In this work, the feasibility of using low-sampled vibration signals for bolt joint tightness detection was investigated. Testing was carried out on multiple bolt joint configurations using a bench top electrodynamic ...
详细信息
In this work, the feasibility of using low-sampled vibration signals for bolt joint tightness detection was investigated. Testing was carried out on multiple bolt joint configurations using a bench top electrodynamic shaker rig. Two data-processing methods were successfully used to deduce bolt joint loosening from the accelerometer measurements, namely the resonant frequency and regression methods (ARX and AR-ARX). Both methods were able to detect loosening of bolt joints, however, the latter possesses higher sensitivity in detecting the position of the loosened bolt among an array of bolts. As the resonant frequency of wind turbines is low (0.35-2 Hz), the minimum sampling rate for bolt joint tightness detection is consequently also low (twice the resonant frequency). This facilitates potential use of existing accelerometer instrumentation on wind turbines, typically sampled at low rates.
Plants produce a variety of metabolites that are essential for plant growth and human *** fully understand the diversity of metabolites in certain plants,lots of methods have been developed for metabolites detection a...
详细信息
Plants produce a variety of metabolites that are essential for plant growth and human *** fully understand the diversity of metabolites in certain plants,lots of methods have been developed for metabolites detection and data *** the data-processing procedure,how to effectively reduce false-positive peaks,analyze large-scale metabolic data,and annotate plant metabolites remains *** this review,we introduce and discuss some prominent methods that could be exploited to solve these problems,including a five-step filtering method for reducing false-positive signals in LC-MS analysis,QPMASS for analyzing ultra-large GC-MS data,and MetDNA for annotating *** main applications of plant metabolomics in species discrimination,metabolic pathway dissection,population genetic studies,and some other aspects are also *** further promote the development of plant metabolomics,more effective and integrated methods/platforms for metabolite detection and comprehensive databases for metabolite identification are highly *** the improvement of these technologies and the development of genomics and transcriptomics,plant metabolomics will be widely used in many fields.
Because of its simplicity and reasonable accuracy, the p-y-curve method is widely used for analyzing laterally loaded piles. The effectiveness of existing approaches for deriving p-y curves is case dependent;thus, a s...
详细信息
Because of its simplicity and reasonable accuracy, the p-y-curve method is widely used for analyzing laterally loaded piles. The effectiveness of existing approaches for deriving p-y curves is case dependent;thus, a systematic assessment of these interpretation methods is necessary. This study compared p-y curves derived using four data interpretation methods. Instead of experiments, the numerical simulation program LPILE was used to produce hypothetical moment data for positions along a short pile in layered soil. The deduced p-y curves were compared with the "true" p-y curves used for numerical simulations to evaluate the accuracy of the interpretation methods. The comparison demonstrated that the cubic spline method and difference method were the best among the four considered methods for deriving p-y curves. However, the difference method generated a large resistance at the soil surface. Because of this error, the cubic spline method is the preferred method for deriving the response of a laterally loaded pile in layered soil. The results of this study will be useful for obtaining more accurate p-y curves from experimental data and for more effective planning of future experiments.
暂无评论