An improved Corten-Dolan’s model based on damage and stress state effects

Huiying Gao,Hong-Zhong Huang,Zhiqiang Lv,Fang-Jun Zuo,Hai-Kun Wang 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.8

The value of exponent d in Corten-Dolan’s model is generally considered to be a constant. Nonetheless, the results predicted on thebasis of this statement deviate significantly from the real values. In consideration of the effects of damage and stress state on fatigue lifeprediction, Corten-Dolan’s model is improved by redefining the exponent d used in the traditional model. The improved model performsbetter than the traditional one with respect to the demonstration of a fatigue failure mechanism. Predictions of fatigue life on thebasis of investigations into three metallic specimens indicate that the errors caused by the improved model are significantly smaller thanthose induced by the traditional model. Meanwhile, predictions derived according to the improved model fall into a narrower dispersionzone than those made as per Miner’s rule and the traditional model. This finding suggests that the proposed model improves the life predictionaccuracy of the other two models. The predictions obtained using the improved Corten-Dolan’s model differ slightly from thosederived according to a model proposed in previous literature; a few life predictions obtained on the basis of the former are more accuratethan those derived according to the latter. Therefore, the improved model proposed in this paper is proven to be rational and reliable giventhe proven validity of the existing model. Therefore, the improved model can be feasibly and credibly applied to damage accumulationand fatigue life prediction to some extent.

Stable Cu-Co/C carbon-based composites for efficiency catalytic degradation of Orange II by PMS: Effect factors, application potential analysis, and mechanism

Xiaodan Huang,Caihua Liu,Zhiyong Zhang,V. Vasanthakumar,Huiying Ai,Lei Xu,Ming-Lai Fu,Baoling Yuan 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.126 No.-

Carbon-based metallic catalysts (CMCs) have emerged as efficient materials for removing water contaminants,but preparing CMCs with high efficiency and stability remains a great challenge. In this study, weprepared a bimetallic composite of Cu-Co/C catalyst via a gelation and calcination method to degradeOrange II by activating peroxymonosulfate (PMS). The characterization results demonstrated that thespecific surface area and pore size of Cu-Co/C catalysts were 1.675 m2/g and 6.313 nm, respectively,which can provide larger catalytic active sites for boosting PMS activation. Moreover, the effects of differentfactors on Orange II degradation efficiency, cyclic experiments, and possible application in realwater bodies were investigated. The Cu-Co/C catalyst can effectively activate PMS, and 50 mg/L ofOrange II was almost completely removed within 15 min. Additionally, the Cu-Co/C catalyst exhibitedhigh degradation efficiency for other organic dye pollutants. The radical quenching experiments indicatedthat the main active species for Cu-Co/C catalyzed degradation of Orange II were SO4and singlet oxygen(1O2). The catalyst demonstrated good stability and performance in real water bodies. We believe thatthis study will promote the application of carbon-based bimetallic catalysts in the environmental remediationprocess that utilize SO4based advanced oxidation.

An Improved Haze Removal Algorithm Based on Genetic Fuzzy Clustering

Xiaoguang Li,Huiying Huang 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.8

Aiming at the degeneration phenomenon of images taken in mist, according to the features of the degraded images, an improved haze removal algorithm based on genetic fuzzy clustering is presented in this paper after analyzing its defects and shortcomings. Firstly, the improved atmospheric scattering model is established. Secondly, the original image is converted into a standard image through the improved model, and then we present a new multi-scale image edge detection by genetic fuzzy clustering, Based on this observation, we can use the multi-scale image edge detection to estimate the haze thickness directly and recover a high quality haze-free image. The new algorithm uses good global search ability of the genetic algorithm, which will implement the transfer from the scene defogging problem into the optimal estimation problem under global contrast optimal point. Compared with other algorithms for degraded images, the improved haze removal algorithm not only detects image edge precisely, but also has better performance in situations of dense haze. Theoretical analysis and experimental results demonstrate that, the new algorithm improved in this paper are effective for removal of fog-degraded images, and can be applied to the practical situations.

Lifetime prediction for turbine discs based on a modified Walker strain model

Zhiqiang Lv,Hong-Zhong Huang,Huiying Gao,Fang-Jun Zuo,Hai-Kun Wang 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.10

We created three-dimensional models of turbine disc and blades of a type of aero-engine according to their geometries. Extant studies show that low cycle fatigue is the main failure mechanism of turbine disc. By using a non-linear elastic-plasticfinite element method, the static stress and strain state of the critically high stress regions, which can lead to operational failures,are determined. On the basis of stress-strain relation, a modified Walker strain life prediction model is proposed with norequired knowledge on the mean stress correction. Then the predicted life data from the modified Walker strain model arecompared with the testing results. After the verification, the modified Walker strain life prediction model and Miner’s rule wereapplied to predict the lifetime of the turbine disc under various operating conditions.

Determining the Walker exponent and developing a modified Smith-Watson-Topper parameter model

Zhiqiang Lv,Hong-Zhong Huang,Hai-Kun Wang,Huiying Gao,Fang-Jun Zuo 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.3

Mean stress effects significantly influence the fatigue life of components. In general, tensile mean stresses are known to reduce the fatigue life of components, whereas compressive mean stresses are known to increase it. To date, various methods that account for mean stress effects have been studied. In this research, considering the high accuracy of mean stress correction and the difficulty in obtaining the material parameter of the Walker method, a practical method is proposed to describe the material parameter of this method. The test data of various materials are then used to verify the proposed practical method. Furthermore, by applying the Walker material parameter and the Smith-Watson-Topper (SWT) parameter, a modified strain-life model is developed to consider sensitivity to mean stress of materials. In addition, three sets of experimental fatigue data from super alloy GH4133, aluminum alloy 7075-T651, and carbon steel are used to estimate the accuracy of the proposed model. A comparison is also made between the SWT parameter method and the proposed strainlife model. The proposed strain-life model provides more accurate life prediction results than the SWT parameter method.

Enhanced Secondary Electron Emission from Group III Nitride/ZnO Coaxial Nanorod Heterostructures

Lau, Shu ,Ping,Huang, Lei,Yu, Siu ,Fung,Yang, Huiying,Yoo, Jin ,Kyoung,An, Sung ,Jin,Yi, Gyu-Chul WILEY-VCH Verlag 2006 Small Vol.2 No.6

<B>Graphic Abstract</B> <P>Needle work: AlN/ZnO and GaN/ZnO coaxial nanoneedle heterostructures (see TEM image) have a higher secondary electron emission (SEE) yield (σ) than thin films of AlN and GaN deposited on Si substrates. The dependence of the SEE on the incidence angle of the beam indicates that these heterostructures do not follow the power law. The σ value of the heterostructures is enhanced by the inherited nanostructure from the ZnO nanoneedle template. <img src='wiley_img/16136810-2006-2-6-SMLL200500424-content.gif' alt='wiley_img/16136810-2006-2-6-SMLL200500424-content'> </P>

RNAi-Mediated Gene Silencing of Trcot1 Induces a Hyperbranching Phenotype in Trichoderma reesei

Fei Gao,Mengzhu Li,Weiquan Liu,Yingguo Bai,Tu Tao,Yuan Wang,Jie Zhang,Huiying Luo,Bin Yao,Huoqing Huang,Xiaoyun Su 한국미생물·생명공학회 2020 Journal of microbiology and biotechnology Vol.30 No.2

Trichoderma reesei is the major filamentous fungus used to produce cellulase and there is huge interest in promoting its ability to produce higher titers of cellulase. Among the many factors affecting cellulase production in T. reesei, the mycelial phenotype is important but seldom studied. Herein, a close homolog of the Neurospora crassa COT1 kinase was discovered in T. reesei and designated TrCOT1, which is of 83.3% amino acid sequence identity. Functional disruption of Trcot1 in T. reesei by RNAi-mediated gene silencing resulted in retarded sporulation on potato dextrose agar and dwarfed colonies on minimal medium agar plates containing glucose, xylan, lactose, xylose, or glycerol as the sole carbon source. The representative mutant strain, SUS2/Trcot1i, also displayed reduced mycelia accumulation but hyperbranching in the MM glucose liquid medium, with hyphal growth unit length values decreased to 73.0 μm/tip compared to 239.8 μm/tip for the parent strain SUS2. The hyperbranching phenotype led to slightly but significantly increased cellulase secretion from 24 to 72 h in a batch culture. However, the cellulase production per unit of mycelial biomass was much more profoundly improved from 24 to 96 h.

Protective Effects of Gypenosides against Fatty Liver Disease Induced by High Fat and Cholesterol Diet and Alcohol in Rats

Renan Qin,Hong Nie,Jianyu Zhang,Chuyuan Li,Xiaoqi Zhang,Aihua Xiong,Feng Huang,Zhen Yin,Kongyan Li,Wenyu Qin,Mingzhen Chen,Shubing Zhang,Lingyi Liang,Huiye Zhang,Wencai Ye 대한약학회 2012 Archives of Pharmacal Research Vol.35 No.7

In the present study, the protective effects of gypenosides from Gynostemma pentaphyllum on fatty liver disease (FLD) were examined in rats treated with high fat and cholesterol diet and alcohol. Male SD rats were divided into seven groups: control, model, lovastatin, silymarin, gypenosides high-, medium- and low-treatment groups. The latter 6 groups were fed high-fat and cholesterol diet and administered alcohol intragastricly once a day. Body weight was measured every week for 10 weeks, and the hepatic index was measured after 10 weeks. Compared with model group, levels of serum triglyceride (TG), total cholesterol (TC), free fatty acid (FFA), and low density lipoprotein cholesterol (LDL-C) level, malondialdehyde (MDA), serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity, and hepatocyte apoptosis were significantly decreased in gypenosides groups; while serum high density lipoprotein cholesterol (HDL-C), superoxide dismutase (SOD) activity in both serum and hepatic tissue and mRNA and protein level of peroxisome proliferator-activated receptor α (PPAR-α) were significantly increased. Moreover, hepatic steatosis and mitochondrial damage were improved. These results suggested that gypenosides could prevent liver fatty degeneration in fatty liver disease through modulating lipid metabolism, ameliorating liver dysfunction and reducing oxidative stress.