A robust detector for rolling element bearing condition monitoring based on the modulation signal bispectrum and its performance evaluation against the Kurtogram

Envelope analysis is a widely used method for rolling element bearing fault detection. To obtain high detection accuracy, it is critical to determine an optimal frequency narrowband for the envelope demodulation. However, many of the schemes which are used for the narrowband selection, such as the Kurtogram, can produce poor detection results because they are sensitive to random noise and aperiodic impulses which normally occur in practical applications. To achieve the purposes of denoising and frequency band optimisation, this paper proposes a novel modulation signal bispectrum (MSB) based robust detector for bearing fault detection. Because of its inherent noise suppression capability, the MSB allows effective suppression of both stationary random noise and discrete aperiodic noise. The high magnitude features that result from the use of the MSB also enhance the modulation effects of a bearing fault and can be used to provide optimal frequency bands for fault detection. The Kurtogram is generally accepted as a powerful means of selecting the most appropriate frequency band for envelope analysis, and as such it has been used as the benchmark comparator for performance evaluation in this paper. Both simulated and experimental data analysis results show that the proposed method produces more accurate and robust detection results than Kurtogram based approaches for common bearing faults under a range of representative scenarios

2018 Research & Innovation Day Program

A one day showcase of applied research, social innovation, scholarship projects and activities.https://first.fanshawec.ca/cri_cripublications/1005/thumbnail.jp

Deacetylation degree of chitosan by various bases and its metal adsorption ability related on antioxidant activity

© 2015, Journal of Chemical and Pharmaceutical Research. All Rights Reserved.Chitosan is the result of deacetylation process of chitin compounds commonly found in the outer skin of the animal groups crustaceans such as shrimp and crab. The purpose of this research is to obtain scientific data about the comparative degree of deacetylation of chitosan tiger shrimp shells using several strong bases and the ability of chitosan to adsorb ferrous metals as one method of antioxidants testing. The first stage is the produce of chitin from shrimp shells by demineralization, deproteination and depigmentation, the second phase is produce of chitosan with deacetylation used several base at a concentration of 50% (w/v). Chitosan produced from this process is analyzed degree of deacetylation with FT-IR spectrophotometer through analysis functional groups of amine and hydroxyl. Strong base that produces the best degree of deacetylation of chitosan further optimized. Chitosan obtained are then tested antioxidant activity through the ferrous metal adsorption. The amount of metal that can be adsorbed by chitosan was observed using a UV-VIS spectrophotometer. The results showed the degree of deacetylation of chitosan by using NaOH, KOH and Ca(OH)2 respectively by 52.34%, 37.89% and 42.17%. Results of the optimization degree of deacetylation by the use of NaOH 60% (w/v) of 81.94%. Metal ion adsorption test results on chitosan weight of 50 mg, 250 mg and 500 mg respectively 47.65%, 80.07% and 87.00%. It showed that chitosan is able to act as an antioxidant by adsorption of the metal ions

Numerical Simulation and Experimental Study of a Two Stage Reciprocating Compressor for Condition Monitoring

A numerical simulation of a two-stage reciprocating compressor has replicated the operations of the compressor under various conditions for the development of diagnostic features for predictive condition monitoring. The simulation involves the development of a mathematical model of five different physical processes: speed–torque characteristics of an induction motor, cylinder pressure variation, crankshaft rotational motion, flow characteristics through valves and vibration of the valve plates. Modelling both valve leakage and valve spring deterioration has also been achieved. The simulation was implemented in a MATLAB environment for an efficient numerical solution and ease of result presentation. For normal operating conditions, the simulated results are in good agreement with the test results for cylinder pressure waveforms and crankshaft instantaneous angular speed (IAS). It has been found that both the IAS fluctuation and pressure waveform are sensitive detection features for compressor faults such as valve leakage and valve spring deterioration. However, IAS is preferred because of its non-intrusive measurement nature. Further studies using the model and experiments are being undertaken in order to develop fault detection features for compressor driving motors and transmission systems