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Tytuł:
The structure and properties of eucalyptus fiber/phenolic foam composites under N-β(aminoethyl)-γ-aminopropyl trimethoxy silane pretreatments
Autorzy:
Ma, Y.
Wang, C.
Chu, F.
Powiązania:
https://bibliotekanauki.pl/articles/778793.pdf
Data publikacji:
2017
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
eucalyptus fiber
pheonlic foam
N-β(aminoethyl)-γ-aminopropyl trimethoxy silane
surface modification
composites
Opis:
Eucalyptus fibers were modified with N-β(aminoethyl)-γ-aminopropyl trimethoxy silane to research the fiber surface’s changes and the influence of the treatment on the mechanical properties, flame resistance, thermal conductivity and microstructure of eucalyptus fiber composite phenolic foams (EFCPFs). The results showed that the partial of hemicelluloses, waxes, lignin and impurities from the fiber surface were dissolved and removed. Compared with untreated EFCPFs, the mechanical properties of treated EFCPFs were increased dramatically; The size of cells was smaller and the distribution was more uniform; The thermal conductivities were basically reduced; Especially the ratio of mass loss decreased obviously. However limited oxygen indexs (LOIs) reduced. And the mechanical properties and LOIs of EFCPFs were basically decreased with the increase of eucalyptus fibers. By comprehensive analysis, the results showed that the interfacial compatibility has been significantly improved between eucalyptus fibers and phenolic resin. And the suitable dosage of eucalyptus fibers was about 5%.
Źródło:
Polish Journal of Chemical Technology; 2017, 19, 4; 116-121
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical research of the viscous effect of the bilge keel on the damping moment
Autorzy:
Deng, R.
Duan, W.
Ma, S.
Ma, Y.
Powiązania:
https://bibliotekanauki.pl/articles/258868.pdf
Data publikacji:
2015
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
calculation model
viscous code
phase difference
damping mpment
bilge keel
Opis:
Bilge keels are effective passive devices in mitigating the rolling motion, and the usage of them covers almost all the sea going vessels. This paper focuses on the viscous effect of the bilge keel, ignored the effect of the free surface and the effect of the ship hull, for the general viscous characteristic of the bilge keel. In order to investigate the viscous effect of the bilge keel on the total damping moment, a special 2 dimensional numerical model, which includes a submerged cylinder with and without bilge keels, is designed for the simulation of forced rolling. Three important factors such as bilge keels width, rolling periods, as well as maximal rolling angles are taken into account, and the viscous flow field around the cylinder is simulated by some codes based on the viscous method in different conditions, in which the three factors are coupled. Verification and validation based on the ITTC method are performed for the cylinder without bilge keels in the conditions of different rolling periods and maximal rolling angles. The primary calculation of damping moment induced by the cylinder with 0mm, 4mm, and 10mm width bilge keels shows some interesting results, and a systematic analysis is conducted. The analysis of the damping moment components suggests there is phase difference between the damping moment induced by the cylinder and the bilge keels, and when the bilge keels width reaches a special size, the total damping moment is mitigated. The calculation of the damping moments induced by the cylinder with some larger bilge keels are also performed, and the results suggest that, the damping moment induced by the bilge keels is increased rapidly and becomes the dominant part in the total damping moment while the width of the bilge keels are increased, but the damping moment induced by the cylinder is not changed significantly. Some illustration of the vortices formation and shedding is included, which is the mechanism of the damping moment caused by the bilge keels. The present work shows an interesting problem, and it is useful for the bilge keel design.
Źródło:
Polish Maritime Research; 2015, S 1; 67-74
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new genus of lance lacewings from the Middle Jurassic of Inner Mongolia, China
Autorzy:
Ma, Y.
Shih, C.
Ren, D.
Wang, Y.
Powiązania:
https://bibliotekanauki.pl/articles/2082186.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Insecta
Neuroptera
Osmylidae
Osmylinae
Mesozoic
Asia
China
Opis:
Fossils of Osmylinae are rare, currently only one fossil genus of this subfamily is known, Lithosmylus which is recorded from the late Eocene Florissant Formation of USA. Herein, we report a new Osmylinae genus with two new species, Vetosmylus tentus gen. et sp. nov. and Vetosmylus maculosus gen. et sp. nov. from the Middle Jurassic Jiulongshan Formation of Daohugou Village, Inner Mongolia, China, The new genus shares many apomorphic characters with extant osmyline relatives, e.g., forked subcostal veinlets in forewing; dense cross-veins present in radial sector, usually forming one complete outer gradate series in forewing; the region between MA and MP significantly broadened in hind wing, but with only one row of cells, implying a likely morphological stasis during the evolution of Osmylinae. The new genus Vetosmylus, the first and earliest record hitherto of Osmylinae from the Mesozoic, enhances our understanding of the early stages of their evolution.
Źródło:
Acta Palaeontologica Polonica; 2020, 65, 2; 363-369
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A novel reliability model for multi-component systems subject to multiple dependent competing risks with degradation rate acceleration
Nowatorski model niezawodności dla systemów wieloelementowych narażonych na liczne zależne ryzyka konkurujące uwzględniający przyspieszenie tempa degradacji
Autorzy:
Zhang, Y.
Ma, Y.
Liu, L.
Ouyang, L.
Powiązania:
https://bibliotekanauki.pl/articles/300977.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
zależne ryzyka konkurujące
analiza czułości
przyspieszenie tempa degradacji
model niezawodności
metoda funkcji kopuły
dependent competing risks
degradation rate acceleration
reliability model
copula method
sensitivity analysis
Opis:
The purpose of this paper is to establish a new reliability model of the system subject to multiple dependent competing risks. For a system subject to multiple dependent competing risks, the total degradation consists of natural degradation amount and sudden degradation increments (SDIs) caused by random shocks arriving at the system. Most researchers on this topic only focus on the SDIs. However, the impact of random shocks on degradation rate is ignored. In this paper, a novel reliability model considering degradation rate acceleration (DRA) caused by random shocks is proposed, in which the degradation model is based on the degradation path. The dependence relationship between multiple degradation processes is dealt with by copula method, and the arrival time of shocks is assumed to follow a non-homogeneous Poisson process (NHPP). Finally, the effectiveness of the proposed reliability model is demonstrated by an example of a series system. Moreover, the effect of model parameters is evaluated through sensitivity analysis.
Celem niniejszej pracy było stworzenie nowego modelu niezawodności systemu narażonego na liczne zależne ryzyka konkurujące. W przypadku systemu eksponowanego na wiele zależnych ryzyk konkurujących, na wartość całkowitą degradacji składa się wartość degradacji naturalnej oraz wartość nagłych przyrostów degradacji (sudden degradation increments, SDI) powodowanych przez losowe zaburzenia systemu. Większość badaczy tej tematyki koncentruje się wyłącznie na SDI, ignorując tym samym wpływ zaburzeń losowych na tempo degradacji. W niniejszym artykule zaproponowano nowy model niezawodności uwzględniający przyspieszenie tempa degradacji powodowane zaburzeniami losowymi, w którym model degradacji opiera się na krzywej degradacji. Zależność między mnogimi procesami degradacji rozpatrywano za pomocą metody funkcji kopuły przy założeniu, że czas wystąpienia zaburzenia odpowiada niejednorodnemu procesowi Poissona. Skuteczność proponowanego modelu niezawodności zademonstrowano na przykładzie systemu szeregowego. Ponadto, wykorzystano analizę czułości do oceny wpływu parametrów modelu na niezawodność systemu.
Źródło:
Eksploatacja i Niezawodność; 2018, 20, 4; 579-589
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
3-D simulation of vertical-axial tidal current turbine
Autorzy:
Zhang, Z.
Ma, Y.
Jiang, J.
Liu, W.
Ma, Q.
Powiązania:
https://bibliotekanauki.pl/articles/260421.pdf
Data publikacji:
2016
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
tidal current energy
vertical-axial turbine
hydrodynamic performance
CFD
numerical simulation
3-D effect
Opis:
Vertical-axial tidal current turbine is the key for the energy converter, which has the advantages of simple structure, adaptability to flow and uncomplex convection device. It has become the hot point for research and application recently. At present, the study on the hydrodynamic performance of vertical-axial tidal current turbine is almost on 2-D numerical simulation, without the consideration of 3-D effect. CFD (Computational Fluid Dynamics) method and blade optimal control technique are used to improve accuracy in the prediction of tidal current turbine hydrodynamic performance. Numerical simulation of vertical-axial tidal current turbine is validated. Fixed and variable deflection angle turbine are comparatively studied to analysis the influence of 3-D effect and the character of fluid field and pressure field. The method, put the plate on the end of blade, of reduce the energy loss caused by 3-D effect is proposed. The 3-D CFD numerical model of vertical-axial tidal current turbine hydrodynamic performance in this study may provide theoretical, methodical and technical reference for the optimal design of turbine.
Źródło:
Polish Maritime Research; 2016, 4; 73-83
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fabrication, Structural Characterization and Optical Properties of the Flower-Like ZnO Nanowires
Autorzy:
Feng, L.
Liu, A.
Ma, Y.
Liu, M.
Man, B.
Powiązania:
https://bibliotekanauki.pl/articles/1538755.pdf
Data publikacji:
2010-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.07.Bc
81.05.Dz
81.10.Aj
Opis:
Multipod flower-like zinc oxide (ZnO) nanowires have been successfully synthesized on Si(111) substrates using a pulsed laser deposition prepared Zn film as "self-catalyst" by the simple thermal evaporation oxidation of the metallic zinc powder at 850°C without any other catalysts or additives. The pre-deposited Zn films by pulsed laser deposition on the substrates can promote the formation of the ZnO nuclei effectively. Also it can further advance the growth of the flower-like ZnO nanowires accordingly. X-ray diffraction, scanning electron microscope, high-resolution transmission electron microscopy, Fourier transform infrared spectrum, and photoluminescence were used to analyze the structure, morphology, composition and optical properties of the as-synthesized products. The results demonstrate that the nanowires were single crystalline with hexagonal wurzite structure, grown along the [0001] in the c-axis direction. Room temperature photoluminescence spectrum of the ZnO nanowires shows a nearband-edge ultraviolet emission (peak at ≈ 384 nm) and a deep-level green emission (peak at ≈ 513 nm). In addition, the growth mechanism of the flower-like ZnO nanowires is discussed in detail.
Źródło:
Acta Physica Polonica A; 2010, 117, 3; 512-517
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A novel DOPO-g-KH550 modification wood fibers and its effects on the properties of composite phenolic foams
Autorzy:
Ma, Y.
Geng, X.
Zhang, X.
Wang, C.
Chu, F.
Powiązania:
https://bibliotekanauki.pl/articles/949373.pdf
Data publikacji:
2018
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
DOPO
Wood Fiber
Γ-amino propyl triethoxy silane
Composites
Characterization
Opis:
A novel 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) graft γ-amino propyl triethoxy silane (KH550) was synthesized and introduced on the surface of wood fi ber. Finally DOPO-g-KH550 treated wood fi ber (DKTWF) was used to prepare DKTWF composite phenolic foams (DKTWFCPF). The structures of DOPO-g- KH550 was acknowledged by Fourier transform infrared (FT-IR) and nuclear magnetic resonance (1 H-NMR). The structures of DKTWF were confirmed by FT-IR. Compared with wood fi ber, the diffraction peaks’ position was basically unchanged, but the crystallinity was slightly increased and thermal stability were dramatically improved, T5%  and Tmax  increased by 21.9° and 36.1° respectively. But the char yield (800°) was slightly reduced. With the dosage of DKWF, there were different degrees of improvement including the mechanical properties, flame retardancy and microstructure of DKTWFCPF. Comprehensive analysis, the interfacial compatibility was signifi cantly improved between DKTWF and phenolic resin, and the suitable content of DKTWF was 4%.
Źródło:
Polish Journal of Chemical Technology; 2018, 20, 2; 47-53
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Actuator failure compensation for two linked 2WD mobile robots based on multiple-model control
Autorzy:
Ma, Y.
Cocquempot, V.
El Badaoui El Najjar, M.
Jiang, B.
Powiązania:
https://bibliotekanauki.pl/articles/331196.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
actuator failure
multiple model control
physically linked robot
two wheel drive
awaria siłownika
sterowanie wielomodelowe
robot połączony
Opis:
This paper develops a new actuator failure compensation scheme for two linked two-wheel drive (2WD) mobile robots based on multiple-model control. First, a configuration of two linked 2WD robots is described, and their kinematics and dynamics are modeled. Then, a multiple-model based failure compensation scheme is developed to compensate for actuator failures, consisting of a kinematic controller, multiple dynamic controllers and a control switching mechanism, which ensures system stability and asymptotic tracking properties. Finally, simulation results verify the effectiveness of the proposed failure compensation control system.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2017, 27, 4; 763-776
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Model construction and experimental verification of the equivalent elastic modulus of a double-helix wire rope
Autorzy:
Chen, H. Y.
Zhang, K.
Bai, Y. X.
Ma, Y.
Deng, H. Z.
Powiązania:
https://bibliotekanauki.pl/articles/280950.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
mechanical properties
wire rope
double-helix wire rope
spatial configuration curve
equivalent elastic modulus
Opis:
To accurately describe mechanical properties of a complex wire rope, a double-helix wire rope is used as an example in this study. According to the spatial structure characteristics of the central helical line of each wire rope, the spatial configuration curve for the double- -helix wire rope is obtained by using differential geometry theory. On the basis of this curve, the mathematical model of the equivalent elastic modulus of the wire rope is developed, and the elastic modulus of a 6×7+IWS wire rope is measured using a universal tensile testing machine. The experimental results are compared with the predicted results to verify correctness of the elastic modulus prediction of the double-helix wire rope.
Źródło:
Journal of Theoretical and Applied Mechanics; 2018, 56, 4; 951-960
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Chinese cabbage BrMYB34.2 transcription factor regulates indolic glucosinolates biosynthesis in Arabidopsis
Autorzy:
Zhao, Y.
Zhang, Y.
Guo, X.
Ma, Y.
Zhang, P.
Liu, H.
Liu, G.
Guo, J.
Powiązania:
https://bibliotekanauki.pl/articles/12705984.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet Przyrodniczy w Lublinie. Wydawnictwo Uniwersytetu Przyrodniczego w Lublinie
Opis:
Glucosinolates (GS) are a group of sulfur- and nitrogen-rich plant secondary metabolites that originate from amino acids and exist mainly in plants in the order Brassicales, such as Arabidopsis thaliana (Arabidopsis) and Chinese cabbage (Brassica rapa ssp. pekinensis). To date, several regulatory components responsible for GS biosynthesis have been identified in Arabidopsis. However, the functions of GS biosynthesis regulators in Chinese cabbage have not been clarified. In our current study, a putative ATR1/MYB34 orthologous gene, BrMYB34.2, was isolated from Chinese cabbage leaves. To investigate the function of this gene, we engineered Arabidopsis plants that overexpress BrMYB34.2 ectopically and phenotypic analysis was performed. Moreover, we assayed the accumulation levels of indolic GS (IGS) and aliphatic glucosinolates in transgenic plants and test the expression of key genes of IGS biosynthesis and tryptophan synthesis by Real-time quantitative PCR. And further analysed the resistance of transgenic plants in 5MT stress treatment. The results indicate that ectopic expression of the BrMYB34.2 gene in Arabidopsis was able to up-regulate the accumulation level of IGS due to the increased expression of IGS and Trp biosynthetic genes. Moreover, overexpression of BrMYB34.2 conferred Arabidopsis 5MT resistance. These results suggest that the BrMYB34.2 gene may function as one of the regulators of IGS and Trp biosynthesis in Chinese cabbage.
Źródło:
Acta Scientiarum Polonorum. Hortorum Cultus; 2020, 19, 1; 85-95
1644-0692
Pojawia się w:
Acta Scientiarum Polonorum. Hortorum Cultus
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microstructure and Mechanical Behavior of Mg-0.5Si-xSn Alloys
Autorzy:
Fu, X.
Yang, Y.
Ma, Q. Y.
Peng, X.
Xu, T.
Powiązania:
https://bibliotekanauki.pl/articles/379670.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
low silicon magnesium alloy
eutectic Mg2Si
microstructure behavior
mechanical behavior
stop magnezu
stop Mg2Si
zachowanie mechaniczne
Opis:
Mg-0.5Si-xSn (x=0.95, 2.9, 5.02wt.%) alloys were cast and extruded at 593K (320 ºC) with an extrusion ratio of 25. The microstructure and mechanical properties of as-cast and extruded test alloys were investigated by OM, SEM, XRD and tensile tests. The experimental results indicate that the microstructure of the Mg-0.5Si-xSn alloys consists of primary α-Mg dendrites and an interdendritic eutectic containing α-Mg, Mg2Si and Mg2Sn. There is no coarse primary Mg2Si phase in the test alloys due to low Si content. With the increase in the Sn content, the Mg2Si phase was refined. The shape of Mg2Si phase was changed from branch to short bar, and the size of them were reduced. The ultimate tensile strength and yield strength of Mg-0.52Si-2.9Sn alloy at the temperature of 473K (200 ºC) reach 133MPa and 112MPa respectively. Refined eutectic Mg2Si phase and dispersed Mg2Sn phase with good elevated temperature stability are beneficial to improve the elevated temperature performance of the alloys. However, with the excess addition of Sn, large block-like Mg2Sn appears around the grain boundary leading to lower mechanical properties.
Źródło:
Archives of Foundry Engineering; 2017, 17, 4; 179-184
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of hadronic rescattering on the elliptic flow after the hydrodynamics model
Autorzy:
Ma, G.
Ma, Y.
Sa, B.
Cai, X.
He, Z.
Huang, H.
Long, J.
Shen, W.
Zhong, Ch.
Chen, J.
Zuo, J.
Zhang, S.
Shi, X.
Powiązania:
https://bibliotekanauki.pl/articles/148372.pdf
Data publikacji:
2006
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
elliptic flow
hydrodynamic model
hadronic rescattering
LUCIAE model
Opis:
Abstract A hydrodynamics + hadronic rescattering model is used to simulate Au+Au collisions at 200 GeV and a Cooper-Frye method is adopted for hadronization. The effect of hadronic rescattering on elliptic flow V2 in 20 40% Au+Au collisions at 200 GeV has been investigated. It is found that the hadronic rescattering can suppress elliptic flow V2 and makes an asymmetric system in momentum space tend to be less anisotropic. The suppression effect becomes weak with increasing transverse momentum. In addition, the effect of hadronic rescattering on transverse momentum spectra and anisotropy of hadronic coordinate space is presented.
Źródło:
Nukleonika; 2006, 51,suppl.3; 21-27
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Research on Characterization of Crushability for Foundry Sand Particles
Autorzy:
Dai, Y.
Ma, Q. Y.
Li, X. H.
Zhang, X.
Hu, F. P.
Zhang, Y.
Xie, W. D.
Powiązania:
https://bibliotekanauki.pl/articles/379689.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
foundry sand particle
mechanical load
AFS grain fineness
crushability
piasek odlewniczy
obciążenie mechaniczne
rozdrobnienie ziarna
Opis:
In this paper, crushability of foundry sand particles was studied. Three kinds of in-service silica sands in foundry enterprises selected as the study object, and foundry sand particles were subjected to mechanical load and thermal load during service were analyzed. A set of methods for simulating mechanical load and thermal load by milling and thermal-cold cycling were designed and researched, which were used to characterize the crushability for silica sand particles, the microstructure was observed by SEM. According to the user’s experience in actual application, the crushability of Sand C was the best and then Sand B, the last Sand A. The results indicated that mechanical load, thermal load and thermal-mechanical load can all be used to characterize the crushability of foundry sand particles. Microscopic appearances can qualitatively characterize the crushability of foundry sand particles to a certain extent, combining with the additions and cracks which are observed on the surface.
Źródło:
Archives of Foundry Engineering; 2017, 17, 4; 231-235
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Szacowanie współczynników interakcyjnych do analizy uszkodzeń interakcyjnych
Estimating interactive coefficients for analysing interactive failures
Autorzy:
Sun, Y.
Ma, L.
Powiązania:
https://bibliotekanauki.pl/articles/301078.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
uszkodzenia zależne
uszkodzenia interakcyjne
współczynniki interakcyjne
niezawodność
system złożony
dependent failures
interactive failures
interactive coefficients
reliability
complex system
Opis:
Środki techniczne to często systemy złożone. W złożonym systemie, między komponentami często zachodzą interakcje uszkodzeniowe prowadzące do uszkodzeń interakcyjnych. Występowanie w systemie uszkodzeń interakcyjnych może prowadzić do wzmożonego prawdopodobieństwa uszkodzenia. Stąd też, przy projektowaniu i eksploatacji złożonych systemów inżynieryjnych, może zaistnieć potrzeba wzięcia pod uwagę uszkodzeń interakcyjnych. Odnosząc się do tego zagadnienia, Sun i in. stworzyli analityczny model uszkodzeń interakcyjnych. W modelu tym stopień interakcji między dwoma komponentami jest wyrażany przez współczynniki interakcyjne. Aby można było użyć tego modelu do analizy uszkodzeń należy więc oszacować współczynniki interakcyjne. Jednakże nie opisano jeszcze metod szacowania współczynników interakcyjnych. Aby wypełnić tę lukę, w niniejszej pracy zaprezentowano pięć metod szacowania współczynników interakcyjnych, wliczając w to metodę probabilistyczną, metodę analizy opartej na danych o uszkodzeniach, eksperymentalną metodę laboratoryjną, metodę opartą na mechanizmie interakcji między uszkodzeniami oraz metodę oceny eksperckiej. Podano przykłady pokazujące zastosowania proponowanych metod, a także dokonano porównania między nimi.
Engineering assets are often complex systems. In a complex system, components often have failure interactions which lead to interactive failures. A system with interactive failures may lead to an increased failure probability. Hence, one may have to take the interactive failures into account when designing and maintaining complex engineering systems. To address this issue, Sun et al have developed an analytical model for the interactive failures. In this model, the degree of interaction between two components is represented by interactive coefficients. To use this model for failure analysis, the related interactive coefficients must be estimated. However, methods for estimating the interactive coefficients have not been reported. To fill this gap, this paper presents five methods to estimate the interactive coefficients including probabilistic method; failure data based analysis method; laboratory experimental method; failure interaction mechanism based method; and expert estimation method. Examples are given to demonstrate the applications of the proposed methods. Comparisons among these methods are also presented.
Źródło:
Eksploatacja i Niezawodność; 2010, 2; 67-72
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Automation detection of driver fatigue using visual behavior variables
Automatyczna ocena zmęczenia kierowcy z wykorzystaniem wizualnych zmiennych zachowania
Autorzy:
Wang, Y.
Ma, J.
Powiązania:
https://bibliotekanauki.pl/articles/231258.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
czas jazdy
zachowania wizualne
poziom zmęczenia
skala senności Stanford
czynnik prognostyczny
zmęczenie kierowcy
driving duration
visual behaviors
fatigue level
Stanford sleepiness scale
predictor
driver fatigue
Opis:
To examine the correlation of driver visual behaviors and subjective levels of fatigue, a total of 36 commercial drivers were invited to participate in 2-h, 3-h, and 4-h naturalistic driving tests during which their eye fixation, saccade, blinking variables, and self-awareness of their fatigue levels were recorded. Then, one-way ANOVA was applied to analyze the variations of each variable among different age groups over varying time periods. The statistical analysis revealed that driving duration had a significant effect on the variation of visual behaviors and feelings of fatigue. After 2h of driving, only the average closure duration value and subjective level of fatigue had an increase of one-fifth or more. After 4h of driving, however, all these variables had a significant change except for the number of saccades and pupil diameter measurements. Particularly, driver saccadic eye movement was more sensitive to driving fatigue, and the elderly were more likely to be affected by the duration of the drive. Finally, a predictor of driver fatigue was determined to detect the real-time level of fatigue and alert at the critical moment.
Kierowcy zawodowi spędzają długie godziny za kierownicą i szybciej odczuwają zmęczenie podczas prowadzenia pojazdu. Z tego powodu, identyfikacja poziomu zmęczenia w czasie rzeczywistym ma kluczowe znaczenie dla zapewnienia bezpieczeństwa ruchu drogowego i zapobiegania wypadkom, w szczególności w odniesieniu do osób zajmujących się dalekobieżnym transportem komercyjnym. Łącznie 26 kierowców zawodowych w czterech grupach wiekowych zostało zaproszonych do udziału w naturalistycznym egzaminie na prawo jazdy, podczas którego każdy uczestnik został poproszony o ukończenie 2-godzinnych, 3-godzinnych i 4-godzinnych zadań związanych z prowadzeniem pojazdu, obejmujących przerwę na odpoczynek, na trzech drogach ekspresowych w Shandong, Chiny, celem zarejestrowania zmiennych skupienia wzroku, ruchu gałek ocznych i mrugania oczami, jak również subiektywnego poziomu zmęczenia. Następnie, zastosowano jednoczynnikową analizę wariancji w celu przeanalizowania zmienności każdego wizualnego wskaźnika według grup wiekowych w czasie, a analiza statystyczna wykazała, że nieprzerwana jazda ma istotny wpływ na zmiany wskaźników wizualnych i zgłaszany poziom zmęczenia. Po 2 godzinach prowadzenia pojazdu, zarówno średnia wartość czasu zamknięcia, jak i średni subiektywny poziom zmęczenia uległy znacznej zmianie. Po 4 godzinach prowadzenia pojazdu, wszystkie wizualne wskaźniki kierowcy, inne niź średnia liczba ruchów gałek ocznych i średnia średnica źrenicy, uległy znaczącej zmianie. Z drugiej strony, zmiana poziomu zmęczenia jest dodatnio związana ze zmianą średnicy źrenicy, czasem skupienia wzroku, częstotliwościmrugania, czasem mrugania i czasem zamknięcia. Z drugiej strony, zmiana poziomu zmęczenia była ujemnie związana z ilością skupień wzroku, kątem poszukiwań, liczbą ruchu gałek ocznych, szybkością ruchu gałek ocznych i amplitudą ruchu gałek ocznych. Mówiąc dokładniej, ruch gałek ocznych kierowcy był bardziej czuły na poziom zmęczenia podczas jazdy, a u osób starszych występowało większe prawdopodobieństwo, że wpłynie to na długość jazdy w zmienności zachowań wizualnych i uczucie zmęczenia. W przypadku kierowców zawodowych, przepisy ruchu drogowego powinny ściśle kontrolować długość nieprzerwanej jazdy, a osoby starsze powinny zyskać więcej czasu na odpoczynek. Wreszcie, czynnik prognostyczny zmęczenia kierowcy został określony poprzez zmianę współczynnika wizualnych zmiennych, w celu wykrycia poziomu zmęczenia i ostrzegania w krytycznym momencie, w czasie rzeczywistym.
Źródło:
Archives of Civil Engineering; 2018, 64, 2; 175-185
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optymalizacja zależnego od stanu technicznego utrzymania urządzeń dla dwuskładnikowego systemu szeregowego nie wymagająca z góry ustalonej struktury strategii
Condition-based Maintenance Optimisation without a Predetermined Strategy Structure for a Two-component Series System
Autorzy:
Zhang, Z.
Zhou, Y.
Sun, Y.
Ma, L.
Powiązania:
https://bibliotekanauki.pl/articles/301595.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
semimarkowski proces decyzyjny
condition-based maintenance
system wieloskładnikowy
semi-Markov decision process
multi-component system
Opis:
Większość badań nad optymalizacją utrzymania systemów wieloskładnikowych bierze pod uwagę jedynie rozkład czasu życia elementów składowych. Kiedy przyjmie się dla systemów wieloskładnikowych strategię utrzymania urządzeń zależną od ich bieżącego stanu technicznego (condition-based maintenance, CBM), struktura strategii staje się złożona w związku z dużą liczbą stanów składowych oraz ich kombinacji. W konsekwencji, często przyjmuje się pewne z góry ustalone struktury strategii utrzymania przed optymalizacją utrzymania systemu wieloskładnikowego w kontekście CBM. Opracowanie takich z góry ustalonych struktur strategii wymaga jednak specjalistycznego doświadczenia, a i tak brak dowodów na optymalność tych strategii. W artykule zaproponowano metodę optymalizacji utrzymania szeregowego systemu dwuskładnikowego, która nie wymaga wcześniej ustalonej struktury strategii. Proponowaną metodę opracowano na podstawie semimarkowskiego procesu decyzyjnego (SMDP). Badanie symulacyjne pokazało, że za pomocą proponowanej metody można ustalać optymalną strategię utrzymania w sposób adaptacyjny dla różnych kosztów utrzymania oraz parametrów procesów degradacyjnych. Za pomocą symulacji badano także optymalną strukturę strategii utrzymania, jako punkt odniesienia dla przyszłych studiów nad optymalizacją systemów wieloskładnikowych.
Most existing research on maintenance optimisation for multi-component systems only considers the lifetime distribution of the components. When the condition-based maintenance (CBM) strategy is adopted for multi-component systems, the strategy structure becomes complex due to the large number of component states and their combinations. Consequently, some predetermined maintenance strategy structures are often assumed before the maintenance optimisation of a multicomponent system in a CBM context. Developing these predetermined strategy structure needs expert experience and the optimality of these strategies is often not proofed. This paper proposed a maintenance optimisation method that does not require any predetermined strategy structure for a two-component series system. The proposed method is developed based on the semi-Markov decision process (SMDP). A simulation study shows that the proposed method can identify the optimal maintenance strategy adaptively for different maintenance costs and parameters of degradation processes. The optimal maintenance strategy structure is also investigated in the simulation study, which provides reference for further research in maintenance optimisation of multi-component systems.
Źródło:
Eksploatacja i Niezawodność; 2012, 14, 2; 120-129
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on the Mechanical Properties and Curing Networks of Energetic GAP/TDI Binders
Autorzy:
Ma, S.
Li, Y.
Li, G.
Luo, Y.
Powiązania:
https://bibliotekanauki.pl/articles/358300.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
glycidyl azide polymer (GAP)
curing networks
hydrogen bonding
entanglement
integrity
Opis:
This research focused on correlations between the macroscopic mechanical performance and microstructures of energetic binders. Initially a series of glycidyl azide polymer (GAP)/toluene diisocyanate (TDI) binders, catalyzed by a mixture of dibutyltin dilaurate (DBTDL) and triphenyl bismuth (TPB), was prepared. Uniaxial tensile testing, and low-field nuclear magnetic resonance and infrared spectroscopy were then used to investigate the mechanical properties, curing networks, and hydrogen bonding (H-bonds) of these binders. Additionally, a novel method based on the molecular theory of elasticity and the statistical theory of rubber elasticity was used to analyze the integrity of the networks. The results showed that the curing parameter R strongly influences the mechanical properties and toughness of the binders, and that a tensile stress (σm) of 1.6 MPa and an elongation (εm) of 1041% was observed with an R value of 1.6. The cross-linking density increased sharply with the curing parameter, but only modestly with an R value ≥ 1.8. The proportion of H-bonds formed by the imino groups increased with the R value and reached 72.61% at an R value of 1.6, indicating a positive correlation between the H-bonds and σm. Molecular entanglement was demonstrated to increase with R and to contribute dramatically to the mechanical performance. The integrity of these networks, evaluated by a correction factor (A), varies with R, and a network of the GAP/TDI binder with an R value of 1.6 is desirable.
Źródło:
Central European Journal of Energetic Materials; 2017, 14, 3; 708-725
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Case study of developing an integrated water and nitrogen scheme for agricultural system on the North China Plain
Autorzy:
Liu, Y.
Tao, F.
Lao, Y.
Ma, J.
Powiązania:
https://bibliotekanauki.pl/articles/25700.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Opis:
Appropriate irrigation and nitrogen fertilization, along with suitable crop management strategies, are essential prerequisites for optimum yields in agricultural systems. This research attempts to provide a scientific basis for sustainable agricultural production management for the North China Plain and other semi-arid regions. Based on a series of 72 treatments over 2003-2008, an optimized water and nitrogen scheme for winter wheat/summer maize cropping system was developed. Integrated systems incorporating 120 mm of water with 80 kg N ha-1 N fertilizer were used to simulate winter wheat yields in Hebei and 120 mm of water with 120 kg N ha-1 were used to simulate winter wheat yields in Shandong and Henan provinces in 2000-2007. Similarly, integrated treatments of 40 kg N ha-1 N fertilizer were used to simulate summer maize yields in Hebei, and 80 kg N ha-1 was used to simulate summer maize yields in Shandong and Henan provinces in 2000-2007. Under the optimized scheme, 341.74 107 mm ha-1 of water and 575.79 104 Mg of urea fertilizer could be saved per year under the wheat/maize rotation system. Despite slight drops in the yields of wheat and maize in some areas, water and fertilizer saving has tremendous long-term eco-environmental benefits.
Źródło:
International Agrophysics; 2013, 27, 4
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New bizarre micro-spiriferid brachiopod from the Early Carboniferous of China
Autorzy:
Sun, Y
Balinski, A.
Ma, X.
Zhang, Y.
Powiązania:
https://bibliotekanauki.pl/articles/22087.pdf
Data publikacji:
2004
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Carboniferous
verneuiliid brachiopod
brachiopod
China
Muhua Formation
Verneuiliidae
Early Carboniferous
Brachiopoda
Changshunella yangi
paleontology
Opis:
The verneuiliid brachiopod Changshunella yangi gen. et sp. nov. is described from the Early Carboniferous Muhua Formation of Guizhou, China. This rather unusual form is characterized by having very small shell dimensions (2.6–4 mm in length), a very high flat procline ventral interarea, and by having three prominent plications on both valves that are arranged in opposed folding; the last feature is characteristic for the family Verneuiliidae. We suggest that the family has been derived from an offshoot of the stock that produced the superfamilies Spiriferoidea, Paeckelmanelloidea, and Brachythyridoidea by developing opposed folding and loss of dental plates or dental adminicula as exemplified by Verneuilia and Changshunella gen. nov.
Źródło:
Acta Palaeontologica Polonica; 2004, 49, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A novel process of dye wastewater treatment by linking advanced chemical oxidation with biological oxidation
Autorzy:
Zou, H.
Ma, W.
Wang, Y.
Powiązania:
https://bibliotekanauki.pl/articles/204846.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
dye wastewater
Fenton's oxidation
biological oxidation
biological aerated filter
advanced oxidation processes
Opis:
Dye wastewater is one of typically non-biodegradable industrial effluents. A new process linking Fenton’s oxidation with biological oxidation proposed in this study was investigated to degrade the organic substances from real dye wastewater. During the combination process, the Fenton’s oxidation process can reduce the organic load and enhance biodegradability of dye wastewater, which is followed by biological aerated filter (BAF) system to further remove organic substances in terms of discharge requirement. The results showed that 97.6% of chemical oxygen demand (COD) removal by the combination process was achieved at the optimum process parameters: pH of 3.5, H22
Źródło:
Archives of Environmental Protection; 2015, 41, 4; 33-39
2083-4772
2083-4810
Pojawia się w:
Archives of Environmental Protection
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of waste heat recovery systems on energy efficiency improvement of a heavy-duty diesel engine
Autorzy:
Ma, Z.
Chen, H.
Zhang, Y.
Powiązania:
https://bibliotekanauki.pl/articles/240819.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
energy efficiency design index
energy efficiency operational indicator
waste heat recovery system
performance analysis
reduction factor
wskaźnik efektywności energetycznej
wskaźniki eksploatacyjny efektywności energetycznej
system odzysku ciepła odpadowego
analiza wydajności
współczynnik redukcyjny
Opis:
The increase of ship’s energy utilization efficiency and the reduction of greenhouse gas emissions have been high lightened in recent years and have become an increasingly important subject for ship designers and owners. The International Maritime Organization (IMO) is seeking measures to reduce the CO2 emissions from ships, and their proposed energy efficiency design index (EEDI) and energy efficiency operational indicator (EEOI) aim at ensuring that future vessels will be more efficient. Waste heat recovery can be employed not only to improve energy utilization efficiency but also to reduce greenhouse gas emissions. In this paper, a typical conceptual large container ship employing a low speed marine diesel engine as the main propulsion machinery is introduced and three possible types of waste heat recovery systems are designed. To calculate the EEDI and EEOI of the given large container ship, two software packages are developed. From the viewpoint of operation and maintenance, lowering the ship speed and improving container load rate can greatly reduce EEOI and further reduce total fuel consumption. Although the large container ship itself can reach the IMO requirements of EEDI at the first stage with a reduction factor 10% under the reference line value, the proposed waste heat recovery systems can improve the ship EEDI reduction factor to 20% under the reference line value.
Źródło:
Archives of Thermodynamics; 2017, 38, 3; 63-75
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Performance optimization of organic Rankine cycles for waste heat recovery for a large diesel engine
Autorzy:
Ma, Z.
Wu, J.
Zhang, Y.
Powiązania:
https://bibliotekanauki.pl/articles/240064.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
low grade waste heat
organic rankine cycle
thermodynamic optimization
thermoeconomic optimization
intelligent marine diesel engine
organiczny obieg Rankine'a
optymalizacja termodynamiczna
optymalizacja termoekonomiczna
Opis:
In order to recover the low grade waste heat and increase system fuel economy for main engine 10S90ME-C9.2-TII(part load, exhaust gas bypass) installed on a 10000 TEU container ship, a non-cogeneration and single-pressure type of waste heat recovery system based on organic Rankine cycle is proposed. Organic compound candidates appropriate to the system are analyzed and selected. Thermodynamic model of the whole system and thermoeconomic optimization are performed. The saturated organic compound vapor mass flow rate, net electric power output, pinch point, thermal efficiency and exergy efficiency varied with different evaporating temperature are thermodynamically analyzed. The results of thermodynamic and thermoeconomic optimization indicate that the most appropriate organic compound candidate is R141b due to its highest exergy efficiency, biggest unit cost benefit and shortest payback time.
Źródło:
Archives of Thermodynamics; 2018, 39, 1; 3-23
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on Underwater Explosive Welding of Al-Steel Coaxial Pipes
Autorzy:
Yu, Y.
Ma, H.
Zhao, K.
Shen, Z.
Cheng, Y.
Powiązania:
https://bibliotekanauki.pl/articles/358620.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
metal-matrix composites
explosive welding
surface ablation
microstructures
bonding interface
Opis:
In order to solve the aluminum surface ablation issue of Al-Steel bimetallic pipes manufactured by the explosive welding technique, a novel explosive welding system has been designed to weld Al-Steel coaxial pipes. The stand-off distance was chosen according to an empirical formula. A special Explosive Cord with an aluminum coating was used as the explosive. Four experiments were performed using Explosive Cords 1, 2, 3 and 4, respectively. In each experiment, three reliable PVDF (Polyvinylidene Fluoride) piezoelectric film sensors were used to sample the impact pressure between the parent pipe and the flyer pipe along the detonation direction. p-t Curves were obtained at different points on the bimetallic pipe manufactured by Explosive Cord 1. In order to observe the inner surface and to judge the bonding interface, specimens were cut along the axial direction. BSE (Backscattering Electron) images of the interfaces were obtained. According to these pictures from all of the specimens cut along the axial direction, the surface ablation phenomenon has disappeared. The bimetallic pipe manufactured by the new welding system using Explosive Cord 3 has an irregular wavy interface, between micro and small wavy interface, which is one of the best bonding forms.
Źródło:
Central European Journal of Energetic Materials; 2017, 14, 1; 251-265
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical simulations of linearly stratified flow past submerged bodies
Autorzy:
Ma, W.
Li, Y.
Ding, Y.
Hu, K.
Lan, L.
Powiązania:
https://bibliotekanauki.pl/articles/259150.pdf
Data publikacji:
2018
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
stratified flow
circular cylinder
internal wave
Suboff
equation of state
Opis:
In this study, a methodology was presented to predict density stratified flows in the near-field of submerged bodies. The energy equation in temperature form was solved coupled with momentum and mass conservation equations. Linear stratification was achieved by the definition of the density as a function of temperature. At first, verifications were performed for the stratified flows passing a submerged horizontal circular cylinder, showing excellent agreement with available experimental data. The ability of the method to cope with variable density was demonstrated. Different turbulence models were used for different Re numbers and flow states. Based on the numerical methods proposed in this paper, the stratified flow was studied for the real scale benchmark DAPRA Suboff submarine. The approach used the VOF method for tracing the free surface. Turbulence was implemented with a k − ω based Detached Eddy Simulation (DES) approach. The effects of submarine speed, depth and density gradient on the free surface wave pattern were quantitatively analyzed. It was shown that, with the increasing of the speed of the submarine, the wavelength and wave height of the free surface wave were gradually increasing. The wave height of the free surface wave was gradually reduced as the submarine’s depth increased. Relative to the speed and submarine depth, the changes of the gradient density gradient have negligible effects on the free surface wave field.
Źródło:
Polish Maritime Research; 2018, S 3; 68-77
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Control system design for multi-rotor MAV
Autorzy:
Wang, W.
Ma, H.
Sun, C.-Y.
Powiązania:
https://bibliotekanauki.pl/articles/280407.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
MAV
attitude control
altitude control
LQG
memory based control
Opis:
Abstract MAVs (Micro Air Vehicles) have attracted more and more attention in recent years because of their wide applications, such as investigations of inhospitable environment, nuclear or hazardous material polluted regions and other inaccessible areas. In this paper, both attitude and altitude controls of a Quad-Rotor type MAV are discussed and analyzed. To stabilize the attitude, one order memory based controller is selected, the performance of which is independent of the detail model information, leading to enhanced robustness. While for the altitude, a Linear Quadratic Gaussian (LQG) controller is proposed. The experimental results of the real flight demonstrate the stability and robustness of the controllers.
Źródło:
Journal of Theoretical and Applied Mechanics; 2013, 51, 4; 1027-1038
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prognozowanie trwałości środków technicznych z wykorzystaniem wielu wskaźników degradacji i zdarzeń awaryjnych w ujęciu modelu ciągłej przestrzeni stanów
Asset life prediction using multiple degradation indicators and failure events: a continuous state space model approach
Autorzy:
Zhou, Y.
Ma, L.
Mathew, J.
Sun, Y.
Wolff, R.
Powiązania:
https://bibliotekanauki.pl/articles/301478.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
prognozowanie trwałości środków
model degradacji
algorytm maksymalizacji wartości oczekiwanej
model przestrzeni stanów
asset life prediction
degradation model
expectation-maximisation algorithm
state space model
Opis:
Prognozowanie trwałości środków z wykorzystaniem wskaźników degradacji wiąże się z dwoma zagadnieniami praktycznymi:(1) identyfikacją progów niepewnego uszkodzenia dla wskaźników degradacji oraz (2) łączeniem licznych wskaźników degradacji otrzymanych na podstawie danych z monitorowania stanu. Model degradacji w przestrzeni stanów stanowi efektywne podejście do tych dwóch zagadnień. Jednakże dotychczasowe badania dotyczące tego modelu w dużej mierze przyjmują założenie dyskretnego czasu lub dyskretnych stanów, które wymaga równych odstępów między przeglądami lub dyskretyzacji ciągłych wskaźników degradacji. Aby uniknąć konieczności zakładania dyskretnego czasu i dyskretnych stanów, w niniejszej pracy zaproponowano model przestrzeni stanów oparty na procesie Gamma. Proces Gamma charakteryzuje własność monotoniczna rosnącą, która odpowiada nieodwracalnym procesom degradacji środków technicznych w trakcie jednego cyklu serwisowego. Własność monotoniczna rosnąca ułatwia również ustalenie funkcji prawdopodobieństwa, gdy brane są pod uwagę czasy uszkodzeń. W artykule sformułowano algorytmy estymacji parametrów oraz prognozowania czasu życia dla modelu przestrzeni stanów opartego na procesie Gamma. Dodatkowo określono metodę oceny efektywności wskaźników w modelowaniu degradacji. Proponowany model przestrzeni stanów oparty na procesie Gamma oraz jego algorytmy weryfikowano przy użyciu danych symulacyjnych oraz danych terenowych pozyskanych z przedsiębiorstwa zajmującego się ciekłym gazem ziemnym.
Two practical issues are involved in asset life prediction using degradation indicators: (1) identifying uncertain failure thresholds of degradation indicators and (2) fusing multiple degradation indicators extracted from condition monitoring data. The state space degradation model provides an effective approach to address these two issues. However, existing research on the state space degradation model largely adopts a discrete time or states assumption which requires equal inspection intervals or discretising continuous degradation indicators. To remove the discrete time and states assumptions, this paper proposes a Gamma-based state space model. The Gamma process has a monotonically increasing property that is consistent with the irreversible degradation processes of engineering assets within a single maintenance cycle. The monotonically increasing property also makes the establishment of the likelihood function more straightforward when failure times are considered. In this paper, parameter estimation and lifetime prediction algorithms for the Gamma-based state space model are developed. In addition, an effectiveness evaluation approach for indicators in degradation modelling is established. The proposed Gamma-based state space model and algorithms are validated using both simulated data and a field dataset from a liquefied natural gas company.
Źródło:
Eksploatacja i Niezawodność; 2009, 4; 72-81
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Range Identification for a Perspective Dynamic System with a Single Homogeneous Observation
Autorzy:
Ma, L.
Chen, Y.
Moore, K. L.
Powiązania:
https://bibliotekanauki.pl/articles/908492.pdf
Data publikacji:
2005
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
system identyfikacji
układ dynamiczny
obserwator nieliniowy
range identification
perspective dynamic systems
nonlinear observer
Opis:
Perspective problems arise in machine vision when using a camera to observe the scene. Essential problems include the identification of unknown states and/or unknown parameters from perspective observations. Range identification is used to estimate the states/positions of a moving object with known motion parameters. Range estimation has been discussed in the literature using nonlinear observers with full homogeneous observations derived from the image plane. In this paper, the same range identification problem is discussed with a single homogeneous observation using nonlinear observers. Our simulation results verify the convergence of the observers when their observability conditions are satisfied.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2005, 15, 1; 63-72
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Early and Middle Frasnian brachiopod faunas and turnover on the South China shelf
Autorzy:
Ma, X -P
Becker, R.T.
Li, H.
Sun, Y.-Y.
Powiązania:
https://bibliotekanauki.pl/articles/21029.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Early Frasnian
Middle Frasnian
Frasnian
paleontology
brachiopod fauna
South China shelf
Devonian
Brachiopoda
Cyrtospirifer
faunal turnover
Opis:
The first appearance of the brachiopod Cyrtospirifer and related forms in the Late Devonian of South China significantly postdates the beginning of the Frasnian and the entry of the group in other parts of the world. Scattered data from different sections suggest that its first entry, associated with the emergence of other plicate spiriferids, such as theodossid and conispiriferid brachiopods, was late in the Middle Frasnian. At the same time, many rhynchonellids disappeared or became extinct locally in South China. This brachiopod faunal overturn near the Palmatolepis punctata–Early Pa. hassi zonal boundary is the most significant event in the Early–Middle Frasnian of South China, characterized by about a 35% loss of existing species and the flourishing of the plicate spiriferids, which was coeval with the end of a major biogeochemical perturbation recently recognized in the Pa. punctata Zone. By contrast, atrypid brachiopods do not seem to show any significant diversity change. The brachiopod faunal change was probably related to a (local?) transgressive event in South China, which also brought new pelagic faunas northwards into some intra−shelf deeper water areas, such as the Shetianqiao area in central Hunan Province. Fifteen brachiopod species are described and illustrated, which include some taxa that are first recorded or recognized in South China, e.g., the spiriferid Pyramidaspirifer, which is now known from both North America and South China. One new species, Desquamatia qiziqiaoensis, is erected.
Źródło:
Acta Palaeontologica Polonica; 2006, 51, 4; 789-812
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Strong Laser Field Induced Modifications of Electron-Transfer Processes in Ne⁺-He Collisions
Autorzy:
Lu, Z.
Sun, Y.
Ma, L.
Liu, J.
Powiązania:
https://bibliotekanauki.pl/articles/1032308.pdf
Data publikacji:
2017-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
32.70.Jz
34.50.-s
Opis:
A strong laser field ( ≈ 10¹⁵ W/cm²) induced low-collisional-energy charge transfer process in Ne⁺-He system is explored. In the low collisional energy regime, the cross-section can be ≈ 10¯¹⁷ cm² which is about two orders of magnitude higher than the collision-only process. With increasing collisional energy the cross-section curve displays flattens and the charge capture tends to be practically independent of the laser detuning. In addition, we find that the capture probability in this Ne⁺-He system varies significantly with the laser polarization angle.
Źródło:
Acta Physica Polonica A; 2017, 131, 6; 1519-1524
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Laser Induced Quadrupole-Dipole Collisional Energy Transfer in Ca-Sr
Autorzy:
Lu, Z.
Sun, Y.
Ma, L.
Liu, J.
Powiązania:
https://bibliotekanauki.pl/articles/1400504.pdf
Data publikacji:
2015-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
32.70.Jz
34.50.-s
Opis:
A laser induced quadrupole-dipole collisional energy transfer system of Ca-Sr is proposed and the four-state quadrupole-dipole laser induced collisional energy transfer model is presented. The excitation spectrum calculated for the Ca-Sr system is characterized by a doublet structure and a width which is about twice wider than the dipole-dipole laser induced collisional energy transfer results. Calculating results show that the full width at half peak of the profile becomes larger and the quasi-static wing tends to be a broad flat as the field intensity increases, which are different from the reported results of dipole-dipole laser induced collisional energy transfer processes, dipole-quadrupole and quadrupole-quadrupole. A cross-section of $2.48 \times 10^{-14} cm^{2}$ at a laser field intensity of $5.21 \times 10^{7}$ V/m is obtained which indicates that the quadrupole-dipole process can be an effective way to transfer energy selectively.
Źródło:
Acta Physica Polonica A; 2015, 127, 6; 1620-1624
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rugose corals and brachiopods across the Frasnian-Famennian boundary in Central Hunan, South China
Autorzy:
Ma, X
Sun, Y.
Hao, W.
Liao, W.
Powiązania:
https://bibliotekanauki.pl/articles/21047.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
fossil distribution
brachiopod fauna
brahiopod
Rugosa
China
rugose coral
Ostracoda
Brachiopoda
Famennian
Frasnian
Devonian
extinction
coral
paleontology
Hunan
Opis:
We present taxonomic revision of rugose corals and brachiopods from several Frasnian–Fammenian (F–F) boundary sections in central Hunan Province, China. Diversity of shallow−water rugose corals gradually increased during the Frasnian, but ended with sudden extinction near the end of Frasnian. Ostracods were abundant during the Frasnian; their extinction coincided with anoxic deposition of the end−Frasnian black shale deposits. The early Famennian ostracod fauna is of low diversity. The brachiopod fauna of the late Frasnian (Palmatolepis rhenana and Pa. linguiformis zones) is dominated by atrypids, small−sized cyrtospiriferids, and the rhynchonellid Hunanotoechia. All atrypids disappeared before the F–F boundary with highest rates of extinction below the boundary (probably low in the Pa. linguiformis Zone). The Frasnian cyrtospiriferid fauna is also of low diversity and dominated by small taxa. All but one of the cyrtospiriferid taxa crossed the F–F boundary. The early Famennian post−extinction recovery brachiopod fauna was the result of rapid radiation of new forms shortly after the terminal Frasnian event. The early Famennian fauna is characterized by diverse cyrtospiriferids, abundant Yunnanellina and productoids. Above the early recovery fauna another fauna was recovered, with brachiopods Hunanospirifer and Yunnanella and is correlated with the late or latest Pa. crepida Zone. Sinalosia rugosa gen. et sp. nov. (Productida) is erected.
Źródło:
Acta Palaeontologica Polonica; 2002, 47, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An optimization approach to the intermodal transportation network in fruit cold chain, considering cost, quality degradation and carbon dioxide footprint
Autorzy:
Ma, Q.
Wang, W.
Peng, Y.
Song, X.
Powiązania:
https://bibliotekanauki.pl/articles/260179.pdf
Data publikacji:
2018
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
intermodal transport network
quality model
refrigerated container
fruit cold chain
integer linear programming
Opis:
This model optimizes port hinterland intermodal refrigerated container flows , considering both cost and quality degradation, which is distinctive from the previous literature content in a way that it quantifies the influence of carbon dioxide (CO2) emission in different setting temperature on intermodal network planning. The primary contribution of this paper is that the model is beneficial not only to shippers and customers for the novel service design, but also offer , for policy-makers of the government, insights to develop inland transport infrastructures in consideration of intermodal transportation. The majority of models of multimodal system have been established with an objective of cost minimization for normal commodities. As the food quality is possible to be influenced by varying duration time required for the storage and transportation, and transportation accompanied with refrigeration producing more CO2 emission, this paper aims to address cost minimization and quality degradation minimization within the constraint of CO2 footprint. To achieve this aim, we put the quality degradation model in a mixed-integer linear programming model used for intermodal network planning for cold chain. The example of Dalian Port and Yingkou Port offer insight into trade-offs between transportation temperature and transport mode considering CO2 footprint. Furthermore, the model can offer a useful reference for other regions with the demand for different imported food, which requires an uninterrupted cold chain during the transportation and storage.
Źródło:
Polish Maritime Research; 2018, 1; 61-69
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On a New Approach to SNR Estimation of BPSK Signals
Autorzy:
Moazzeni, T.
Amei, A.
Ma, J.
Jiang, Y.
Powiązania:
https://bibliotekanauki.pl/articles/227148.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
digital communication
statistical analysis
AWGN channels
Opis:
Signal-to-noise ratio (SNR) information is required in many communication receivers and their proper operation is, to a large extent, related to the SNR estimation techniques they employ. Most of the available SNR estimators are based on approaches that either require large observation length or suffer from high computation complexity. In this paper, we propose a low complexity, yet accurate SNR estimation technique that is sufficient to yield meaningful estimation for short data records. It is shown that our estimator is fairly close to the (CRLB) for high SNR values. Numerical results also confirm that, in terms of convergence speed, the proposed technique outperforms the popular moment based method, M2M4.
Źródło:
International Journal of Electronics and Telecommunications; 2012, 58, 3; 273-278
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Flotation behavior of nickel sulfide ore in a cyclonic flotation column
Autorzy:
Deng, L.
Li, G.
Cao, Y.
Ma, Z.
Powiązania:
https://bibliotekanauki.pl/articles/109906.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
cyclonic flotation column
floatability
flotation
nickel sulfide ore
Opis:
This study aimed to show the flotation behavior of a nickel sulfide ore in a cyclonic flotation column. The flotation experiments were carried out using a sample of nickel sulfide ore obtained from a mineral processing plant of China. Representative samples collected from the feed, concentrate, tailing, and circulation middling were sieved using a cyclonic particle analyzer to collect different size fractions for analysis. The function of the column cyclonic zone of was evaluated by comparing the quality of tailing and circulation middling. The flotation results showed that the concentrate with Ni grade of 1.78% and recovery of 65.56% was obtained under given test conditions. The content of main sulfide minerals and coarse particles in the circulation middling was higher than that in the tailing. The results indicated that, unlike conventional cyclone classification, separation achieved in the cyclonic zone of the column was not dependent on the particle size and density. Sulfide minerals with good floatability were easily captured by bubbles and moved toward the center of the column, even if these particles were coarser and heavier.
Źródło:
Physicochemical Problems of Mineral Processing; 2017, 53, 2; 770-780
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Facile Synthesis of 3,3'-Dinitro-5,5'-diamino-bi-1,2,4-triazole and a Study of Its Thermal Decomposition
Autorzy:
Ma, Q.
Lu, H.
Qu, Y.
Liao, L.
Li, J.
Fan, G.
Chen, Y.
Powiązania:
https://bibliotekanauki.pl/articles/358272.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
3,3’-dinitro-5,5’-diamino-bi-1,2,4-triazole
facile synthesis
DSC-TG
RSFTIR
TG-IR
thermolysis
Opis:
3,3’-Dinitro-5,5’-diamino-bi-1,2,4-triazole (DABNT) was synthesized by a facile method and its crystalline density was determined as 1.839 g·cm−3 at 293(2) K by X-ray diffraction. Its thermal decomposition kinetics and mechanism were studied by means of differential scanning calorimetry-thermogravimetry (DCS-TG), in situ thermolysis by rapid-scan Fourier transform infrared spectroscopy (RSFTIR) and simultaneous TG-IR technology. The results showed that the apparent activation energies obtained by the Kissinger, Ozawa and Starink methods were 122.9 kJ·mol−1, 123.2 kJ·mol−1 and 123.5 kJ·mol−1, respectively. The thermodynamic parameters of ΔS≠, ΔH≠ and ΔG≠ were −37.5 J·K−1·mol−1, 118.4 kJ·mol−1 and 138.7 kJ·mol−1, respectively. The decomposition reaction process of DABNT starts with the transformation from a primary amine to a secondary amine and then the loss of one nitro-group from the DABNT structure. Gaseous products, such as N2O and H2O, were detected from decomposition in the range of 50-300 °C. Density functional theory (DFT) calculations were further employed to illustrate the decomposition mechanism. The above-mentioned information on the synthesis and thermal behaviour is quite useful for the scale-up and evaluation of the thermal safety of DABNT.
Źródło:
Central European Journal of Energetic Materials; 2017, 14, 2; 281-295
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
De novo sequencing and comparative transcriptome analysis of white petals and red labella in Phalaenopsis for discovery of genes related to flower color and floral differentiation
Autorzy:
Yang, Y.
Wang, J.
Ma, Z.
Sun, G.
Zhang, C.
Powiązania:
https://bibliotekanauki.pl/articles/58306.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Botaniczne
Tematy:
sequencing
RNA sequence
transcriptome
Phalaenopsis
gene
flower
colour
floral differentiation
diversity
Opis:
Phalaenopsis is one of the world’s most popular and important epiphytic monopodial orchids. The extraordinary floral diversity of Phalaenopsis is a reflection of its evolutionary success. As a consequence of this diversity, and of the complexity of flower color development in Phalaenopsis, this species is a valuable research material for developmental biology studies. Nevertheless, research on the molecular mechanisms underlying flower color and floral organ formation in Phalaenopsis is still in the early phases. In this study, we generated large amounts of data from Phalaenopsis flowers by combining Illumina sequencing with differentially expressed gene (DEG) analysis. We obtained 37 723 and 34 020 unigenes from petals and labella, respectively. A total of 2736 DEGs were identified, and the functions of many DEGs were annotated by BLAST-searching against several public databases. We mapped 837 up-regulated DEGs (432 from petals and 405 from labella) to 102 Kyoto Encyclopedia of Genes and Genomes pathways. Almost all pathways were represented in both petals (102 pathways) and labella (99 pathways). DEGs involved in energy metabolism were significantly differentially distributed between labella and petals, and various DEGs related to flower color and floral differentiation were found in the two organs. Interestingly, we also identified genes encoding several key enzymes involved in carotenoid synthesis. These genes were differentially expressed between petals and labella, suggesting that carotenoids may influence Phalaenopsis flower color. We thus conclude that a combination of anthocyanins and/or carotenoids determine flower color formation in Phalaenopsis. These results broaden our understanding of the mechanisms controlling flower color and floral organ differentiation in Phalaenopsis and other orchids.
Źródło:
Acta Societatis Botanicorum Poloniae; 2014, 83, 3
0001-6977
2083-9480
Pojawia się w:
Acta Societatis Botanicorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A monospecific assemblage of terebratulide brachiopods in the Upper Cretaceous seep deposits of Omagari, Hokkaido, Japan
Autorzy:
Kaim, A.
Bitner, M.A.
Jenkins, R.G.
Hikida, Y.
Powiązania:
https://bibliotekanauki.pl/articles/22963.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
terebratulid brachiopod
brachiopod
Upper Cretaceous
Cretaceous
seep deposit
Omagari
Hokkaido
Japan
Brachiopoda
Chlidonophoridae
Eucalathis
Campanian
Mesozoic
Opis:
The Campanian (Upper Cretaceous) seep carbonate at Omagari (Hokkaido, Japan) yields a monospecific association of the terebratulide brachiopod Eucalathis methanophila Bitner sp. nov. The association is the only occurrence of brachiopods known from the post−Early Cretaceous history of chemosynthesis−based communities. Unlike many earlier rhynchonellide−dominated hydrocarbon seep associations—which disappeared in Aptian times—this association is composed of chlidonophorid terebratulides. It is hypothesised here that large rhynchonellide brachiopods have been outcompeted from chemosynthesis−based associations by large chemosymbiotic bivalves (especially lucinids) and that this seep association containing numerous terebratulide brachiopods originated as a result of immigration from the background fauna settling in a seep that lacked numerous large bivalves but offered some hard substrates for brachiopod attachment. Some living chlidonophorids are known to settle around seep/vent localities or more generally in deep−water hard−substrate settings. We review occurrences of brachiopods in chemosynthesis−based associations and show that brachiopods immigrated repeatedly to seep/vent environments. Eucalathis methanophila Bitner sp. nov. represents the oldest and single Mesozoic record of the genus. The new species is similar in ornamentation to three living species, Indo−Pacific E. murrayi, eastern Atlantic E. tuberata, and Caribbean E. cubensis but differs in having a higher beak and wider loop. Additionally the studied species is nearly twice as large as E. tuberata.
Źródło:
Acta Palaeontologica Polonica; 2010, 55, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Role of dissolved mineral species in quartz flotation and siderite solubility simulation
Autorzy:
Luo, X.
Wang, Y.
Ma, M.
Song, S.
Zhang, Y.
Deng, J.
Liu, J.
Powiązania:
https://bibliotekanauki.pl/articles/109459.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
quartz
solubility
siderite
calcium ion
temperature
flotation
Opis:
Quartz is, in most cases, the major gangue mineral found in the iron ores. Although it can be activated by calcium at strong alkaline pH, quartz nevertheless, reports to the concentrate with Fe when the iron ores contain siderite. It causes a poor concentrate grade and separation between quartz and iron minerals. The effect of siderite on reverse anionic flotation of quartz from hematite was studied in our previous investigations. In this work, the effect of siderite dissolution on the quartz recovery in the froth product and the effect of pH, ions and temperature on siderite dissolution were investigated. Microflotation, PHREEQC simulation, solution chemistry calculation and Fourier transform infrared spectroscopy (FTIR) measurements were conducted. It was observed that the dissolved species of siderite exhibited negative impact on quartz flotation. This influence became weak to some extent by either stripping the dissolved species or shortening dissolution time. Siderite was easily dissolved in the presence of calcium ion under strong alkaline conditions and its solubility increased with increasing the calcium ion concentrate and temperature. When the calcium ion was added as an activator of quartz under strong alkaline conditions (pH>9.96), calcium existed mainly in the CaCO3 precipitation form according to the solubility rule in the presence of siderite. This form could adsorb onto quartz surfaces and further the chemical reaction between starch and quartz was monitored by FTIR measurements. This study provides a further supplement for previous study. A potential strategy is suggested that finding a collector used at low temperature or flotation under neutral (or weak alkaline) medium is helpful to the reverse flotation of iron ores containing siderite.
Źródło:
Physicochemical Problems of Mineral Processing; 2017, 53, 2; 1241-1254
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on electric spring control method considering noncritical load voltage constraint
Autorzy:
Chen, Y.
Ma, G.
Xu, U.
Zhang, H.
Ju, R.
Powiązania:
https://bibliotekanauki.pl/articles/140516.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
electric spring
noncritical load
voltage excursion
reactive power compensation
Opis:
With the increasing penetration rate of grid-connected renewable energy generation, the problem of grid voltage excursion becomes an important issue that needs to be solved urgently. As a new type of voltage regulation control method, electric spring (ES) can alleviate the fluctuations of renewable energy output effectively. In this paper, the background and basic principle of the electric spring are introduced firstly. Then, considering the influence of an electric spring on noncritical load voltage, noncritical loads are classified reasonably, and based on the electric spring phasor diagram, the control method to meet the noncritical load voltage constraint is proposed. This control method can meet the requirements of voltage excursions of different kinds of noncritical load, increase the connection capacity of the noncritical load and improve the voltage stabilization capacity of the electric spring. Finally, through the simulation case, the feasibility and validity of electric spring theory and the proposed control method are verified.
Źródło:
Archives of Electrical Engineering; 2018, 67, 4; 709-724
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on the impact of electric vehicle charging load on nodal voltage deviation
Autorzy:
Ma, G.
Jiang, L.
Chen, Y.
Dai, C.
Ju, R.
Powiązania:
https://bibliotekanauki.pl/articles/141119.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
distribution network
electric vehicle charging load (EVCL)
stochastic load
voltage deviation
Opis:
The promotion and application of electric vehicles will contribute to the solution of several problems, such as energy shortage and environmental pollution, and the achievement of country economy and energy security. But a large-scale vehicle-to-grid system may cause adverse effects in the distribution network operation, the power network planning and such other parts. First, this paper collects the factors that influence the electric vehicle charging load and establishes the EV charging load model with a Monte- Carlo method. Then, we analyze the effect that the EV charging load made on the nodal voltage deviation under different permeability based on the IEEE30 node system. At last, this research gets the conclusion that the nodal voltage deviation is closely related to EV permeability, node type and node location. This research conclusion will provide practical guidance to the charging station planning.
Źródło:
Archives of Electrical Engineering; 2017, 66, 3; 495-505
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
HGRP: hybrid grid routing protocol for heterogeneous hierarchical wireless networks
Autorzy:
Shen, Y.
Pei, Q.
Xu, Q.
Xi, N.
Ma, J.
Powiązania:
https://bibliotekanauki.pl/articles/206219.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
hybrid grid routing protocol
mobile ad hoc networks
heterogeneous wireless networks
ad hoc on-demand distance vector routing protocol
zone routing protocol
Opis:
The heterogeneous mobile terminals coexist in the next generation wireless networks. The most common routing schemes for mobile ad hoc networks are designed for homogeneous wireless networks. The heterogeneous wireless network routing protocols are needed urgently in many important applications. This paper improves the routing scheme utilizing different capability of terminals and the Hybrid Grid Routing Protocol (HGRP) is proposed. The network is organized in the grid form, that is, the network deployment area is divided into square cells according to the location. Each cell contains one backbone node and several ordinary nodes. This proposed protocol consists of four parts: grid construction, local routing, global routing, and routing correction. Analysis and simulation results indicate that the proposed protocol has the advantages of lower routing cost, lower energy consumption, smaller delay and higher throughput, compared to AODV and ZRP.
Źródło:
Control and Cybernetics; 2012, 41, 2; 353-371
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Energy feature of a multi-flow column flotation process
Autorzy:
Cheng, G.
Yu, Y.
Ma, L.
Xia, W.
Xu, H.
Powiązania:
https://bibliotekanauki.pl/articles/109768.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
flotation column
turbulent kinetic energy
turbulent dissipation rate
bubble
Opis:
A cyclonic-static micro-bubble flotation column (FCSMC) has been widely used in mineral separation. FCSMC includes countercurrent, cyclone and jet flow mineralization zones in a single column. In this study, the energy feature of the three different zones was compared. The turbulent flow was evaluated in terms of the turbulent kinetic energy (k) and the turbulent dissipation rate (ε). An appropriate computing model was determined by comparing the flow field value measured by PIV with the results of the Fluent numerical simulation. Jet flow separation exhibited the maximum k and ε values among the three columns, whereas counter-current separation displayed the minimum values. The high circulating volumetric flowrate means great energy input and turbulent intensity. The higher turbulent dissipation rate, the smaller the bubble is. The better performance of the FCSMC was mainly attributed to the multiple mineralization steps. The floatability of mineral particles gradually decreases with an increase in flotation time, the mineralization energy gradually increased to overcome the decrease in mineral floatability. By contrast, the countercurrent was beneficial for recovering the coarse particles, and the jet flow was beneficial for recovering the fine particles.
Źródło:
Physicochemical Problems of Mineral Processing; 2017, 53, 2; 1266-1284
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theoretical Profile of Ring-Spun Slub Yarn and its Experimental Validation
Teoretyczne oznaczenie geometrii fantazyjnej przędzy obrączkowej typu slub i weryfikacja eksperymentalna
Autorzy:
Ma, C Q
Zhou, B M
Liu, Y
Hu, C S
Powiązania:
https://bibliotekanauki.pl/articles/232346.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
slub yarn
mathematical model
slub profile
slub length
basic yarn length
przędza obrączkowa typu slub
model matematyczny
profil slub
długość slub
podstawowa długość przędzy
Opis:
A mathematical model for the yarn count of ring-spun slub yarn was established to predict the yarn profile based on process parameters such as the fibre length, the velocities of rollers and the time of over-feeding. The theoretical study shows that the slub length depends mostly on the process parameters above. The actual slub length is a fibre length greater than the slub length designed, and the actual length of basic yarn is a fibre length less than the length of basic yarn designed. The validity of the model was then verified using four sets of experiments. The experimental results agreed well with the model predictions and showed that the present model had high prediction accuracy, which may aid in the design and production of a desired slub yarn with controlling spinning parameters.
Model matematyczny masy liniowej przędzy obrączkowej typu slub został wyznaczony w celu określenia geometrii przędzy na podstawie parametrów procesu, takich jak długość włókien, prędkości rolek i wielkości naddatku. Badania teoretyczne wskazują, że długość odcinków przędzy typu slub zależy głównie od powyżej wymienionych parametrów procesu. W artykule podano właściwości zależności teoretycznych i rzeczywistych dla przędzy fantazyjnej. Prawidłowość tego modelu została następnie poddana weryfikacji przy użyciu cztery zestawów eksperymentalnych o zróżnicowanych warunkach. Wyniki badań eksperymentalnych potwierdziły przewidywania modelu i pokazały, że obecny model zapewnia wysoką dokładność przewidywania i dzięki temu ułatwia projektowanie i produkcję określonych włókien fantazyjnych.
Źródło:
Fibres & Textiles in Eastern Europe; 2013, 1 (97); 29-34
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Physical properties of unproductive soils of Northern China
Autorzy:
Malik, Z.
Malik, M.A.
Zong, Y.-T.
Lu, S.-G.
Powiązania:
https://bibliotekanauki.pl/articles/24211.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
unproductive soil
soil property
pH
organic matter content
surface area
tensile strength
shear strength
cracking
physical property
Northern China
China
Opis:
The general characteristics: particle size distribution, pH, cation exchange capacity, organic matter content, total NPK, surface area; and physical properties: coefficient of linear extensibility, tensile strength, shear strength and cracking, were investigated in unproductive soils of Northern China. Principle component analysis showed that tensile strength, cohesion, cracking characteristics, clay content, cation exchange capacity and coefficient of linear extensibility were positively correlated with each other, whereas negatively correlated with angle of friction, indicating that these properties were subjected to clay % and smectite content. These correlations might be mainly responsible for low productivity (low yields) in Northern China.
Źródło:
International Agrophysics; 2014, 28, 4
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Variation of leaf area index and leaf water potential of young dwarf apple trees under different irrigation methods
Autorzy:
Senyigir, U.
Dagdelen, N.
Askin, M.A.
Kadayifci, A.
Ucar, Y.
Powiązania:
https://bibliotekanauki.pl/articles/62620.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Infrastruktura i Ekologia Terenów Wiejskich PAN
Tematy:
yield
variation
leaf area index
leaf water potential
apple tree
dwarf apple tree
irrigation system
Opis:
In this research which was carried out inSuleymanDemirel University Research and Application Farm during 2007 and 2008 years, apple leaf area index (LAI) and leaf water potential (LWP) were observed in Jersey Mac (V1) and Williams Pride (V2) young apple varieties budded on M9 rootstock irrigated with different irrigation methods. Drip (D), subsurface drip (SD), surface (S) and undertree micro sprinkler (M) irrigation methods were used in the research. The amount of applied irrigation water was as much as 100% of Class A Pan evaporation measured during five days irrigation intervals. The amount of irrigation water was ranged between 348.3 (D, SD) – 1186 (S, M) mm depending on irrigation methods during the experimental years. Furthermore, maximum and minimum crop evapotranspiration values were determined as 426.1 (DV2) and 1334.7 (MV2) mm respectively. LAI values related to treatments ranged from 0.32 to 0.52 in 2007, 0.73 to 1.12 in 2008. LAI values increased by approximately 126.3% for all treatments. In both years, generally, the highest LAI values were observed in drip irrigation (D) for both varieties. Linear correlation (r=0.99, n=16) was obtained between fruit yields and leaf area index (LAI) values of the apple trees. Leaf water potential (LWP) measurements were repeated one day before and after irrigation during the irrigation period. The measurements were also conducted once along a day in the middle of the season. Changes in value of LWP were similar among the treatments.
Źródło:
Infrastruktura i Ekologia Terenów Wiejskich; 2013, 1/III
1732-5587
Pojawia się w:
Infrastruktura i Ekologia Terenów Wiejskich
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Motion prediction of catamaran with a semisubmersible bow in wave
Autorzy:
Sun, H.
Jing, F.
Jiang, Y.
Zou, J.
Zhuang, J.
Ma, W.
Powiązania:
https://bibliotekanauki.pl/articles/258596.pdf
Data publikacji:
2016
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
SSB catamaran
model test
overset grid
motion region
motion response
Opis:
Compared with standard vessels, a slender catamaran with a semi-submerged bow (SSB) demonstrates superior seakeeping performance. To predict the motion of an SSB catamaran, computational fluid dynamics methods are adopted in this study and results are validated through small-scale model tests. The pitch, heave, and vertical acceleration are calculated at various wavelengths and speeds. Based on the overset grid and motion region methods, this study obtains the motion responses of an SSB catamaran in regular head waves. The results of the numerical studies are validated with the experimental data and show that the overset grid method is more accurate in predicting the motion of an SSB catamaran; the errors can be controlled within 20%. The movement data in regular waves shows that at a constant speed, the motion response initially increases and then decreases with increasing wavelength. This motion response peak is due to the encountering frequency being close to the natural frequency. Under identical sea conditions, the motion response increases with the increasing Froude number. The motion prediction results, that derive from a shortterm irregular sea state, show that there is an optimal speed range that can effectively reduce the amplitude of motion.
Źródło:
Polish Maritime Research; 2016, 1; 37-44
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Water-exit process modeling and added-mass calculation of the submarine-launched missile
Autorzy:
Yang, J.
Feng, J.
Li, Y.
Liu, A.
Hu, J.
Ma, Z.
Powiązania:
https://bibliotekanauki.pl/articles/260251.pdf
Data publikacji:
2017
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
submarine-launched missile
fluid-structure interaction
water-exit dynamic model
time-varying added-mass
numerical simulation
Opis:
In the process that the submarine-launched missile exits the water, there is the complex fluid solid coupling phenomenon. Therefore, it is difficult to establish the accurate water-exit dynamic model. In the paper, according to the characteristics of the water-exit motion, based on the traditional method of added mass, considering the added mass changing rate, the water-exit dynamic model is established. And with help of the CFX fluid simulation software, a new calculation method of the added mass that is suit for submarine-launched missile is proposed, which can effectively solve the problem of fluid solid coupling in modeling process. Then by the new calculation method, the change law of the added mass in water-exit process of the missile is obtained. In simulated analysis, for the water-exit process of the missile, by comparing the results of the numerical simulation and the calculation of theoretical model, the effectiveness of the new added mass calculation method and the accuracy of the water-exit dynamic model that considers the added mass changing rate are verified.
Źródło:
Polish Maritime Research; 2017, S 3; 152-164
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of flow softening mechanisms of a nickel-based superalloy with o phase
Autorzy:
Lin, Y. C.
He, D.-G
Chen, M. S.
Chen, X.-M.
Zhao, C.-Y.
Ma, X.
Powiązania:
https://bibliotekanauki.pl/articles/958203.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
alloys
hot deformation
flow softening behavior
microstructural evolution
Opis:
The flow softening behaviors of a nickel-based superalloy with o phase are investigated by hot compression tests over wide ranges of deformation temperature and strain rate. Electron backscattered diffraction (EBSD). optical microscopy (OM), and scanning electron microscopy (SEM) are employed to study the flow softening mechanisms of the studied superalloy. It is found that the flow softening behaviors of the studied superalloy are sensitive to deformation temperature and strain rate. At high strain rate and low deformation temperature, the obvious flow softening behaviors occur. With the increase of deformation temperature or decrease of strain rate, the flow softening degree becomes weaken. At high strain rate (1s-1), the flow softening is mostly induced by the plastic deformation heating and flow localization. However, at low strain rate domains (0.001-0.01s-1), the effects of deformation heating on flow softening are slight. Moreover, the flow softening at low strain rates is mainly induced by the discontinuous dynamic recrystallization and the dissolution of 6 phase (Ni3Nb).
Źródło:
Archives of Metallurgy and Materials; 2016, 61, 3; 1537-1546
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamic electric vehicles charging load allocation strategy for residential area
Autorzy:
Wang, Y.
Ma, X.
Wang, F.
Hou, X.
Sun, H.
Zheng, K.
Powiązania:
https://bibliotekanauki.pl/articles/140939.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
electric vehicles
charging power management
allocation strategy
priority assessment
Opis:
A large amount of electric vehicles (EVs) charging load will bring significant impact to the power system. An appropriate resource allocation strategy is required for securing the power system safety and satisfying EVs charging demand. This paper proposed a power coordination allocation strategy of EVs’ in distribution systems. The strategy divides the allocation into two stages. The first stage is based on scores assigned to EVs through an entropy method, whereas the second stage allocates energy according to EV’s state of charge. The charging power is delivered in order to maximize EV users’ satisfaction and fairness without violation of grid constraints. Simulation on a typical power-limited residential distribution network proves the effectiveness of the strategy. The analysis results indicate that compared with traditional methods, EVs, which have higher charging requirement and shorter available time will get more energy delivered than others. The root-mean-square-error (RMSE) and standard-deviation (SD) results prove the effectiveness of the methodology for improving the balance of power delivery.
Źródło:
Archives of Electrical Engineering; 2018, 67, 3; 641--654
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Development of a rapid immunochromatographic assay for detection of antibodies against porcine epidemic diarrhea virus
Autorzy:
Li, R.
Ma, J.
Tian, X.
Yu, Y.
Qiao, S.
Wang, Z.
Powiązania:
https://bibliotekanauki.pl/articles/2087760.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
porcine epidemic diarrhea virus
immunochromatographic test strip
nucleocapsid protein
diagnosis
Źródło:
Polish Journal of Veterinary Sciences; 2018, 21, 1; 139-147
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-50 z 76

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