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Tytuł:
The relationship between manganism and the workplace environment in China
Autorzy:
Wang, Yongyi
Xue, Jian
Cheng, Shuqun
Ding, Yubin
He, Junlin
Liu, Xueqing
Chen, Xuemei
Wang, Yingxiong
Feng, Xiangyu
Xia, Yinyin
Powiązania:
https://bibliotekanauki.pl/articles/2180079.pdf
Data publikacji:
2012-09-01
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
manganese
occupational exposure
welding
mining
occupational intoxication
chronic manganism
Opis:
Manganese is a trace element and a cofactor of many enzymes, so it is essential for physiologic functioning, but it is also a neurotoxin at high doses. Manganism is most often caused by occupational exposure. It is manifested by a myriad of signs and symptoms ranging from the neurasthenia syndrome, such as headache and dizziness, to the Parkinson-like syndrome, depending on the blood manganese levels as well as the duration of exposure. We are reporting a case of manganism using both clinical and occupational hygiene investigation methods. The patient presented the neurasthenia syndrome accompanied by hypertonicity of arm muscles and was diagnosed to have mild chronic manganism. Finally, the patient was discharged from the hospital after the treatment had improved her condition. In China, there are many chronic manga nese cases, partly due to a rapid industrial development with great use of Mn and the low self-protection awareness among the workers and the factories management that cannot catch up with the speed of the economical development. Therefore, factories are responsible for improving the conditions at the workplace.
Źródło:
International Journal of Occupational Medicine and Environmental Health; 2012, 25, 4; 501-505
1232-1087
1896-494X
Pojawia się w:
International Journal of Occupational Medicine and Environmental Health
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The mechanism study on deep eutectic solvent for desilication of magnetite by reverse flotation
Autorzy:
He, Zhan
Liu, Cai
Mei, Guangjun
Zhao, Yuanyuan
Cheng, Qian
Song, Xianwei
Powiązania:
https://bibliotekanauki.pl/articles/1845237.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
reverse flotation
deep eutectic solvents collector
desilication
magnetie
quartz
Opis:
Magnetite reverse flotation using a new deep eutectic solvent synthesized by lactic acid and CTAC as the collector has been investigated in this work. The flotation test results were compared with dodecylamine. The CTAC/lactic acid DES increased the grade of total iron to 66.69%, and the reduce quartz content to 6.67%, which were preferable to dodecylamine (the grade of Fe in the concentrate is 63.47%, and the grade of quartz in the concentrate is 9.13%). The depression performance and adsorption mechanism of CTAC/lactic acid DES on surface of magnetite and quartz are investigated by FT-IR, zeta potential and XPS. The results show that the adsorption of CTAC/lactic acid DES on quartz surface is more effective than that of magnetite. Therefore, deep eutectic solvent is an effective reagent for reverse flotation of magnetite as collector.
Źródło:
Physicochemical Problems of Mineral Processing; 2021, 57, 6; 12-22
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The mechanism study on deep eutectic solvent for desilication of magnetite by reverse flotation
Autorzy:
He, Zhan
Liu, Cai
Mei, Guangjun
Zhao, Yuanyuan
Cheng, Qian
Song, Xianwei
Powiązania:
https://bibliotekanauki.pl/articles/2146858.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
reverse flotation
deep eutectic solvents collector
desilication
magnetie
quarto
Opis:
Magnetite reverse flotation using a new deep eutectic solvent synthesized by lactic acid and CTAC as the collector has been investigated in this work. The flotation test results were compared with dodecylamine. The CTAC/lactic acid DES increased the grade of total iron to 66.69%, and the reduce quartz content to 6.67%, which were preferable to dodecylamine (the grade of Fe in the concentrate is 63.47%, and the grade of quartz in the concentrate is 9.13%). The depression performance and adsorption mechanism of CTAC/lactic acid DES on surface of magnetite and quartz are investigated by FT-IR, zeta potential and XPS. The results show that the adsorption of CTAC/lactic acid DES on quartz surface is more effective than that of magnetite. Therefore, deep eutectic solvent is an effective reagent for reverse flotation of magnetite as collector.
Źródło:
Physicochemical Problems of Mineral Processing; 2021, 57, 6; 12--22
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of Al(III) and Fe(III) ions on the flotation behavior of Kfeldspar with sodium oleate as the collector
Autorzy:
Chen, Yi
Zhou, Jikui
He, Guichun
Hu, Hongxi
Liu, Chao
Yang, Jiping
Lyu, Xianjin
Powiązania:
https://bibliotekanauki.pl/articles/27323648.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
K-feldspar flotation
aluminum ion
iron ion
sodium oleate
action mechanism
Opis:
The present study investigates the effects and mechanisms of aluminum (Al(III)) and iron (Fe(III)) ions on the flotation efficiency of potassium feldspar (K-feldspar) within oleate collector systems. The study employs micro-flotation experiments, solution chemistry calculations, zeta potential measurements, and FT-IR and XPS analyses to demonstrate that Al(III) and Fe(III) ions can significantly improve the flotation recovery of K-feldspar by altering its surface charge, bonding properties, and adsorption modes. The study also develops adsorption models for the flotation of K-feldspar activated by Al(III) and Fe(III), revealing the synergistic impacts of metal ion hydrolysis products and sodium oleate in the formation of hydrophobic complexes.
Źródło:
Physicochemical Problems of Mineral Processing; 2023, 59, 6; art. no. 174724
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Bending, Impact Fracture Behavior and Characteristics of Stainless Steel Clad Plates with Different Rolling Temperature
Autorzy:
An, Q.
Fan, K. Y.
Ge, Y. F.
Liu, B. X.
He, J.
Wang, S.
Chen, C. X.
Ji, P. G.
Tolochko, O.
Powiązania:
https://bibliotekanauki.pl/articles/2049433.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
stainless steel clad plate
interface characteristics
bending behavior
impact morphologies
delamination crack
Opis:
The interface characteristics, bending and impact behavior, as well as fracture characteristics of stainless steel clad plates fabricated by vacuum hot rolling at different rolling temperatures of 1100°C, 1200°C and 1300°C are investigated in detail. The interface bonding strength is gradually increased with the increasing rolling temperature due to the sufficient diffusion behavior of alloy element. The bending toughness and impact toughness are gradually decreased, while the bending strength increase with the increase of the rolling temperature, which is attributed to mechanisms of matrix softening and interface strengthening at high rolling temperature. Due to the weak interface at 1100°C, the bending and impact crack propagation path was displaced by delamination cracks, which in turn lead to reduction in stress intensity of the main crack, playing an effective role in toughening the stainless steel clad plates. Moreover, the impact fracture morphologies of clad plates show a typical ductile-brittle transition phenomenon, which is attributed to the matrix softening behavior with the increasing rolling temperature.
Źródło:
Archives of Metallurgy and Materials; 2021, 66, 1; 229-239
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis and characterization of TiO2/ZSM-5 photocatalysts for degradation of rhodamine
Autorzy:
Liu, Rulai
Hu, Jiapeng
Rau, Juiye
Lin, Hao
He, Huan
Gao, Biao
Lai, Wenliang
Powiązania:
https://bibliotekanauki.pl/articles/2086909.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
photodegradation
TiO2
ZSM-5
kaolin clay
fotodegradacja
glinka kaolinowa
Opis:
ZSM-5 synthesized by the hydrothermal method from raw kaolin clay was used as support to prepare TiO2/ZSM-5 catalysts via the sol-gel method. All prepared samples were characterized by X-ray fluorescence spectrometry (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), ultraviolet-visible spectroscopy (UV-Vis), transmission electron microscopy (TEM), particle size analysis and surface area measurement. The photocatalytic performance of TiO2/ZSM-5 was investigated based on rhodamine B (RhB) removal under UV radiation (450-600 nm. The results showed that the kaolin clay was successfully transformed into ZSM-5. The BET surface area and pore size distribution of the synthesized ZSM-5 were 364 m2/g and 0.54 nm, respectively. SEM and TEM revealed that TiO2 nanoparticles were well distributed on the surface of ZSM-5. The composite TiO2/ZSM-5 catalyst showed 98.53% removal, which is higher than that of pure TiO2 (80.13%) due to adsorption and degradation of RhB (5.0 mg/dm3) under 60 min UV light irradiation at 1 g/dm3 photocatalyst loading. The synergistic effect of TiO22 and ZSM-5, including adsorption, conduction band electron (e-), and valence-band holes (h+), makes the composite superior to pure TiO2, showing its potential for the degradation of organic dye.
Źródło:
Environment Protection Engineering; 2022, 48, 2; 29--42
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on stability of self-compacting concrete applied for filling layer structure from paste, mortar and concrete
Autorzy:
Liu, He
Zhang, Jingyi
Yang, Yanhai
Powiązania:
https://bibliotekanauki.pl/articles/2174048.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
stabilność
beton samozagęszczalny
warstwa wypełniająca
lepkość plastyczna
proporcja mieszanki
stability
self-compacting concrete
filling layer
plastic viscosity
mix proportion
Opis:
Self compacting concrete (SCC) filling layer is core structure of China rail track system (CRTS) ? type ballastless track. Construction quality, service performance and durability of CRTS ? ballastless structure are affected by stability of SCC for filling layer. In this study, the stability of SCC of filling layer is researched at three levels as paste, mortar and concrete by theory and experiment. Evaluation indices including bleeding (B), surface bubble rate (θ), thickness of paste (paste) and thickness of surface mortar (L) are proposed based on the theoretical calculation and analysis. The threshold viscosity of paste 0.394 Pa·s and mixture satisfied area are obtained at paste level based on the relationship between viscosity and B, θ of paste. The mixture satisfied area was defined at mortar level under criterions of maximum value of paste and slump flow. Optimal range of gap between neighboring aggregates (λca) 12.4 mm-14.1 mm is chosen by flow ability, passing ability, stable ability of SCC. These research results will help to further understand the stability of SCC.
Źródło:
Archives of Civil Engineering; 2022, 68, 3; 501--522
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on Noise Attenuation Characteristics of Hydrofoil with Specific Cavitation Number
Autorzy:
Xiaohui, He
Zhongle, Liu
Chao, Yang
Zhiyong, Yuan
Powiązania:
https://bibliotekanauki.pl/articles/31339799.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
sound pressure spectrum
noise
sound power spectrum
numerical prediction
Opis:
In this study, the modified Sauer cavitation model and Kirchhoff-Ffowcs Williams and Hawkings (K-FWH) acoustic model were adopted to numerically simulate the unsteady cavitation flow field and the noise of a three-dimensional NACA66 hydrofoil at a constant cavitation number. The aim of the study is to conduct and analyze the noise performance of a hydrofoil and also determine the characteristics of the sound pressure spectrum, sound power spectrum, and noise changes at different monitoring points. The noise change, sound pressure spectrum, and power spectrum characteristics were estimated at different monitoring points, such as the suction side, pressure side, and tail of the hydrofoil. The noise characteristics and change law of the NACA66 hydrofoil under a constant cavitation number are presented. The results show that hydrofoil cavitation takes on a certain degree of pulsation and periodicity. Under the condition of a constant cavitation number, as the attack angle increases, the cavitation area of the hydrofoil becomes longer and thicker, and the initial position of cavitation moves forward. When the inflow velocity increases, the cavitation noise and the cavitation area change more drastically and have a superposition tendency toward the downstream. The novelty is that the study presents important calculations and analyses regarding the noise performance of a hydrofoil, characteristics of the sound pressure spectrum, and sound power spectrum and noise changes at different monitoring points. The article may be useful for specialists in the field of engineering and physics.
Źródło:
Archives of Acoustics; 2023, 48, 3; 359-372
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of Molecular Perovskite (H2dabco)[NH4(ClO4)3]/Carbon Nanotubes Energetic Composite
Autorzy:
Hu, Li-shuang
Liu, Yang
He, Dan
Yang, Yajun
Gong, Shida
Guang, Chunyu
Deng, Peng
Hu, Shuangqi
Powiązania:
https://bibliotekanauki.pl/articles/27788083.pdf
Data publikacji:
2022
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
ammonium perchlorate
(H2dabco)[NH4(ClO4)3]
carbon nanotubes
mechanical sensitivity
thermal stability
Opis:
An ammonium perchlorate (AP, NH4(ClO4)3)-based molecular perovskite energetic material (H2dabco)[NH4(ClO4)3]/carbon nanotubes (DAP/CNTs) composite was prepared and characterized. Molecular perovskite DAP samples were synthesized by a facile one-pot reaction of triethylenediamine, perchloric acid (PCA, HClO4), and AP via a molecular assembly strategy. The results showed that the mechanical sensitivity (impact and friction sensitivities: >120 cm and 20%) and electrostatic spark sensitivity (8.90 J) of the DAP/CNTs energetic composite with 10 wt.% CNTs exhibited less sensitivity than that of DAP (impact, friction and electrostatic spark sensitivities: 112.3 cm, 45%, and 5.39 J, respectively), because of the mixing desensitization mechanism of CNTs. Compared with the pure DAP, the DAP/CNTs energetic composite has better performance with respect to thermal stability, exothermic capacity, and excellent continuous combustion properties. The DAP/CNTs energetic composite has potential application in a weapons system.
Źródło:
Central European Journal of Energetic Materials; 2022, 19, 1; 91--105
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Strength and Fracture Analysis of Single-Lap Self-Pierce Riveted Joints
Autorzy:
He, X.
Lu, Y.
Liu, F.
Xing, B.
Zeng, K.
Powiązania:
https://bibliotekanauki.pl/articles/1192386.pdf
Data publikacji:
2015-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
46.70.-p
Opis:
Due to the increased use of lightweight sheet materials, there has been a significant increase in the use of self-pierce riveting. This paper deals with the strength and fracture mechanism of single-lap self-pierce riveted joints. The online window technique was introduced in the single-lap self-pierce riveting processes for evaluating the quality of joints. Signals obtained from sensors were amplified and transferred to the data acquisition system which measures, processes and saves the signals. Monotonic tensile tests were carried out to measure the ultimate tensile strengths for the single-lap self-pierce riveted joints. For investigating the fracture mechanism of the single-lap self-pierce riveted joints, the electrolytic polishing and anode film coating were used for dealing with the cross-section. The differential interference contrast method was used for observing the micro-structure of the cross-section of the joints. The distribution of the hardness in the cross-section of the single-lap self-pierce riveted joints was also studied. The normal hypothesis tests were performed to examine the rationality of the test data.
Źródło:
Acta Physica Polonica A; 2015, 127, 4; 1424-1426
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Shock Ignition and Growth of HMX-based PBXs under Different Temperature Conditions
Autorzy:
Liu, Rui
Han, Yong
Li, Ming
Jiang, Zhihai
He, Songwei
Powiązania:
https://bibliotekanauki.pl/articles/358417.pdf
Data publikacji:
2019
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
shock ignition and growth
Lagrange test
HMX-based PBXs
high temperatures
Lee-Tarver model
Opis:
The Lagrange test was conducted to investigate the shock ignition and growth of HMX-based polymer bonded explosives (PBXs) under different temperature conditions. In this study, three temperature conditions, 25 °C, 80 °C and 120 °C were used. The pressure history values along the direction of the detonation wave propagation were obtained and presented as the characteristics of the shock ignition and growth. Manganin piezoresistive pressure gauges were used to measure the pressure. The results showed that the distance to detonation was clearly reduced as the temperature was increased. A distance greater than 9 mm at 25 °C was changed to less than 3 mm at 120 °C. In order to understand this phenomenon in more detail, the Lee-Tarver ignition and growth model was employed to simulate the Lagrange test, and the simulated pressures were compared with the measured pressures. The results demonstrated that the intrinsic mechanism of the phenomenon was that the high temperature changed both the equation of state of the unreacted explosive and the chemical reaction rate. It was remarkable that the parameter R2 in the model was reduced from −0.05835 to −0.06338, and the parameter G1 in the model was increased from 1.3 to 2.12.
Źródło:
Central European Journal of Energetic Materials; 2019, 16, 1; 21-32
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Serum activities of liver enzymes in workers exposed to sub-TLV levels of dimethylformamide
Autorzy:
He, Jinjiang
Liu, Jie
Kong, Yulin
Yang, Weiwei
Zhang, Zengli
Powiązania:
https://bibliotekanauki.pl/articles/2177403.pdf
Data publikacji:
2015-03-27
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
dimethylformamide
workers
liver enzymes
TWA
sub-TLV
urine
Opis:
Objectives The aim of this study has been to investigate serum activities of liver enzymes in workers exposed to sub-TLV levels of dimethylformamide (DMF). Material and Methods Seventy-two workers and 72 healthy controls participated in the study. All subjects underwent complete physical examinations and abdominal ultrasound examination. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and c-glutamyl transpeptidase (c-GT) were determined by an auto-chemistry analyzer. The data of airborne concentrations of DMF was obtained from the local Center of Disease Control and Prevention. The level of urine N-acetyl-S-(N-methylcarbamoyl)cysteine (AMCC) was measured by means of high-performance liquid chromatography. Results Time weighted average (TWA) concentration of the DMF in workplace was 18.6 (range: 9.8–36.2) mg/m³. The concentration of the AMCC in workers’ urine was 28.32 (range: 1.8–58.6) mg/l and 9 workers’ AMCC exceeded the biological exposure index (40 mg/l). Thirty-one workers reported gastrointestinal symptoms (abdominal pain, nausea, anorexia) and 10 workers reported headache, dizziness and/or palpitation in the exposed group. Serum analysis revealed that both the mean of serum activities of liver enzymes (ALT, AST and c-GT) and the percentage of workers with abnormal liver function were significantly higher in the exposed group as compared to the controls. Conclusions Dimethylformamide can cause liver damage even if air concentration is in the sub-threshold limit value (sub-TLV) level. The protection of skin contact against the exposure to the DMF might be a critical issue as far as the occupational health is concerned.
Źródło:
International Journal of Occupational Medicine and Environmental Health; 2015, 28, 2; 395-398
1232-1087
1896-494X
Pojawia się w:
International Journal of Occupational Medicine and Environmental Health
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rheological properties of paste for self-compacting concrete with admixtures
Autorzy:
Liu, He
Duan, Guangchao
Zhang, Jingyi
Yang, Yanhai
Powiązania:
https://bibliotekanauki.pl/articles/2174035.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
beton samozagęszczalny
właściwości reologiczne
zagęszczenie
ścinanie
krytyczne naprężenie ścinające
lepkość minimalna
domieszka
self-compacting concrete
rheologic properties
shear thickening
critical shear stress
minimum viscosity
admixture
Opis:
The paste content in the self-compacting concrete is about 40% in unit volume. The rheological properties of paste directly determine the properties of self-compacting concrete. In this paper, the effect of silica fume (2, 3, 4, and 5%), limestone powder (5, 10 and 15%), and the viscosity modified admixture (2, 3, 4, 5, 6, and 7%) on the rheological properties were investigated. The effect of admixtures on shear thickening response was discussed based on the modified Bingham model. The results indicate that yield stress and plastic viscosity increased with increased silica fume and viscosity modified admixture replacement. The paste’s yield stress increases and then decreases with limestone powder replacement. The critical shear stress and minimum plastic viscosity are improved by silica fume and viscosity modifying admixture. The critical shear stress first increases and decreases as the limestone powder replacement increases. A reduction in the shear thickening response of paste was observed with silica fume and viscosity modified admixture replacement increase.
Źródło:
Archives of Civil Engineering; 2022, 68, 3; 585--599
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on optimal design of spudcan structures to ease spudcan-footprint interactions in clay and comparative analyses with different measures
Autorzy:
Yu, Huafeng
Sun, Zhenzhou
He, Linlin
Yang, Liu
Powiązania:
https://bibliotekanauki.pl/articles/32890971.pdf
Data publikacji:
2022
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
spudcan-footprint interaction
novel spudcan shape
VHM curves
stomping
perforation drilling
Opis:
In order to ease consequences of spudcan-footprint interactions during jack-up rigs reinstalling in the vicinity of an existing seabed footprint, three new types of spudcan shapes, that is, a lotus-shaped spudcan with six circular holes, a flat-bottomed spudcan, and a concave-shaped spudcan, were proposed to perform an optimizing study of the spudcan structures, and the effectiveness of them were analyzed comparatively with other different measures. Firstly, 3D Large Deformation Finite Element (LDFE) analyses were carried out using the Coupled Eulerian-Lagrangian (CEL) method in the commercial finite element package ABAQUS. After calibrating the validity of the numerical calculation model against existing centrifuge test data and LDFE results, the differences in interaction mechanism between the novel spudcans and the generic spindle-shaped spudcan were studied when penetrating near an existing footprint with an eccentric distance of 0.5D, and the horizontal range of plastic deformation of the disturbed soils, the inclination angle of the spudcan and the offset distance of the pile legs were analyzed comparatively as well. The results show that the proposed novel spudcans can mitigate the maximum horizontal sliding force and the maximum bending moment at the top of the pile leg obviously, compared with those of the generic one, which were reduced by 32.59%, 22.47%, 28.18%, and 26.32%, 12.88%, 18.02%, respectively. It also can be seen that all novel structures can ease the adverse consequences of spudcan-footprint interactions effectively, and can improve the in -place stability of the spudcan as well. Finally, three possible measures in mitigating interactions of the spudcan-footprint were contrasted, that is, the novel spudcan (represented by the lotus-shaped spudcan with six holes), stomping method, and perforation drilling method. The results show that all of them can reduce adverse impacts induced by interactions of the spudcan-footprint, and also can improve the in-place stability of the spudcan during reinstallation. In addition, among them, according to the effect of reducing the additional stress of the spudcan, the effectiveness of them can be listed as follows: perforation drilling near an existing footprint > the lotus-shaped spudcan with six holes > stomping method. In terms of the vertical bearing capacity of the spudcan, the lotus-shaped spudcan with six holes can improve it as much as 16.33% compared with the spindle-shaped structure due to the particularity of the structure. While reducing the continuity and strength of soil foundations, the perforation drilling measure leads to the decrease of the vertical bearing capacity of the spudcan by 13.07%. It can be concluded that all the three measures have merits and demerits, so the relevant construction environment conditions and engineering practice should be fully considered when selecting measures to deal with interactions of the spudcan-footprint.
Źródło:
Polish Maritime Research; 2022, 1; 43-56
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reliability analysis for multi-state system based on triangular fuzzy variety subset bayesian networks
Analiza niezawodności systemu wielostanowego z zastosowaniem sieci bayesowskich opartych na rozmytych podzbiorach zmienności opisanych przez trójkątną funkcję przynależności
Autorzy:
He, Q.
Zha, Y.
Zhang, R.
Sun, Q.
Liu, T.
Powiązania:
https://bibliotekanauki.pl/articles/302183.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
teoria zbiorów rozmytych
system wielostanowy
sieć bayesowska
wypadek podczas ruchu wózka windy
analiza niezawodności
reliability analysis
fuzzy set theory
Multi-State System
Bayesian network
elevator free movement accident
Opis:
W niniejszej pracy zaproponowano nową metodę analizy niezawodności systemów wielostanowych wykorzystującą sieci Bayesa (BN) oparte na rozmytych podzbiorach zmienności opisanych za pomocą trójkątnej funkcji przynależności. Metoda ta uwzględnia rozmyty charakter danych dotyczących uszkodzeń, wielostanowość systemu oraz zmienność prawdopodobieństwa wystąpienia uszkodzenia w czasie. BN, które znalazły zastosowanie w modelowaniu i metodach obliczeniowych, wykorzystuje się także do analizy niezawodności. W przedstawionych badaniach, analizę BN uzupełniono o elementy teorii zbiorów rozmytych wykorzystując do opisu prawdopodobieństwa wystąpienia uszkodzenia, podzbiory zmienności opisane przez trójkątną funkcję przynależności. Niepewność zależności logicznej pomiędzy awariami reprezentowanymi przez różne węzły sieci opisano za pomocą tabel rozmytego prawdopodobieństwa warunkowego. W pierwszej kolejności analizowano prawdopodobieństwo uszkodzenia każdego korzenia (węzła głównego) w funkcji czasu. Następnie, wyznaczono trójkątny rozmyty podzbiór zmienności, za pomocą którego opisano rozmyte prawdopodobieństwo uszkodzenia węzłów głównych. Podzbiór ten wykorzystano do analizy niezawodności systemu wielostanowego przy pomocy rozmytych BN. Artykuł kończy opis wypadku podczas ruchu wózka windy szybkobieżnej, który potwierdza skuteczność i możliwość praktycznego wykorzystania proponowanej metody. Wyniki pokazują, że proponowane podejście może skutecznie rozwiązywać na wczesnym etapie problemy związane z niepewnością informacji oraz wielostanowością systemu.
In this paper, a novel reliability analysis method for multi-state system is proposed on the basis of triangular fuzzy variety subset Bayesian network (BN). The method considers fuzziness, multi-state, and variety of failure probability over time. With advantages in modeling and computation, the BN is utilized for reliability analysis. Fuzzy set theory is introduced into the BN analysis by using triangular fuzzy variety subset to describe failure probability. The uncertainty of fault logical relationship between different nodes is described through fuzzy conditional probability tables. As a function of time, the failure probability of each root node is analyzed first. Subsequently, the triangle fuzzy variety subset is established to describe the fuzzy failure probability of root nodes. This subset is applied to analyze the reliability of multi-state system fuzzy BN. Finally, a case study on the car free movement accident of flexible high-speed elevator lift system is used to demonstrate the effectiveness and practicality of the proposed method. Results show that the proposed approach could effectively address the problems on information uncertainty and multi-state in the early stage.
Źródło:
Eksploatacja i Niezawodność; 2017, 19, 2; 158-165
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł

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