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    Wyświetlanie 1-31 z 31
    Tytuł:
    Fatigue and Corrosion Fatigue of 18Ni Maraging Steel
    Autorzy:
    Yongmei, Zhu
    Junjie, Chen
    Wenxian, Tang
    Weicheng, Cui
    Xiaorong, Wang
    Fang, Wang
    Baoji, Yin
    Powiązania:
    https://bibliotekanauki.pl/articles/2049558.pdf
    Data publikacji:
    2021
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    corrosion fatigue
    18Ni (250)
    loading frequency
    stress ratio
    3.5%NaCl solution
    Opis:
    This study focused on the fatigue and corrosion fatigue of maraging steel 18Ni (250). The 18Ni (250) samples were tested for axial fatigue in air and 3.5% NaCl solution. The effects of loading frequency and stress ratio on the fatigue strength of 18Ni (250) were studied. In air, the loading frequency was 10 Hz, and the stress ratio was 0.5. However, three loading methods were used in the 3.5% NaCl solution: (i) the loading frequency of 1 Hz and stress ratio of 0.5; (ii) the loading frequency of 1 Hz and stress ratio 0.1, and (iii) the loading frequency 5 Hz and stress ratio 0.5. The corrosion fatigue strength of samples in the 3.5% NaCl solution was 63.3% lower than that of the samples in air. The fractures in the samples were observed after the test.
    Źródło:
    Archives of Metallurgy and Materials; 2021, 66, 1; 321-330
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Fatigue and Corrosion Fatigue of 18Ni Maraging Steel
    Autorzy:
    Yongmei, Zhu
    Junjie, Chen
    Wenxian, Tang
    Weicheng, Cui
    Xiaorong, Wang
    Fang, Wang
    Baoji, Yin
    Powiązania:
    https://bibliotekanauki.pl/articles/2049667.pdf
    Data publikacji:
    2021
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    corrosion fatigue
    18Ni (250)
    loading frequency
    stress ratio
    3.5%NaCl solution
    Opis:
    This study focused on the fatigue and corrosion fatigue of maraging steel 18Ni (250). The 18Ni (250) samples were tested for axial fatigue in air and 3.5% NaCl solution. The effects of loading frequency and stress ratio on the fatigue strength of 18Ni (250) were studied. in air, the loading frequency was 10 Hz, and the stress ratio was 0.5. however, three loading methods were used in the 3.5% NaCl solution: (i) the loading frequency of 1 Hz and stress ratio of 0.5; (ii) the loading frequency of 1 Hz and stress ratio 0.1, and (iii) the loading frequency 5 Hz and stress ratio 0.5. The corrosion fatigue strength of samples in the 3.5% NaCl solution was 63.3% lower than that of the samples in air. The fractures in the samples were observed after the test.
    Źródło:
    Archives of Metallurgy and Materials; 2021, 66, 2; 381-390
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Research on sand resistance performance of comprehensive protection facilities for desert hinterland highways under strong wind environment
    Autorzy:
    Yan, Wenhua
    Wang, Xu
    Wu, Yongxiang
    Wang, Fang
    Powiązania:
    https://bibliotekanauki.pl/articles/2174072.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Opis:
    Based on the test and observation of the desert hinterland wind field, combined with the numerical simulation of Fluent wind-sand two-phase flow, the sand resistance performances of comprehensive protection in the desert hinterland under strong wind environment are researched. The transient wind speed and wind direction around the comprehensive protection facility are measured by two 3D ultrasonic anemometers on the highway in the desert hinterland, and the initial wind speed of the sand flow is provided for the numerical simulation boundary. The sedimentary sand particles around the comprehensive protection facility are collected for particle size analysis, and the particle size distributions of sedimentary sand particles at different locations are obtained. Numerical models of high vertical sand barriers, grass checkered sand barriers and roadbeds are established by Fluent, the wind-sand flow structures around the comprehensive protection facilities and desert hinterland highway under the strong wind environment are obtained, and the influence laws of the comprehensive protection facilities on the movement of wind-sand flow and sand deposition characteristics are obtained. The study found that the comprehensive protection facilities disturbed the wind and sand flow, and there are significant airflow partitions around the comprehensive protection facilities. The wind speed decreases rapidly after the wind-sand flows through the high vertical sand barrier; the wind-sand flow rises at the end of the high vertical sand barrier. When the wind-sand flow moves around the grass checkered sand barrier, the wind speed has dropped to the range of 0-3 m/s, and the wind speed near the ground by the grass checkered sand barrier is further reduced. Due to the existence of the concave surface of the grass grid, there are small vortices inside the grass grid sand barrier. Large sand particles are mainly deposited on the windward side and inside of high vertical sand barriers. The grass checkered sand barrier forms a stable concave surface to generate backflow, which can ensure that the sand surface does not sand itself in a strong wind environment, and can also make a small amount of sand carried in the airflow accumulate around the groove of the grass checkered sand barrier. The numerical simulation results are consistent with the measured results, and the comprehensive protection measures have achieved good sand control effects.
    Źródło:
    Archives of Civil Engineering; 2022, 68, 4; 683--698
    1230-2945
    Pojawia się w:
    Archives of Civil Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Low-Complexity Non-uniform Constellation Demapping Algorithm for Broadcasting System
    Autorzy:
    Wang, Chen
    Wang, Fang
    Li, Mingqi
    Tian, Jinfeng
    Powiązania:
    https://bibliotekanauki.pl/articles/226497.pdf
    Data publikacji:
    2019
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    non-uniform constellation
    soft demapping
    complexity
    QAM
    NGB-W
    Opis:
    This paper presents a novel low-complexity soft demapping algorithm for two-dimensional non-uniform spaced constellations (2D-NUCs) and massive order one-dimensional NUCs (1D-NUCs). NUCs have been implemented in a wide range of new broadcasting systems to approach the Shannon limit further, such as DVB-NGH, ATSC 3.0 and NGB-W. However, the soft demapping complexity is extreme due to the substantial distance calculations. In the proposed scheme, the demapping process is classified into four cases based on different quadrants. To deal with the complexity problem, four groups of reduced subsets in terms of the quadrant for each bit are separately calculated and stored in advance. Analysis and simulation prove that the proposed demapper only introduces a small penalty under 0.02dB with respect to Max-Log-MAP demapper, whereas a significant complexity reduction ranging from 68.75% to 88.54% is obtained.
    Źródło:
    International Journal of Electronics and Telecommunications; 2019, 65, 3; 413-420
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Virtual–real fusion maintainability verification based on adaptive weighting and truncated spot method
    Autorzy:
    Ge, Zhexue
    Zhang, Yi
    Wang, Fang
    Luo, Xu
    Yang, Yongmin
    Powiązania:
    https://bibliotekanauki.pl/articles/2200935.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
    Tematy:
    virtual–real fusion maintainability
    maintainability verification
    adaptive weighting method
    truncated SPOT method
    Opis:
    Maintainability is an important general quality characteristic of products. Insufficient maintainability will lead to long maintenance time and high maintenance cost, thus affecting the availability of products. Maintainability verification is an important means to ensure maintainability meets design requirements. However, the cost of traditional real maintainability verification method is very high, and the virtual maintenance method has insufficient verification accuracy due to the lack of large maintenance force feedback when the human body is moving. In order to reduce the evaluation error and test sample size, the paper conducts maintainability verification based on the mixed physical and virtual maintainability test scenarios. Aiming at the problem that traditional methods are difficult to deal with the real test information and synchronous virtual simulation information in the test process, this study proposes a virtual–real fusion maintainability evaluation algorithm based on adaptive weighting and truncated SPOT (Sequential Posterior Odd Test) method. It can weigh real test information and virtual human simulation information adaptively to obtain a virtual–real fusion maintainability test sample. Then, the SPOT method is used to evaluate the maintainability of small samples. The adjustment of valve clearance, replacement of air filter element and replacement of starting motor maintenance tasks of ship engine are taken as examples for demonstration. The virtual–real fusion and virtual maintainability verification methods are respectively used for verification, and compared with the physical maintenance scenario constructed by 3D printing, indicating that the accuracy of virtual–real fusion maintainability test verification is 89%, while the virtual maintainability verification is only 33%.
    Źródło:
    Eksploatacja i Niezawodność; 2022, 24, 4; 738--746
    1507-2711
    Pojawia się w:
    Eksploatacja i Niezawodność
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Development and application of an experimental device for measuring storage coefficient in a coal mine underground reservoir
    Opracowanie i zastosowanie eksperymentalnego urządzenia do pomiarów współczynnika odsączalności w podziemnych zbiornikach wody w kopalniach węgla
    Autorzy:
    Wang, Bei-Fang
    Sun, Ke-Ming
    Liang, Bing
    Sun, Wei-Ji
    Powiązania:
    https://bibliotekanauki.pl/articles/219035.pdf
    Data publikacji:
    2019
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    podziemny zbiornik w kopalni
    fragmenty skał i węgla o podobnym składzie jak w rejonie ściany
    obciążenie stopniowe
    wzajemne oddziaływania wody i skał
    współczynnik odsączalności
    dynamiczny rozkład czasowo-przestrzenny
    coal mine underground reservoir
    rock and coal fragments made from similar materials
    partition loading
    water-rock interaction
    storage coefficient
    space time dynamic evolution
    Opis:
    With the rise of coal mine underground reservoir engineering in the Shendong Mining Area, the space time dynamic evolution prediction of storage coefficient is becoming one of the critical technical problems for long-term reservoir operation. This coefficient directly determines the storage capacity and the comprehensive benefits of the operation of a coal mine underground reservoir. To this end, the proposed underground reservoir in Daliuta coal mine (No. 22616 working face) is selected in this study for the development and application of an experimental device to measure the storage coefficient. Rock and coal fragments from similar materials are prepared, which are filled and loaded according to the caving rock nature as well as the lumpiness and accumulation mode characteristics pertaining to No. 22616 working face. Subsequently, the measured storage coefficient under circulating water injection conditions revealed a four-dimensional spatial and temporal pattern. It followed the law of storage coefficient under joint interaction of water-rock and stress. The results showed that, prior to the experiment, rock and coal fragments made from similar materials had good water resistance when the paraffin content was set at 8%. The three stress zones were defined based on a theoretical analysis, which were applied on the corresponding loads. During the experiments, significant regional differences were found in the top surface with persisting subsidence of each stress loading zone. Hence, compared with its initial state, the maximum subsidence in the stress stability zone, the stress recovery zone, and the low-stress zone was 7.89, 5.8, and 1.83 mm, respectively. While the storage capacity and the storage coefficient gradually decreased, the former ranged from 0.2429 to 0.2397 m3, and the latter ranged from 0.270 to 0.266. The experimental results are verified by drainage engineering tests in the Shendong Mining Area. In essence, the storage coefficient had remarkable spatial distribution characteristics and a time-varying effect. In space, the stor-age coefficient increased with height along the vertical direction of the coal mine underground reservoir. However, it decreased with the distance from the boundary of the dam body in the horizontal direction. With time, the storage coefficient decreased dynamically. This study provides a new way of predicting the storage coefficient of a coal mine underground reservoir.
    Przy rosnącej intensywności prac inżynieryjnych prowadzonych w rejonie Zagłębia Węglowego w Shendong, określanie współczynnika odsączalności i jego zmienności w czasie i przestrzeni stało się jednym z głównych problemów w długofalowej eksploatacji górniczej, mającej wpływ na kształtowanie się współczynnika odsączalności oraz na całościowe korzyści płynące z eksploatacji złoża. Zaproponowano by rejon prac wydobywczych prowadzonych w ścianie No 22616 w kopalni węgla Daliuta wykorzystany został jako teren eksperymentalny dla pomiarów współczynnika odsączalności dla zbiornika podziemnego znajdującego się w kopalni węgla. W tych warunkach przetestowano opracowane narzędzie pomiarowe. Do eksperymentu przygotowano fragmenty skał i węgla o podobnym składzie jak w rejonie ściany 22616, z zachowaniem ich układu zalegania i zwięzłości; następnie obciążono je w sposób analogiczny do obciążeń działających w warunkach rzeczywistego prowadzenia stropu. Dokonano pomiaru współczynnika odsączalności po wpompowaniu do próbek wody, w rezultacie uzyskując czterowymiarowy rozkład współczynnika odsączalności w czasie i przestrzeni w warunkach wzajemnych oddziaływań pomiędzy wodą a warstwami skał, oraz w warunkach działających naprężeń. Wyniki eksperymentu były następujące: Przed rozpoczęciem eksperymentu, wykorzystywane fragmenty skał i węgla charakteryzowały się wysoką odpornością na wodę gdy zawartość parafiny wynosiła 8%; następnie trzy obszary próbek wyodrębnione w oparciu o analizy teoretyczne i charakteryzujące określony poziom naprężeń poddano wielokrotnemu działaniu naprężeń o kontrolowanej wielkości. W trakcie trwania eksperymentu zaobserwowano znaczące różnice lokalne na powierzchni, w postaci utrzymującej się niecki osiadania nad poszczególnym strefami oddziaływania naprężeń. W porównaniu do stanu początkowego, maksymalne wartości osiadania w strefie stabilnych naprężeń, w strefie odprężenia i w strefie niskich naprężeń wyniosły odpowiednio: 7.89 mm, 5.8 mm i 1.83 mm. Współczynnik odsączalności stopniowo malał, od początkowego zakresu 0.270-0.266 do zakresu końcowego 0.2429 m3-0.2397 m3. Wyniki badań eksperymentalnych potwierdzone zostały następnie poprzez badania od-prowadzania wody przeprowadzone w rejonie Zagłębia Węglowego Shendong. Stwierdzono, że współ-czynnik odsączalności wykazuje znaczną zmienność w czasie i przestrzeni. W ujęciu przestrzennym, wartość współczynnika odsączalności wzrasta wraz z wysokością mierzoną w kierunku pionowym osi zbiornika podziemnego, z kolei maleje ona wraz z odległością od granicy tamy mierzonej w kierunku poziomym. W ujęciu czasowym, wartość współczynnika odsączalności gwałtownie rośnie w czasie. Badania powyższe dostarczyły nowych metod do prognozowania wartości współczynnika odsączalności w podziemnych zbiornikach na terenie kopalni węgla.
    Źródło:
    Archives of Mining Sciences; 2019, 64, 4; 655-670
    0860-7001
    Pojawia się w:
    Archives of Mining Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Study on safe disposal of cephalosporins based on kinetic pyrolysis mechanism
    Autorzy:
    Fan, Jiangxue
    Zhang, Meng
    Hou, Xiaofei
    Wang, Fang
    Bai, Mengyuan
    Jiao, Ruoxi
    Yang, Zhongyu
    Duan, Erhong
    Cheng, Fengfei
    Zhou, Wen
    Powiązania:
    https://bibliotekanauki.pl/articles/27315672.pdf
    Data publikacji:
    2023
    Wydawca:
    Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
    Tematy:
    Distillation residues
    Thermal analysis kinetics
    Template “3-2-2”
    Template “1+1”
    Pyrolysis mechanism
    Opis:
    Based on the global goals for cleaner production and sustainable development, the pyrolysis behavior of cephalosporin residues was studied by TG-MS method. The influence of full temperature window on the safe disposal of residues was analyzed based on the “3-2-2” and “1+1” of thermal analysis kinetics, and the gas by-products of thermal degradation were monitored. Results showed that the pyrolysis of distillation residues were divided into low and high-temperature zones, including six stages. Maximum error rate (8.55%) by multiple scan rate was presented based on “3-2-2” pattern and maximum total fluctuation (33.7) by single scan rate was presented based on “1+1” pattern, which implied that the comprehensive multi-level comparison method was very reliable. The E value “E” of six stages showed an increasing trend ranging 166.8 to 872.8 kJ/mol. LgA(mean) was 27.28. Most mechanism function of stage 1, 2 were Z-L-T equation (3D), stage 3, 4, 6 were Avrami-Erofeev equation (AE3, AE4, AE2/3) and stage 5 was Reaction Order (O2). In addition, various small molecular micromolecule substances were detected such as C2H4O, C2H6, NH3, CH4, CO2 under full temperature windows and a possible pyrolysis path of residues was provided.
    Źródło:
    Polish Journal of Chemical Technology; 2023, 25, 4; 52--60
    1509-8117
    1899-4741
    Pojawia się w:
    Polish Journal of Chemical Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Rheological Properties and Water-in-Oil Structural Stability of Emulsion Matrixes
    Autorzy:
    Wang, L.
    Fang, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/357954.pdf
    Data publikacji:
    2013
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
    Tematy:
    emulsifier
    emulsion matrix
    rheological properties
    viscoelasticity
    water-in-oil structural stability
    Opis:
    The emulsion explosive is one of the important industrial explosives.The structural stability of the water-in-oil (W/O) emulsion matrix of an emulsion ex plosive determines the reliability of its initiation, safety and detonation performance. It is known that the emulsifier is one of the most important factors affecting W/O structural stability. In this paper, several emulsifiers with the functionalities of imide, amide, ester, salt, and sorbin monooleate (SMO) were selected. From the perspective of the rheological properties, the effects of the emulsifier structure and its functionality on the viscosity and visco-elastic properties of the emulsion matrix were analyzed and researched. The results show that emulsifiers with imide/amide functionality and their corresponding emulsion matrixes have higher viscosity at normal temperatures and better fluidity at high temperatures than those of the others. The linear visco-elastic region (LVR) for emulsion matrixes containing these emulsifiers is wider than that of the others. The effect of a change in ambient temperature on the viscosity for a complex emulsifier is small. The emulsion matrix containing the emulsifier named LZ2727B is the most stable, followed by the emulsifier named LZ2727D. This conclusion is consistent with the conclusions from tension tests and from high and low temperature cycling experiments. From the emulsifiers studied in this paper, LZ2727B and LZ2727D emulsifiers are very suitable for manufacturing packaged emulsion explosives. On the other hand emulsifiers based on SMO functionalities, named LZ2731 and LZ2735, are the best choices for manufacturing bulk emulsion explosives.
    Źródło:
    Central European Journal of Energetic Materials; 2013, 10, 1; 87-102
    1733-7178
    Pojawia się w:
    Central European Journal of Energetic Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Classification and inspection of milling surface roughness based on a broad learning system
    Autorzy:
    Fang, Runji
    Yi, Huaian
    Wang, Shuai
    Niu, Yilun
    Powiązania:
    https://bibliotekanauki.pl/articles/2173883.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    broad learning system
    classification
    milling surface roughness
    rapid training
    Opis:
    Current vision-based roughness measurement methods are classified into two main types: index design and deep learning. Among them, the computation procedure for constructing a roughness correlation index based on image data is relatively difficult, and the imaging environment criteria are stringent and not universally applicable. The roughness measurement method based on deep learning takes a long time to train the model, which is not conducive to achieving rapid online roughness measurement. To tackle with the problems mentioned above, a visual measurement method for surface roughness of milling workpieces based on broad learning system was proposed in this paper. The process began by capturing photos of the milling workpiece using a CCD camera in a normal lighting setting. Then, the train set was augmented with additional data to lower the quantity of data required by the model. Finally, the broad learning system was utilized to achieve the classification prediction of roughness. The experimental results showed that the roughness measurement method in this paper not only had a training speed incomparable to deep learning models, but also could automatically extract features and exhibited high recognition accuracy.
    Źródło:
    Metrology and Measurement Systems; 2022, 29, 3; 483--503
    0860-8229
    Pojawia się w:
    Metrology and Measurement Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Improved virtual space vector modulation for neutral point voltage oscillation and common-mode voltage reduction in neutral point clamped three-level inverter
    Autorzy:
    Fang, Junlong
    Wang, Guangya
    Li, Ran
    Liu, Siyuan
    Wang, Shuyu
    Powiązania:
    https://bibliotekanauki.pl/articles/1841339.pdf
    Data publikacji:
    2021
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    three-level inverter
    vector conversion
    virtual space vector modulation
    falownik trójpoziomowy
    konwersja wektorowa
    modulacja wektora przestrzeni wirtualnej
    Opis:
    The neutral point clamped (NPC) three-level inverter is widely used in high-voltage and high-power applications. However, neutral point voltage oscillation (NPVO) and common-mode voltage (CMV) problems exist in the NPC three-level inverter. In this paper, an improved virtual space vector modulation (VSVM) is proposed based on the reconstruction of a virtual small vector and a virtual medium vector. Compared with the traditional VSVM, an improved VSVM can effectively reduce the CMV. On this basis, a vector conversion method is proposed to further reduce the NPVO in the whole range. Simulation results verify the effectiveness and superiority of the improved VSVM.
    Źródło:
    Archives of Electrical Engineering; 2021, 70, 1; 203-218
    1427-4221
    2300-2506
    Pojawia się w:
    Archives of Electrical Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Optimization of optical uniformity factors of backlight module using robust design method
    Autorzy:
    Wang, Ju-Chi
    Fan, Yu-Cheng
    Fang, Te-Hua
    Tran, Anh-Son
    Cheng, Yu-Ting
    Powiązania:
    https://bibliotekanauki.pl/articles/2060680.pdf
    Data publikacji:
    2022
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    backlight module
    uniformity
    Taguchi method
    LightTools
    Opis:
    In order to meet the advent of the high-definition liquid crystal display (LCD) era, in addition to the high-quality panel manufacturing technology, how the backlight module can provide a uniform backlight with higher uniformity for a better experience in viewing, is a very important and urgent issue. In this study, the 15.6-inch side-in backlight module was used as the benchmark, and the Taguchi method was applied to find the high uniformity. The matching of the fishbone diagram affects the optical uniformity factor of the backlight module, such as the size of the light guide plate dot, the color of the plastic frame, the color of the fixed gel of the light guide plate, and the difference of the reflection surface. The optical analog software LightTools is used according to the orthogonal table. The signal-to-noise (S/N) ratio of the average uniformity characteristics is obtained, then it is converted into the best response factor of the factor response table and the factor reaction diagram. The homogeneity at 13 points is as high as 90.12%, which is 4.72% higher than the original design factor. The contribution of the four factors to the uniformity can be obtained by using the variance analysis. Finally, the influence of each factor level on the uniformity is discussed.
    Źródło:
    Optica Applicata; 2022, 52, 1; 5--20
    0078-5466
    1899-7015
    Pojawia się w:
    Optica Applicata
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Gastrodin ameliorates spinal cord injury via antioxidant and anti-inflammatory effects
    Autorzy:
    Du, Fangtao
    Wang, Xiaoning
    Shang, Bo
    Fang, Jifeng
    Xi, Yuting
    Li, Aijuan
    Diao, Yenze
    Powiązania:
    https://bibliotekanauki.pl/articles/1038788.pdf
    Data publikacji:
    2016
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    spinal cord injury
    gastrodin
    inflammation
    oxidative stress
    Nrf2
    Opis:
    Spinal cord injury (SCI) is one of the most severe traumatic injuries that results in dysfunction of limbs and trunk below the damaged section. Recent studies have shown that gastrodin (GAS) could improve the recovery of SCI. In the current study, we aimed to examine the possible mechanism underlying the effect of GAS on recovery of SCI in rats. In rats with SCI, GAS improved locomotor functions and decreased permeability of blood-spinal cord barrier, as illustrated by increase of Basso-Beattie-Bresnahan scores and decrease of Evans blue leakage. In addition, GAS inhibited inflammation, as evidenced by decrease of proinflammatory cytokines, including tumor necrosis factor α (TNFα) and interleukin-1β (IL-1β) in rats following SCI. Moreover, increase of TBARS content and decrease of glutathione (GSH) content and superoxide dismutase (SOD) activities in SCI rats were inhibited by GAS. Furthermore, GAS enhanced mRNA expression of nuclear factor (erythroid-derived 2)-like 2 (Nrf2), catalytic subunit of γ-glutamylcysteine ligase (GCLc) and modified subunit of γ-glutamylcysteine ligase (GCLm). The data suggested that GAS may promote the recovery of SCI through the enhancement of Nrf2-GCLc/GCLm signaling pathway, and subsequent improvement of oxidative stress and inflammation, resulting in decrease of permeability of BSCB and improved recovery of locomotor function in rats with SCI. The results have provided novel insights into GAS-related therapy of SCI and associated neurodegenerative diseases.
    Źródło:
    Acta Biochimica Polonica; 2016, 63, 3; 589-593
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Synthesis of kaempferide Mannich base derivatives and their antiproliferative activity on three human cancer cell lines
    Autorzy:
    Nguyen, Van-Son
    Shi, Ling
    Luan, Fang-Qian
    Wang, Qiu-An
    Powiązania:
    https://bibliotekanauki.pl/articles/1039003.pdf
    Data publikacji:
    2015
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    kaempferide
    flavonoids
    Mannich base derivatives
    synthesis
    antiproliferative activity
    Opis:
    Kaempferide (3,5,7-trihydroxy-4'-methoxyflavone, 1), a naturally occurring flavonoid with potent anticancer activity in a number of human tumour cell lines, was first semisynthesized from naringin. Based on Mannich reaction of kaempferide with various secondary amines and formaldehyde, nine novel kaempferide Mannich base derivatives 2-10 were synthesized. The aminomethylation occurred preferentially in the position at C-6 and C-8 of the A-ring of kaempferide. All the synthetic compounds were tested for antiproliferative activity against three human cancer cell lines (Hela, HCC1954, SK-OV-3) by the standard MTT method. The results showed that compounds 1, 2 and 5-10 were more potent against Hela cells with IC50 values of 12.47-28.24 μM than the positive control cis-platin (IC50 41.25 μM), compounds 5, 6, 8 and 10 were more potent against HCC1954 cells with IC50 values of 8.82-14.97 μM than the positive control cis-platin (IC50 29.68 μM), and compounds 2, 3, 5, 6 and 10 were more potent against SK-OV-3 cells with IC50 values of 7.67-18.50 μM than the positive control cis-platin (IC50 21.27 μM).
    Źródło:
    Acta Biochimica Polonica; 2015, 62, 3; 547-552
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Expression of follicle-stimulating hormone receptor (FSHR), protein kinase B-2 (AKT2) and adapter protein with PH domain, PTB domain, and leucine zipper (APPL1) in pig ovaries
    Autorzy:
    Ning Zhou
    Ning Wang
    Xiang Qin
    Qian Liu
    Juhua Wang
    Hui Dong
    Jie Zhou
    Fugui Fang
    Powiązania:
    https://bibliotekanauki.pl/articles/2087861.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    pigs
    immunohistochemistry
    FSHR
    AKT2
    APPL1
    Źródło:
    Polish Journal of Veterinary Sciences; 2017, 4; 661-667
    1505-1773
    Pojawia się w:
    Polish Journal of Veterinary Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Maintenance policy of degradation components based on the two-phase Wiener process
    Autorzy:
    Song, Minqiao
    Zhang, Yingzhi
    Yang, Fang
    Wang, Xiaofeng
    Guo, Guiming
    Powiązania:
    https://bibliotekanauki.pl/articles/28328273.pdf
    Data publikacji:
    2023
    Wydawca:
    Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
    Tematy:
    condition-based maintenance
    two-phase inspection
    two-phase Wiener process
    Particle Swarm Optimization
    sensitivity analysis
    Opis:
    This paper proposes a condition-based maintenance policy for the two-phase Wiener degradation process components. The main contribution of this article is to provide the time distribution of degradation failures for the two-phase Wiener process degradationcomponent, as well as the modeling and solving methods for two-phase maintenance. The two-phase maintenance policy includes two-phase inspection and preventive replacement maintenance operations. The established optimization maintenance policy model aims to minimize long-term operation costs. The specific cost calculation equation and the solution method of the maintenance model are given. The feasibility of the maintenance policy model is verified using the two-phase degradation data of the Liquid Coupling Devices. The Particle swarm optimization algorithm can stably solve the described problem, and the results show that the two-phase maintenance policy can be more economical and improve components availability. After that, we also analyzed the impact of the cost parameters on the maintenance policy through sensitivity analysis.
    Źródło:
    Eksploatacja i Niezawodność; 2023, 25, 4; art. no. 172537
    1507-2711
    Pojawia się w:
    Eksploatacja i Niezawodność
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Key fault propagation path identification of CNC machine tools based on maximum occurrence probability
    Autorzy:
    Zhang, Yingzhi
    Zhou, Yutong
    Yang, Fang
    Wang, Zhiqiong
    Sun, Mo
    Powiązania:
    https://bibliotekanauki.pl/articles/27312788.pdf
    Data publikacji:
    2023
    Wydawca:
    Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
    Tematy:
    fault propagation
    CNC machine tools
    key fault propagation path
    improved Pagerank
    fault propagation probability
    Opis:
    In order to revise the deviation caused by ignoring the dynamic character of fault propagation in traditional fault propagation path identification methods, a method based on the maximum occurrence probability is proposed to identify the key fault propagation path. Occurrence probability of fault propagation path is defined by dynamic importance, dynamic fault propagation probability and fault rate. Taking the fault information of CNC machine tools whichsubject to Weibull distribution as an example, this method has been proven to be reasonable through comparative analysis. Result shows that the key fault propagation path of CNC machine tools is not unique, but changes with time. Before 1000 hours, key fault propagation path is electrical component (E) to mechanical component (M); after 1000 hours, key fault propagation path is auxiliary component (A) to mechanical component (M). This change should be taken into account when developing maintenance strategies and conducting reliability analysis.
    Źródło:
    Eksploatacja i Niezawodność; 2023, 25, 3; art. no. 169887
    1507-2711
    Pojawia się w:
    Eksploatacja i Niezawodność
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effect of Ultraviolet Absorber on Photo-Degradation of Epoxy Coating Studied by Slow Positron Beam
    Autorzy:
    Wang, Zheng
    Liu, Fuwei
    Li, Jingjing
    He, Chunqing
    Peng, Xiangyang
    Huang, Zhen
    Fang, Pengfei
    Powiązania:
    https://bibliotekanauki.pl/articles/1033239.pdf
    Data publikacji:
    2017-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    epoxy coating
    photo-degradation
    ultraviolet absorber
    slow positron beam
    microstructure
    Opis:
    The photo-degradation progress of epoxy coating and the effect of ultraviolet absorber under UV-B irradiation have been investigated in slow positron beam and by the Fourier transform infrared spectrometer. After 120 h of irradiation, the value of S parameter in sample bulk is reduced while compared with the virgin sample. The result is mostly due to post-cure process happening in this initial irradiation stage. As the irradiation time increases to 360 h, the S parameter decreases sharply. This is due to the growth of carbonyl group and the generation of free radical. After 528 h or longer time of irradiation, a very low S value was obtained near sample surface, indicating the formation of a dead surface layer. Positron results also reveal that the addition of ultraviolet absorber suppresses the development of the dead layer after long-term UV-B irradiation. Ultraviolet absorber has a suppressing effect on generation of polar groups towards sample bulk. The addition of ultraviolet absorber is a key factor that affects the photo-degradation of epoxy coating.
    Źródło:
    Acta Physica Polonica A; 2017, 132, 5; 1523-1526
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Influence of Processing Techniques on Mechanical Properties and Impact Initiation of an Al-PTFE Reactive Material
    Autorzy:
    Feng, B.
    Fang, X.
    Li, Y.-C.
    Wu, S.-Z.
    Mao, Y.-M.
    Wang, H.-X.
    Powiązania:
    https://bibliotekanauki.pl/articles/358654.pdf
    Data publikacji:
    2016
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
    Tematy:
    Al-PTFE
    reactive materials
    quasi-static compression
    impact initiation
    Opis:
    Reactive materials (RMs) or impact-initiated materials have received much attention as a class of energetic materials in recent years. To assess the influence of processing techniques on mechanical properties and impact initiation behaviors of an Al-PTFE reactive material, quasi -static compression tests and drop-weight tests were performed. Scanning electron microscopy (SEM) was used to identify the characteristics of the interior microstructures of the Al-PTFE samples. A sintering process was found to transform Al-PTFE from a brittle to a ductile material with an increased elasticity modulus (from 108-160 MPa to 256-336 MPa) and yield stress (from 12-16 MPa to 19-20 MPa). Increasing the molding pressure from 36 MPa to 182 MPa increased the elastic modulus of all Al-PTFE samples and also the yield stress of unsintered ones. Unsintered samples in general required less energy to initiate than sintered ones. As the molding pressure increased, the impact initiation energy for sintered Al-PTFE fell from 96 J to 68 J, whereas the initiation energy for unsintered Al-PTFE rose from 68 J to 85 J. PTFE nanofiber networks observed in sintered samples formed under the higher molding pressures could contribute to the opposite trends observed in the impact initiation energy of unsintered and sintered Al-PTFE samples.
    Źródło:
    Central European Journal of Energetic Materials; 2016, 13, 4; 989-1004
    1733-7178
    Pojawia się w:
    Central European Journal of Energetic Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Estimation of phosphorus recovery by struvite crystallization from animal manure wastewater in China
    Autorzy:
    Fang, C.
    Zhang, T.
    Czechowska-Kosacka, A.
    Pawlowski, A.
    Łagód, G.
    Jiang, R.
    Wang, Q.
    Powiązania:
    https://bibliotekanauki.pl/articles/207381.pdf
    Data publikacji:
    2015
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    animal manure wastewater
    phosphorus recovery
    struvite
    płynne odchody zwierzęce
    odzysk fosforu
    struwit
    Opis:
    Intensive farming is main industry which produces large amount of animal manure wastewater with high content of phosphorus. Its discharging to surface water leads to eutrophication. On the other hand, phosphorus is vital for plant growth and its natural reserves are rapidly exhausted. Therefore, recovering phosphorus from animal manure wastewater can achieve two important goals: prevention of eutrophication and recovery of non-renewable phosphorus compounds. The method of struvite precipitation has been presented for phosphorus recovery from animal manure wastewater. Based on scenario study, 8.76 million tons of struvite could be produced from animal manure wastewater in China.
    Źródło:
    Environment Protection Engineering; 2015, 41, 4; 195-207
    0324-8828
    Pojawia się w:
    Environment Protection Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Characterization of an acidic α-galactosidase from hemp (Cannabis sativa L.) seeds and its application in removal of raffinose family oligosaccharides (RFOs)
    Autorzy:
    Zhang, Weiwei
    Du, Fang
    Tian, Guoting
    Zhao, Yongchang
    Wang, Hexiang
    Ng, Tzi
    Powiązania:
    https://bibliotekanauki.pl/articles/1038364.pdf
    Data publikacji:
    2018
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    α-galactosidases
    Cannabis sativa L.
    purification
    raffinose family oligosaccharides
    Opis:
    An acidic α-galactosidase designated as hemp seed α-galactosidase (HSG) was purified from hemp (Cannabis sativa L.) seeds. By means of chromatographic procedures which involved chromatography on the cation-exchangers CM-cellulose and SP-Sepharose, chromatography on the anion-exchangers DEAE-cellulose and Q-Sepharose, and gel filtration on Superdex 75 using fast protein liquid chromatography, HSG was purified to electrophoretic homogeneity. Results of SDS-PAGE and gel filtration on FPLC Superdex 75 revealed that the enzyme was a monomeric protein with a molecular weight of 38 kDa. Sequences of the inner peptides of the α-galactosidase obtained by MALDI-TOF-MS showed that HSG was a novel α-galactosidase since there was a little similarity to the majority of α-galactosidases recorded in the literature. A pH of 3.0 and a temperature of 50°C were optimal for the activity of the enzyme. The activity of HSG was inhibited by the chemical modification with N-bromosuccinimide (NBS) reagent. HSG contained 16 tryptophan residues and two tryptophan residues on the surface, which were crucial to the α-galactosidase activity. The heavy metal ions Cd2+, Cu2+, Hg2+ and Zn2+ inhibited its activity. The Km and Vmax for the hydrolysis of pNPGal (4-nitrophenyl α-D-galactopyranoside) were respectively 0.008 mM and 68 μM min-1 mg-1. HSG also catalyzed the hydrolysis of raffinose and other natural substrates. Hence the α-galactosidase possesses a tremendous potential for food and feed industries in the elimination of indigestible oligosaccharides from leguminous products.
    Źródło:
    Acta Biochimica Polonica; 2018, 65, 3; 383-389
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Preparation of α-calcium sulfate hemihydrate from industrial by-product gypsum: a review
    Autorzy:
    Guan, Qingjun
    Sui, Ying
    Zhang, Fang
    Yu, Weijian
    Bo, Yongjie
    Wang, Ping
    Peng, Wenqing
    Jin, Jiao
    Powiązania:
    https://bibliotekanauki.pl/articles/1448527.pdf
    Data publikacji:
    2021
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    α-calcium sulfate hemihydrate
    industrial by-product gypsum
    FGD gypsum
    phosphogypsum
    preparation method
    Opis:
    In recent years, the massive accumulation of industrial by-product gypsum, especially flue gas desulfurization (FGD) gypsum and phosphogypsum (PG), not only encroaches on lands but also causes serious environmental pollution. The preparation of α-calcium sulfate hemihydrate (α-HH) from industrial by-product gypsum is an important way to solve the massive accumulation. α-HH possessing larger, dense and well-grown crystals with fewer cracks and pores has high added value and a wide range of application. Hitherto the preparation methods of α-HH from industrial by-product gypsum mainly include the autoclave process, salt/acid solution process, or alcohol-water solution process. Thereinto, the autoclave process is the only method to realize industrialization. In order to solve the high energy consumption and unfavorable continuous operation of the autoclave process, researchers suggested alternative approaches, such as salt/acid solution process and alcohol-water solution process. However, these methods are basically in the laboratory stage or pilot scale test at present. Compared with FGD gypsum, the utilization rate of PG with a larger emission is very low owing to the high impurity content. And combining the preparation of α-HH with the recovery of valuable impurities from PG seems a promising way to solve the bulk deposition of PG.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2021, 57, 1; 168-181
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Time-frequency Representation -enhanced Transfer Learning for Tool Condition Monitoring during milling of Inconel 718
    Autorzy:
    Zhou, Yuqing
    Sun, Wei
    Ye, Canyang
    Peng, Bihui
    Fang, Xu
    Lin, Canyu
    Wang, Gonghai
    Kumar, Anil
    Sun, Weifang
    Powiązania:
    https://bibliotekanauki.pl/articles/24200823.pdf
    Data publikacji:
    2023
    Wydawca:
    Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
    Tematy:
    tool condition monitoring
    time-frequency analysis
    Markov Transition Field
    transfer learning
    Opis:
    Accurate tool condition monitoring (TCM) is important for the development and upgrading of the manufacturing industry. Recently, machine-learning (ML) models have been widely used in the field of TCM with many favorable results. Nevertheless, in the actual industrial scenario, only a few samples are available for model training due to the cost of experiments, which significantly affects the performance of ML models. A time-series dimension expansion and transfer learning (TL) method is developed to boost the performance of TCM for small samples. First, a time-frequency Markov transition field (TFMTF) is proposed to encode the cutting force signal in the cutting process to two-dimensional images. Then, a modified TL network is established to learn and classify tool conditions under small samples. The performance of the proposed TFMTF-TL method is demonstrated by the benchmark PHM 2010 TCM dataset. The results show the proposed method effectively obtains superior classification accuracies for small samples and outperforms other four benchmark methods.
    Źródło:
    Eksploatacja i Niezawodność; 2023, 25, 2; art. no. 165926
    1507-2711
    Pojawia się w:
    Eksploatacja i Niezawodność
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Generation of chirped microwave signal with any central frequency based on a nonuniformly spaced finite impulse response filter
    Autorzy:
    Chen, D.
    Wang, R.
    Pu, T.
    Xiang, P.
    Fang, T.
    Zheng, J.
    Xiong, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/174334.pdf
    Data publikacji:
    2016
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    microwave photonics
    microwave photonic filter
    chirped microwave signal
    dual drive Mach–Zehnder modulator
    Opis:
    A novel optical approach to generating a chirped microwave signal by using a nonuniformly spaced finite impulse response filter is proposed and demonstrated. In this scheme, a narrowband Gaussian pulse is used as the original chirped-free signal, which is easy to be acquired. To eliminate the need of a wideband chirped-free signal, a mixer and a radio frequency signal are used to up-convert the spectrum of the original Gaussian signal. Therefore, the required frequency response can be calculated and reconstructed by a finite impulse response filter with nonuniformly spaced taps. Besides, a dual drive Mach–Zehnder modulator is used to realize single sideband modulation of the chirpedfree signal. Thus, the transfer function induced by the fiber dispersion is eliminated and the chirped microwave signal with any central frequency can be generated. In this paper, a design example of a filter with a central frequency of 10GHz is provided, and generation of the target chirped microwave signal is also demonstrated by numerical simulations.
    Źródło:
    Optica Applicata; 2016, 46, 3; 399-408
    0078-5466
    1899-7015
    Pojawia się w:
    Optica Applicata
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Dispersion-compensating en/decoder for a time-spreading/wavelength-hopping optical code-division multiplexing (OCDM) system
    Autorzy:
    Zheng, J.
    Wang, R.
    Pu, T.
    Lu, L.
    Fang, T.
    Su, Y.
    Li, L.
    Yang, Q.
    Chen, X.
    Powiązania:
    https://bibliotekanauki.pl/articles/174365.pdf
    Data publikacji:
    2013
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    optical code-division multiplexing (OCDM)
    fiber Bragg grating (FBG)
    dispersion
    Opis:
    A novel dispersion-compensating fiber Bragg grating (FBG)-based en/decoder is proposed to compensate both the out-band and in-band dispersion in a time-spreading/wavelength-hopping (TS/WH) optical code-division multiplexing (OCDM) system. The experimental realization of such en/decoders only needs a uniform-pitch phase mask and a sub-micrometer precision moving stage. Such an en/decoder pair with the ability of compensating the dispersion of transmission in 20-km single mode fiber (SMF) is simulated and experimentally fabricated. Both the simulation and experimental results show that the decoded pulse can be recovered without any distortion owing to the elimination of dispersion.
    Źródło:
    Optica Applicata; 2013, 43, 3; 485-495
    0078-5466
    1899-7015
    Pojawia się w:
    Optica Applicata
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Generation of three-port splitter by double-layer grating in second-order Littrow configuration
    Autorzy:
    Gao, Chenhao
    Wang, Bo
    Fu, Chen
    Fang, Jimin
    Wen, Kunhua
    Meng, Ziming
    Nie, Zhaogang
    Xing, Xiangjun
    Chen, Li
    Lei, Liang
    Zhou, Jinyun
    Powiązania:
    https://bibliotekanauki.pl/articles/174662.pdf
    Data publikacji:
    2020
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    three-port splitter
    second-order Littrow
    double-layer grating
    Opis:
    In this paper, a novel double-layer three-port grating is described. The incident grating structure is in the second-order Littrow configuration. The grating region is composed of fused silica and Ta2O5.The designed grating beam splitter has high efficiency under TE polarization and TM polarization, respectively. The efficiency of two polarizations is more than 90%. In addition, compared with a single-layer three-port grating, this new beam splitter has good fabrication tolerance and incident bandwidth. Therefore, the optimized structure has a good application value.
    Źródło:
    Optica Applicata; 2020, 50, 2; 271-280
    0078-5466
    1899-7015
    Pojawia się w:
    Optica Applicata
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A mechanism reliability analysis method considering environmental influence and failure modes’ correlation : a case study of rifle automaton
    Autorzy:
    Fang, Yi-chuan
    Wang, Yong-juan
    Sha, Jin-long
    Gu, Tong-guang
    Zhang, He
    Powiązania:
    https://bibliotekanauki.pl/articles/24200826.pdf
    Data publikacji:
    2023
    Wydawca:
    Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
    Tematy:
    mechanism reliability
    environmental influence
    failure modes’ correlation
    copula function
    Kaplan-Meier estimation
    rifle automaton
    Opis:
    In order to overcome the challenge of quantifying the influence of environmental conditions and the coexistence of multiple failure modes involved in mechanism reliability modelling under different environments. In this paper, we propose a method for the analysis of mechanism reliability that takes into account the influence of environmental factors and failure modes’ correlation, quantifies the influence of environmental factors as the random distribution and degradation path of parameters, and derives the Copula description of failure mode correlation from the historical data of environmental experiments. On the basis of the discrete mechanism dynamics model, the output parameters of the characteristic points are calculated, and the failure rate of each failure mode is calculated based on the failure criterion and the performance margin theory. Additionally, the dynamic change pattern of the mechanism reliability is compared with the Kaplan-Meier estimation of the corresponding environmental test history data to assess the validity of the calculation results. The reliability modelling problem of a motion mechanism of an automatic rifle automaton in a high and low temperature environment is applied to the method, and the reliability calculation results are close to those of Kaplan-Meier estimation of the test history data, and all are within the upper and lower bounds given by the reliability boundary theory, demonstrating the method's validity.
    Źródło:
    Eksploatacja i Niezawodność; 2023, 25, 2; art. no. 166145
    1507-2711
    Pojawia się w:
    Eksploatacja i Niezawodność
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Factors influencing the mental health status of support nurses and their workload during the COVID-19 epidemic
    Autorzy:
    Dai, Zhen-Juan
    Xu, Shen-Ting
    Xue, Fang-Ying
    Zhou, Jian-Ying
    Chen, Jian-Qin
    Wang, Xue-Min
    Powiązania:
    https://bibliotekanauki.pl/articles/23369109.pdf
    Data publikacji:
    2023-12-15
    Wydawca:
    Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
    Tematy:
    COVID-19
    mental health
    epidemic prevention and control
    general mental health questionnaire
    NASA-TLX
    support nurse
    Opis:
    Objectives The authors used the National Aeronautics and Space Administration Task Load Index (NASA-TLX) and general health questionnaire to analyze the factors influencing the mental health status and the workload of support nurses during the COVID-19 epidemic. Material and Methods The authors conducted a cross-sectional survey of 349 support nurses in April–October 2022. Using QuestionStar, a powerful online survey tool, the authors administered surveys to the participants, collected data on the mental health status and workload of support nurses, and analyzed the influencing factors based on the collected data. Results A total of 316 questionnaires were successfully collected, with an effective rate of 98.75%. The proportion of support nurses with mental health problems was 25% and the value of the NASA-TLX questionnaire was: M±SD 68.91±7.28 pts. Multi-factor analysis revealed that the number of children, family support, and nursing support location were the influencing factors of mental health status, while the multivariate analysis revealed that the presence of symptoms, nursing support location, support work type, and total 12-item General Health Questionnaire (GHQ-12) score were the influencing factors of the workload of support nurses. Conclusions Compared to their counterparts in the plains, nurses working in isolated plateau regions who were caring for children and lacked family support, were more likely to have mental health issues. There was a positive correlation between the changes in GHQ-12 and NASA-TLX scores of the study participants. Compared to their counterparts in the plains and the tropical regions, nurses working in plateau regions had a heavier workload. As part of the follow-up measures to prevent and treat patients impacted by the COVID-19 epidemic, it is important to improve the mental health evaluation, consultation, and treatment of the support nurses to guarantee the high quality of the first-line support work.
    Źródło:
    International Journal of Occupational Medicine and Environmental Health; 2023, 36, 6; 761-772
    1232-1087
    1896-494X
    Pojawia się w:
    International Journal of Occupational Medicine and Environmental Health
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Internal Friction of Li7La3Zr2O12 Based Lithium Ionic Conductors
    Autorzy:
    Wang, X. P.
    Song, L.
    Hu, J.
    Xia, Y. P.
    Xia, Y.
    Gao, Y. X.
    Zhang, L. C.
    Magalas, L. B.
    Fang, Q. F.
    Powiązania:
    https://bibliotekanauki.pl/articles/958222.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    lithium ionic conductor
    Li7La3Zr2O12
    internal friction
    Opis:
    The diffusion mechanisms of lithium ions in tetragonal phase as well as in Al and Nb stabilized cubic Li7La3Zr2O12 compounds were investigated by low-frequency internal friction technique. In the cubic Li7La3Zr2O12 phase, a remarkable relaxation-type internal friction peak PC with a peak height up to 0.12 was observed in the temperature range from 15°C to 60°C. In the tetragonal phase however, the height of the PT peak dropped to 0.01. The obvious difference of the relaxation strength between the cubic and tetragonal phases is due to the different distribution of lithium ions in lattice, ordered in the tetragonal phase and disordered in the cubic phase. Based on the crystalline structure of the cubic garnet-type Li7La3Zr2O12 compound, it is suggested that the high internal friction peak in the cubic phase may be attributed to two diffusion processes of lithium ions: 96h↔96h and 96h↔24d.
    Źródło:
    Archives of Metallurgy and Materials; 2016, 61, 1; 21-24
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Balancing reliability and maintenance cost rate of multi-state components with fault interval omission
    Równoważenie wskaźników niezawodności i kosztów utrzymania elementów wielostanowych z pominięciem przedziału wystąpienia uszkodzenia
    Autorzy:
    Dong, Wenjie
    Liu, Sifeng
    Yang, Xiaoyu
    Wang, Huan
    Fang, Zhigeng
    Powiązania:
    https://bibliotekanauki.pl/articles/301323.pdf
    Data publikacji:
    2019
    Wydawca:
    Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
    Tematy:
    multi-state systems (MSSs)
    fault effect omission
    stochastic process
    repairable model
    maintenance cost rate
    systemy wielostanowe (MSS)
    pominięcie wpływu uszkodzenia
    proces stochastyczny
    model naprawialny
    polityka utrzymania ruchu
    Opis:
    For the repairable multi-state component, reliability indexes are analyzed based on a homogenous Continuous Time Markov Chain (CTMC). If the component can work well when its repair time is sufficiently short, a threshold value for maintenance is introduced. When the fault interval is less than threshold time, the fault effect is considered neglected. In this paper, comparisons of availability show differences of the new model and the original model with or without fault interval omission. In addition, balancing the maintenance cost and lifetime of multi-state components is an important issue when threshold values are considered. Both constants and non-negative random variables are modeled respectively. Finally, numerical examples are presented to illustrate the results obtained in this paper.
    W przypadku naprawialnych elementów wielostanowych, wskaźniki niezawodności analizuje się w oparciu o łańcuch Markowa z czasem ciągłym. Jeśli element może działać prawidłowo, mimo uszkodzenia, dzięki wystarczająco krótkiemu czasowi naprawy, wprowadza się próg czasowy dla konserwacji. Gdy przedział czasu, w którym następuje uszkodzenie jest krótszy niż próg czasowy dla działań konserwacyjnych, wpływ uszkodzenia uważa się za nieistotny. Przeprowadzone w niniejszym artykule porównania gotowości wykazały różnice między nowym modelem a modelem oryginalnym z pominięciem lub bez pominięcia przedziału wystąpienia uszkodzenia. Ponadto, przy rozważaniu wartości progowych, ważną kwestią jest równoważenie kosztów utrzymania i żywotności elementów wielostanowych. W pracy próg wystąpienia uszkodzenia zamodelowano, odpowiednio, zarówno jako wartość stałą jak i nieujemną zmienną losową. Na koniec przedstawiono przykłady ilustrujące wyniki przedstawionych badań.
    Źródło:
    Eksploatacja i Niezawodność; 2019, 21, 1; 37-45
    1507-2711
    Pojawia się w:
    Eksploatacja i Niezawodność
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Mechanical Spectroscopy of Equal-Channel Angular Pressed Fe-Cr Alloys and Tungsten
    Spektroskopia mechaniczna stopów Fe-Cr i wolframu wyciskanych przez kanał kątowy
    Autorzy:
    Hao, T.
    Tang, H.
    Jiang, W.
    Wang, X.
    Fang, Q.
    Powiązania:
    https://bibliotekanauki.pl/articles/352822.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    mechanical spectroscopy
    internal friction technique
    Fe-18wt.%Cr alloy and pure W
    equal-channel angular
    spektroskopia mechaniczna
    technika tarcia wewnętrznego
    stop Fe-18wt%Cr i czystego W
    kanał kątowy
    Opis:
    nternal friction technique was used to investigate the microstructural stability of equal-channel angular pressed (ECAP) 9Cr1Mo steel (T91), Fe-18wt.%Cr alloy, and pure W. Several non-relaxation internal friction peaks are observed in three ECAP-strained specimens, which are related to the microstructural transition from a severely deformed state to a static recovery state of dislocations, and to recrystallized state. Along with the disappearance of the P1 peak, another relaxation internal friction peak P2 is observed during the second heating run only in Fe-18wt.%Cr alloy, and it does not disappear even during subsequent third heating run. This peak is not observed in T91 steel and W. The P2 peak is likely associated with a process of grain boundary (GB) sliding. Unlike T91, no abundant carbide precipitates distribute on GBs to pin GB and repulse GB sliding, thus, the P2 peak only occurs in Fe-18wt.%Cr alloy. It is concluded that high-temperature internal friction measurements are required to detect the grain boundary peak in pure W.
    Technika tarcia wewnętrznego została użyta do zbadania stabilności mikrostruktury poddanych wyciskaniu przez kanał kątowy stali 9Cr1Mo (T91), stopu Fe-18wt%Cr, i czystego W. Zaobserwowano wiele nie-relaksacyjnych pików tarcia wewnętrznego w trzech próbkach odkształconych przez ECAP, które są związane z przejściem ze stanu silnie odkształconego do statycznego stanu zdrowienia dyslokacji, i do stanu zrekrystalizowanego. Wraz z zanikiem piku P1, tylko w przypadku stopu Fe-18wt%Cr obserwowany jest inny pik P2 relaksacji tarcia wewnętrznego podczas drugiego ogrzewania, i nie znika nawet w kolejnym trzecim etapie ogrzewania. Pik ten nie jest obserwowany w stali T91 i W. Pik P2 prawdopodobnie związany jest procesem poślizgu granicy ziaren. W przeciwieństwie do stali T91, brak bogatych w węglik wydzieleń na granicach ziaren, które by unieruchomiły granice i uniemożliwiły poślizg, stąd pik P2 występuje tylko w przypadku stopu Fe-18wt.%Cr. Stwierdzono, że pomiary tarcia wewnętrznego w wysokiej temperaturze są potrzebne, aby wykryć pik granicy ziarna w czystym W.
    Źródło:
    Archives of Metallurgy and Materials; 2015, 60, 3A; 2101-2106
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Lifetime prediction of self-lubricating spherical plain bearings based on physics-of-failure model and accelerated degradation test
    Prognozowanie czasu pracy samosmarujących łożysk ślizgowych w oparciu o model fizyki uszkodzeń oraz przyspieszone badania degradacji
    Autorzy:
    Wang, Y.
    Fang, X.
    Zhang, C.
    Chen, X.
    Lu, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/300754.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
    Tematy:
    accelerated degradation test
    self-lubricating spherical plain bearing
    lifetime prediction
    physicsof-failure model
    przyspieszone badanie degradacji
    samosmarujące łożysko ślizgowe
    prognozowanie czasu pracy
    model fizyki uszkodzeń
    Opis:
    Due to small friction coefficient and no need for lubrication during operation, self-lubricating spherical plain bearings (SSPBs) have been widely used in operation and transmission systems in aerospace, nuclear power plants, and ship equipment and they are key components of these systems. SSPBs failure will directly affect the operational reliability and safety of the equipment; therefore, it is necessary to accurately predict the service life of SSPBs to define reasonable maintenance plans and replacement cycles and to ensure reliability and safety of vital equipment. So far, lifetime prediction of SSPB has been primarily based on empirical formulae established by most important bearing manufacturers. However, these formulae are lack of strong theoretical basis; the correction coefficients are difficult to determine, resulting in low accuracy of lifetime prediction. In an accelerated degradation test (ADT), the load is increased to accelerate the SSPB wear process. ADT provides a feasible way for accurate lifetime prediction of SSPB in a short period. In this paper, wear patterns are studied and methods of wear analysis are presented. Then, physics-offailure model which considers SSPB wear characteristics, structure parameters and operation parameters is established. Moreover, ADT method for SSPB is studied. Finally, lifetime prediction method of SSPBs based on physics-of-failure model and ADT is established to provide a theoretical method for quick and accurate lifetime prediction of SSPBs.
    W związku z niskim współczynnikiem tarcia oraz brakiem konieczności smarowania podczas pracy,samosmarujące łożyska ślizgowe (self-lubricating spherical bearings, SSPB) znajdują szerokie zastosowanie w układach pracy oraz układach przełożeń urządzeń w przemyśle lotniczym, elektrowniach jądrowych, oraz na statkach, stanowiąc kluczowe elementy tych układów. Uszkodzenie łożyska SSPB ma bezpośredni wpływ na niezawodność eksploatacyjną oraz bezpieczeństwo sprzętu; dlatego też istnieje konieczność precyzyjnego prognozowania resursu łożysk SSPB, pozwalającego na odpowiednie planowanie konserwacji oraz cykli wymiany , które ma na celu zapewnienie niezawodności i bezpieczeństwa kluczowego sprzętu. Dotychczas czas pracy łożysk SSPB prognozowano przede wszystkim w oparciu o wzory empiryczne podawane przez największych producentów łożysk. Wzory te, jednak, nie mają solidnej podstawy teoretycznej; trudno jest dla nich określić współczynniki korygujące, co zmniejsza trafność prognozowania czasu pracy. W przyspieszonych badaniach degradacji zwiększa się obciążenie celem przyspieszenia procesu zużycia łożysk SSPB. Badania przyspieszone umożliwiają trafne przewidywanie czasu pracy łożysk SSPB w krótkim okresie czasu. W przedstawionej pracy analizowano wzorce zużycia badanych łożysk oraz przedstawiono metody analizy zużycia. Następnie opracowano model fizyki uszkodzeń, który uwzględnia charakterystyki zużycia, parametry konstrukcyjne oraz parametry eksploatacyjne omawianych łożysk ślizgowych. Ponadto rozpatrywano możliwość zastosowania badań przyspieszonych dla tego typu łożysk. W wyniku przeprowadzonych badań, opracowano metodę prognozowania czasu pracy łożysk SSPB opartą na modelu fizyki uszkodzeń oraz badaniach przyspieszonych, która pozwala na szybkie i trafne prognozowanie czasu pracy samosmarujących łożysk ślizgowych.
    Źródło:
    Eksploatacja i Niezawodność; 2016, 18, 4; 528-538
    1507-2711
    Pojawia się w:
    Eksploatacja i Niezawodność
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
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