Rolling Element Bearing Condition Monitoring using Filtered Acoustic Emission

The defect present in the bearing of a rolling element may affect the performance of the rotating machinery and may reduce its efficiency. For this reason the condition monitoring of a rolling element bearing is very essential. So many measuring parameters are there to diagnose the fault in a rolling element bearing. Acoustic signature monitoring is one of them. Every rolling element bearing has its own acoustic signature when it is in healthy condition and when the bearing get defected then there is a change in its original acoustic signature. This change in acoustic signature can be monitored and analyzed to detect the fault present in the bearing. But the noise present in the acquired acoustic signal may affect the analysis. So the noisy acoustic signal must be filtered before the analysis. In this work the experiment is performed in two stages. In first stage the filtration of the acquired acoustic signal is done by employing the active noise cancellation (ANC) filtering techniques. In second stage the filtered signal is used for the further analysis. For the analysis initially the static analysis is done and then the frequency and the time-frequency analysis is done to diagnose the defect in the bearing. From all the three analysis the information about the defect present in the bearing is well detected

Study of Compression-Induced Supramolecular Nanostructures of an Imidazole Derivative by Langmuir–Blodgett Technique

In this communication, we report the design and synthesis as well as the supramolecular assembly behavior of a 2,4,5-triaryl imidazole derivative (compound <b>1</b>) at the air–water interface and in thin films using Langmuir–Blodgett (LB) technique. The main idea for such a chemical structure is that the long alkyl chain and N–H of the imidazole core may help to form supramolecular architecture through the hydrophobic–hydrophobic interaction and hydrogen bonding, respectively. Accordingly, the interfacial behavior as well as morphology of <b>1</b> in thin films were studied through a series of characterization methods such as surface pressure–area (π–<i>A</i>) isotherm, hysteresis analysis, ultraviolet–visible (UV–vis) absorption and steady-state fluorescence spectroscopies, Fourier transform infrared, X-ray diffraction, Brewster angle microscopy (BAM), and atomic force microscopy (AFM) measurements, and so forth. Pressure–area isotherm is an indication toward the formation of supramolecular nanostructures instead of an ideal monolayer at the air–water interface. This has been confirmed by the hysteresis analysis and BAM measurement at the air–water interface. AFM images of <b>1</b> in the LB monolayer exhibits the formation of supramolecular nanowires as well as nanorods. By controlling different film-forming parameters, it becomes possible to manipulate these nanostructures. With the passage of time, the nanowires come close to each other and become straight. Similarly, nanorods come close to each other and form bundles of several rods in the LB films. H-bonding, J-aggregation, as well as compression during film formation might play a key role in the formation of such nanostructures. Electrical switching behavior of compound <b>1</b> was also observed because of the presence of an electron donor–acceptor system in <b>1</b>. This type of organic switching behavior may be promising for next-generation organic electronics