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Tytuł:
Gaussian process dynamic modeling and backstepping sliding mode control for magnetic levitation system of maglev train
Autorzy:
Sun, Yougang
Wang, Sumei
Lu, Yang
Xu, Junqi
Powiązania:
https://bibliotekanauki.pl/articles/2086959.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
maglev train
Gaussian process
sliding mode control
parameter perturbations
Opis:
The maglev trains are strongly nonlinear and open-loop unstable systems with external disturbances and parameters uncertainty. In this paper, the Gaussian process method is utilized to get the dynamic parameters, and a backstepping sliding mode controller is proposed for magnetic levitation systems (MLS) of maglev trains. That is, for a MLS of a maglev train, a nonlinear dynamic model with accurate parameters is obtained by the Gaussian process regression method, based on which a novel robust control algorithm is designed. Specifically, the MLS is divided into two sub-systems by a backstepping method. The inter virtual control inputs and the Lyapunov function are constructed in the first sub-system. For the second sub-system, the sliding mode surface is constructed to fulfil the design of the whole controller to asymptotically regulate the airgap to a desired trajectory. The stability of the proposed control method is analyzed by the Lyapunov method. Both simulation and experimental results are included to illustrate the superior performance of the presented method to cope with parameters perturbations and external disturbance.
Źródło:
Journal of Theoretical and Applied Mechanics; 2022, 60, 1; 49--62
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fault detection for DFIG based on sliding mode observer of new reaching law
Autorzy:
Li, RuiQi
Yu, WenXin
Wang, JunNian
Lu, Yang
Jiang, Dan
Zhong, GuoLiang
Zhou, ZuanBo
Powiązania:
https://bibliotekanauki.pl/articles/2128165.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
fault detection
doubly-fed induction generator
sliding mode observer
new reaching law
wykrywanie uszkodzeń
generator indukcyjny dwustronnie zasilany
obserwator w trybie przesuwnym
nowe prawo osiągania
Opis:
For fault detection of doubly-fed induction generator (DFIG), in this paper, a method of sliding mode observer (SMO) based on a new reaching law (NRL) is proposed. The SMO based on the NRL (NRL- SMO) theoretically eliminates system chatter caused by the reaching law and can be switched in time with system interference in terms of robustness and smoothness. In addition, the sliding mode control law is used as the index of fault detection. Firstly, this paper gives the NRL with the theoretically analyzes. Secondly, according to the mathematical model of DFIG, NRL-SMO is designed, and its analysis of stability and robustness are carried out. Then this paper describes how to choose the optimal parameters of the NRL-SMO. Finally, three common wind turbine system faults are given, which are DFIG inter-turn stator fault, grid voltage drop fault, and rotor current sensor fault. The simulation models of the DFIG under different faults is established. The simulation results prove that the superiority of the method of NRL-SMO in state tracking and the feasibility of fault detection.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2021, 69, 3; e137389, 1--13
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fault detection for DFIG based on sliding mode observer of new reaching law
Autorzy:
Li, RuiQi
Yu, WenXin
Wang, JunNian
Lu, Yang
Jiang, Dan
Zhong, GuoLiang
Zhou, ZuanBo
Powiązania:
https://bibliotekanauki.pl/articles/2173629.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
fault detection
doubly-fed induction generator
sliding mode observer
new reaching law
wykrywanie uszkodzeń
generator indukcyjny dwustronnie zasilany
obserwator w trybie przesuwnym
nowe prawo osiągania
Opis:
For fault detection of doubly-fed induction generator (DFIG), in this paper, a method of sliding mode observer (SMO) based on a new reaching law (NRL) is proposed. The SMO based on the NRL (NRL- SMO) theoretically eliminates system chatter caused by the reaching law and can be switched in time with system interference in terms of robustness and smoothness. In addition, the sliding mode control law is used as the index of fault detection. Firstly, this paper gives the NRL with the theoretically analyzes. Secondly, according to the mathematical model of DFIG, NRL-SMO is designed, and its analysis of stability and robustness are carried out. Then this paper describes how to choose the optimal parameters of the NRL-SMO. Finally, three common wind turbine system faults are given, which are DFIG inter-turn stator fault, grid voltage drop fault, and rotor current sensor fault. The simulation models of the DFIG under different faults is established. The simulation results prove that the superiority of the method of NRL-SMO in state tracking and the feasibility of fault detection.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2021, 69, 3; art. no. e137389
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some non-homogeneous Hardy spaces on locally compact Vilenkin groups
Autorzy:
Lu, Shanzhen
Yang, Dachun
Powiązania:
https://bibliotekanauki.pl/articles/965121.pdf
Data publikacji:
1996
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
Vilenkin group
dual space
Herz space
atom
Hardy space
molecule
Źródło:
Colloquium Mathematicum; 1996, 69, 1; 1-17
0010-1354
Pojawia się w:
Colloquium Mathematicum
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Littlewood-Paley function and φ-trans-form characterizations of a new Hardy space HK₂ associated with the Herz space
Autorzy:
Lu, Shanzhen
Yang, Dachun
Powiązania:
https://bibliotekanauki.pl/articles/1293317.pdf
Data publikacji:
1992
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Opis:
We give a Littlewood-Paley function characterization of a new Hardy space HK₂ and its φ-transform characterizations in M. Frazier & B. Jawerth's sense.
Źródło:
Studia Mathematica; 1991-1992, 101, 3; 285-298
0039-3223
Pojawia się w:
Studia Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The local versions of $H^p(ℝ^n)$ spaces at the origin
Autorzy:
Zhen Lu, Shan
Yang, Da
Powiązania:
https://bibliotekanauki.pl/articles/1388598.pdf
Data publikacji:
1995
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Opis:
Let 0 < p ≤ 1 < q < ∞ and α = n(1/p - 1/q). We introduce some new Hardy spaces $HK̇_q^{α,p}(ℝ^n)$ which are the local versions of $H^p(ℝ^n)$ spaces at the origin. Characterizations of these spaces in terms of atomic and molecular decompositions are established, together with their φ-transform characterizations in M. Frazier and B. Jawerth's sense. We also prove an interpolation theorem for operators on $HK̇_q^{α,p}(ℝ^n)$ and discuss the $HK̇_q^{α,p}(ℝ^n)$-boundedness of Calderón-Zygmund operators. Similar results can also be obtained for the non-homogeneous Hardy spaces $HK_q^{α,p}(ℝ^n)$.
Źródło:
Studia Mathematica; 1995, 116, 2; 103-131
0039-3223
Pojawia się w:
Studia Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Safety evaluation for a high signal operator with electric field exposure induced by contact wires
Autorzy:
Yang, Chang-Qiong
Lu, Mai
Powiązania:
https://bibliotekanauki.pl/articles/1841301.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
contact wires
electric field
finite element method (FEM)
high signal operator
ICNIRP standards
occupational exposure
safety evaluation
Opis:
To evaluate the occupational safety of a high signal operator exposed to the electric field induced by contact wires with a frequency of 50 Hz and a voltage of 27.5 kV, this study established a model of a high signal operator working in the vicinity of single and double-track railways. The electric field distribution in the operator’s body and his head were calculated and analyzed during the operation using the finite element method (FEM). The calculated results were compared with the international standard occupational exposure limits formulated by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and action levels (ALs), exposure limit values (ELVs) in Directive 2013/35/EU (EU Directive). In the case of a single-track railway exposure, the maximum electric field strength in the worker’s body, in the scalp layer, and inside the brain are 227 mV/m, 2.76 kV/m, and 0.14 mV/m, respectively. For a double-track railway exposure, the maximum internal electric field strength of the operator is 310 mV/m, which is 37.85% of the occupational exposure basic restriction limit. The maximum electric field strength in the head layers is 3.42 kV/m, which is 34.2% of the occupational exposure reference level and 34.2% of the low ALs. The maximum electric field strength of the brain is 0.19 mV/m, which is 0.19% of the occupational basic restriction limit and 0.135% of the sensory effects ELVs. Results show that the electric field exposure of the high signal operator to contact wires in single- and double-track railways is lower than the occupational exposure limits provided by the ICNIRP and EU Directive standards and is thus regarded as safe for workers.
Źródło:
Archives of Electrical Engineering; 2021, 70, 2; 431-444
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Proposed genotype definition of Porcine sapelovirus
Autorzy:
Yang, T.
Lu, Y.
Zhang, L.
Powiązania:
https://bibliotekanauki.pl/articles/2087188.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Porcine sapelovirus
genotype
phylogenetic and genetic analyses
Źródło:
Polish Journal of Veterinary Sciences; 2021, 24, 2; 307-312
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Lower Bound on the Number of Hamiltonian Cycles of Generalized Petersen Graphs
Autorzy:
Lu, Weihua
Yang, Chao
Ren, Han
Powiązania:
https://bibliotekanauki.pl/articles/32083755.pdf
Data publikacji:
2020-02-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
generalized Petersen graph
Hamiltonian cycle
partition number
1-factor
Opis:
In this paper, we investigate the number of Hamiltonian cycles of a generalized Petersen graph $ P(N, k) $ and prove that $ \Psi(P(N,3)) \ge N \cdot \alpha_N $, where $ \Psi (P(N, 3)) $ is the number of Hamiltonian cycles of $P(N, 3)$ and $ \alpha_N $ satisfies that for any $ \epsilon > 0 $, there exists a positive integer $M$ such that when $ N > M $, $ ((1− \epsilon ) \frac{ (1−r^3) }{6r^3+5r^2+3) }( 1/r )^{N+2} < \alpha_N < ( (1+ɛ) \frac{ (1−r^3) }{6r^3+5r^2+3) }( 1/r )^{N+2} $, where $ 1/r = \text{max} \{ | \frac{1}{r_j} | : j=1,2,…,6 \} $, and each $ r_j $ is a root of equation $ x^6 + x^5 + x^3 − 1 = 0 $, $ r \approx 0.782 $. This shows that $ \Psi (P (N, 3) $ is exponential in $N$ and also deduces that the number of 1-factors of $ P(N, 3)$ is exponential in $N$.
Źródło:
Discussiones Mathematicae Graph Theory; 2020, 40, 1; 297-305
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Supervisory fault tolerant control with integrated fault detection and isolation: a switched system approach
Autorzy:
Yang, H.
Jiang, B.
Cocquempot, V.
Lu, L.
Powiązania:
https://bibliotekanauki.pl/articles/331374.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
sterowanie tolerujące uszkodzenia
detekcja uszkodzeń
lokalizacja uszkodzeń
sterowanie rozdzielcze
układ komutowany
fault-tolerant control
fault detection
fault isolation
switching control
switched systems
Opis:
This paper focuses on supervisory fault tolerant control design for a class of systems with faults ranging over a finite cover. The proposed framework is based on a switched system approach, and relies on a supervisory switching within a family of pre-computed candidate controllers without individual fault detection and isolation schemes. Each fault set can be accommodated either by one candidate controller or by a set of controllers under an appropriate switching law. Two aircraft examples are included to illustrate the efficiency of the proposed method.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2012, 22, 1; 87-97
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Emergence Angle on Acoustic Transmission in a Shallow Sea
Autorzy:
Lu, Yanyang
Yang, Kunde
Liu, Hong
Huang, Chunlong
Powiązania:
https://bibliotekanauki.pl/articles/177665.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
underwater acoustic
emergence angle
transmission loss
active sonar detection
Opis:
In this study, the effect of the emergence angle of a source array on acoustic transmission in a typical shallow sea is simulated and analyzed. The formula we derived for the received signal based on the Normal Mode indicates that the signal is determined by the beamform on the modes of all sources and the samplings of all modes at the receiving depth. Two characteristics of the optimal emergence angle (OEA) are obtained and explained utilizing the aforementioned derived formula. The observed distributions of transmission loss (TL) for different sources and receivers are consistent with the obtained characteristics. The results of this study are valuable for the development and design of active sonar detection.
Źródło:
Archives of Acoustics; 2020, 45, 1; 3-9
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Luminescence of hydrothermally fabricated PbF2:Er3+ particles and their application in bifacial silicon solar cells
Autorzy:
Yang, F
Wu, C.
Hao, X
Chen, Y.
Lu, J.
Yang, Sh.
Powiązania:
https://bibliotekanauki.pl/articles/174503.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
PbF2
Er3+ particles
hydrothermal method
upconversion
Opis:
We report the synthesis of PbF2:Er3+ particles using a hydrothermal method. The structure and upconversion emission properties of the products are investigated by scanning electron microscopy, X-ray diffractometer, Raman spectrophotometer and fluorescence spectrometry. An increase in Er3+ concentration in the crystals changes the PbF2 structure from a mixed phase to a cubic phase and decreases the grain size to nanoscale levels. Enhanced upconversion efficiency is achieved after annealing resulted from the formation of the cubic phase and the increase of grain size. The optimal Er3+ concentration is found to be 4% after annealing, and applied to the back of a bifacial silicon solar cell, maximum external quantum efficiencies of 0.38% and 0.79% are respectively obtained under 0.77 W/cm2 laser excitation (1560 nm) and AM1.5 + laser co-excitation.
Źródło:
Optica Applicata; 2014, 44, 3; 463-473
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preparation and Performance Optimization of Organosilicon Slag Exothermic Insulating Riser
Autorzy:
Lu, Jijun
Qian, Jiangbing
Yang, Lei
Wang, Huafang
Powiązania:
https://bibliotekanauki.pl/articles/27314121.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
organosilicon slag
exothermic insulation
optimization
żużel krzemoorganiczny
izolacje
optymalizacja
Opis:
The exothermic insulating riser played an important role in the solidification process of metal liquid for the improvement of casting quality. This paper focused on the use of organosilicon slag to replace part of the aluminum powder as an exothermic agent for the riser, to reduce production costs and turn waste into treasure. The experiments firstly studied the effect of organosilicon slag content on the combustion temperature and holding time and determined the components of the riser exothermic agent and organosilicon slag. On this basis, the effects of the content of Na3AlF6 flux and alkali phenolic resin binder on the combustion heating time and strength properties of the riser were studied. And the ratio of mixed oxidants was determined by single-factor orthogonal experiments to optimize the addition of three oxidants, Fe3O4, MnO2, and KNO3. Finally, the performance of the riser prepared after optimization was compared with that of the riser prepared with general aluminum powder. The results showed that with the mixture of 21% organosilicon slag and 14% aluminum powder as the exothermic agent, the highest combustion temperature of the prepared exothermic insulating riser was 1451℃ and the holding time was 193 s; the optimal content of Na3AlF6 flux was 4%, and the best addition alkali phenolic resin binder was 12%; the optimized mixing ratio of three oxidants was 12% for Fe3O4, 6% for MnO2, and 6% for KNO3. Under the optimized ratio, the maximum combustion temperature of the homemade riser was 52℃ and the heat preservation time was 14% longer compared with the conventional exothermic insulating riser with 25-35% aluminum powder.
Źródło:
Archives of Foundry Engineering; 2023, 23, 1; 75--82
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nanoslotted microring resonator for high figure of merit refractive index sensing
Autorzy:
Yang, Daquan
Duan, Bing
Zhang, Xuan
Lu, Hui
Powiązania:
https://bibliotekanauki.pl/articles/174324.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
nanoslot
microring resonator
refractive index sensor
figure of merit
integrated nanophotonics
3D-FDTD
Opis:
A nanoslotted microring resonator (NSMR) with enhanced light-matter interaction has been designed, which can be used for high sensitive refractive index sensing. The performance of the device is investigated theoretically based on a three-dimensional finite-difference time-domain (3D-FDTD) method. In order to achieve high figure of merit sensing, the nanoslot geometry is exploited to make the optical field strongly localized inside the low index region and overlap sufficiently with the analytes. By using the 3D-FDTD method, the proposed NSMR sensor device achieves a high Q-factor (Q > 105) and sensitivity ~100 nm/RIU (RIU – refractive index unit). Moreover, the strong light confinement introduced by the nanoslot in NSMR results in the sensor figure of merit as high as 6.73 × 103. Thus, the design we proposed is a promising platform for refractive index-based biochemical sensing and lab-on-a-chip applications.
Źródło:
Optica Applicata; 2020, 50, 1; 37-47
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamical modeling and coupling characteristic analysis of the multistage gears system in a continuous miner
Autorzy:
Lu, Wenjia
Zhang, Yimin
Cheng, Hongchuan
Yang, Zhou
Powiązania:
https://bibliotekanauki.pl/articles/279213.pdf
Data publikacji:
2020
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
planets
multistage gear
continuous miner
acceleration
Opis:
The lumped parameter method is adopted to establish a dynamic model of two stage planets and multistage fixed-shaft gears in which the effect of coupling shaft section radius on the system in a continuous miner is considered. The acceleration test of the system proves the accuracy of the proposed model. With the increase of cross section size of the coupled shaft, the influence of the first stage meshing frequency on the second stage planetary system is enhanced. The acceleration decreases gradually with the increase of the size of coupled carrier. It is shown that the modeling by considering the coupled size contributes to reduction of the vibration level.
Źródło:
Journal of Theoretical and Applied Mechanics; 2020, 58, 1; 45-58
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on striking ship with loading impact on the performance of the double hull oil tanker collision
Autorzy:
Wu, W.
Yang, Y.
Zhang, J.
Lu, J.
Powiązania:
https://bibliotekanauki.pl/articles/258890.pdf
Data publikacji:
2018
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
ship collision
fluid-structure interaction
impact parameters
numerical simulation
Opis:
Due to the great danger of the collision of oil tankers, lots of research on the collision of oil tankers has been carried out. But, at present, the research on the collision of oil tankers mainly focuses on the loading condition of the struck ship, ignores the impact on the loading condition of the striking ship. However, during the actual oil tanker collision, the striking ship is generally in the state of loading. Therefore, it is necessary to carry out the analysis of the impact of the loading condition of the striking ship on the collision damage of the oil tanker. In this paper, the effect of striking ship with loading on the impact performance of the side structure during the collision of the cargo double hull oil tanker has been investigated. The ship collision model was established by using the finite element software ANSYS/ LS-DYNA which is based on 7000 tons of double hull oil tankers. Based on the analysis of the collision force, impact of striking speed changes, impact of striking deep changes and structural energy absorption during the collision process, the influence of the striking ship with loading on the damage mechanism and the impact performance of the double shell oil ship side structure was expounded. The results show that the influence of the striking ship with loading can be great to the damage to side hull during the research of the collision performance of the oil tanker.
Źródło:
Polish Maritime Research; 2018, S 2; 42-48
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mean failure mass and mean failure repair time: parameters linking reliability, maintainability and supportability
Średnia masa uszkodzenia i średni czas naprawy uszkodzenia: parametryłączące niezawodność, obsługiwalność i utrzymywalność
Autorzy:
Yang, Y.
Lu, Z.
Luo, X.
Ge, Z.
Qian, Y.
Powiązania:
https://bibliotekanauki.pl/articles/301018.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
średnia masa uszkodzenia
średni czas naprawy uszkodzenia
niezawodność
obsługiwalność
LRU
mean failure mass
mean failure repair time
reliability
maintainability
Opis:
Jak dotąd w inżynierii niezawodności nie istniały parametry łączące niezawodność, obsługiwalność i utrzymywalność. Wskaźniki takie jak gotowość mogą być stosowane w celu sprawdzenia zgodności tych cech RAM (Reliability, Availability, Maintainability – Niezawodność, Gotowość, Obsługiwalność) dopiero po uzyskaniu indywidualnego wskaźnika każdej charakterystyki, takich jak MTBF, MTTR, itp. W ten sposób dostępne metody równoważenia owych trzech cech nie są wystarczająco skuteczne i bezpośrednie w fazie projektowania produktu . Niniejszy artykuł przedstawia pojęcia średniej masy uszkodzenia i średniego czasu naprawy uszkodzenia. Badając zależność prawdopodobieństwa uszkodzenia i masy produktu, uzyskuje się cechę łączącą niezawodność i utrzymywalność. Podobnie, badając zależność prawdopodobieństwa uszkodzenia i średniego czasu naprawy produktu, uzyskuje się cechę łączącą niezawodność i obsługiwalność. Na bazie powyższych definicji osiągnięto kompromisowe podejście do niezawodności, obsługiwalności i utrzymywalności podczas fazy projektowania. Skuteczności obu nowych koncepcji dowodzi przykład równoważenia niezawodności i obsługiwalności podsystemu stacji kosmicznej.
Up to now, no parameters linking reliability, maintainability and supportability directly are available in reliability engineering. Index such as availability can be used to check the compatibility of those RAM features only after individual index of every characteristic is obtained such as MTBF, MTTR, etc. Thus available methods to balance those three features are not efficient and direct during the product design phase. In this paper, concepts of mean failure mass and mean failure repair time are presented. By investigating the relationship of the failure probability and the mass of a product, a feature linking reliability and supportability is obtained. Similarly, by studying the relationship of the failure probability and the mean time to repair of a product, a feature linking reliability and maintainability is obtained. Based on above definitions, an approach of reliability, maintainability and supportability trade-off during design phase is achieved. Effectiveness of both of the new concepts is demonstrated by an example of balancing the maintainability and supportability of a subsystem of a space station.
Źródło:
Eksploatacja i Niezawodność; 2014, 16, 2; 307-312
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on Reclamation of CO2-hardened Sodium Silicate Used Sands by CaO Powder
Autorzy:
Lu, Jijun
Yang, Lei
Qian, Jiangbing
He, Wei
Wang, Huafang
Powiązania:
https://bibliotekanauki.pl/articles/2174624.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sodium silicate sands
reclamation
orthogonal experiment
wet reclamation
dry reclamation
hardening of the sands
masa krzemianowo-sodowe
regeneracja
utwardzanie
eksperyment
Opis:
Aiming at the problems of wet reclamation consuming a lot of water, dry (mechanical) reclamation having wear and power consumption, this paper to find suitable reclamation reagents to reduce the influence of harmful substances in used sodium silicate sands. By comparing the reclamation effect of CaO, Ca(OH)2 and Ba(OH)2 reclamation powder reagents, it was concluded that CaO had the best reclamation effect. Through the single factor experiment, the influence of CaO on the reclamation effect was explored: 1. addition amount of CaO; 2. the additional amount of water; 3. reclamation time. The orthogonal results showed that the CaO reclamation effect was the best when the amount of CaO was 1.5%, the amount of sodium silicate was 4.0%, the amount of water added was 6.0%, and the reclamation time was 12.0h. In this experiment, 82.2% carbonate and 75.0 % silicate in used sands can be removed. The microscopic analysis of the reclamation sands was carried out by scanning electron microscope (SEM); The surface was relatively smooth, without large area cracks and powder accumulation. Compared with the used sands, the instant, 24h ultimate, and residual strengths of the reclaimed sands were increased by 536.5%, 458.1%, and 89.8%, respectively, which was beneficial to the reclamation of the CO2 sodium silicate used sands.
Źródło:
Archives of Foundry Engineering; 2022, 22, 3; 99--106
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of fuel cold energy in CO2 BOG reliquefaction system on ammonia-powered CO2 carrier
Autorzy:
Lin, Yiqun
Lu, Jie
Li, Boyang
Li, Yajing
Yang, Qingyong
Powiązania:
https://bibliotekanauki.pl/articles/34608726.pdf
Data publikacji:
2023
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
mmonia-powered CO2 carrier
liquid ammonia cold energy
CO2 BOG
reliquefaction system
Aspen HYSYS
Opis:
A CO2 boiled off gas (CO2 BOG) reliquefaction system using liquid ammonia cold energy is designed to solve the problems of fuel cold energy waste and the large power consumption of the compressor in the process of CO2 BOG reliquefaction on an ammonia-powered CO2 carrier. Aspen HYSYS is used to simulate the calculation, and it is found that the system has lower power consumption than the existing reliquefaction method. The temperature of the heat exchanger heater-1 heat flow outlet node (node C-4) is optimised, and it is found that, with the increase of the node C-4 temperature, the power consumption of the compressor gradually increases, and the liquefaction fraction of CO2 BOG gradually decreases. Under 85% conditions, when the ambient temperature is 0°C and the temperature of node C-4 is -9°C, the liquid fraction of CO2 BOG reaches the maximum, which is 74.46%, and the power of Compressor-1 is the minimum, which is 40.90 kW. According to this, the optimum temperature of node C-4 under various working conditions is determined. The exergy efficiency model is established, in an 85% ship working condition with the ambient temperature of 40°C, and the exergy efficiency of the system is the maximum, reaching 59.58%. Therefore, the CO2 BOG reliquefaction system proposed in this study could realise effective utilisation of liquid ammonia cold energy.
Źródło:
Polish Maritime Research; 2023, 3; 22-34
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stability analysis of high-order Hopfield-type neural networks based on a new impulsive differential inequality
Autorzy:
Liu, Y.
Yang, R.
Lu, J.
Wu, B.
Cai, X.
Powiązania:
https://bibliotekanauki.pl/articles/330348.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
impulsive differential inequality
globally exponential stability
high order Hopfield type neural network
nierówność różniczkowa
stabilność wykładnicza
sieć neuronowa Hopfielda
Opis:
This paper is devoted to studying the globally exponential stability of impulsive high-order Hopfield-type neural networks with time-varying delays. In the process of impulsive effect, nonlinear and delayed factors are simultaneously considered. A new impulsive differential inequality is derived based on the Lyapunov–Razumikhin method and some novel stability criteria are then given. These conditions, ensuring the global exponential stability, are simpler and less conservative than some of the previous results. Finally, two numerical examples are given to illustrate the advantages of the obtained results.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2013, 23, 1; 201-211
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Methyl Silicone Oil to Moisture Resistance of Sodium Silicate Sands by Microwave Hardening
Autorzy:
Wang, Huafang
Gao, Xiang
Yang, Lei
He, Wei
Lu, Jijun
Powiązania:
https://bibliotekanauki.pl/articles/2126894.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sodium silicate sands
microwave hardening
methyl silicon oils
moisture absorption
piaski sodowo-krzemianowe
hartowanie mikrofalowe
olej metylosilikonowy
wchłanianie wilgoci
Opis:
The sodium silicate sands hardened by microwave have the advantages of high strength, fast hardening speed and low residual strength with the lower addition of sodium silicate. However, the sodium ion in the sands will absorb moisture from the atmosphere, which would lead to lower storing strength, so the protection of a bonding bridge of sodium silicate between the sands is crucial. Methyl silicone oil is a cheap hydrophobic industrial raw material. The influence of the addition amount of methyl silicone oil modifier on compressive strength and moisture absorption of sodium silicate sands was studied in this work. The microscopic analysis of modified before and after sodium silicate sands has been carried on employing scanning electron microscopy(SEM) and energy spectrum analysis(EDS). The results showed that the strength of modified sodium silicate sands was significantly higher than that of unmodified sodium silicate sands, and the best addition of methyl silicone oil in the quantity of sodium silicate was 15%. It was also found that the bonding bridge of modified sodium silicate sands was the density and the adhesive film was smooth, and the methyl silicone oil was completely covered on the surface of the sodium silicate bonding bridge to protect it.
Źródło:
Archives of Foundry Engineering; 2022, 22, 1; 43--47
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of particle size on the oxidation and flotation behavior of galena particles
Autorzy:
Lu, Yalin
Tong, Xiong
Xie, Xian
Yang, Bo
Hua, Zhongbao
Powiązania:
https://bibliotekanauki.pl/articles/110497.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
galena
particle size
surface oxidation
flotation behavior
Opis:
The aim of this study was to determine the effect of particle size on the oxidation and flotation behavior of galena particles. Coarse (-0.074+0.038 mm), intermediate (-0.038+0.025 mm) and fine (-0.025 mm) galena particles were used in this study. Dissolution tests demonstrated that the amount of oxidation products increased with the decrease of particle sizes. The surface oxidization of galena was the greatest at pH 7.3, followed by pH 12 and 9, which were consist with the result of XPS. The micro-flotation results indicated that the effect of pH on the flotation recovery of galena enhanced with the reduction of particle sizes. The decreasing of particle sizes increases both the sorption rate of collector and the dissolution of galena, while the generation of hydrophilic product caused by dissolution is dominant, rendering the mineral hydrophilic. This study shows the differences in the surface oxidation and flotation behavior of different size fractions of galena particles. To promote the flotation recovery of the fine size fraction of galena particles, alleviating their oxidation is the key.
Źródło:
Physicochemical Problems of Mineral Processing; 2019, 55, 1; 208-216
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental study of an anomalous hollow beam with orbital angular momentum
Autorzy:
Lu, Xingyuan
Zhao, Chengliang
Hoenders, Bernhard J.
Yang, Yuanjie
Cai, Yangjian
Powiązania:
https://bibliotekanauki.pl/articles/173518.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
anomalous hollow beam
orbital angular momentum
focused intensity
Fourier transform
Opis:
Anomalous hollow beam has potential applications in the optical trapping and free space optical communications, etc. It is noted that, thus far, although a large number of studies have been carried out in this field, most of them are theoretical studies and only quite a few cases have experimental results. Here, we experimentally study the generating of anomalous hollow beam carrying orbital angular momentum, and measure its topological charge. We show that the number of dark rings in the Fourier transform of intensity patterns is equal to the topological charge. The experimental results agree well with the simulations.
Źródło:
Optica Applicata; 2019, 49, 2; 217-226
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of manganese ions addition orders on the flotation behavior of scheelite
Autorzy:
Lu, Kuanwei
Chen, Rong
Zhang, Ying
Luo, Hongying
Yang, Hu
Cai, Jiaozhong
Powiązania:
https://bibliotekanauki.pl/articles/1845215.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
manganese ion
addition order
scheelite
sodium silicate
flotation
Opis:
In this study, the effect of MnCl2 on scheelite flotation with sodium oleate (NaOL) as a collector and sodium silicate as a depressant was assessed by a combination of flotation experiments, Fouriertransform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and solution chemistry. The flotation experiments confirmed that the addition of MnCl2 before sodium silicate showed an adverse effect on flotation and the recovery of scheelite gradually decreased as the amount of MnCl2 was increased. When MnCl2 was added afte r sodium silicate, the recovery of scheelite gradually increased with an increase in the amount of MnCl2. The results of FTIR, XPS, and solution chemistry indicated that MnCl2 acted on the surface of scheelite in the form of manganese ions. When MnCl2 was added before sodium silicate, manganese ions adsorbed on the surface of scheelite reacted with sodium silicate to form a hydrophilic silicate, which covers the surface of scheelite and blocks the adsorption of NaOL. However, when MnCl2 was added after sodium silicate, manganese ions are continued to be adsorbed on the surface of scheelite, which increases the cations on the surface of scheelite, and hence the condition becomes conducive for the interaction between scheelite and NaOL.
Źródło:
Physicochemical Problems of Mineral Processing; 2020, 56, 5; 860-873
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
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