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    Wyświetlanie 1-14 z 14
    Tytuł:
    Research on hybrid modeling and predictive energy management for power split hybrid electric vehicle
    Autorzy:
    Wang, Shaohua
    Zhang, Sheng
    Shi, Dehua
    Sun, Xiaoqiang
    Yang, Tao
    Powiązania:
    https://bibliotekanauki.pl/articles/2173576.pdf
    Data publikacji:
    2021
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    power split HEV
    energy management
    mixed logical dynamical model
    piecewise affine
    model predictive control
    podział mocy
    zarządzanie energią
    silnik hybrydowy
    model dynamiczny
    model mieszany
    model logiczny
    technologia fragmentarycznie pokrewna
    kontrola predykcyjna modelu
    Opis:
    Due to the coexistence of continuity and discreteness, energy management of a multi-mode power split hybrid electric vehicle (HEV) can be considered a typical hybrid system. Therefore, the hybrid system theory is applied to investigate the optimum energy distribution strategy of a power split multi-mode HEV. In order to obtain a unified description of the continuous/discrete dynamics, including both the steady power distribution process and mode switching behaviors, mixed logical dynamical (MLD) modeling is adopted to build the control-oriented model. Moreover, linear piecewise affine (PWA) technology is applied to deal with nonlinear characteristics in MLD modeling. The MLD model is finally obtained through a high level modeling language, i.e. HYSDEL. Based on the MLD model, hybrid model predictive control (HMPC) strategy is proposed, where a mixed integer quadratic programming (MIQP) problem is constructed for optimum power distribution. Simulation studies under different driving cycles demonstrate that the proposed control strategy can have a superior control effect as compared with the rule-based control strategy.
    Źródło:
    Bulletin of the Polish Academy of Sciences. Technical Sciences; 2021, 69, 3; art. no. e137064
    0239-7528
    Pojawia się w:
    Bulletin of the Polish Academy of Sciences. Technical Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Research on hybrid modeling and predictive energy management for power split hybrid electric vehicle
    Autorzy:
    Wang, Shaohua
    Zhang, Sheng
    Shi, Dehua
    Sun, Xiaoqiang
    Yang, Tao
    Powiązania:
    https://bibliotekanauki.pl/articles/2128153.pdf
    Data publikacji:
    2021
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    power split HEV
    energy management
    mixed logical dynamical model
    piecewise affine
    model predictive control
    podział mocy
    zarządzanie energią
    silnik hybrydowy
    model dynamiczny
    model mieszany
    model logiczny
    technologia fragmentarycznie pokrewna
    kontrola predykcyjna modelu
    Opis:
    Due to the coexistence of continuity and discreteness, energy management of a multi-mode power split hybrid electric vehicle (HEV) can be considered a typical hybrid system. Therefore, the hybrid system theory is applied to investigate the optimum energy distribution strategy of a power split multi-mode HEV. In order to obtain a unified description of the continuous/discrete dynamics, including both the steady power distribution process and mode switching behaviors, mixed logical dynamical (MLD) modeling is adopted to build the control-oriented model. Moreover, linear piecewise affine (PWA) technology is applied to deal with nonlinear characteristics in MLD modeling. The MLD model is finally obtained through a high level modeling language, i.e. HYSDEL. Based on the MLD model, hybrid model predictive control (HMPC) strategy is proposed, where a mixed integer quadratic programming (MIQP) problem is constructed for optimum power distribution. Simulation studies under different driving cycles demonstrate that the proposed control strategy can have a superior control effect as compared with the rule-based control strategy.
    Źródło:
    Bulletin of the Polish Academy of Sciences. Technical Sciences; 2021, 69, 3; e137064, 1--15
    0239-7528
    Pojawia się w:
    Bulletin of the Polish Academy of Sciences. Technical Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Experimental study on the joint application of innovative techniques for the improved drivage of roadways at depths over 1 km: a case study
    Autorzy:
    Zhang, Wei
    Tang, Jia-Jia
    Zhang, Dong-Sheng
    Zhang, Lei
    Sun, Yuyan
    Zhang, Wei-Sheng
    Powiązania:
    https://bibliotekanauki.pl/articles/219958.pdf
    Data publikacji:
    2020
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    pomiar naprężeń
    wiercenie
    piaskowanie
    odkształcenie
    roadways at depth over 1 km
    in-situ stress measurements
    efficient drivage
    rapid drilling and blasting
    deformation control of SRR
    industrial test
    Opis:
    Finding effective ways to efficiently drive roadways at depths over 1 km has become a hotspot research issue in the field of mining engineering. In this study, based on the local geological conditions in the Xinwen Mining Area (XMA) of China, in-situ stress measurements were conducted in 15 representative deep roadways, which revealed the overall tectonic stress field pattern, with the domination of the horizontal principal stresses. The latter values reached as high as 42.19 MPa, posing a significant challenge to the drivage work. Given this, a comprehensive set of innovative techniques for efficiently driving roadways at depths over 1 km was developed, including (i) controlled blasting with bidirectional energy focusing for directional fracturing, (ii) controlled blasting with multidirectional energy distribution for efficient rock fragmentation, (iii) wedge-cylinder duplex cuts centered on double empty holes, and (iv) high-strength supports for deep roadways. The proposed set of techniques was successfully implemented in the –1010 west rock roadway (WRR) drivage at the Huafeng Coal Mine (HCM). The improved drivage efficiency was characterized by the average and maximum monthly advances of 125 and 151 m, respectively. The roadway cross-sectional shape accuracy was also significantly improved, with the overbreak and underbreak zones being less than 50 mm. The deformation in the surrounding rock of roadway (SRR) was adequately controlled, thus avoiding repeated maintenance and repair. The relevant research results can provide technical guidance for efficient drivage of roadways at depths over 1 km in other mining areas in China and worldwide.
    Źródło:
    Archives of Mining Sciences; 2020, 65, 1; 159-178
    0860-7001
    Pojawia się w:
    Archives of Mining Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Research on new process for separation of silicon wafers and glass from decommissioned photovoltaic module
    Autorzy:
    Zhang, Jian wen
    Wang, Hai dong
    Zhang, Sheng guang
    Liang, Han
    Guo, Hui
    Tao, Si-yao
    Powiązania:
    https://bibliotekanauki.pl/articles/2175425.pdf
    Data publikacji:
    2022
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    crystalline silicon photovoltaic modules
    decommissioned photovoltaic modules
    silicon
    solar cell
    tempered glass
    vibration separation
    Opis:
    In view of the disadvantages of the existing electrostatic separation process of decommissioned photovoltaic modules, which can only achieve the separation of fine silicon wafers and glass and has high energy consumption, a new process to solve the efficient dry separation of coarse silicon wafers and glass in decommissioned photovoltaic modules is proposed- the vibration separation method. Based on the theoretical analysis of the vibration separation of flaky silicon wafer and polyhedral glass particles, the effects of feed size, feed amount, vibration voltage, vibration frequency, horizontal inclination angle and longitudinal inclination angle on the product indexes of wafer and glass separation were investigated by single factor experiment. The optimal experimental conditions were obtained as follows: feed particle size +0.83mm, feed amount 0.15 t/h, vibration voltage 190 V, vibration frequency 48 Hz, horizontal inclination Angle 8°, longitudinal inclination Angle 3°. Under this optimized condition, the content of metal Si in the obtained silicon wafer product is 84.47%, the recovery rate of is 83.73%, the content of impurity SiO2 is 1.09%, and the content of SiO2 in the obtained glass product is 65.69%, and the recovery rate is 98.95%, the impurity metal Si content is 0.56%. This study provides a research idea for the industrial separation of silicon wafers and glass from decommissioned photovoltaic modules.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2022, 58, 6; art. no. 151679
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Phytochelatins of Cladophora rupestris in Pb2+ absorption and its detoxification
    Autorzy:
    Zhang, Lu-Sheng
    Yang, Liu
    Li, Lingsheng
    Feng, Xiaoyu
    Cao, De-Ju
    Liu, Zhao-Wen
    Powiązania:
    https://bibliotekanauki.pl/articles/27323982.pdf
    Data publikacji:
    2023
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    phytochelatins
    heavy metals
    detoxification
    Cladophora rupestris
    Pb+
    fitochelatyny
    metale ciężkie
    detoksykacja
    Opis:
    Phytochelatins (PCs) exist widely in plants and are closely related to plant resistance to heavy metals (HMs). Glutathione (GSH) and nonprotein thiols (NPTs) are the major components of PCs. This study investigates the role of the PCs of Cladophora rupestris in Pb2+ accumulation and detoxification. The distribution of Pb2+ in the PCs of C. rupestris was studied. FTIR and XPS are used to characterize the chelating power of Pb2+ with PCs in C.rupestris. The curve fitting of the secondary protein structure is used to identify the functional groups with Pb2+. Results showed that the content of Pb2+ in the PCs of C. rupestris increased with an increase in Pb2+ stress. Pb content increased to 352 and 314 mg/kg in NPTs and GSH, respectively, when Pb stress concentration reached 7.5 mg/dm3 . The Pb2+ fraction of C. rupestris PCs reached a maximum of 10.8 and 9.3% in NPTs and GSH, respectively. The Pb2+ uptake by GSH and NPTs was 40–48% and 52–60%, respectively. Pb2+ bound with the PCs of C. rupestris, forming complexes that contained Pb–OOC, Pb–C=O, CO–Pb, –N=Pb, Pb–NH2, Pb–O, Pb–N–, Pb–C–, Pb–S, and Pb2+ with multiple groups of PCs as bridging ligand atoms.
    Źródło:
    Environment Protection Engineering; 2023, 49, 3; 31--42
    0324-8828
    Pojawia się w:
    Environment Protection Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Evaluation of differential serum expression of three factors and pulmonary function in patients with silicosis
    Autorzy:
    Zhu, Ying
    Duan, Xia Yu
    Cheng, Yun Qi
    Yao, Xin Jing
    Xu, Hong
    Zhang, Kui Sheng
    Li, Feng Shi
    Yang, Fang
    Liu, Liang He
    Yuan, Xiang Ju
    Powiązania:
    https://bibliotekanauki.pl/articles/2086531.pdf
    Data publikacji:
    2021-08-05
    Wydawca:
    Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
    Tematy:
    silicosis
    pulmonary function
    early diagnosis
    ROC
    PTPN2
    factor B
    Opis:
    ObjectivesSilicosis is a chronic occupational lung disease. As was previously found by the authors, some proteins increased in the lung tissue of activated rats, and protein tyrosine phosphatase non-receptor type 2 (PTPN2), factor B, and vaccinia-related kinase 1 (VRK1) showed highly differential expressions.Material and MethodsIn this study, serum and bronchoalveolar lavage fluid samples were collected from patients with silicosis and healthy people to verify the expression of PTPN2, factor B, and VRK1. The diagnostic value of differentially expressed proteins for silicosis was judged.ResultsThe expression levels of serum PTPN2, VRK1, and factor B in patients with silicosis were significantly higher than those in the control group (p < 0.01). Higher serum PTPN2 and factor B concentrations significantly and negatively correlated with the ratio of forced expiratory volume in 1 s to forced vital capacity (FEV1/FVC), maximum vital capacity (VCmax), FEV1, and FVC, suggesting that the high expression of PTPN2 and factor B is associated with decreased pulmonary ventilation function and restrictive ventilatory impairment in patients with silicosis. All area under curve (AUC) measurements generated from single detection events were >0.744, with PTPN2 reaching the highest value (0.858). The AUC, sensitivity, and specificity for the combined diagnosis using factor B and PTPN2 were 0.907, 86.91% and 85.07%, respectively, for factor B and PTPN2. The 3 differentially expressed proteins are potential classes of predictive biomarkers for silicosis.ConclusionsRegarding the economy and test practicality, the best diagnostic combination is factor B and PTPN2 for the analysis of AUC, sensitivity and specificity.
    Źródło:
    International Journal of Occupational Medicine and Environmental Health; 2021, 34, 4; 527-540
    1232-1087
    1896-494X
    Pojawia się w:
    International Journal of Occupational Medicine and Environmental Health
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Microstructures and Microwave-Absorbing Properties of ZnO Smoke from Zinc Leach Residue Treated by Carbothermal Reduction
    Autorzy:
    Ma, Zhiwei
    Wang, Sheng
    Du, Xueyan
    Zhang, Ji
    Zhao, Ruifeng
    Zhang, Shengquan
    Powiązania:
    https://bibliotekanauki.pl/articles/2049146.pdf
    Data publikacji:
    2021
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    zinc leach residue
    carbothermal reduction
    ZnO smoke
    microwave-absorbing properties
    Opis:
    Much zinc residue is produced during the traditional processes involved in zinc hydrometallurgy in the leaching stage: its composition is complex and valuable metals are difficult to recover therefrom. If not handled properly, it can lead to a waste of resources and environmental pollution. To solve this problem, zinc leach residue specimens were treated using the carbothermal reduction method (CTR) that is easy to operate and has a high energy utilisation rate. The methods, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and scanning transmission electron microscopy (STEM) were used for analytical characterisation. Based on this, this research investigated a structure-function relationship between microstructures and microwave-absorbing properties of ZnO smoke from CTR-treated zinc leach residue. The results demonstrate that microstructures and macro-properties of ZnO smoke obtained at different temperatures differ greatly. Under conditions including a calcination temperature of 1250°C, holding time of 60 min, and addition of 50% and 10% of powdered coal and CaO separately, the ZnO content in the obtained smoke is 99.14%, with regular micron-sized ZnO particles therein. For these particles, the minimum reflection loss (RLmin) reached –25.56 dB at a frequency of 15.84 GHz with a matching thickness of 5 mm. Moreover, frequency bandwidth corresponding to RL < –10 dB can reach 2.0 GHz. ZnO smoke obtained using this method is found to have excellent microwave-absorbing performance, which provides a new idea for high-value applications of zinc-rich residue.
    Źródło:
    Archives of Metallurgy and Materials; 2021, 66, 4; 1163--1170
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Noise Source Identification Method for a Warp Machine Based on MEEMD_AIC
    Metoda identyfikacji źródła hałasu maszyny dziewiarskiej oparta na MEEMD_AIC
    Autorzy:
    Xu, Yang
    Zhang, Ziyu
    Li, Angang
    Sheng, Xiaowei
    Powiązania:
    https://bibliotekanauki.pl/articles/231620.pdf
    Data publikacji:
    2020
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
    Tematy:
    warp knitting machine
    noise source identification
    modified ensemble empirical mode decomposition
    MEEMD
    Akaike Information Criterion
    maszyna dziewiarska
    źródło hałasu
    zmodyfikowany zespół dekompozycji trybu empirycznego
    kryterium informacyjne Akaike
    Opis:
    In order to recognise the noise source of a warp knitting machine, a method based on Modified Ensemble Empirical Mode Decomposition (MEEMD) and Akaike Information Criterion (AIC) is proposed. The MEEMD_AIC method is applied to measure the noise signal of a warp knitting machine and analyse every single effective component selected. Noise source identification is realised by combining the vibration signal characteristics of the main parts of the warp knitting machine. Firstly, MEEMD is used to decompose the measured noise signal of the warp knitting machine into a finite number of intrinsic mode function (IMF) components. Then, singular value decomposition (SVD) is performed on the covariance matrix of the component matrix to get the eigen value of the matrix. Next, the number of effective components is estimated based on the AIC criterion, and the effective components are selected by combining the energy characteristic index and the Pearson correlation coefficient method. The results show that the noise signal of the warp knitting machine is a mixture of multiple noise source signals. The main noise sources of the warp knitting machine, including the vibration of the pulling roller, the main shaft of the loop forming mechanism and the push rod of the guide bar traverse the mechanism, provide theoretical support for recognition of the active noise reduction of the warp knitting machine using the MEEMD_AIC method.
    W celu rozpoznania źródła szumu maszyny dziewiarskiej zaproponowano metodę rozpoznawania źródła hałasu opartą na zmodyfikowanym zespole dekompozycji trybu empirycznego (MEEMD) i Akaike Information Criterion (AIC). Metodę MEEMD_AIC zastosowano do pomiaru sygnału szumu maszyny dziewiarskiej i do analizy każdego elementu maszyny dziewiarskiej. Identyfikacja źródła hałasu odbywała się poprzez połączenie charakterystyki sygnału wibracji głównych części maszyny dziewiarskiej. Po pierwsze, MEEMD zastosowano do dekompozycji zmierzonego sygnału szumowego maszyny dziewiarskiej na skończoną liczbę elementów składowych funkcji trybu wewnętrznego (IMF). Następnie przeprowadzono rozkład wartości pojedynczej (SVD) na macierz kowariancji macierzy składowej uzyskując wartość własną macierzy. Następnie oszacowano liczbę składników efektywnych na podstawie kryterium AIC, a składniki efektywne wybrano poprzez połączenie wskaźnika charakterystyki energetycznej i metody współczynnika korelacji Pearsona. Wyniki pokazały, że sygnał szumu maszyny dziewiarskiej jest mieszaniną wielu sygnałów źródeł hałasu. Na główne źródło hałasu maszyny dziewiarskiej składają się wibracje wałka ciągnącego oraz hałas głównego wału mechanizmu formowania pętli i popychacza mechanizmu poprzecznego prowadnicy. Przeprowadzona za pomocą metody MEEMD_AIC identyfikacja zapewnia teoretyczne wsparcie dla aktywnej redukcji hałasu dziania.
    Źródło:
    Fibres & Textiles in Eastern Europe; 2020, 3 (141); 55-61
    1230-3666
    2300-7354
    Pojawia się w:
    Fibres & Textiles in Eastern Europe
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Influence of grouting pressure volatility on additional response of adjacent pile foundation in shield construction
    Autorzy:
    Zhang, Chuan-Chuan
    Li, Dan-Mei
    Zhang, Jun
    Yu, Tong-Sheng
    Chen, Qiang
    Powiązania:
    https://bibliotekanauki.pl/articles/2086958.pdf
    Data publikacji:
    2022
    Wydawca:
    Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
    Tematy:
    grouting pressure fluctuations
    adjacent loaded-pile foundation
    normal distribution
    FLAC3D
    Opis:
    Soil parameters along the heading direction are subjected to spatial variability during shield construction, so grouting pressure requires constant adjustment to ensure ground stress sta- bility. This causes grouting pressure to fluctuate around the design pressure/curve. There- fore, the influence of the grouting pressure volatility on the adjacent loaded-pile foundation should be considered in shield tunneling. In this study, a refined numerical simulation of the shield construction process is conducted using the Fast Lagrangian Analysis of Continua in Three Dimensions (FLAC3D) software. A total of 300 groups of grouting pressure pa- rameters with a skewed normal distribution are input into the numerical model. Then, the influence of the construction parameter uncertainty on the adjacent loaded-pile foundation is analyzed. Finally, the back analysis method is conducted based on the monitored data to evaluate how the construction process affects the pile foundation. The calculation results are compared with those of the traditional finite element method. The results indicate that in the tunneling process, the grouting pressure fluctuation greatly affects the additional bend- ing moment of the adjacent pile foundation. Under the influence of the grouting pressure, the additional axial force and additional bending moment of the pile foundation also follow the skewed normal distribution. The back analysis results of the pile foundation are greater than those of the typical numerical method by about 60% 100%, that is using the back analysis calculation results to evaluate the pile foundation additional response can reduce the risk.
    Źródło:
    Journal of Theoretical and Applied Mechanics; 2022, 60, 1; 33--47
    1429-2955
    Pojawia się w:
    Journal of Theoretical and Applied Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Research on influencing factors of emergency power support for voltage source converter-based multi-terminal high-voltage direct current transmission system
    Autorzy:
    Li, Congshan
    Zhen, Zikai
    Sheng, Tingyu
    Liu, Yan
    Zhong, Pu
    Zhang, Xiaowei
    Powiązania:
    https://bibliotekanauki.pl/articles/2172797.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    coordinated control
    emergency DC power support
    influencing factors
    VSC- MTDC transmission
    Opis:
    Voltage source converter-based multi-terminal high-voltage direct current (VSCMTDC) transmission system can realize a multi-point power supply, multi-drop power receiving, and mutual coordination between the converter stations to ensure the reliability of the transmission. Based on the PSCAD/EMTDC platform, a five-terminal DC transmission system model is established. According to the fast power regulation capability and overload capacity of theVSC-MTDC power transmission system, an analysis of additional emergency power support for a transmission system under large disturbance conditions was carried out. A new control strategy for emergency power support that introduces its basic principle is proposed in this paper. It uses the short-term overload capability of the DC system. By changing the power reserve of the converter station and the electrical distance between the converter stations, the influence of the power reserve and the electrical distance on the emergency power supply guarantee is analyzed the stability of the system is improved, thereby improving the sudden change of power caused by voltage fluctuations, and the feasibility of the control module is verified by PSCAD simulation. The simulation results show that when the system power supply suddenly changes, the converter stations at a short distance and large power reserve has a better effect on emergency power supply protection. A comparative study of the active power support of a single converter station and multiple converter stations is carried out. The research results show that the use of emergency power support in the DC transmission system has a good effect on maintaining the stability of the inter-connection system and the reliability of the power supply.
    Źródło:
    Archives of Electrical Engineering; 2022, 71, 4; 881--894
    1427-4221
    2300-2506
    Pojawia się w:
    Archives of Electrical Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Acoustic Emission Response and Damage Process for Q235 Steel in an in Situ Tensile Test
    Autorzy:
    Zhang, Ying
    Li, Yue
    Lai, Huan Sheng
    Bai, Chunmei
    Liu, Kang Lin
    Powiązania:
    https://bibliotekanauki.pl/articles/177752.pdf
    Data publikacji:
    2019
    Wydawca:
    Polska Akademia Nauk. Czasopisma i Monografie PAN
    Tematy:
    Q235
    damage
    acoustic emission
    in situ tensile test
    Opis:
    Q235 steel is widely used in engineering and construction. Therefore, it is important to identify the damage mechanism and the acoustic emission (AE) response of the material to ensure the safety of structures. In this study, an AE monitor system and an in situ tensile test with an optical microscope were used to investigate the AE response and insight into the damage process of Q235 steel. The surface of the specimen was polished and etched before the test in order to improve the quality of micrographs. Two kinds of AE responses, namely a burst and a continuous signal, were recorded by the AE monitor system during the test. Based on the in situ test, it was observed that the damage of Q235 steel was induced by the crystal slip and the inclusion fracture. Since the crystal slip was an ongoing process, continuous AE signals were produced, while burst AE signals were possibly produced by the inclusion fracture which occurred suddenly with released higher energy. In addition, a great number of AE signals with high amplitude were observed during the yielding stage and then the number and amplitude decreased.
    Źródło:
    Archives of Acoustics; 2019, 44, 4; 807-813
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Using high level roadway to control gas emission in a longwall mining face – numerical simulation study
    Autorzy:
    Ma, Yongzhen
    Cheng, Jianwei
    Zhang, Rui
    Wang, Zui
    Ran, Dezhi
    Sheng, Shuping
    Zhang, Jufeng
    Si, Junhong
    Yu, Zhaoyang
    Powiązania:
    https://bibliotekanauki.pl/articles/2203351.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    symulacja numeryczna
    wentylacja górnicza
    kopalnia węgla
    high level roadway
    gob
    numerical simulation
    u+hLR ventilation method
    Opis:
    With the increase of coal mining depth, the gas content in coal seams could also become larger and larger, which could suddenly cause an inrush of gas into the longwall mining face. It is very dangerous for miners’ safety in the underground. The U-shaped ventilation pattern of longwall mining face that underground coal mines currently use is not enough to deliver sufficient air quantities to dilute gases in mining faces, which could result in the gas concentration over the required celling limit by government laws. Thus, the mine must stop production. In this paper, the high level roadway (HLR) is designed and the U + HLR new ventilation pattern is proposed to control gas emission in a longwall mining face. Using computational fluid dynamics simulation (CFD) software, the flow field and gas transportation in the mine gob are studied. The optimized ventilation parameters are summarized. It is found that the best vertical distance of the HLR is 35 m over the coal seam and the horizontal distance is 25 m from the air return roadway. It is recommended that the negative suction pressure design of the high level roadway should be ranged from 9000 Pa to 10000 Pa. Based on the study outcomes, the gas emission could be well controlled in mining faces and avoid any gas disaster accidents.
    Źródło:
    Archives of Mining Sciences; 2022, 67, 4; 715--728
    0860-7001
    Pojawia się w:
    Archives of Mining Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Color image encryption scheme based on quaternion discrete multi-fractional random transform and compressive sensing
    Autorzy:
    Ye, Huo-Sheng
    Dai, Jing-Yi
    Wen, Shun-Xi
    Gong, Li-Hua
    Zhang, Wen-Quan
    Powiązania:
    https://bibliotekanauki.pl/articles/2033985.pdf
    Data publikacji:
    2021
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    color image encryption
    quaternion discrete multi-fractional random transform
    compressive sensing
    confusion-diffusion strategy
    Opis:
    A color image compression-encryption algorithm by combining quaternion discrete multi-fractional random transform with compressive sensing is investigated, in which the chaos-based fractional orders greatly improve key sensitivity. The original color image is compressed and encrypted with the assistance of compressive sensing, in which the partial Hadamard matrix adopted as a measurement matrix is constructed by iterating Chebyshev map instead of utilizing the entire Guassian matrix as a key. The sparse images are divided into 12 sub-images and then represented as three quaternion signals, which are modulated by the quaternion discrete multi-fractional random transform. The image blocking and the quaternion representation make the proposed cryptosystem avoid additional data extension existing in many transform-based methods. To further improve the level of security, the plaintext-related key streams generated by the 2D logistic-sine-coupling map are adopted to diffuse and confuse the intermediate results simultaneously. Consequently, the final ciphertext image is attained. Simulation results reveal that the proposed cryptosystem is feasible with high security and has strong robustness against various attacks.
    Źródło:
    Optica Applicata; 2021, 51, 3; 349-364
    0078-5466
    1899-7015
    Pojawia się w:
    Optica Applicata
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Comprehensive Analysis of Metal Deformation Law Based on Numerical Simulation of Cold Rolling Process
    Autorzy:
    Yan, Zhu-Wen
    Wang, Bao-Sheng
    Bu, He-Nan
    Li, Hao
    Hong, Lei
    Zhang, Dian-Hua
    Powiązania:
    https://bibliotekanauki.pl/articles/2106570.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    3D elastic-plastic FEM
    work roll deflection
    lateral thickness
    flatness regulation effect
    rolling pressure
    Opis:
    Through taking the cold rolling process as the research object, the three-dimensional finite element model of the strip rolling process is established by using ANSYS/LS-DYNA software. The actual rolling product data has strong consistency with the finite element simulation results. The rolling process is dynamically simulated, and the distribution curves of important rolling parameters such as equivalent stress, control efficiency coefficient, transverse rolling pressure, lateral thickness and work roll deflection is obtained. Based on summarizing the influence of rolling parameters on rolling deformation, the research results of this paper can play an important role in the actual rolling process control. The research results have certain guiding significance for the development and optimization of the rolling control system.
    Źródło:
    Archives of Metallurgy and Materials; 2022, 67, 2; 623--635
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
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