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Wyświetlanie 1-15 z 88
Tytuł:
Energy efficiency – selected thermo-ecological problems
Autorzy:
Ziębik, Andrzej
Stanek, Wojciech
Powiązania:
https://bibliotekanauki.pl/articles/239928.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
energy efficiency
system analysis
exergy
thermo-ecology
energy ecological
efficiency
Opis:
The paper is devoted to some problems connected with last modification of EU directive on energy efficiency, viz.: free choice of the measure concerning the improvement of energy efficiency, i.e. final or primary energy consumption, corresponding energy savings or energy-consumption index; however without cumulative consumption or cumulative savings of primary energy. In EU directive it has been stressed the importance of measurements systems (reliable measurement information); but has not been recommended any advanced validation of measurements results, nor energy auditing or algorithms of calculating the energy savings due to improvement of energy efficiency concerning large industrial plants. Evaluation of complex buildings should be realized by means of the system method (input-output analysis). The separate problem is devoted to application of thermo-ecological approach in the analysis of complete results of improving the energy efficiency. Human activity is connected with the depletion of nonrenewable resources, including primary energy, due to not only production of consumer goods but also the necessity of compensating the unfavourable effects of harmful emissions from energy-technological processes. Therefore the index of energy-ecological efficiency has been proposed as the most competent evaluation of improvement energy efficiency of production processes and systems.
Źródło:
Archives of Thermodynamics; 2020, 41, 2; 277-299
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
System approach to the analysis of an integrated oxy-fuel combustion power plant
Autorzy:
Ziębik, A.
Gładysz, P.
Powiązania:
https://bibliotekanauki.pl/articles/240507.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
system approach
input-output analysis
oxy-fuel combustion
cumulative energy
exergy consumption
system exergy losses
thermoecological cost
zarządzanie jakością
analiza wejścia-wyjścia
spalanie w tlenie
energia skumulowana
zużycie egzergii
straty egzergii
koszt termoekologiczny
Opis:
Oxy-fuel combustion (OFC) belongs to one of the three commonly known clean coal technologies for power generation sector and other industry sectors responsible for CO2 emissions (e.g., steel or cement production). The OFC capture technology is based on using high-purity oxygen in the combustion process instead of atmospheric air. Therefore flue gases have a high concentration of CO2 - Due to the limited adiabatic temperature of combustion some part of CO2 must be recycled to the boiler in order to maintain a proper flame temperature. An integrated oxy-fuel combustion power plant constitutes a system consisting of the following technological modules: boiler, steam cycle, air separation unit, cooling water and water treatment system, flue gas quality control system and CO2 processing unit. Due to the interconnections between technological modules, energy, exergy and ecological analyses require a system approach. The paper present the system approach based on the 'input-output' method to the analysis of the: direct energy and material consumption, cumulative energy and exergy consumption, system (local and cumulative) exergy losses, and thermoecological cost. Other measures like cumulative degree of perfection or index of sustainable development are also proposed. The paper presents a complex example of the system analysis (from direct energy consumption to thermoecological cost) of an advanced integrated OFC power plant.
Źródło:
Archives of Thermodynamics; 2014, 35, 3; 39-57
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of the accuracy of reconstruction of the geometry driving wheel of gear pump with application of CATIA system
Analiza dokładności odwzorowania geometrii koła zębatego pompy zębatej z zastosowaniem systemu CATIA
Autorzy:
Zaborniak, M.
Tofil-Kozdra, I.
Powiązania:
https://bibliotekanauki.pl/articles/176168.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
CAD
cylindrical gears
accuracy analysis
system CAD
walcowe koła zębate
analiza dokładności
Opis:
Modern methods of design and manufacture of gears are based on Computer Aided Engineering Systems. This article presents one of the methods to analyze the accuracy of mapping geometry of the model of driving wheel of gear pump designed in CATIA v5 System. Comparison of the accuracy of mapping of the geometry of the hybrid model has been performed with the source model of gear (model .stl format).
Podstawą nowoczesnych metod projektowania i wytwarzania kół zębatych są komputerowe systemy wspomagania prac inżynierskich. W pracy przedstawiono jedną z metod analizy dokładności odwzorowania geometrii modelu koła zębatego pompy zębatej w systemie CATIA v5. Przeprowadzono porównanie dokładności odwzorowania geometrii modelu hybrydowego ze źródłowym modelem koła zębatego (model .stl).
Źródło:
Advances in Manufacturing Science and Technology; 2015, 39, 2; 49-60
0137-4478
Pojawia się w:
Advances in Manufacturing Science and Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of the accuracy of reconstruction of the geometry driving wheel of gear pump with application of CATIA system
Analiza dokładności odwzorowania geometrii koła zębatego pompy zębatej z zastosowaniem systemu CATIA
Autorzy:
Zaborniak, M.
Tofil-Kozdra, I.
Powiązania:
https://bibliotekanauki.pl/articles/176165.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
CAD
cylindrical gear
accuracy analysis
system CAD
koło zębate walcowe
analiza dokładności
Opis:
Modern methods of design and manufacture of gears are based on Computer Aided Engineering Systems. This article presents one of the methods to analyze the accuracy of mapping geometry of the model of driving wheel of gear pump designed in CATIA v5 System. Comparison of the accuracy of mapping of the geometry of the hybrid model has been performed with the source model of gear (model .stl format).
Podstawą nowoczesnych metod projektowania i procesu wytwarzania kół zębatych są komputerowe systemy wspomagania prac inżynierskich. W pracy przedstawiono jedną z metod analizy dokładności odwzorowania geometrii modelu koła zębatego pompy zębatej wykonanego w systemie CATIA v5. Przeprowadzono analizę i porównanie dokładności odwzorowania geometrii modelu hybrydowego oraz źródłowego modelu koła zębatego (model .stl).
Źródło:
Advances in Manufacturing Science and Technology; 2016, 40, 1; 55-66
0137-4478
Pojawia się w:
Advances in Manufacturing Science and Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vibration control and performance analysis of full car active suspension system using fractional order terminal sliding mode controller
Autorzy:
Yuvapriya, T.
Lakshami, P.
Rajendiran, S.
Powiązania:
https://bibliotekanauki.pl/articles/230099.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
active suspension system
fractional order terminal sliding mode controller
ISO8608
ISO2631
stability analysis
vibration dose value
Opis:
The main goal of introducing Active Suspension System in vehicles is to reduce the vehicle body motion under road obstacles which improves the ride comfort of the passenger. In this paper, the Full Car Model (FCM) with seven Degrees of Freedom is considered and simulated by MATLAB/Simulink. The Terminal Sliding Mode Controller (TSMC) and Fractional Order Terminal Sliding Mode Controller (FOTSMC) are designed to enhance the ride quality, stability and passenger comfort for FCM. The designed FOTSMC has the ability to provide higher control accuracy in a finite time. The performances of the designed controllers are evaluated by measuring the vehicle body vibration in both angular and vertical direction under bump input and ISO-8608 random input against passive suspension system. The Frequency Weighted Root Mean Square (FWRMS) and Vibration dose value of Body Acceleration as per ISO-2631 are evaluated for FOTSMC, TSMC and PSS. The stability of the FCM is proved by Lyapunouv theory. Further analysis with sprung mass and speed variation of FCM demonstrate the robustness of proposed controller. To investigate the performances of designed controllers, comparison is made with existing Sliding Mode Controller (SMC) which proves that the designed FOTSMC performs better than existing SMC.
Źródło:
Archives of Control Sciences; 2020, 30, 2; 295-324
1230-2384
Pojawia się w:
Archives of Control Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Intelligent System in the Context of Business Process Modelling
Autorzy:
Yaremko, Svetlana A.
Kuzmina, Elena M.
Savina, Nataliia B.
Gromaszek, Konrad
Yeraliyeva, Bakhyt
Borankulova, Gauhar
Powiązania:
https://bibliotekanauki.pl/articles/1844622.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
business process
automation
simulation modelling
intelligent system
expert system
intelligence analysis
forecasting
Opis:
The article deals with the features and characteristics of intelligent systems for modelling business processes. Their classification was made and criteria for comparison were developed. According to the comparative analysis of existing expert systems for intelligent analysis, a reasonable choice of system for modelling business processes of a particular enterprise has been carried out. In general, it was found that the introduction of intelligent systems for modelling business processes of the enterprise and forecasting its activities for future allows management of the company to obtain relevant and necessary information for the adoption of effective management decisions and the development of a strategic plan.
Źródło:
International Journal of Electronics and Telecommunications; 2021, 67, 2; 163-168
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Clamped Bar Model for the Sompoton Vibrator
Autorzy:
Wong, T. H.
Dayou, J.
Ngu, M. C. D.
Hang, J. H. W.
Liew, W. Z. H.
Powiązania:
https://bibliotekanauki.pl/articles/176855.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
vibrator
clamped bar
single degree of freedom system
exact analysis
resonance frequency
Opis:
The sompoton is one of famous traditional musical instruments in Sabah. This instrument consists of several parts with the vibrator being the most important one. In this paper, the vibrator is modeled as a clamped bar with a uniformly distributed mass. By means of this model, the fundamental frequency is analyzed with the use of an equivalent single degree of freedom system (SDOF) and exact analysis. The vibrator is made of aluminum in different sizes and is excited using a constant air jet to obtain its fundamental resonance frequency. The fundamental frequency obtained from the experimental measurement is compared with the theoretical values calculated based on the equivalent SDOF and exact analysis theories. It is found that the exact analysis gives a closer value to the experimental results as compared to the SDOF system. Although both the experimental and theoretical results exhibit the same trend, they are different in magnitude. To overcome the differences in both theories, a correction factor is added to account for the production errors.
Źródło:
Archives of Acoustics; 2013, 38, 3; 425-432
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The 8AE-PD computer measurement system for registration and analysis of acoustic emission signals generated by partial discharges in oil power transformers
Autorzy:
Witos, Franciszek
Opilski, Zbigniew
Szerszeń, Grzegorz
Setkiewicz, Maciej
Powiązania:
https://bibliotekanauki.pl/articles/220623.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
acoustic emission
partial discharge
multichannel system
acoustic signal detection
acoustic signal processing
signal analysis
voltage preamplifier
Opis:
A computer measurement system, designed and built by authors, dedicated to location and description of partial discharges (PD) in oil power transformers examined by means of the acoustic emission (AE) method is presented. The measurement system is equipped with 8 measurement channels and ensures: monitoring of signals, registration of data in real time within a band of 25-1000 kHz in laboratory and real conditions, basic and advanced analysis of recorded signals. The basic analysis carried out in the time, frequency and time-frequency domains deals with general properties of the AE signals coming from PDs. The advanced analysis, performed in the discrimination threshold domain, results in identification of signals coming from different acoustic sources as well as location of these sources in the examined transformers in terms of defined by authors descriptors and maps of these descriptors on the side walls of the tested transformer tank. Examples of typical results of laboratory tests carried out with the use of the built-in measurement system are presented.
Źródło:
Metrology and Measurement Systems; 2019, 26, 2; 403-418
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fuzzy arithmetical analysis of multibody systems with uncertainties
Analiza systemów wieloczłonowych z niepewnościami wykorzystująca arytmetykę rozmytą
Autorzy:
Walz, N. P.
Hanss, M.
Powiązania:
https://bibliotekanauki.pl/articles/950684.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
fuzzy arithmetic
uncertainty
multibody system
robustness analysis
arytmetyka rozmyta
niepewność
układ wieloczłonowy
analiza odporności
Opis:
The consideration of uncertainties in numerical simulation is generally reasonable and is often indicated in order to provide reliable results, and thus is gaining attraction in various fields of simulation technology. However, in multibody system analysis uncertainties have only been accounted for quite sporadically compared to other areas. The term uncertainties is frequently associated with those of random nature, i.e. aleatory uncertainties, which are successfully handled by the use of probability theory. Actually, a considerable proportion of uncertainties incorporated into dynamical systems, in general, or multibody systems, in particular, is attributed to so-called epistemic uncertainties, which include, amongst others, uncertainties due to a lack of knowledge, due to subjectivity in numerical implementation, and due to simplification or idealization. Hence, for the modeling of epistemic uncertainties in multibody systems an appropriate theory is required, which still remains a challenging topic. Against this background, a methodology will be presented which allows for the inclusion of epistemic uncertainties in modeling and analysis of multibody systems. This approach is based on fuzzy arithmetic, a special field of fuzzy set theory, where the uncertain values of the model parameters are represented by so-called fuzzy numbers, reflecting in a rather intuitive and plausible way the blurred range of possible parameter values. As a result of this advanced modeling technique, more comprehensive system models can be derived which outperform the conventional, crisp-parameterized models by providing simulation results that reflect both the system dynamics and the effect of the uncertainties. The methodology is illustrated by an exemplary application of multibody dynamics which reveals that advanced modeling and simulation techniques using some well-thought-out inclusion of the presumably limiting uncertainties can provide significant additional benefit.
Uwzględnienie niepewności w symulacji numerycznej jest generalnie rzeczą rozsadną. Podejście to często prowadzi do wiarygodnych rezultatów, toteż zyskuje na atrakcyjności w wielu dziedzinach technik symulacyjnych. Niemniej, w analizie systemów wieloczłonowych – inaczej niż w innych dziedzinach – niepewności były dotąd brane pod uwagę jedynie sporadycznie. Termin ”niepewność” jest często kojarzony z czynnikami o charakterze przypadkowym, tzn. niepewnościami aleatorycznymi, z którymi można z powodzeniem radzić sobie metodami teorii prawdopodobieństwa. W rzeczywistości, znaczna część niepewności występujących w systemach dynamicznych, a w szczególności w systemach wieloczłonowych, jest powiązana z tzw. niepewnościami epistemologicznymi, które obejmują m.in. niepewności spowodowane brakiem wiedzy, subiektywnością w implementacji modelu numerycznego, a także niepewności wynikajace z uproszczeń i idealizacji. Tak więc, by modelować niepewności epistemologiczne w systemach wieloczłonowych wymagana jest odpowiednia teoria, która wciąż stanowi poważne wyzwanie. Na tym tle, autorzy przedstawiają metodologię, która pozwala na włączenie niepewności epistemologicznych w proces modelowania i analizy systemów wieloczłonowych. Prezentowane podejście jest oparte na arytmetyce rozmytej, specjalnej dziedzinie teorii zbiorów rozmytych, gdzie niepewne wartości parametrów modelu są reprezentowane przez tzw. liczby rozmyte, które odzwierciedlają, w sposób raczej intuicyjny lecz przekonywujący, nieostry zakres możliwych wartości parametrów. W rezultacie użycia tej zaawansowanej techniki modelowania uzyskuje się bardziej wszechstronny model systemu, który daje lepsze wyniki niż modele tradycyjne, o sztywnej parametryzacji. Wyniki symulacji, uzyskane przy zastosowaniu takiego modelu, odzwierciedlają zarówno dynamikę systemu, jak i efekty związane z niepewnościami. Prezentowana metodologia jest zilustrowana przykładowym zastosowaniem do dynamiki systemu wieloczłonowego. Przykład pokazuje, że użycie zaawansowanych technik modelowania i symulacji, w których w sposób dobrze przemyślany uwzględniono prawdopodobne niepewności graniczne, może dostarczyć znacznych korzyści dodatkowych.
Źródło:
Archive of Mechanical Engineering; 2013, LX, 1; 109-125
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Results of the promethee method application in selecting the technological system at the Majdan III open pit mine
Wyniki zastosowania metody promethee do wyboru systemu technologicznego w kopalni odkrywkowej Majdan III
Autorzy:
Vujic, S.
Hudej, M.
Miljanovic, I.
Powiązania:
https://bibliotekanauki.pl/articles/218810.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
analiza obejmująca wiele zmiennych
metoda promethee
wspomaganie procesów decyzyjnych
wybór ciągu technologicznego
kopalnia odkrywkowa Majdan III
multi-variate analysis
decision-making support
technological system selection
Majdan III open pit mine
Opis:
This paper discusses the application of the PROMETHEE model and the results achieved in practice, following the example of the multi-criteria selection of the technological system at the Majdan III clay mineral raw material open pit mine of the Potisje Company, Republic of Serbia. After the introduction comments, reasons are explained for selecting the new technological system, conditions and limitations for the seven alternative solutions considered are described, mathematical foundation for the PROMETHEE method and a multi-criteria model of the problem in question are presented. The solution with the following structure was ranked first and accepted by the Company management as the best: Bucket chain excavator - Conveyor belts - Spreader (ECS), alongside a decision is made on the acquisition of machinery and system construction. The system was put into operation in 2000. The experience and the data accumulated in the previous twelve years confirm that the decision made on the application of the ECS technology was just, and the conclusion lists the benefits achieved.
W artykule omówiono zastosowanie modelu Promethee i przedyskutowano uzyskane w ten sposób wyniki na przykładzie wielokryterialnego wyboru systemu technologicznego do zastosowania w kopalni odkrywkowej minerałów ilastych Majdan III, należącej do przedsiębiorstwa górniczego Potisje (Republika Serbii). Po uwagach wprowadzających przedstawiono powody wyboru nowego ciągu technologicznego, omówiono warunki oraz ograniczenia dla siedmiu alternatywnych rozwiązań, podstawy matematyczne metody Promethee oraz wielokryterialny model zagadnienia. Rozwiązanie uznane za najlepsze i zaaprobowane przez zarząd przedsiębiorstwa zakłada zastosowanie następującego ciągu technologicznego: koparka łancuchowa jednonaczyniowa - przenośniki taśmowe - rozkładarka(system ECS). Podjęto także decyzje odnośnie zakupu sprzętu i instalacji systemu, który uruchomiony został w 2000 roku. Doświadczenia i danezebrane z przeciągu ostatnich dwunastu lat potwierdzają zasadność wyboru systemu technologicznego. W podsumowaniu zestawiono listę uzyskanych korzyści.
Źródło:
Archives of Mining Sciences; 2013, 58, 4; 1229-1240
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Economic effectiveness evaluation of the free piston Stirling engine-based micro-combined heat and power unit in relation to classical systems
Autorzy:
Uchman, Wojciech
Remiorz, Leszek
Kotowicz, Janusz
Powiązania:
https://bibliotekanauki.pl/articles/240538.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
heating systems
cost analysis
stirling engine
micro-cogeneration
system ciepłowniczy
analiza kosztów
mikrokogeneracja
Opis:
In this article, a comparison of economic effectiveness of various heating systems dedicated to residential applications is presented: a natural gas-fueled micro-cogeneration (micro-combined heat and power – µCHP) unit based on a free-piston Stirling engine that generates additional electric energy; and three so-called classical heating systems based on: gas boiler, coal boiler, and a heat pump. Calculation includes covering the demand for electricity, which is purchased from the grid or produced in residential system. The presented analyses are partially based on an experimental investigation. The measurements of the heat pump system as well as those of the energy (electricity and heat) demand profiles in the analyzed building were conducted for a single-family house. The measurements of the µCHP unit were made using a laboratory stand prepared for simulating a variable heat demand. The overall efficiency of the µCHP was in the range of 88.6– 92.4%. The amounts of the produced/consumed energy (electricity, heat, and chemical energy of fuel) were determined. The consumption and the generation of electricity were settled on a daily basis. Operational costs of the heat pump system or coal boiler based heating system are lower comparing to the micro-cogeneration, however no support system for natural gas-based µCHP system is included.
Źródło:
Archives of Thermodynamics; 2019, 40, 1; 71-83
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rotating combustion chambers as a key feature of effective timing of turbine engine working according to Humphrey cycle – CFD analysis
Autorzy:
Tarnawski, Piotr
Ostapski, Wiesław
Powiązania:
https://bibliotekanauki.pl/articles/2173712.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
pressure gain combustion
Humphrey cycle
turbine engine
CFD analysis
valve timing system
isochoric combustion
engine energy efficiency
sealing system
ciśnienie spalania
cykl Humphreya
silnik turbinowy
analiza CFD
układ rozrządu
spalanie izochoryczne
sprawność energetyczna silnika
system uszczelniający
Opis:
The paper presents a concept of a new turbine engine with the use of rotating isochoric combustion chambers. In contrast to previously analyzed authors’ engine concepts, here rotating combustion chambers were used as a valve timing system. As a result, several practical challenges could be overcome. An effective ceramic sealing system could be applied to the rotating combustion chambers. It can assure full tightness regardless of thermal conditions and related deformations. The segment sealing elements working with ceramic counter-surface can work as self-alignment because of the centrifugal force acting on them. The isochoric combustion process, gas expansion, and moment generation were analyzed using the CFD tool (computational fluid dynamics). The investigated engine concept is characterized by big energy efficiency and simple construction. Finally, further improvements in engine performance are discussed.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2022, 70, 5; art. no. e143100
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Probabilistic elements in analysis of performance of multiprocessor systems
Autorzy:
Taborek, K.
Hrynkiewicz, E.
Powiązania:
https://bibliotekanauki.pl/articles/201505.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
arbitration circuit
multiprocessor system
performance analysis
queueing model
arbitraż
system wieloprocesorowy
analiza wydajności
model kolejkowy
Opis:
The paper presents important probabilistic elements that should be taken into consideration in the analysis of performance of classical multiprocessor systems. These elements represent the following quantities: modified arrival rate for processor requests and a few probabilities, which determine the frequency of certain events when a multiprocessor system is working. There are four peculiar events: service of another job, existence of the queue, a processor request while the given task is waiting into the queue and the return of another task into the queue while the given task is waiting in the queue. The first three events happen more often when a system consists of less number of processors, whereas the fourth event happens more often when more processors work in a system. Including (or not) the probabilities of these events to the analysis of performance of multiprocessor systems exerts its much influence on the precision of computations. All the mentioned quantities were described in detail. Formulas for these quantities were derived. Examples of applications of the formulas to the prediction of performance of various multiprocessor systems were presented.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2014, 62, 4; 765-771
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on stability and sensitivity of the rotating machines with overhung rotors to lateral vibrations
Autorzy:
Szolc, Tomasz
Konowrocki, Robert
Powiązania:
https://bibliotekanauki.pl/articles/2090690.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
overhung rotor-shaft
lateral vibrations
stability analysis
sensitivity analysis
system imperfection
wał wirnika
drgania boczne
analiza stabilności
analiza wrażliwości
niedoskonałość systemu
Opis:
The rotating machines with overhung rotors form a broad class of devices used in many types of industry. For this kind of rotor machine in the paper, there is investigated an inf luence of dynamic and static unbalance of a rotor, parallel and angular misalignments of shafts, and inner anisotropy of rigid couplings on system dynamic responses. The considerations are performed through a hybrid structural model of the machine rotor-shaft system, consisting of continuous beam finite elements and discrete oscillators. Numerical calculations are carried out for parameters characterizing a heavy blower applied in the mining industry. The main goal of the research is to assess the sensitivity of the imperfections mentioned above on excitation severity of rotor-shaft lateral vibrations and motion stability of the machine in question.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2021, 69, 6; e137987, 1--13
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of parameters for a design of the stable electro-dynamic passive magnetic support of a high-speed flexible rotor
Autorzy:
Szolc, T.
Falkowski, F.
Henzel, M.
Kurnyta-Mazurek, P.
Powiązania:
https://bibliotekanauki.pl/articles/201250.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
rotor dynamics
electrodynamic passive magnetic bearings
active magnetic damper
stability analysis
rotor- shaft system
dynamika rotora
wirnik
amortyzator magnetyczny
analiza stabilności
pasywne łożysko magnetyczne
Opis:
Electro-dynamic passive magnetic bearings are now viewed as a feasible option when looking for support for high-speed rotors. Nevertheless, because of the skew-symmetrical visco-elastic properties of such bearings, they are prone to operational instability. In order to avoid this, the paper proposes the addition of external damping into the newly designed vibrating laboratory rotor-shaft system. This may be achieved by means of using simple passive dampers that would be found among the components of the electro-dynamic bearing housings along with magnetic dampers, which satisfy the operational principles of active magnetic bearings. Theoretical investigations are going to be conducted by means of a structural computer model of the rotor-shaft under construction, which will take into consideration its actual dimensions and material properties. The additional damping magnitudes required to stabilize the most sensitive lateral eigenmodes of the object under consideration have been determined by means of the Routh-Hurwitz stability criterion.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2019, 67, 1; 91-105
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 88

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