of FV520B-I is novel and has an important significance in guaranteeing the accuracy of the actual fatigue analysis of FV520B-I in the remanufacturing engineering.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 1; 347-357
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of modelling and simulation to evaluate the theta method used in diagnostics of automotive shock absorbers
Autorzy:
Lozia, Zbigniew
Powiązania:
https://bibliotekanauki.pl/articles/2124764.pdf
Data publikacji:
2022
Wydawca:
Sieć Badawcza Łukasiewicz. Przemysłowy Instytut Motoryzacji
Tematy:
frequency domain analysis
quarter car model
theta method
suspension damping
automotive diagnostics
Opis:
The dynamic properties of the car's suspension largely depend on the damping that results from the state of the shock absorbers. Their technical condition is essential for vehicle occupants’ comfort and traffic safety. It changes with the time and intensity of use of the vehicle. Therefore, adequate methods of non-destructive (diagnostic) testing of suspension damping have been sought for many years. The on-vehicle tests are particularly useful thanks to their low cost and short test duration time. The newest method is the ‘theta’ method which is the subject of the presented article. Notation ‘theta’ usually means relative damping (damping ratio) in the vibrating system. The paper asses four variants of the method. Two versions come from modal analysis and are also known as the ‘peak-picking method’ or ‘half-power method’. Two other versions are described in cited patent documentations. Three linear ‘quarter car' models with their description in the frequency domain were used to assess mentioned variants of the ‘theta’ method. Calculations were made for two typical datasets corresponding to the front and rear suspension system of a medium-class motor car. This provided grounds for general qualitative and (within a limited scope) quantitative assessment of the usefulness of individual variants of the method under analysis and for comparisons between them. The paper is to help in choosing the variant of the ‘theta’ method that would most likely find the application and that might be recommended to manufacturers and would-be purchasers of diagnostic suspension testers. The author has also highlighted the importance of possible further research.
Źródło:
Archiwum Motoryzacji; 2022, 96, 2; 5--30
1234-754X
2084-476X
Pojawia się w:
Archiwum Motoryzacji
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on low frequency ripple suppression technology of inverter based on model prediction
Autorzy:
Liu, Haiyang
Chen, Yiwen
Luo, Sixu
Jiang, Jiahui
Jian, Haojun
Powiązania:
https://bibliotekanauki.pl/articles/24202730.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
boost type
low frequency ripple suppression
model predictive control
single stage inverter
Opis:
The low frequency ripple of the input side current of the single-phase inverter will reduce the efficiency of the power generation system and affect the overall performance of the system. Aiming at this problem, this paper proposes a two-modal modulation method and its MPC multi-loop composite control strategy on the circuit topology of a single-stage boost inverter with a buffer unit. The control strategy achieves the balance of active power on both sides of AC and DC by controlling the stable average value of the buffer capacitor voltage, and provides a current reference for inductance current of the DC input side. At the same time, the MPC controller uses the minimum inductor current error as the cost function to control inductor current to track its reference to achieve low frequency ripple suppression of the input current. In principle, it is expounded that the inverter using the proposed control strategy has better low frequency ripple suppression effect than the multi-loop PI control strategy, and the conclusion is proved by the simulation data. Finally, an experimental device of a single-stage boost inverter using MPC multi-loop composite control strategy is designed and fabricated, and the experimental results show that the proposed research scheme has good low frequency ripple suppression effect and strong adaptability to different types of loads.
Źródło:
Archives of Electrical Engineering; 2023, 72, 2; 443--460
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Badania doświadczalne i symulacyjne światłowodowego czujnika rytmu oddechu
The experimental and simulation investigations of the optical sensor to breathing rythm measurement
Autorzy:
Zięba, J.
Frydrysiak, M.
Powiązania:
https://bibliotekanauki.pl/articles/151436.pdf
Data publikacji:
2007
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
tekstronika
pomiar częstotliwości oddechu
czujnik światłowodowy
model symulacyjny
textronic
breath frequency measurement
optical fibers sensors
simulation model
Opis:
W pracy opisano budowę i zasadę działania światłowodowego czujnika do pomiaru rytmu oddechów zaprojektowanego i wykonanego w Katedrze Automatyzacji Procesów Włókienniczych. Czujnik przebadano w warunkach statycznych oraz dynamicznych. Wyniki badań zamieszczono w postaci charakterystyk i wybranych przebiegów. Dla części mechanicz-nej czujnika zbudowano model, który został poddany badaniom symulacyjnym w programie Matlab-Simulink. Wyniki badań przedstawiono w postaci przebiegów składowej siły oddechu, częstości i przemieszczenia końców światłowodów czujnika.
The aim for measuring of this paper is to present research work into design and functioning of a textronic sensor to breathe frequency. It was designed and constructed the Department of Automation of Textile Processes. This Breath Frequency Sensor (BFS) may be used a medical applications or for any uniformed services as firefighter's uniforms. The first part of this work aimed at describing the physiological mechanism of breathing. The aim of this work was also present the prototype of textile sensor based on optical fibres. The authors built a mathematical model of the mechanical part of the sensor in Matlab Simulink program. The results were presented course of a component force of breathing, speed changes and chest movement. The breathing sensor works properly for human groups of different age, during different physical efforts.
Źródło:
Pomiary Automatyka Kontrola; 2007, R. 53, nr 9, 9; 83-87
0032-4140
Pojawia się w:
Pomiary Automatyka Kontrola
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical approximation of self-consistent Vlasov models for low-frequency electromagnetic phenomena
Autorzy:
Besse, N.
Mauser, N. J.
Sonnendrücker, E.
Powiązania:
https://bibliotekanauki.pl/articles/929699.pdf
Data publikacji:
2007
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
model Vlasova-Darwina
model Vlasova-Poiswell'a
metoda Lagrangiana
niskoczęstotliwościowe zjawisko elektromagnetyczne
Vlasov-Darwin model
Vlasov-Poisswell model
semi-Lagrangian method
low-frequency electromagnetic
Opis:
We present a new numerical method to solve the Vlasov-Darwin and Vlasov-Poisswell systems which are approximations of the Vlasov-Maxwell equation in the asymptotic limit of the infinite speed of light. These systems model low-frequency electromagnetic phenomena in plasmas, and thus “light waves” are somewhat supressed, which in turn allows the numerical discretization to dispense with the Courant-Friedrichs-Lewy condition on the time step. We construct a numerical scheme based on semi-Lagrangian methods and time splitting techniques. We develop a four-dimensional phase space algorithm for the distribution function while the electromagnetic field is solved on a two-dimensional Cartesian grid. Finally, we present two nontrivial test cases: (a) the wave Landau damping and (b) the electromagnetic beam-plasma instability. For these cases our numerical scheme works very well and is in agreement with analytic kinetic theory.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2007, 17, 3; 361-374
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Invariant piezoresonance devices based on adaptive multifrequency systems with a predictive standard
Niezmienne urządzenia piezorezonansowe na podstawie adaptacyjnych wieloczęstotliwościowych systemów z prognozowanym standardem
Autorzy:
Pidchenko, S.
Taranchuk, A.
Powiązania:
https://bibliotekanauki.pl/articles/407719.pdf
Data publikacji:
2018
Wydawca:
Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Tematy:
invariant multi-frequency piezoelectric resonance system
optimal control
mathematical model
niezmienne wieloczęstotliwościowe układy piezoresonansowe sterowanie optymalne
model matematyczny
Opis:
The paper presents conceptual provisions for the construction of invariant multi-frequency piezoelectric resonance devices with a predictive reference model. The law of the optimal control of the system in real time is formulated, aimed at minimizing energy costs to ensure the trajectory of the system. The results of piezoelectric resonance system mathematical modelling in the conditions of temperature and vibration perturbations are presented.
W artykule przedstawiono koncepcyjne zasady konstruowania niezmiennych wieloczęstotliwościowych piezoelektrycznych urządzeń z predykcyjnym modelem odniesienia. Zostało sformułowane prawo optymalnego sterowania systemem w czasie rzeczywistym, aby przy minimalnych stratach energii zapewnić trajektorię ruchu systemu. Przedstawiono wyniki matematycznego modelowania układu piezorezonansowego w warunkach zaburzeń temperatury i drgań.
Źródło:
Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska; 2018, 8, 1; 20-23
2083-0157
2391-6761
Pojawia się w:
Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design of a new engine dynamometer test stand for driving cycle simulation
Autorzy:
Kęder, M.
Grzeszczyk, R.
Merkisz, J.
Fuć, P.
Lijewski, P.
Powiązania:
https://bibliotekanauki.pl/articles/246315.pdf
Data publikacji:
2014
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
dynamic engine test stand
combustion engine
variable frequency drive
induction motor
vehicle model
Opis:
Dynamic combustion engine test stand allows a very accurate analysis of the engine work. The prototype of such a system was developed and built in a cooperation of Poznan University of Technology with the ODIUT Automex company. The system consists of an asynchronous motor controlled by a regenerative variable-frequency drive with an ability to return braking energy back to the power system. Together they permit to set very precise work points of the combustion engine in every time moment, unlike test stands with eddy current dynamometer, which are only able to brake the engine. Measuring system is used to gather data from all sensors, especially torque sensor, which records the torque on a drive shaft. Sensors are connected to electronic boards, which provide signal processing, and data acquisition. Fuel mass flow meter with temperature and pressure control allows regulating the parameters of fuel supplied to the engine. A set of applications is used for test stand management and data presentation and visualization. Real conditions and vehicle dynamics are emulated using advanced models to allow a comprehensive research of the combustion engine on the test stand. The paper covers the description of developed system, its components, software and models adapted in emulation. Moreover, it provides schematics of the system as well as a block diagram of the vehicle dynamic model.
Źródło:
Journal of KONES; 2014, 21, 4; 217-224
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Time-domain Windowing on Isolated Speech Recognition System Performance
Autorzy:
Ananthakrishna, Thalengala
Anitha, H.
Girisha, T.
Powiązania:
https://bibliotekanauki.pl/articles/2055228.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
hidden Markov model
HMM
isolated speech recognition system
ISR
Kannada language
mono-phone model
Mel frequency cepstral coefficients
MFCC
Opis:
Speech recognition system extract the textual data from the speech signal. The research in speech recognition domain is challenging due to the large variabilities involved with the speech signal. Variety of signal processing and machine learning techniques have been explored to achieve better recognition accuracy. Speech is highly non-stationary in nature and therefore analysis is carried out by considering short time-domain window or frame. In the speech recognition task, cepstral (Mel frequency cepstral coefficients (MFCC)) features are commonly used and are extracted for short time-frame. The effectiveness of features depend upon duration of the time-window chosen. The present study is aimed at investigation of optimal time-window duration for extraction of cepstral features in the context of speech recognition task. A speaker independent speech recognition system for the Kannada language has been considered for the analysis. In the current work, speech utterances of Kannada news corpus recorded from different speakers have been used to create speech database. The hidden Markov tool kit (HTK) has been used to implement the speech recognition system. The MFCC along with their first and second derivative coefficients are considered as feature vectors. Pronunciation dictionary required for the study has been built manually for mono-phone system. Experiments have been carried out and results have been analyzed for different time-window lengths. The overlapping Hamming window has been considered in this study. The best average word recognition accuracy of 61.58% has been obtained for a window length of 110 msec duration. This recognition accuracy is comparable with the similar work found in literature. The experiments have shown that best word recognition performance can be achieved by tuning the window length to its optimum value.
Źródło:
International Journal of Electronics and Telecommunications; 2022, 68, 1; 161--166
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Study on the Low Frequency Transients in Power Transformers and Some Protection-Related Issues
Autorzy:
Saied, M. M.
Powiązania:
https://bibliotekanauki.pl/articles/1203944.pdf
Data publikacji:
2014
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie
Tematy:
transformer cores
inrush current
protection
transients
modeling
equivalent circuit
low frequency
nonlinear model
simulation
Opis:
This paper presents typical results for the non-linear low frequency transients following the energization of power transformers. The three operating conditions of no-load, full-load and internal faults are considered. A direct analytical procedure is applied for solving the corresponding set of differential equations describing the transformers equivalent circuit. The core representation is based on the use of curve fitting applied to their magnetization curves. The results include plots versus time for the supply current, the core flux, the magnetizing current as well as the internal induced voltage. Moreover, graphs for the hysteresis loops relating the instantaneous values of both the excitation current and the core flux are given. An approach is also presented for the numerical determination of the amplitudes of the different harmonics existing in any of these signals utilizing the corresponding equidistant samples. As examples, the DC offset as well as harmonics up to the fourth order are considered. It is shown that several useful features can be extracted from the results in both the time and harmonic domains that can assist in differentiating between overcurrents resulting from short-circuits or inrush phenomena.
Źródło:
Electrical Power Quality and Utilisation. Journal; 2014, 17, 2; 9-16
1896-4672
Pojawia się w:
Electrical Power Quality and Utilisation. Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling of synchronous generators for the analysis of frequency transients above 1 Hz/s
Autorzy:
Assenkamp, Alf
Powiązania:
https://bibliotekanauki.pl/articles/2135729.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
control system
distributed energy systems
frequency support
generator model
RoCoF
synchronous generators
synchronous machines
Opis:
Large synchronous generators are of high importance for the stability of power systems. They generate the frequency of the system and stabilize it in case of severe grid faults like trips of large in-feeders or loads. In distributed energy systems, in-feed via inverters will replace this generation in large parts. Modern inverters are capable of supporting grid frequency during severe faults by different means on the one hand. On the other hand, higher Rates of Change of Frequency (RoCoF) after incidents need to be accustomed by future systems. To be able to analyse the RoCoF withstand capability of synchronous or induction generators, suitable models need to be developed. Especially the control and excitation system model need enhancements compared to models proposed in standards like IEEE Std 421.5. This paper elaborates on the necessary modelling depth and validates the approach with example results.
Źródło:
Archives of Electrical Engineering; 2022, 71, 3; 687--700
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Non-linear modelling of elastic hysteretic damping in the time domain
Autorzy:
Spitas, C.
Dwaikat, M. M. S.
Spitas, V.
Powiązania:
https://bibliotekanauki.pl/articles/38606055.pdf
Data publikacji:
2020
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
hysteresis
damping
modified viscous model
dynamics time-domain
mechanical vibration
frequency
non-linear modeling
Opis:
Elastic hysteretic damping is defined as the dissipation of energy at a rate that is weakly dependent on frequency of vibration. In this article, we propose that the elastic hysteretic damping can be achieved by a simple modification to the viscous damping model. The proposed modification is based on computing an instantaneous correction factor that recursively depends on the state variables of the system. This correction factor is related to the rate by which the velocity changes with respect to the displacement. The new model compares quite favourably with the other existing solutions in the time-domain and differences between the solutions become evident for higher damping ratios. It is found that the new model predicts consistently the weak variation in the loss factor as a function of frequency. In addition to its simple mathematical formulation, the proposed model is superior to the existing solutions in that it does not require knowledge of the past history of motion neither the knowledge of the excitation frequency and is extensible to any type of loading. Various aspects pertaining to the linearity of the proposed approach are finally discussed.
Źródło:
Archives of Mechanics; 2020, 72, 4; 323-353
0373-2029
Pojawia się w:
Archives of Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
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