The newly developed technique of wavelet transform enables us to observe the evolution in time of the frequency content of a signal. This property makes it very suitable for the detection of vibration transients. However, current algorithms for vibration analysis either have low resolution of features for detailed analysis in the frequency-band scale or are very time consuming. In this paper, we present fast wavelet-based algorithms for vibration analyses. The approximated Morlet wavelet is used to develop an infinite impulse response causal filter with the error kept at an acceptable level. Using this filter, the continuous wavelet transform (CWT) can be computed. The rapid computation of the CWT, together with autocorrelation enhancement, is developed for the detailed on-line vibration analysis. Thus, the raw vibration signal can be continuously processed and monitored, with warning or alarm signals being generated when pre-programmed levels are exceeded. Examples are used to illustrate the application of arbitrary fine frequency-band scale analysis and single specified central frequency in the time domain using the wavelet power spectrum, which enables small defect detection of bearings. Real-time condition monitoring, fault detection, tool wear monitoring, etc., which are related to vibration, can be achieved and implemented with the detailed analysis of vibration signals.

Some wood species have antimicrobial properties, making them a better choice over inert surfaces in certain circumstances. However, the organic and porous nature of wood raises questions regarding the use of this material in hygienically important places. Therefore, it is reasonable to investigate the microbial survival and the antimicrobial potential of wood via a variety of methods. Based on the available literature, this review classifies previously used methods into two broad categories: one category tests wood material by direct bacterial contact, and the other tests the action of molecules previously extracted from wood on bacteria and fungi. This article discusses the suitability of these methods to wood materials and exposes knowledge gaps that can be used to guide future research. This information is intended to help the researchers and field experts to select suitable methods for testing the hygienic safety and antimicrobial properties of wood materials.