A new species of the hyphomycete genus Chalara is described. It has been frequently isolated from stems and branches and sometimes also from roots of wilting and dying Fraxinus excelsior in Poland. ...It differs from previously described species of Chalara by its small, short cylindrical phialoconidia extruded in chains or in slimy droplets, morphological features of the phialophores and by colony characteristics. It is non-tolerant to cycloheximide.
In this paper, the idea of using a convolutional neural network (CNN) for the detection and classification of induction motor stator winding faults is presented. The diagnosis inference of the stator ...inter-turn short-circuits is based on raw stator current data. It offers the possibility of using the diagnostic signal direct processing, which could replace well known analytical methods. Tests were carried out for various levels of stator failures. In order to assess the sensitivity of the applied CNN-based detector to motor operating conditions, the tests were carried out for variable load torques and for different values of supply voltage frequency. Experimental tests were conducted on a specially designed setup with the 3 kW induction motor of special construction, which allowed for the physical modelling of inter-turn short-circuits in each of the three phases of the machine. The on-line tests prove the possibility of using CNN in the real-time diagnostic system with the high accuracy of incipient stator winding fault detection and classification. The impact of the developed CNN structure and training method parameters on the fault diagnosis accuracy has also been tested.
This paper deals with monitoring of interturn short circuits of induction-motor (IM) stator windings operating under the direct field-oriented control (DFOC). Time transients are presented to ...illustrate the performance of the field-oriented speed control under the stator-winding damage. Novel detection algorithm is introduced, based on an analysis of the internal signals from the control structure: controller outputs and control path decoupling variables. The spectral analysis of these signals is used to detect the stator-winding incipient damages. Significant changes of the constant component f dc and the double-fundamental harmonic component 2f s observed in these signals' spectra under the stator-winding failure become the basis for the failure diagnostics in various operating conditions of the DFOC IM drive. The superiority of the proposed detection algorithm over the classical motor current signature analysis (MCSA) method is described. The online monitoring process is shown. Simulation and experimental results are presented to validate the proposed detection algorithm.
Summary
Ash dieback, caused by the pathogen Chalara fraxinea, is an emerging lethal disease of Fraxinus excelsior, threatening the host species in large parts of Europe. The ascomycete Hymenoscyphus ...albidus (Helotiaceae, Helotiales) was identified as the teleomorph of C. fraxinea by culturing from ascospores, morphological comparison and nuclear ribosomal internal transcribed spacer (ITS) sequencing.
Currently, AC motors are a key element of industrial and commercial drive systems. During normal operation, the machines may become damaged, which may pose a threat to the users. Therefore, it is ...important to develop a fault detection method that allows for the detection of a fault at an early stage. Among the currently used diagnostic systems, applications based on deep neural structures are dynamically developed. Despite many examples of applications of deep learning methods, there are no formal rules for selecting the network structure and parameters of the training process. Such methods would make it possible to shorten the implementation process of deep networks in diagnostic systems of AC machines. The article presents a detailed analysis of the influence of deep convolutional network hyperparameters and training procedures on the precision of the interturn short-circuits detection system. The studies take into account the direct analysis of phase currents through the convolutional network for induction motors and permanent magnet synchronous motors. The research results presented in the article are an extension of the authors’ previous research.
BACKGROUND AND PURPOSE The G protein‐coupled receptor 119 (GPR119) mediates insulin secretion from pancreatic β cells and glucagon‐like peptide 1 (GLP‐1) release from intestinal L cells. While ...GPR119‐mediated insulin secretion is glucose dependent, it is not clear whether or not GPR119‐mediated GLP‐1 secretion similarly requires glucose. This study was designed to address the glucose‐dependence of GPR119‐mediated GLP‐1 secretion, and to explore the cellular mechanisms of hormone secretion in L cells versus those in β cells.
EXPERIMENTAL APPROACH GLP‐1 secretion in response to GPR119 agonists and ion channel modulators, with and without glucose, was analysed in the intestinal L cell line GLUTag, in primary intestinal cell cultures and in vivo. Insulin secretion from Min6 cells, a pancreatic β cell line, was analysed for comparison.
KEY RESULTS In GLUTag cells, GPR119 agonists stimulated GLP‐1 secretion both in the presence and in the absence of glucose. In primary mouse colon cultures, GPR119 agonists stimulated GLP‐1 secretion under glucose‐free conditions. Moreover, a GPR119 agonist increased plasma GLP‐1 in mice without a glucose load. However, in Min6 cells, GPR119‐mediated insulin secretion was glucose‐dependent. Among the pharmacological agents tested in this study, nitrendipine, an L‐type voltage‐dependent calcium channel blocker, dose‐dependently reduced GLP‐1 secretion from GLUTag cells, but had no effect in Min6 cells in the absence of glucose.
CONCLUSIONS AND IMPLICATIONS Unlike that in pancreatic β cells, GPR119‐mediated GLP‐1 secretion from intestinal L cells was glucose‐independent in vitro and in vivo, probably because of a higher basal calcium tone in the L cells.
The issues of monitoring and fault diagnosis of drives with permanent magnet synchronous motors (PMSMs) are currently very relevant because of the increasing use of these drives in safety-critical ...devices. Every year, more and more articles are published on this subject. Therefore, the objective of this article is to update the overview of diagnostic methods and techniques for PMSM drives. Each of the main chapters of the article focuses on a specific element of the drive system (motor, power converter, measuring sensors), with particular emphasis on the components of the motor (stator windings, magnets, bearings, and rotor). The main sections on PMSM fault diagnosis are divided according to the type of methods used to obtain the symptoms of the damage. In addition, a review of methods that use the analysis of signals of the control structure for the diagnosis of damage to a vector-controlled motor is presented, as well as the latest achievements of researchers in the field of shallow and deep neural networks for the detection and classification of failures of PMSM drives. Based on the analyses presented in the literature, some development trends and challenges related to the development of diagnostics and fault-tolerant control of PMSM drives are discussed in the conclusion part.
Electrical winding faults, namely stator short-circuits and rotor bar damage, in total constitute around 50% of all faults of induction motors (IMs) applied in variable speed drives (VSD). In ...particular, the short circuits of stator windings are recognized as one of the most difficult failures to detect because their detection makes sense only at the initial stage of the damage. Well-known symptoms of stator and rotor winding failures can be visible in the stator current spectra; however, the detection and classification of motor windings faults usually require the knowledge of human experts. Nowadays, artificial intelligence methods are also used in fault recognition. This paper presents the results of experimental research on the application of the stator current symptoms of the converter-fed induction motor drive to electrical fault detection and classification using Kohonen neural networks. The experimental tests of a diagnostic setup based on a virtual measurement and data pre-processing system, designed in LabView, are described. It has been shown that the developed neural detectors and classifiers based on self-organizing Kohonen maps, trained with the instantaneous symmetrical components of the stator current spectra (ISCA), enable automatic distinguishing between the stator and rotor winding faults for supplying various voltage frequencies and load torque values.
This paper presents a comparative study on the application of different neural network structures to early detection of electrical faults in induction motor drives. The diagnosis inference of the ...stator inter-turn short-circuits and broken rotor bars is based on the analysis of an axial flux of the induction motor. In order to automate the fault detection process, three different structures of neural networks were used: multi-layer perceptron, self-organizing Kohonen network and recursive Hopfield network. Tests were carried out for various levels of stator and rotor failures. In order to assess the sensitivity of the applied neural detectors, the tests were carried out for variable load conditions and for different values of the supply voltage frequency. Experimental results of the elaborated neural detectors are presented and discussed.
Cryptic speciation in Hymenoscyphus albidus Queloz, V.; Grünig, C. R.; Berndt, R. ...
Forest pathology = Journal de pathologie forestière = Zeitschrift für Forstpathologie,
04/2011, Letnik:
41, Številka:
2
Journal Article
Recenzirano
Summary
Ash dieback caused by the mitosporic ascomycete Chalara fraxinea is a novel disease of major concern affecting Fraxinus excelsior and Fraxinus angustifolia in large parts of Europe. Recently, ...its teleomorph was detected and assigned to Hymenoscyphus albidus, which has been known from Europe since 1851. In this study, we present molecular evidence for the existence of two morphologically very similar taxa, H. albidus, which is lectotypified and Hymenoscyphus pseudoalbidus sp. nov. Differences were found between the species in the loci calmodulin, translation elongation factor 1‐α and the internal transcribed spacers of the rDNA genes, and strong differentiation was obtained with ISSR markers. It is likely that H. albidus is a non‐pathogenic species, whereas H. pseudoalbidus is a virulent species causing ash dieback. Genotyping herbarium specimens showed that H. pseudoalbidus has been present in Switzerland for at least 30 years prior to the outbreak of the epidemic.
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