Weak fault feature extraction of rolling bearing under strong poisson noise and variable speed conditions

Qiang Ma,Shuqian Cao,Tao Gong,Jianhua Yang 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.11

Fault feature extraction of the rolling bearing under strong background noise is always a difficult problem in bearing fault diagnosis. At present, most of the research focuses on weak signal extraction under Gaussian white noise and has certain practical significance. However, the noise in engineering is often complex and changeable, Gaussian white noise cannot fully simulate the actual strong background noise. Poisson white noise is a type of typical non-Gaussian noise, which widely exists in complex mechanical impact. It is of great significance to study the weak fault feature extraction of a faulty bearing under this type of noise. At the same time, variable speed conditions occupy most rotating machinery speed conditions. Non-stationary vibration signals make it difficult to extract fault features, and the frequency spectrum ambiguity will occur because of speed fluctuation. To solve the above problems, a method of weak feature extraction of a faulty bearing based on computed order analysis (COA) and adaptive stochastic resonance (SR) is proposed. Firstly, by numerical simulation, the nonstationary fault characteristic signal corrupted with strong Poisson noise is transformed into a stationary signal in the angle domain by COA. Secondly, the influence of the parameters of the pulse arrival rate and noise intensity of Poisson white noise on the optimal SR response in the angle domain are studied, and the influence of the parameters of Poisson white noise on the fault feature extraction is given. Then, adaptive SR method is used to extract and enhance fault feature information. Finally, the effectiveness of this method in weak fault characteristic signal extraction under strong Poisson noise is verified by experiments. Numerical simulation and experimental results verify the effectiveness of the proposed method in bearing fault diagnosis under strong Poisson noise and variable speed conditions.

An Improved Circuit for Rolling Bearing Fault Detection Based On Square Demodulation and Stochastic Resonance

Zengqiang Ma,Jianhua Liang,Yingna Yang,Yachaona Li 보안공학연구지원센터 2014 International Journal of Multimedia and Ubiquitous Vol.9 No.3

Cavitation–silt erosion in sand suspensions

Yu Wang,Jianhua Wu,Fei Ma 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.12

Cavitation–silt erosion in sand suspensions has elicited research attention. However, erosion characteristics in various conditions of liquids remain unknown due to their complex mechanisms. Thus, the effects of sand size, concentration, and temperature of sand suspensions on cavitation–silt erosion and viscosity were experimentally investigated in the present work. The findings proved the existence of critical sand size. The silt–cavitation erosion decreased with the increase of sand concentration when the sand was smaller than the critical size, and it increased with the increment of the sand size and temperature. A good relationship between the viscosity and the sand size, concentration, and temperature was determined. Moreover, the cavitation–silt erosion mechanisms were obtained on the basis of the viscosity and impingement erosion analysis standpoint.

Experimental Investigation of the Hydraulic Performance of a Hydraulic-Jump-Stepped Spillway

Yu Zhou,Jianhua Wu,Fei Ma,Shangtuo Qian 대한토목학회 2021 KSCE Journal of Civil Engineering Vol.25 No.10

For a traditional stepped spillway, low energy dissipation and cavitation damage may occur when the unit discharge is larger than a limit due to reduced air entrainment in the flow. In the present work, a new type of stepped spillway called hydraulic-jump-stepped spillway (HJSS) was developed, and the air was efficiently entrained into the flow by means of a hydraulic jump in the aeration basin, which was an aeration element of this stepped spillway. Compared with the traditional stepped spillway, various aspects of the hydraulic performance of the HJSS were experimentally investigated, including the flow pattern, energy dissipation, air entrainment characteristics and time-averaged pressure. Physical model results demonstrated that the HJSS achieved a higher energy dissipation, a more favorable air entrainment performance, and a more reasonable pressure distribution. The HJSS successfully increased the unit discharge from 50 – 60 m2/s for a traditional stepped spillway to 101.47 m2/s.

Designing a Dangerous Location Aware Service Using Space-Oriented Metadata

Katsuhiro Takata,Jianhua Ma 제어로봇시스템학회 2006 제어로봇시스템학회 국제학술대회 논문집 Vol.2006 No.10

Separation and Characterization of Organic Chlorides in a Chinese Crude Oil

Xiaohui Li,Rui Ma,Liang Ding,Huiying Yuan,Bencheng Wu,Jianhua Zhu 대한화학회 2018 Bulletin of the Korean Chemical Society Vol.39 No.4

A crude oil from Shengli oilfield of China was extracted with N,N‐dimethylformamide (DMF) for separation and enrichment of organic chlorides. The resulting extract with relatively higher chlorine concentration was analyzed with gas chromatography–mass spectrometry (GC/MS). Among the identified heteroatom compounds in the extract sample, nitrogen‐containing compounds were most abundant in the extract sample, followed by chlorine‐, sulfur‐, and oxygen‐containing compounds, respectively. Four organochlorines with an aromatic core structure, i.e., 5‐chloro‐2‐methylaniline, 2‐chloro‐6‐methylaniline, 4‐chloro‐2‐nitrotoluene, and 1‐(5‐chloro‐2‐hydroxyphenyl)ethanone, were identified from crude oil extract. The dominant abundant organic chloride is 5‐chloro‐2‐methylaniline with relative content of 65.1% in the total of identified organic chlorides, followed by 1‐(5‐chloro‐2‐hydroxyphenyl)ethanone of 16.3%, 2‐chloro‐6‐methylaniline of 14.5%, and 4‐chloro‐2‐nitrotoluene of 4.1%, respectively.

A DRM Model for Copyrights Protection based on Hiding Information

Deok Gyu Lee,Jianhua Ma 보안공학연구지원센터 2006 International Journal of Multimedia and Ubiquitous Vol.1 No.4

There have been researches into digital watermarking technology or Fingerprinting vigorously to safeguard 'Protective rights for knowledge and poverty' for digital contents. DRM, Digital Rights Management, is not only 'Protective rights for knowledge and poverty', but also management and systems that are necessary to put out, circulate and use for contents. This technology, DRM, encrypts contents to protect digital contents and they are sold users on. Sellers transmit contents with 'Usage Right' and a license including a key of encryption. The key of encryption decodes encoded files. The right of usage restricts users' application of contents. Even if digital contents that are applied the DRM are coped illegally and circulated, contents will be protected from that because a player of DRM checks existence of licenses and allows contents to be restored. However, this method might cause users to feel inconvenient since the users can only restore contents through the licenses offered by a player or a Smartcard. If radio as well as cable is used popularly in the future, there will be a lot of limits to use those kinds of players. In the method of that, the method using players need different players in order to work successfully in wired and wireless environment. In the case of using Smartcards, there might be a dangerous situation when the Smartcards disappeared. This paper proposes two kinds of ideas. One is protecting contents from illegal acts such as illegal copies when the contents are in the process of circulation. The other is the protocol that can give users convenience. Hidden Agents are used so that contents are protected from illegal copies and illegal use in the contents and cuts off those illegal acts. The Agent will be installed without any special setup. In addition, it can replace roles of Watermarking as a protection. Therefore, this paper shows the solution of illegal copies that happens frequently.

Nonisothermal Decomposition Reaction Kinetics, Specific Heat Capacity, Thermodynamic Properties and Adiabatic Time-to-explosion of 4-Amino-1,2,4-triazole Copper Complex

Yinghui Ren,Dan Li,Jianhua Yi,Fengqi Zhao,Haixia Ma,Kangzhen Xu,Jirong Song 대한화학회 2010 Bulletin of the Korean Chemical Society Vol.31 No.7

4-Amino-1,2,4-triazole copper complex (4-ATzCu) was synthesized, and its thermal behaviors, nonisothermal decomposition reaction kinetics were studied by DSC and TG-DTG techniques. The thermal decomposition reaction kinetic equation was obtained as: dα / dt =1022.01 (1−α )[−ln(1−α )]1/3 exp(−2.75×104 /T) . The standard mole specific heat capacity of the complex was determined and the standard molar heat capacity is 305.66 J·mol‒1·K‒1 at 298.15 K. The entropy of activation ( ΔS ≠ ), enthalpy of activation (ΔH ≠), and Gibbs free energy of activation ( ΔG≠) are calculated as 171.88 J·mol‒1·K‒1, 225.81 kJ·mol‒1 and 141.18 kJ·mol‒1, and the adiabatic time-to-explosion of the complex was obtained as 389.20 s.

An Optimal ODAM-Based Broadcast Algorithm for Vehicular Ad-Hoc Networks

( Weifeng Sun ),( Feng Xia ),( Jianhua Ma ),( Tong Fu ),( Yu Sun ) 한국인터넷정보학회 2012 KSII Transactions on Internet and Information Syst Vol.6 No.12

Broadcast routing has become an important research field for vehicular ad-hoc networks (VANETs) recently. However, the packet delivery rate is generally low in existing VANET broadcast routing protocols. Therefore, the design of an appropriate broadcast protocol based on the features of VANET has become a crucial part of the development of VANET. This paper analyzes the disadvantage of existing broadcast routing protocols in VANETs, and proposes an improved algorithm (namely ODAM-C) based on the ODAM (Optimized Dissemination of Alarm Messages) protocol. The ODAM-C algorithm improves the packet delivery rate by two mechanisms based on the forwarding features of ODAM. The first distance-based mechanism reduces the possibility of packet loss by considering the angles between source nodes, forwarding nodes and receiving nodes. The second mechanism increases the redundancy of forwarding nodes to guarantee the packet success delivery ratio. We show by analysis and simulations that the proposed algorithm can improve packet delivery rate for vehicular networks compared against two widely-used existing protocols.

Grape Seed Extracts Inhibit the Overexpression of Inflammatory Cytokines in Mouse Retinas and ARPE-19 Cells: Potentially Useful Dietary Supplement for Age-Related Eye Dysfunction

Zeying Chu,Guanqun Ma,Xiangjun Sun,Zhihan Xu,Jianhua Zhang 한국식품영양과학회 2020 Journal of medicinal food Vol.23 No.5

Aging can cause retinal degeneration, which leads to visual impairment among the elderly population. Age-dependent increases in amyloid beta (Aβ) inducesinflammatory cytokine overexpression in the retinal pigment epithelium (RPE), which promotes the progression of age-related retinal degeneration. However, whether dietary antioxidants are useful for the treatment of RPE degeneration remains to be clarified. This study exposited the protective activities and underlying mechanisms of grape seed extracts (GSEs) against Aβ-induced proinflammatory events in mouse retinas and ARPE-19 cells. The experimental data demonstrated that GSEs attenuated the increases in messenger RNA (mRNA) levels of interleukin 12 (IL-12), interleukin 6 (IL-6), interleukin 1β (IL-1β), and interleukin 18 (IL-18) in the retinal tissues of Aβ-treated mice. The experimental results in mice were confirmed by findings in ARPE-19 cells with or without treatment with GSEs. GSEs affected the protein expression levels of endoplasmic reticulum stress markers in ARPE-19 cells exposed to Aβ. Knockdown of Bip blocked the inhibitory activities of GSEs on mRNA levels of IL-6, IL-1β, IL-18, and IL-8. We conclude that GSEs may suppress proinflammatory cytokines partly by increasing the expression of Bip.