Beamforming Applied to Ultrasound Analysis in Detection of Bearing Defects

The bearings of rotating machinery often fail, leading to unforeseen downtime of large machines in industrial plants. Therefore, condition monitoring can be a powerful tool to aid in the quick identification of these faults and make it possible to plan maintenance before the fault becomes too drastic, reducing downtime and cost. Predictive maintenance is often based on information gathered from accelerometers. However, these sensors are contact-based, making them less attractive for use in an industrial plant and more prone to breakage. In this paper, condition monitoring based on ultrasound is researched, where non-invasive sensors are used to record the noise originating from different defects of the Machinery Fault Simulator. The acoustic data are recorded using a sparse microphone array in a lab environment. The same array was used to record real spatial noise in a fully operational plant which was later added to the acoustic data containing the different defects with a variety of Signal To Noise ratios. In this paper, we compare the classification results of the noisy acoustic data of only one microphone to the beamformed acoustic data. We do this to investigate how beamforming could improve the classification process in an ultrasound condition-monitoring application in a real industrial plant.

Effect of Oil Regeneration on Improving Paper Conditions in a Distribution Transformer

Managing a large fleet of ageing assets has become a technical challenge faced by many electricity utilities in developed countries. Asset managers are increasingly interested in techniques that can help extend the useful lifetime of a transformer. Oil regeneration is one of such techniques. In this paper, oil regeneration experiments were performed on a 6.4/0.4 kV retired distribution transformer to investigate the effect of oil regeneration on improving paper conditions. Oil regeneration was conducted in two stages, with the first stage aimed at ‘cleaning the oil’ and the second stage targeted at ‘cleaning the paper’. Oil samples were collected at regular intervals throughout the process and paper samples were obtained from the transformer before and after each oil regeneration stage. It was found that oil regeneration restores oil parameters, including moisture and acidity, similar to those of new oils at the end of stage 1. Analysis of paper samples indicated a reduction in paper moisture at the end of stage 2 by nearly 40%, while low molecular weight acids (LMA) in paper exhibited a reduction by around 30% on average. It is found that the extended oil regeneration period, i.e., stage 2, is necessary to improve the paper condition and hence to reduce the paper ageing rate.

Power Transformer Insulation Assessment Based on Oil-Paper Measurement Data Using SVM-Classifier

Oil immersed paper insulation condition is a crucial aspect of power transformer’s life condition diagnostic. The measurement testing database collected over the years made it possible for researchers to implement classification analysis to in-service power transformer. This article presents classification analysis of transformer oil-immersed paper insulation condition. The measurements data (dielectric characteristics, dissolved gas analysis, and furanic compounds) of 149 transformers with primary voltage of 150 kV had been gathered and analyzed. The algorithm used for developing classification model is Support Vector Machine (SVM). The model has been trained and tested using different datasets. Different models have been created and the best chosen, resulting in 90.63% accuracy in predicting the oil-immersed paper insulation condition. Further implementation was executed to classify oil-paper condition of 19 Transformers which Furan data is not available. The classification results combined, reviewed, and compared to conventional assessment methods and standards, confirming that the model developed has the ability to do classification of current oil-paper condition based on Dissolved Gasses and Dielectric Characteristics.

CONDITION OF SUBSTANCE SEARCH ALGORITHM FOR SOLVING REACTIVE POWER PROBLEM

In this paper, Condition of Substance Search (COS) algorithm is introduced to solve optimal reactive power dispatch problem. The Condition of Substance Search (COS) algorithm is based on the simulation of the shape of substance incidence. In Condition of Substance Search (COS) algorithm, individuals follow molecules which interrelate to each other by using evolutionary operations which are based on the corporal principles of the thermal-energy motion mechanism. The algorithm is developed by considering each condition of substance in harmony with different exploration–exploitation ratio. The evolutionary progression is alienated into three phases which emulate the three condition of substance: solid, liquid & gas. This technique can considerably improve the equilibrium between exploration–exploitation, however preserving the high-quality search ability of an evolutionary approach. The proposed Condition of Substance Search (COS) algorithm has been tested on standard IEEE 30 bus test system and simulation results show clearly the improved performance of the projected Condition of Substance Search (COS) algorithm in reducing the real power loss and voltage stability also enhanced.

American non profit organizations – a picture from the time of crisis

Non profit organizations play important role in every democratic country. Their role is even bigger when given economy has to cope with different problems, because organizations support these spheres of social life that are neglected by the state. In this paper condition of American non profit sector between 2006 and 2009 is discussed. As a result of conducted analysis of The Center on Philanthropy at Indiana University reports and information from The Internal Revenue Service it turns that, despite the crisis time, non profit organizations are in good shape. It is connected with a big engagement of almost the whole American society that supports organizations in financial way as well as giving time and work. Such big social support non profit organizations stems both from conviction, that this is a pattern of real American society, and from beneficial tax solutions.

Notetaking and Writing from Hypertexts in L1 and L2

This study analyzes the cognitive effort and linguistic procedures of sixty students using information taken from an experimental website in L1 (French) and in L2 (English). The students navigated on the website and took notes on paper or with a word processor. A triple-task paradigm was used to estimate the cognitive load of reading, notetaking, and writing processes in L2. The students had to perform two additional tasks while a main task (notetaking, for example) was being carried out. They had to react as fast as possible to sound signals sent out at random intervals. They also had to identify what they were doing at the time the sound signal was heard (reading, notetaking, or writing). The study focuses on the way the students managed their cognitive resources while exploring the website, selecting and writing down the ideas they considered useful, and reconstructing them later when producing their own text. Surprisingly, no difference in cognitive load was observed between L1 and L2. By relying almost exclusively on the copy and paste functions to retrieve information from the website, the participants using a word processor in L2 succeeded in making reading a less costly activity, and they performed similarly to the notetakers in L1. The students’ difficulties in L2 became apparent only in the paper condition. The strategies and linguistic procedures of the students are described and related to the ways teachers can approach the new dimensions of notetaking and writing with a computer.

Notetaking and Writing from Hypertexts in L1 and L2

This study analyzes the cognitive effort and linguistic procedures of sixty students using information taken from an experimental website in L1 (French) and in L2 (English). The students navigated on the website and took notes on paper or with a word processor. A triple-task paradigm was used to estimate the cognitive load of reading, notetaking, and writing processes in L2. The students had to perform two additional tasks while a main task (notetaking, for example) was being carried out. They had to react as fast as possible to sound signals sent out at random intervals. They also had to identify what they were doing at the time the sound signal was heard (reading, notetaking, or writing). The study focuses on the way the students managed their cognitive resources while exploring the website, selecting and writing down the ideas they considered useful, and reconstructing them later when producing their own text. Surprisingly, no difference in cognitive load was observed between L1 and L2. By relying almost exclusively on the copy and paste functions to retrieve information from the website, the participants using a word processor in L2 succeeded in making reading a less costly activity, and they performed similarly to the notetakers in L1. The students’ difficulties in L2 became apparent only in the paper condition. The strategies and linguistic procedures of the students are described and related to the ways teachers can approach the new dimensions of notetaking and writing with a computer.

Regional Tongue Sensitivity for Sweetness and Pungency of Ethanol-Aspartame Mixtures

Binary mixtures of aspartame prepared at three levels of concentration and dissolved in four ethanolic dilutions were perceptually evaluated. Sweet-pungent combinations were presented in solution or in disks of filter paper (paper) soaked in the solutions. Variations in sweetness and pungency were examined at two oral loci including the tip and the back plus the front of the tongue in the liquid condition or the tip and the back of the tongue in the paper condition. A similar behavior was observed in liquid and paper conditions; as the concentration of aspartame and ethanol increased so did the intensity for sweet and pungent qualities. Whereas sweetness was not influenced by ethanol addition (2-8 % V/V), a suppressive effect of aspartame (1-4 mM) on pungency was noted for liquid but not for the paper condition. Sweetness was enhanced when the back plus the front of the tongue was stimulated by solutions. Finally, there was a complex pattern of regional effects on the perceived pungency of alcoholic-sweet solutions that was not replicated in the paper condition.