Compound Fault Diagnosis for Gearbox Based Using of Euclidean Matrix Sample Entropy and One-Dimensional Convolutional Neural Network

Vibration signals of gearbox under different loads are sensitive to the existence of the fault and composite fault vibration signals are complex. Traditional fault diagnosis methods mostly rely on signal processing methods. It is difficult for signal processing methods to separate effective information from those fault signals. Therefore, traditional fault diagnosis methods are difficult to accurately identify those faults. In this paper, a one-dimensional convolutional neural network (1-D CNN) intelligent diagnosis method with improved SoftMax function is proposed. Local mean decomposition (LMD) decomposes the signals into different physical fictions (PF). PFs are input into the matrix sample entropy based on Euclidean distance (MESE), and the PFs which best reflect fault characteristics are selected. Finally, the PFs by MESE are used to train the CNN to identify the faults of parallel-shaft gearbox. Experiment shows that MESE can quickly and accurately select the PFs with the most significant fault features. 1-D CNN can get nearly 100% recognition rate with less time and the CNN of SoftMax improved can effectively eliminate LMD endpoint effect. This method can successfully identify single faults, combination faults, and faults under different loads of the gearbox. Compared with other methods, this method has the characteristics of high efficiency, accuracy, and strong anti-interference. Therefore, it can effectively solve the problem of complex fault signal decomposition of gearbox and can diagnose the gearbox fault under different load operation. It has great significance for gearbox fault diagnosis in actual production.

Analytical strategy for determination of chloramphenicol in different biological matrices by liquid chromatography - mass spectrometry

Introduction: The main problem in determination of chloramphenicol in food of animal origin is a large number of matrices. The main target of this study was to create a method for determination and confirmation of chloramphenicol in products and food of animal origin. Material and Methods: Each 5 g matrix sample was mixed with 5 mL of water and 10 mL of acetonitrile/ethyl acetate, homogenised, and centrifuged. The organic layer was evaporated and redissolved in 6 mL of 4% NaCl. The extract was cleaned up by SPE technique. Chloramphenicol was analysed by LC-MS/MS in electrospray mode. Results: The procedure was validated according to the Commission Decision No. 2002/657/EC. The apparent recoveries were in the range of 92.1% to 107.1% with a repeatability less than 11.0% (4.4%-11.0%) and within-laboratory reproducibility below 13.6% (4.7%-13.6%). Conclusion: The method was successfully validated and proved to be efficient, precise, and useful for quantification of chloramphenicol in more than 20 different matrices.

Study of Temperature Stability of the Magnetoresistance and Transport Properties in La0.6Sr0.15Na0.10.15MnO3 with the Addition of Ag

A series of bulk polycrystalline samples of La0.6Sr0.15Na0.10.15MnO3( represents vacancy)with Ag addition were prepared by conventional Sol-gel reaction processing in air.The mol proportion between La0.6Sr0.15Na0.10.15MnO3 and Ag is 1:x (x=0.00,0.016,0.04,0.1). This article focuses on the impact of Ag doping on the parent structure, magnetic properties and magnetoresistance. We have gotten the following experimental results:X-ray diffraction patterns show that a weak Ag phase appears when ;The Curie temperature of the doped samples is higher than that of the matrix sample and it reduces as x increases. The resistivity of the doped samples is bigger than that of the parent sample in zero field and it increases as x increases.In a quite wide temperature range (207K-286K), MR maintains the value of 5.08% (0.20%) when x=0.04. So the CMR temperature stability has been improved.

Experimental Study on Friction Characteristics of Hot-Pressing Matrix and Granite under Dry Sliding Conditions

In order to understand the friction characteristics of hot-pressing bit matrix and granite under dry sliding conditions, the influence law of hardness and diamond concentration to the friction coefficient was analyzed and discussed with the data of friction coefficient and torque under different conditions. Three groups of hot-pressing matrix samples of different hardness and three groups of hot-pressing matrix samples with different diamond concentration were chosen. The friction and wear tests were carried out between hot-pressing matrix samples and granite samples. The results showed that the friction torque and coefficient firstly increased, and then decreased with the increase of hardness in dry friction experiments between granite sample and matrix sample without diamond. Compared with data from matrix sample without diamond, the friction torque and friction coefficient decreased significantly when test was carried between granite sample and impregnated diamond matrix sample. The friction torque and coefficient increased with the increase of diamond concentration.

An essay on human and elements, multielement profiles, and depression

The recent development of the analytical techniques offers the unprecedented possibility to study simultaneously concentration of dozens of elements in the same biological matrix sample of 0.5–1.0 g (multielement profiles). The first part of this essay entitled “Think globally… An outline of trace elements in health and disease” aims to introduce the reader to the fascinating field of elements, there importance to our nutrition, their essentiality, deficiency, toxicity and bioavailability to the body and their overall role in health and disease, including the genetic metabolic impairments. In the second part of the essay entitled “… and act locally. The multielement profile of depression” we aimed to show the potential of such a hair multielement profile analysis for the study of human depression in a randomized, double blind, prospective, observational, cross-sectional, clinical, epidemiological, and analytical study. The preliminary results of this ongoing study lead us to put forward the hypothesis that the metabolic origin of depression may be due to some “energostat” failure, probably located in the thalamus, and activated by several essential element deficiencies.