June 2019最新文献_第4页

Assessment of cold stress in avocado cultivars based on visual, physiological and biochemical criteria 基于视觉、生理和生化标准的鳄梨品种冷胁迫评价

June 2019 Pub Date : 2019-06-20 DOI: 10.21475/AJCS.19.13.06.P1593

G. C. Zaro, P. Caramori, C. Oliveira, G. T. Nagashima, J. R. Rosisca, C. Prete

{"title":"Assessment of cold stress in avocado cultivars based on visual, physiological and biochemical criteria","authors":"G. C. Zaro, P. Caramori, C. Oliveira, G. T. Nagashima, J. R. Rosisca, C. Prete","doi":"10.21475/AJCS.19.13.06.P1593","DOIUrl":"https://doi.org/10.21475/AJCS.19.13.06.P1593","url":null,"abstract":"Low temperatures affect avocado plants and their response varies across genetic variants. The objective of this study was to assess cold stress of avocado cultivars based on visual, physiological, and biochemical criteria for evaluating freezing injury in these plants. The avocado cultivars ‘Geada,’ ‘Fortuna,’ ‘Fuerte,’ ‘Quintal,’ ‘Margarida,’ and ‘Primavera’ were subjected to temperatures of −2.5, −4.0, −5.0, and −6.0 °C for 1 h in a growth chamber. Their responses to cold stress were evaluated on the basis of visual damage score, photosynthetic rate, water pressure potential, protein content and enzymatic activity. Moreover, the experimental design was factorial and completely randomized with four replicates of each cultivar. An analysis of variance of the results was performed and the means were compared using Tukey’s post-hoc test (p <0.05). Evaluations based on the plants water pressure potential, total protein content, catalase activity, photosynthetic rate, and visual damage score were efficient in estimating the effects of cold stress in avocado plants. Additionally, photosynthesis and visual damage score were significantly correlated in all evaluations, enabling classification of the cultivars in terms of response to cold stress. We found that Fuerte was the most tolerant cultivar followed by Geada. The Primavera was the most sensitive cultivar.","PeriodicalId":227331,"journal":{"name":"June 2019","volume":"133 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125273012","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

A Fault Diagnosis Method Based on Improved Pattern Spectrum and FOA-SVM 基于改进模式谱和FOA-SVM的故障诊断方法

June 2019 Pub Date : 2019-06-01 DOI: 10.20855/IJAV.2019.24.21461

Dejian Sun, Bing Wang, Xiong Hu, Wei Wang

引用次数: 1

Bifurcation Analysis of a Transversely Cracked Nonlinear Jeffcott Rotor System at Different Resonance Cases 横向裂纹非线性Jeffcott转子系统在不同共振情况下的分岔分析

June 2019 Pub Date : 2019-06-01 DOI: 10.20855/IJAV.2019.24.21309

N. Saeed, M. Eissa

{"title":"Bifurcation Analysis of a Transversely Cracked Nonlinear Jeffcott Rotor System at Different Resonance Cases","authors":"N. Saeed, M. Eissa","doi":"10.20855/IJAV.2019.24.21309","DOIUrl":"https://doi.org/10.20855/IJAV.2019.24.21309","url":null,"abstract":"This work focuses on the dynamical behaviour and bifurcations of a vertically supported Jeffcott rotor system\u0000having a transverse crack and nonlinear stiffness characteristics at the primary, sub-harmonic, and super-harmonic\u0000resonance cases. The nonlinear restoring force due to the bearing-clearance, the crack breathing, the disc eccentricity, and the orientation angle between the crack and imbalance direction are considered in the system model. The\u0000equations governing the system motion are derived and solved analytically by applying the Multiple Scales Perturbation Technique (MSPT). The slow-flow modulating equations are obtained and the spinning speed response\u0000curve is plotted. The whirling orbit and amplitude spectrum are constructed in the three considered resonance\u0000cases. The acquired results provide a better understanding of the main reasons of the super- and sub-harmonic\u0000resonance excitations. In additions, we concluded that the suitable resonance case that can be used for early detections of the cracks in the rotating shafts is the sub-harmonic resonance case. Finally, the obtained results are\u0000confirmed numerically and compared with the work published in the literature","PeriodicalId":227331,"journal":{"name":"June 2019","volume":"371 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116370623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 20

Fault Diagnostics of Wind Turbine Drive-Train using Multivariate Signal Processing 基于多变量信号处理的风电传动系统故障诊断

June 2019 Pub Date : 2019-06-01 DOI: 10.20855//IJAV.2019.24.21527

R. Maheswari, R. Umamaheswari

{"title":"Fault Diagnostics of Wind Turbine Drive-Train using Multivariate Signal Processing","authors":"R. Maheswari, R. Umamaheswari","doi":"10.20855//IJAV.2019.24.21527","DOIUrl":"https://doi.org/10.20855//IJAV.2019.24.21527","url":null,"abstract":"The vibration measured from wind turbine drivetrain components is a mixture of multiple frequency modes. In\u0000practice, in wind turbine drivetrain condition monitoring systems, multiple accelerometer sensors are used to measure the vibration. Inter-channel common modes are not processed in the standard single-channel empirical mode\u0000decomposition (EMD) and it suffers from mode mixing and mode misalignment. Inter-channel correlation implies\u0000the causation of vibration mode shapes. Multivariate EMD (MEMD) possesses an enhanced spatial and spectral\u0000coherence. The mode alignment property of MEMD is used to process the inter-channel common modes, thus\u0000MEMD overcomes the limitation of mode misalignment in single-channel EMD. Still, MEMD exhibits a degree\u0000of mode mixing. White noise powers are added in separate channels to lessen the mode mixing. In this research,\u0000a novel multivariate signal processing technique, noise-assisted multivariate empirical mode signal decomposition\u0000(NA-MEMD) with a competent nonlinear Teager-Kaiser energy operator (NLTKEO), is proposed and tested for\u0000truthful extraction of instantaneous frequency and instantaneous amplitude features, and thereby ensures superior\u0000fault diagnosis performance. The dyadic filter bank structure of the proposed NA-MEMD decomposes the nonstationary vibrations effectively. The proposed method is used to predict the surface damage pattern embedded in\u0000multi-source vibrations at a low-speed planetary gear stage. The effectiveness of the proposed algorithm is tested\u0000with NREL GRC wind turbine condition monitoring benchmark datasets.","PeriodicalId":227331,"journal":{"name":"June 2019","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133303796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

Vibration Characteristic of a Transition Constrained Damping Beam Based on the Shear Dissipating Energy Assumption 基于剪切耗散能量假设的过渡约束阻尼梁振动特性

June 2019 Pub Date : 2019-06-01 DOI: 10.20855/IJAV.2019.24.21538

B. Yan, Huijun Liang, Minjie Jin

{"title":"Vibration Characteristic of a Transition Constrained Damping Beam Based on the Shear Dissipating Energy Assumption","authors":"B. Yan, Huijun Liang, Minjie Jin","doi":"10.20855/IJAV.2019.24.21538","DOIUrl":"https://doi.org/10.20855/IJAV.2019.24.21538","url":null,"abstract":"Adding a “transition layer” could further improve the dissipation ability of the original constrained damping structure to the external vibration. At the same time, the addition of the transition layer brings many difficulties in\u0000establishing the model and acquiring the relevant characteristics of the• structure. Based on the shear dissipating\u0000energy assumption and the Hamilton principle, the finite element model of the transition constrained damping\u0000beam is established. On the basis of this reasonable assumption, the whole derivation process is simplified and\u0000easy to read by regularizing the element stiffness and mass matrix, and the expression of loss factor and natural\u0000frequency of damping beam is obtained. In order to verify the correctness of the model, the computed results are\u0000compared with the analytical solution, and both are found to be in good agreement. Taking the cantilever damping\u0000beam as an example, the influence of the material choice of the transition layer and the structural parameters on\u0000the natural frequency and the loss factor of the structure are discussed. The results of this paper would lay a good\u0000foundation for further optimization and practical engineering application.","PeriodicalId":227331,"journal":{"name":"June 2019","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123610136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Application of Variational Mode Decomposition and Permutation Entropy for Rolling Bearing Fault Diagnosis 变分模态分解和置换熵在滚动轴承故障诊断中的应用

June 2019 Pub Date : 2019-06-01 DOI: 10.20855/IJAV.2019.24.21325

Xiaoxia Zheng, Guowang Zhou, Dongdong Li, Haohan Ren

引用次数: 15

ICSV26: MontrÈal Bridges

June 2019 Pub Date : 2019-06-01 DOI: 10.20855/IJAV.2019.24.2E92

J. Voix, F. Sgard

引用次数: 0

An Intelligent Detection System Development forLocal Faults in a Ball Bearing 球轴承局部故障智能检测系统的研制

June 2019 Pub Date : 2019-06-01 DOI: 10.20855/IJAV.2019.24.21599

Jing Liu, Linfeng Wang, Li Zhou, Liming Wang, Zhifeng Shi

{"title":"An Intelligent Detection System Development for\u0000Local Faults in a Ball Bearing","authors":"Jing Liu, Linfeng Wang, Li Zhou, Liming Wang, Zhifeng Shi","doi":"10.20855/IJAV.2019.24.21599","DOIUrl":"https://doi.org/10.20855/IJAV.2019.24.21599","url":null,"abstract":"Local faults can be produced in ball bearings during their manufacturing process. An efficient, fast and accurate\u0000local fault detection method can help improve the quality of ball bearings. To overcome this problem, an intelligent\u0000detection system for a ball bearing with the local faults is developed based on the NI LabVIEW software. This\u0000system includes the determination of bearing fault parameters, signal acquisition, envelope analysis, time-domain\u0000parameter analysis and bearing fault status modules. In this system, the frequency-domain feature method is based\u0000on the envelope demodulation analysis, the effective statistical indexes, and the Pearson correlation coefficient.\u0000The frequency-domain feature method is used to determine the threshold range for each fault level in the system.\u0000This system can in turn be used to determine the fault location and sizes for the ball bearings. A case study for the\u0000calculation and analysis for the frequency and time-domain acceleration is presented to predict the location and\u0000size of the local faults in a ball bearing. The test data from the Case Western Reserve University Bearing Data\u0000Center is used to verify the developed intelligent detection system for local faults in the ball bearing. The results\u0000show that the proposed detection system can be used to detect the local fault in the ball bearings.","PeriodicalId":227331,"journal":{"name":"June 2019","volume":"182 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124587494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Adaptation and stability of cowpea (Vigna unguiculata (L.) Walp) bean cultivars in the tropical dry forest of Colombia 豇豆的适应性和稳定性哥伦比亚热带干燥森林中的豆品种

June 2019 Pub Date : 2019-06-01 DOI: 10.21475/AJCS.19.13.06.P1965

H. A. Tatis, Miguel Espitia Camacho, C. C. Ayala

{"title":"Adaptation and stability of cowpea (Vigna unguiculata (L.) Walp) bean cultivars in the tropical dry forest of Colombia","authors":"H. A. Tatis, Miguel Espitia Camacho, C. C. Ayala","doi":"10.21475/AJCS.19.13.06.P1965","DOIUrl":"https://doi.org/10.21475/AJCS.19.13.06.P1965","url":null,"abstract":"Cowpea (Vigna unguiculata (L.) Walp) is a source of low cost protein for food, and is currently used in family farming in northern Colombia. The aim of this study was to estimate the adaptability and phenotypic stability of the grain yield (per hectare) of nine advanced lines (plus control) of cowpea and a commercial control in eight contrasting environments of the tropical dry forest of the Colombian Caribbean region. We employed five analysis methods: Eberhart and Russell, Lin and Binns, Annichiarico, Carneiro, and Nascimento et al. A completely randomized block design was used with 9 genotypes +1 control and four repetitions per environment. The analysis of variance detected significant differences in environments, genotypes and in the genotype x environment interaction, confirming that the crops have become sensitive to differences of the environments. At the same time, we forced to consider adaptability and stability for the selection of the best genotype. The five methods of analysis coincided with identification of line L-019 as the best genotype due to its grain yield, adaptability and phenotypic stability. Therefore, L-019 is a new planting alternative for family agriculture of cowpea producers in the Colombian Caribbean.","PeriodicalId":227331,"journal":{"name":"June 2019","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128712486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7

A Fault Diagnosis Approach for Rolling Bearing Based on Wavelet Packet Decomposition and GMM-HMM 基于小波包分解和GMM-HMM的滚动轴承故障诊断方法

June 2019 Pub Date : 2019-06-01 DOI: 10.20855/IJAV.2019.24.21120

Liangpei Huang, H. Huang, Yonghua Liu

{"title":"A Fault Diagnosis Approach for Rolling Bearing Based on Wavelet Packet Decomposition and GMM-HMM","authors":"Liangpei Huang, H. Huang, Yonghua Liu","doi":"10.20855/IJAV.2019.24.21120","DOIUrl":"https://doi.org/10.20855/IJAV.2019.24.21120","url":null,"abstract":"Considering frequency domain energy distribution differences of bearing vibration signal in the different failure\u0000modes, a rolling bearing fault pattern recognition method is proposed based on orthogonal wavelet packet decomposition and Gaussian Mixture Model-Hidden Markov Model (GMM-HMM). The orthogonal three-layer wavelet\u0000packet decomposition is used to obtain wavelet packet decomposition coefficients from low frequency to high frequency. Rolling bearing raw vibration signals are firstly decomposed into the wavelet signals of different frequency\u0000bands, then different frequency band signals are reconstructed respectively to extract energy features, which form\u0000feature vectors as the model input of GMM-HMM. A large number of samples are trained to get model parameters\u0000for different bearing faults, then several groups of test data are adopted to verify GMM-HMMs so different fault\u0000types of rolling bearings are recognized. By calculating the current state appearance probability of monitoring data\u0000in GMM-HMMs, different failure patterns are recognized and evaluated from the maximum probability. Similarly,\u0000we establish GMM-HMMs for different grade fault samples and evaluated the performance degradation state. Test\u0000results show that the proposed fault diagnosis approach can identify accurately the fault pattern of rolling bearings\u0000and evaluate performance degradation of bearings.","PeriodicalId":227331,"journal":{"name":"June 2019","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127547779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 12