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Tytuł:
A Pressure-Dependent Plasticity Model for Polymer Bonded Explosives under Confined Conditions
Autorzy:
Wei, Qiang
Huang, Xi-cheng
Chen, Peng-wan
Liu, Rui
Powiązania:
https://bibliotekanauki.pl/articles/27787985.pdf
Data publikacji:
2021
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
polymer bonded explosives
constitutive model
damage model
confining pressure
mechanical response
Opis:
The safety of explosives is closely related to the stress state of the explosives. Under some stress stimulation, explosives may detonate abnormally. It is of great significance to accurately describe the mechanical response of explosives for the safety evaluation of explosives. The mechanical properties of polymer bonded explosives (PBXs) strongly depend on pressure. In this study, the mechanical behaviour of PBXs under confined conditions was investigated. It was found that the stress-plastic strain response of a PBX under high confining pressures is a combination of the non-linear and linear hardening portions. However, the linear hardening portion has often been neglected in characterizing the mechanical behaviour of a PBX under such pressures. The Karagozian and Case (K&C) model was applied to characterize the mechanical behaviour of PBXs. The numerical results demonstrated that when the confining pressure was high, the K&C model could not adequately match the experimental data due to the limitation of the damage model. Therefore, a new damage model was developed by means of considering intragranular damage and transgranular damage. This modification made it possible to introduce a linear hardening process into the original K&C model. The method proposed to describe the stress-strain results under high confining pressures was to consider the stress-plastic strain curve, including the nonlinear and linear hardening portions. The damage evolution of the original K&C model and a linear hardening model were applied for the nonlinear and linear hardening portions respectively. The influence of the linear hardening model on the damage evolution of the original K&C model was included when describing the nonlinear hardening portion. A comparison between simulation and experiment showed that the modified K&C model could well describe the mechanical response of PBXs under different confining pressures.
Źródło:
Central European Journal of Energetic Materials; 2021, 18, 3; 339--368
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Polarization dependent high refractive index metamaterial with metallic dielectric grating structure in infrared band
Autorzy:
Li, Jianmin
Chen, Peng
Fang, Bo
Cai, Jinhui
Zhang, Le
Wu, Yinglai
Jing, Xufeng
Powiązania:
https://bibliotekanauki.pl/articles/2172825.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
metamaterial
high refractive index
infrared band
Opis:
According to the theory of high refractive index of metamaterials, a composite structure of metal dielectric grating was designed to achieve high refractive index in infrared band. Based on the S-parameter inversion algorithm, we extracted the effective permittivity, the effective permeability, and the effective refractive index of the designed metamaterial. By changing the geometric parameters of the composite grating metamaterial structure, the effective refractive index of the designed metamaterial reaches more than 8.0 at the infrared resonance frequency. This is a high refractive index that many natural materials cannot achieve. It is noteworthy that the metamaterial structure has obvious polarization sensitivity. The metamaterial structure has both high refractive index and wideband zero refractive index properties when different polarized light is incident. At the same time, we further investigate the influence of metamaterial geometric parameters on the effective refractive index of metamaterials. Also, we propose a double grating metamaterial structure to obtain more degrees of freedom of metamaterial on the effective refractive index.
Źródło:
Optica Applicata; 2022, 52, 3; 441--460
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Damage and fracture analysis of bolted joints of composite materials based on peridynamic theory
Autorzy:
Yang, Na-Na
Zhao, Tian-You
Gu, Ji-Guang
Chen, Zhi-Peng
Powiązania:
https://bibliotekanauki.pl/articles/258888.pdf
Data publikacji:
2019
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
peridynamic theory
composite material
damage and fracture
joints
Opis:
It is clear that the advantages of fibre glass-reinforced plastics surpass those of steel, but the failure analysis of composite structures is much more complex than that of isotropic materials as composite materials may fail in a variety of ways. In order to simulate the damage and fracture of bolted joints of fibre reinforced composite, the bond-based peridynamic method suitable for elastic, brittle and anisotropic characteristics of composite material is used. The peridynamic model for composite laminate is validated by the finite element method. Then a peridynamic program of composite damage is applied to calculating the damage of bolted joint structure and the damage propagation process and failure mode of the structure is obtained.
Źródło:
Polish Maritime Research; 2019, 2; 22-32
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of Moving Average and Differential Operation for Wheeze Detection in Spectrograms
Autorzy:
Hsueh, Meng-Lun
Chen, Jin-Peng
Lu, Bing-Yuh
Wu, Huey-Dong
Liu, Pei-Yi
Powiązania:
https://bibliotekanauki.pl/articles/31340111.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
differential operation
moving average
signal
lung sound
wheeze
Opis:
A moving average (MA) is a commonly used noise reduction method in signal processing. Several studies on wheeze auscultation have used MA analysis for preprocessing. The present study compared the performance of MA analysis with that of differential operation (DO) by observing the produced spectrograms. These signal preprocessing methods are not only applicable to wheeze signals but also to signals produced by systems such as machines, cars, and flows. Accordingly, this comparison is relevant in various fields. The results revealed that DO increased the signal power intensity of episodes in the spectrograms by more than 10 dB in terms of the signal-to-noise ratio (SNR). A mathematical analysis of relevant equations demonstrated that DO could identify high-frequency episodes in an input signal. Compared with a two-dimensional Laplacian operation, the DO method is easier to implement and could be used in other studies on acoustic signal processing. DO achieved high performance not only in denoising but also in enhancing wheeze signal features. The spectrograms revealed episodes at the fourth or even fifth harmonics; thus, DO can identify high-frequency episodes. In conclusion, MA reduces noise and DO enhances episodes in the high-frequency range; combining these methods enables efficient signal preprocessing for spectrograms.
Źródło:
Archives of Acoustics; 2022, 47, 3; 383-388
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental study of dam-break-like tsunami bore impact mechanism on a container model
Autorzy:
Chen, Cheng
Chen, Jun
Lin, Peng
Chen, Chiwei
Chen, Haozhe
Powiązania:
https://bibliotekanauki.pl/articles/260608.pdf
Data publikacji:
2020
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
tsunami bore
dam break
container
Froude number
movement distance
coast slope
Opis:
Tsunami disasters have frequently occurred in recent years. More and more researchers are focusing on this topic. To investi-gate the tsunami bore impact mechanism on a container model, a multi-functional slope-changing tsunami flume is built in this study. To simulate a tsunami bore, a dam-break wave was generated by a free-falling gate in a reservoir. A needle water level gauge and a high-speed camera were used to measure the tsunami wave heights and velocities for different storage water levels in the test flume, and the corresponding Froude numbers of tsunami waves were also calculated. The factors af-fecting the movement distance of the tsunami wave impacting the container model are explored in this experiment, and the results show that the movement distance is positively correlated with the storage water level, and negatively correlated with the container density and the coast slope.
Źródło:
Polish Maritime Research; 2020, 1; 53-59
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stigmasterol blocks cartilage degradation in rabbit model of osteoarthritis
Autorzy:
Chen, Wei-Ping
Yu, Chong
Hu, Peng-Fei
Bao, Jia-Peng
Tang, Jing-Li
Wu, Li-Dong
Powiązania:
https://bibliotekanauki.pl/articles/1039645.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
matrix metalloproteinases
stigmasterol
osteoarthritis
Opis:
Stigmasterol has been shown exihbit anti-osteoarthritic properties in vitro studies. However, the in vivo effects of stigmasterol on cartilage are still unclear. This study investigated the anti-osteoarthritic properties of stigmasterol on cartilage degradation in a rabbit model of osteoarthritis (OA). Twenty rabbits underwent bilateral anterior cruciate ligament transection (ACLT) to induce OA. Five rabbits were used as normal control. Two weeks after operation, the rabbits were randomly divided into two groups. Each group of 10 rabbits received intra-articular injection with 0.3 ml of stigmasterol in left knees and vehicle in right knees, once weekly. Group 1 was killed 6 weeks after ACLT and 2 were sacrificed 9 weeks after ACLT. The knee joints were assessed by gross morphology, histology and gene expression analysis. We found that expression of genes encoding matrix metalloproteinases (MMPs) was significantly higher while tissue inhibitors of metalloproteinase (TIMP)-1 was significantly lower in the both joints of the two OA groups compared to normal contrals. Stigmasterol reduced the cartilage degradation as assessed by histological analysis and markedly suppressed MMPs expression both in group 1 and group 2. Our results suggest that stigmasterol may be considered as a possible therapeutical agent in the treatment of OA.
Źródło:
Acta Biochimica Polonica; 2012, 59, 4; 537-541
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Toluene Mono-nitration in a Semi-batch Reactor
Autorzy:
Chen, L. P.
Chen, W. P.
Liu, Y.
Peng, J. H.
Liu, R. H.
Powiązania:
https://bibliotekanauki.pl/articles/358853.pdf
Data publikacji:
2008
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
toluene mono-nitration
apparent activation energy
semi-batch reaction
thermal hazard
Opis:
Toluene mono-nitration in a semi-batch reactor was investigated with reaction calorimeter (RC1). The mixed acid HNO3/H2SO4/H2O (wt%) was used in proportion 13/66/21, which is similar to industrial parameters. The exothermic rates at different reaction temperatures were compared, and then the curves of heat generation rate after dosing were analyzed. The Maximal Temperature attainable by runaway of the desired Synthetic Reaction (MTSR) under different conditions were calculated for the course hazard evaluation. The results showed that the average reaction heat of mono-nitration was between 169.07~177.11 kJ mol-1, and the special heat of reactant was about 2 kJ kg-1 K-1. Average Ea of second order kinetic was about 30 kJ mol-1, and reaction rate was 10-4 mol s-1 l-1 order of magnitude when the strength of sulphuric acid was about 73.5%. It was also found that when temperature or stirring speed increases, the potential heat accumulation decreases.
Źródło:
Central European Journal of Energetic Materials; 2008, 5, 2; 37-47
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on the Acoustic Scattering Characteristics of Multi-Sections Conning Tower Geometries in Monostatic Configuration
Autorzy:
Han, Lin-Jiang
Song, Hao
Chen, Chang-Xiong
Peng, Xi-Rui
Peng, Zi-long
Powiązania:
https://bibliotekanauki.pl/articles/2141632.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
conning tower
Kirchhoff approximation
target strength
monostatic configuration
Opis:
The overall acoustic echo of a submarine is greatly dependent on the conning tower. For enhancing the acoustic stealth performance of a submarine, it is necessary to research an innovative design scheme of the conning tower to reduce its target strength (TS). The aim of this work is to reduce the TS of a conning tower by varying its geometry and streamlining. The accuracy in modelling the acoustic scattering of a conning tower using the Kirchhoff approximation (KA) was validated, compared with finite element analysis (FEA). Several angular conning tower geometries were designed to analyze the effect of streamlining and the number of lateral facets on TS using the KA method. In consideration of the actual situation, the acoustic effect of backing medium was analyzed by compared water-filled elastic hulls with rigid hulls. From the observed TS calculation results, it is shown that the non-streamlined four lateral-facet conning tower geometries are optimal for acoustic stealth performance during the range of incidence angles from −10° to 10°, whereas the streamlined versions have better performance at incidence angles beyond this range. Furthermore, elastic hulls and rigid hulls provide similar spatial distribution regularities in monostatic configuration with the rigidity affecting the magnitude of the TS.
Źródło:
Archives of Acoustics; 2022, 47, 3; 307-317
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Molecular cloning, expression and characterization of Bmserpin-2 gene from Bombyx mori
Autorzy:
Pan, Ye
Xia, Hengchuan
Lü, Peng
Chen, KePing
Yao, Qin
Chen, Huiqin
Gao, Lu
He, Yuanqing
Wang, Lin
Powiązania:
https://bibliotekanauki.pl/articles/1040486.pdf
Data publikacji:
2009
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
serpin-2
Bombyx mori
bioinformatics
subcellular location
qPCR
Opis:
Serpins are a broadly distributed family of protease inhibitors. In this study, the gene encoding Bombyx mori serpin-2 (Bmserpin-2) was cloned and expressed in E. coli. The Bmserpin-2 cDNA contains a 1125 bp open reading frame (ORF). The deduced protein has 374 amino-acid residues, contains a conserved SERPIN domain and shares extensive homology with other invertebrate serpins. RT-PCR analysis showed that Bmserpin-2 was expressed in all developmental stages of B. mori larvae and various larval tissues. Subcellular localization analysis indicated that Bmserpin-2 protein was located in the cytoplasm. Interestingly, real-time quantitative PCR revealed that the expression of Bmserpin-2 in the midgut of susceptible B. mori strain 306 significantly increased at 72 hours post inoculation (hpi) when infected with BmNPV. However, there was no significant increase of the Bmserpin-2 expression in resistant strain NB infected with BmNPV. Thus, our data indicates that Bmserpin-2 may be involved in B. mori antiviral response.
Źródło:
Acta Biochimica Polonica; 2009, 56, 4; 671-677
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Extraction and separation of zinc, lead, silver, and bismuth from bismuth slag
Autorzy:
Xing, Peng
Ma, Baozhong
Wang, Chengyan
Chen, Yongqiang
Powiązania:
https://bibliotekanauki.pl/articles/109744.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
bismuth
zinc
lead
silver
extraction
separation
Opis:
The present paper deals with the extraction and separation of zinc, lead, silver, and bismuth from a refractory bismuth refining slag via a hydrometallurgical route. The process consists of a preliminary leaching of zinc with water, followed by the selective leaching of lead and silver with a calcium chloride solution, leading to the crystallization of lead chloride and the cementation of silver. The diagrams of the total concentrations of [Pb]/[Ag] versus [Cl-] and temperature in the Pb/Ag-Cl-H2O system were drawn, respectively, to determine the optimum concentration of leaching agent and leaching temperature. The potential-pH diagram of the Pb/Ag/Bi-H2O system indicates that the preferential leaching of lead and silver could be achieved. Finally, 98.8% of lead and 90.4% of silver were selectively removed by further leaching the water leaching residue with 400 g/dm3 of CaCl2 solution at pH 4.5 and 80 °C, while only 3.7% of bismuth was leached in this stage. Fifty-nine percent of lead in the leach liquor was separated out as PbCl2 by natural cooling. Ninety-five percent of silver in mother liquor was recovered by cementation with a lead sheet. The depleted CaCl2 solution can be sent to the leaching step again to close the loop.
Źródło:
Physicochemical Problems of Mineral Processing; 2019, 55, 1; 173-183
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Classification techniques and parameter optimization of Cyclone Continuous Centrifugal Separator for hematite ore
Autorzy:
Zhang, Pei
Xie, Haiyun
Jin, Yanling
Chen, Jialing
Zeng, Peng
Li, Yuanhong
Chen, Luzheng
Liu, Dianwen
Powiązania:
https://bibliotekanauki.pl/articles/2200335.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
hematite
Cyclonic Continuous Centrifugal Separator
CCCS
classification
Response Surface Methodology
Opis:
The Cyclonic Continuous Centrifugal Separator (CCCS) is a new type of separation equipment developed based on cyclonic continuous centrifugal separation technology and combined with the separation principle of the fluidized bed. Taking hematite as the research object, the main parameters and conditions of the best hematite classification were determined through the classification test by using CCCS. Based on the classification test, the significance order of each process parameter and their interaction with hematite classification efficiency of the underflow products was analyzed with the Response Surface Methodology, the optimal process parameter of hematite classification was obtained and a multiple regression equation was established. The optimized process conditions were as follows, feeding pressure 55.48 kPa, backwash pressure 9.79 kPa, and underflow pressure 31.94 kPa. Under these conditions, the average hematite ore classification efficiency of coarse fraction (-2~+0.15mm), medium fraction (-0.15~+0.074mm) and fine fraction (-0.074mm) were 85.08%, 65.10% and 51.41%, respectively, and the relative errors with the predicted values were 1.6%, 4.0% and 2.5%, respectively. The results showed that the analytical model has good predictive performance. This research provides a certain prospect for the application of Cyclonic Continuous Centrifugal Separation to hematite ore classification. it provides a reference for the application of the Response Surface Methodology in the classification of hematite by Cyclonic Continuous Centrifugal Separation.
Źródło:
Physicochemical Problems of Mineral Processing; 2023, 59, 1; art. no. 158864
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of foam separation in production of β-glucanase in Pichia
Autorzy:
Yuhang, Qin
Yuqing, Chen
Yajuan, Peng
Wenyao, Shao
Powiązania:
https://bibliotekanauki.pl/articles/2174820.pdf
Data publikacji:
2022
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
Foam separation
β-glucanase
recovery rate
enrichment ratio
Opis:
β-glucanase is widely used in many fields and has great economic value and development space, but it faces the difficulties of separation and nutrient destruction in the process of industrial production. Foam separation is a simple, mild and efficient adsorption separation technique that enables efficient separation and extraction of β-glucanase. In this study, five single factors(loading volume, pH, separation gas velocity, fermentation loading concentration, surfactant concentration) of foam separation and harvest of β-glucanase produced by Pichia pastoris were studied. The best univariate condition was: 600 mL/min separation gas velocity, loading volume of 200 mL, initial enzyme concentration of 100 g/mL, surfactant concentration of 0.3 mg/mL and pH of 5. Based on the best univariate condition, the optimal separation conditions of β-glucanase were further explored, and the five-factor four-level orthogonal test was designed. From the experimental results, the best separation condition was: 600 mL/min, loading volume of 200 mL, initial enzyme concentration of 100 μg/mL, surfactant concentration of 0.5 mg/mL and pH of 5. Under this separation condition, the enrichment ratio (E) was 0.56 and the recovery rate (R) was 96.01%.
Źródło:
Polish Journal of Chemical Technology; 2022, 24, 3; 1--7
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fringe pattern inpainting based on dual-exposure fused fringe guiding CNN denoiser prior
Autorzy:
Peng, Guangze
Chen, Wenjing
Powiązania:
https://bibliotekanauki.pl/articles/2086757.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fringe projection profilometry
phase calculation
convolutional neural network
denoiser prior
Opis:
The intensity of some pixels of the captured fringe will be saturated when fringe projection profilometry is used to measure objects with high reflectivity, which will significantly affect the reconstruction of the measured object. In this paper, we propose a fringe pattern inpainting method based on the convolutional neural network (CNN) denoiser prior guided by additional information from a fringe captured in short exposure time. First, a binary mask obtained by Otsu algorithm from the modulation information of the short exposure fringe is used to detect the high-saturation region in the normal exposure fringe. Then, the corrected gray-scales of the region of the short exposure fringe selected by the mask are inserted in the saturated region of the normal fringe to form an initial fringe for iteration. At last, fringe pattern inpainting is achieved by using a CNN denoiser prior. The correct phase can be reconstructed from the inpainted fringes. The computer simulation and experiments verify the effectiveness of the proposed method.
Źródło:
Optica Applicata; 2022, 52, 2; 179--193
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
HBx and SP1 upregulate DKK1 expression
Autorzy:
Peng, Hong
Li, Yongguo
Liu, Yunzhi
Zhang, Jingnan
Chen, Ke
Huang, Ailong
Tang, Hua
Powiązania:
https://bibliotekanauki.pl/articles/1038681.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
HCC
HBV
DKK1
SP1
Opis:
Numerous evidences suggested that the hepatitis B virus (HBV) was recognized as an important factor in the development of hepatocellular carcinoma (HCC). Dickkopf-1 (DKK1) recently was reported to be involved in the progress of HCC. HBV may regulate DKK1 expression in hematoma carcinogenesis. Here, we demonstrated that HBV could regulate DKK1 promoter activity which resulted in upregulation of its mRNA and protein expression in several HBV existing cell lines, and HBx played a prominent role in this process. Transcription factor binding site search result showed that there is a SP1 site in DKK1 promoter region. Luciferase assay showed that overexpression of SP1 could increase DKK1 promoter activity in a dose dependent manner. Accordingly, siRNA inhibition of SP1 expression reduced DKK1 promoter activity and decreased the expression of DKK1 protein.
Źródło:
Acta Biochimica Polonica; 2017, 64, 1; 35-39
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Free vibration of composite cylindrical shells with orthogonal stiffeners
Autorzy:
Wu, Yongfu
Zhao, Chen
Liang, Haofeng
Yao, Sishi
Xue, Jianghong
Xu, Peng
Powiązania:
https://bibliotekanauki.pl/articles/2086971.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
free vibration
laminated cylindrical shells
stiffener
energy method
Opis:
This paper proposes theoretical and numerical approaches to scrutinize the free vibration of orthogonal stiffened cylindrical shells. According to K´arman-Donnell shell theory, the total energy of the stiffened cylindrical shells is derived. Based on the principle of minimum potential energy, the eigenfunction related to the frequency is established and solved by developing a Matlab program. Analytical solutions of the natural frequency for free vibraion of the stiffened cylindrical shells are calculated and are verified against the finite element results from ABAQUS software. On account of the observations from the parametric study, an optimization scheme of the stiffeners is proposed.
Źródło:
Journal of Theoretical and Applied Mechanics; 2022, 60, 2; 239--252
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New insights into the promotion mechanism of $(NH_4)_2SO_4$ in sulfidization flotation: a combined experimental and computational study
Autorzy:
Chen, Daixiong
Liu, Mengfei
Hu, Bo
Dong, Yanhong
Xue, Wei
He, Peng
Chen, Fang
Zhu, Jianyu
Zhang, Chenyang
Powiązania:
https://bibliotekanauki.pl/articles/1446762.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
malachite
promotion
sulfidization
flotation
mechanism
Opis:
Ammonium sulfate ((NH4)2SO4) exhibits promoting effects in malachite sulfidization flotation. However, the promotion mechanism remains poorly understood. In this study, micro-flotation tests, zeta-potential measurements, scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM-EDS), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and materials studio simulation (DFT) were used to investigated the promotion mechanism of $(NH_4)_2SO_4$. Micro-flotation test demonstrates that the recovery of malachite from 73% increased to 83%, when the (NH4)2SO4 was added. Contact angle and zeta potential test results indicate that addition of $Na_2S•9H_2O$ changes the surface properties of malachite and provide the conditions for adsorption of butyl xanthate (BX). After promoting the sulfidization by $(NH_4)_2SO_4$, BX is more effective in improving the hydrophobicity. SEM-EDS and AFM results show that $(NH_4)_2SO_4$ can improve performance and stability of sulfidization. X-ray photoelectron spectroscopy indicates that after sulfidization, polysulfides and cuprous were appeared in malachite surface, infers that a redox reaction occurs between sulfur and copper on the surface of malachite. After addition of $(NH_4)_2SO_4$, the percentage of polysulfides and cuprous were increased, it implies $(NH_4)_2SO_4$ can accelerate the redox reaction. Computational results show that after adding $(NH_4)_2SO_4$, the adsorption energy of HS- on the malachite surface is reduced, implies that $(NH_4)_2SO_4$ can improve the stability of HS-adsorption on the surface of malachite.
Źródło:
Physicochemical Problems of Mineral Processing; 2021, 57, 5; 57-70
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on Tensile Properties and Microstructures of Different Sites in Al-Si Alloy Casting Component
Autorzy:
Tao, Jianquan
Xiang, Lin
Chen, Xidong
Sun, Jipeng
Wang, Yanbin
Du, Chuanhang
Peng, Feifei
Gao, Shiqing
Chen, Qiang
Powiązania:
https://bibliotekanauki.pl/articles/27765052.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
ZL114A alloy
plaster-mold casting
tensile properties
microstructure
fracture
Opis:
The tensile properties and microstructures of ZL114A alloy component with a complex shape are investigated at room temperature and 200°C, using the tensile tests, scanning electron microscopy and electron backscattering diffraction. Both thin wall and thick structure exhibit excellent properties, of which max ultimate tensile strength and elongation at break reach 314 MPa and 2.5% at room temperature, respectively. The ultimate tensile strengths of thin wall are 40 MPa and 25 MPa greater than those of thick structure at room temperature and 200°C, respectively. Moreover, the eutectic Si phases of thin wall exhibit a predominantly spherical morphology while of the morphology of thick structure are rod-like, resulting in the different mechanical properties between thin wall and thick structure. The fracture morphologies of thin wall and thick structure are studied to explain the difference in performance between thin wall and thick structure.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 2; 585--589
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Abnormal phase removing method in phase measuring profilometry
Autorzy:
Xu, X.
Cao, Y.
Chen, C.
Cao, S.
Peng, K.
Powiązania:
https://bibliotekanauki.pl/articles/173504.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
information optics
phase measuring profilometry
phase shifting algorithm
phase error
phase auto-extracting
Opis:
An abnormal phase removing method in phase measuring profilometry is proposed. In the five equal shifting phase steps algorithm, the shifting phase might be extracted from the deformed patterns captured by CCD camera. But there may be some errors introduced by a digital fringe projector and CCD camera in these deformed patterns. The impurity of the deformed patterns may lead to four classes of abnormalities when extracting the shifting phase. These abnormalities may cause the wrong shifting phase extraction by which the reconstructed object might be misshapen or anamorphic, or even in failure. By this proposed method, the above abnormalities can be removed, and the shifting phase can be auto-extracted precisely from the impure deformed patterns without knowing its value. Experimental results verify the feasibility and effectiveness of the proposed method.
Źródło:
Optica Applicata; 2017, 47, 1; 85-95
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electrostatic Hazards Assessment of Nitramine Explosives: Resistivity, Charge Accumulation and Discharge Sensitivity
Autorzy:
Peng, Q.
Cao, W.
Zhou, W.
He, Z.
Jiang, W.
Chen, W.
Powiązania:
https://bibliotekanauki.pl/articles/358757.pdf
Data publikacji:
2016
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
nitramine explosives
electrostatic hazards
resistivity
charging characteristics
electrostatic discharge sensitivity
Opis:
The electrostatic hazards of nitramine explosives (RDX, HMX) were assessed in this paper. The resistivities of different particle-size RDX and HMX were tested by a device designed and manufactured according to the standard ISO/IEC 80079-20-2:2016. This work shows that the resistivities of uncompacted RDX and HMX increase as the particle size decreases. Charging characteristics test experiments were also carried out using a so-called sieve method. Using this method, the influence of aperture size on charge accumulation of RDX was studied, and the characteristics of electrostatic accumulation of different particle-size RDX and HMX sieved with 50 mesh standard sieve were compared. The results show that the absolute value of the charge accumulation increases as the mesh number increases (i.e. the aperture size decreases), and increases as the particle size is decreased, indicating that nano-sized RDX and nano-sized HMX accumulate static electricity more easily than conventional micron-sized ones. Finally, the electrostatic discharge (ESD) sensitivity of nano-sized RDX and nano-sized HMX was investigated. Nano-sized nitramine explosives were found to have a higher ESD sensitivity than micron-sized ones.
Źródło:
Central European Journal of Energetic Materials; 2016, 13, 3; 755-769
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimization of Square-shaped Bolted Joints Based on Improved Particle Swarm Optimization Algorithm
Autorzy:
Chen, Kui
Yang, Cheng
Zhao, Yongsheng
Niu, Peng
Niu, NaNa
Hongchao, Wu
Powiązania:
https://bibliotekanauki.pl/articles/27312779.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
particle swarm optimization algorithm
bolt connection
bolted joint
fractal theory
Opis:
The bolted joint is widely used in heavy-duty CNC machine tools, which has huge influence on working precision and overall stiffness of CNC machine. The process parameters of group bolt assembly directly affect the stiffness of the connected parts. The dynamic model of bolted joints is established based on the fractal theory, and the overall stiffness of joint surface is calculated. In order to improve the total stiffness of bolted assembly, an improved particle swarm optimization algorithm with combination of time-varying weights and contraction factor is proposed. The input parameters are preloading of bolts, fractal dimension, roughness, and object thickness. The main goal is to maximize the global rigidity. The optimization results show that improved algorithm has better convergence, faster calculation speed, preferable results, and higher optimization performance than standard particle swarm optimization algorithm. Moreover, the global rigidity optimization is achieved.
Źródło:
Eksploatacja i Niezawodność; 2023, 25, 3; art. no. 168487
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental and numerical studies on the shear stability of ship’s thin plates
Autorzy:
Li, Xiaowen
Zhu, Zhaoyi
Chen, Qinglin
Cai, Yingqiang
Peng, Miaojiao
Powiązania:
https://bibliotekanauki.pl/articles/2033266.pdf
Data publikacji:
2021
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
shear stability
ship’s thin plate
full-field strain measurement
buckling
nonlinear
Opis:
The stability of thin plate plays an important role in the design and strength check of ship structure. In order to study the shear stability of ship’s thin plates, in-plane shear buckling tests were carried out using a picture frame fixture and a 3D full-field strain measurement system. The critical buckling load, full-field displacement/strain information, and load-displacement curve were obtained. The finite element model with the frame fixture was established based on ABAQUS, with the eigenvalue buckling analysis and nonlinear buckling analysis being carried out to obtain the mechanical response information of the buckling and post-buckling of the ship’s thin plate. The effectiveness and accuracy of the numerical simulation method are verified by comparing the numerical simulation with the experimental results. On this basis, the critical buckling load obtained by shear test, numerical simulation, and theoretical calculation is analyzed, and the function of the frame shear fixture and its influence on the critical buckling load are defined. The research in this paper provides a useful reference for the testing and simulation of in-plane shear stability of ship’s thin plates.
Źródło:
Polish Maritime Research; 2021, 4; 133-141
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on the mechanism and kinetics of sulfuric acid leaching scandium from rich scandium anatase
Autorzy:
He, Fei
Gao, Likun
Chen, Long
Rao, Bing
Shen, Hairong
Peng, Kebo
Gao, Guangyan
Powiązania:
https://bibliotekanauki.pl/articles/2146896.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
anatase ore
sulfuric acid
leaching
kinetics
scandium
Opis:
Scandium and its compounds have excellent properties, and are widely used in cutting-edge fields such as optics, electronics, and alloys. Thus, scandium is an important strategic metal. However, scandium is extremely sparsely distributed in the earth's crust, rarely occurs as an independent mineral, and requires a complex recovery process. Therefore, the study of the extraction of scandium is of great practical significance. This study examined the leaching test and kinetics of scandium under the acid leaching system of refractory anatase ore. Under appropriate two-stage countercurrent leaching conditions, the first stage of the particle size of fraction of -0.074 mm 82.6%, initial H2SO4 concentration of 6 mol/L, leaching temperature of 100 °C, acid/solid ratio of 3 ml/g, stirring speed of 300 rpm, and leaching time of 50 min; and the second stage of the initial H2SO4 concentration of 11 mol/L, leaching temperature of 150 °C, acid/solid ratio of 4 ml/g, stirring speed of 300 rpm, and leaching time of 50 min, a scandium leaching rate of 96.98% was achieved. The kinetics of scandium leaching conformed to a shrinking-core model, and sulfuric acid concentration and temperature were the most important parameters affecting the scandium leaching rate. The kinetic analysis of scandium leaching at different sulfuric acid concentrations showed that as the concentration increased, the sulfuric acid leaching of scandium changed from being chemical reaction-controlled to internal diffusion-controlled, and the apparent reaction order was 1.2429. The kinetics of scandium leaching at different temperatures showed that the sulfuric acid leaching of scandium was reaction-controlled and the apparent activation energy was 42.21 kJ-mol-1.
Źródło:
Physicochemical Problems of Mineral Processing; 2022, 58, 3; art. no. 146171
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of preoxidation on copper flotation from copper-lead mixed concentrate
Autorzy:
Peng, Zeng
Haiyun, Xie
Yanling, Jin
Pei, Zhang
Jialing, Chen
Liu, Dianwen
Powiązania:
https://bibliotekanauki.pl/articles/24085956.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
copper-lead mixed concentrate
peroxidation
separation of copper and lead
response surface methodology
Opis:
Flotation separation of galena and chalcopyrite is always a difficult problem in mineral processing. In this paper, the selective preoxidation of galena and chalcopyrite with sulfuric acid was developed, and then the two minerals were completely separated by flotation. The surface oxidation mechanism of galena and chalcopyrite with sulfuric acid was analyzed by Fourier transform infrared spectroscopy (FT-IR) and Atomic Force Microscopy (AFM), and the results showed that hydrophilic oxide film was formed on the galena surface, while the surface of chalcopyrite is still hydrophobic sulfide film, which led to the separation of the two minerals by flotation. In addition, the Response Surface Methodology (RSM) was used to analyze the influence of main preoxidation parameters on the flotation separation of copper-lead concentrate, and the parameters were further optimized, as follows: sulfuric acid concentration of 5.3 mol/L, oxidation temperature of 101.8 °C and time of 48.3 min. The mixed concentrate containing Cu 11.57% and Pb 16.75% was preoxidized under the above conditions, and the flotation separation verification results showed that Cu concentrate with Cu grade of 18.09% and recovery of 95.41%, and Pb concentrate with Pb grade of 44.96% and recovery of 95.94% was obtained respectively. This paper provides a new method of preoxidation combined flotation to achieve high-efficiency separation of copper-lead mixed concentrate.
Źródło:
Physicochemical Problems of Mineral Processing; 2023, 59, 2; art. no. 163253
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photo-oxidative Aging Behaviors of Acrylic Coatings during UV Irradiation Investigated by Positron Annihilation Spectroscopy
Autorzy:
Zhao, Xipo
Cai, Xiaolin
Liu, Chang
Chen, Ting
He, Chunqing
Fang, Pengfei
Peng, Shaoxian
Powiązania:
https://bibliotekanauki.pl/articles/1033253.pdf
Data publikacji:
2017-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
Acrylic coating
UV irradiation
positron annihilation spectroscopy
Opis:
Slow positron annihilation spectroscopy, contact angle and scanning electron microscope (SEM) were employed to investigate the surface polarity and morphologies as functions of aging time in acrylic coatings during UV-a irradiation. The S parameter plots of each exposed sample are lower than that of the virgin sample in the whole range of E. The S parameter plots become lower as the exposing longer time, indicated that the irradiation generated more polar groups and increased the oxidation layer depth. Combined with surface morphology and the surface energy of acrylic coating, the variation of contact angle, and surface energy, polar component and dispersive component is related with surface polarity and morphologies.
Źródło:
Acta Physica Polonica A; 2017, 132, 5; 1527-1530
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A novel process for extraction of iron from a refractory red mud
Autorzy:
Ding, Wei
Xiao, Junhui
Peng, Yang
Shen, Siyue
Chen, Tao
Zou, Kai
Wang, Zhen
Powiązania:
https://bibliotekanauki.pl/articles/1450194.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
red mud
sodium sulfate
segregation roasting
magnetic separation
iron recovery
Opis:
Red mud is a kind of solid waste produced during alumina extraction from bauxite. To extraction valuable iron from red mud, the technology of adding sodium sulfate-segregation roasting-magnetic separation to treat red mud was developed. During the paper, the effects of various process parameters on the extraction of iron by segregation roasting-magnetic separation were studied, and the phase transformation behavior and microstructure of iron are explored. Repeated test results showed that magnetic concentrate (mass percent), TFe of 80.29 % and overall iron recovery of 92.08 %was obtained. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) results indicated that after the segregation roasting, the hematite was transformed into a new metal phase consisting mainly of metallic iron and magnetite. The addition of sodium sulfate during the segregation roasting can obviously improve the efficiency of segregation roasting-magnetic separation for iron extraction.
Źródło:
Physicochemical Problems of Mineral Processing; 2020, 56, 6; 125-136
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł

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