Substantiation of informative amplitudes during registration of acoustic emission signals from the friction zone of tribosystems

In this work, the dependence of the change in the probability density of the distribution of the number of pulses and amplitudes of acoustic emission (AE) signals from the friction zone at the steady-state operation of the tribosystem is obtained. Acoustic vibrations that the tribosystem generates during operation are due to the impact interaction of the roughness of the friction surfaces of their elastoplastic deformation, processes of formation and destruction of frictional links, structural and phase rearrangement of materials, the formation and development of microcracks in the surface layers of contacting bodies, separation of wear particles. The dependence allows you to determine a sufficient number of pulses in the signal frame and their amplitude values for diagnosing tribosystems during their operation. The values of the informative amplitudes of the clusters are experimentally substantiated К2, К3, К4 in relation to the base cluster К1. It is shown that an increase in the informative frequency fAE(fix) from 250 to 500 kHz, increases the value of the informative amplitude to 17,6…43,75%. Based on the results obtained, it was concluded that this fact must be taken into account when developing methods, which will increase the accuracy of diagnosing tribosystems. The autocorrelation coefficient characterizes the closeness of the linear relationship of the current and previous frames of the series for each of the analyzed clusters. By the value of the autocorrelation coefficient, one can judge the presence of a linear relationship between the values of the recorded amplitudes, their reproducibility in terms of recording time in the steady-state operation of the tribosystem. To confirm the sufficiency of the selected number of pulses in the clusters of the AE signal frame, as well as the reproducibility of the results of the analysis of frames when they shift in time of registration, an expression is obtained for calculating the autocorrelation function, which reflects the relationship between successive levels of the time series. Based on the results of the experimental data, the values of the autocorrelation coefficients were calculated, equal to 0,82…0,92, which indicates the robustness of the chosen diagnostic technique.

MoIV3⋯[O8Mo4]3 Lewis acid–base cluster pairs: highly efficient and stable Lewis catalysis fields frustrated in crystalline nanoclusters

A new concept of a Lewis catalysis field built of frustrated Lewis acid⋯base cluster pairs has been proposed.

Zirconium Tetrakis(8-hydroxyquinolinolate) and Lithium Schiff-Base Cluster Complex for Efficient Charge Injection and Transfer in Green PHOLED processed by OVPD

ABSTRACTTypical electron transport (2,2′,2″-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi)) and injection (Cs2CO3) materials are successfully replaced by zirconium tetrakis(8-hydroxyquinolinolate) (Zrq4) and lithium 2-((o-tolylimino)methyl)-phenolate (EI-111) in simplified OLED (organic light-emitting diodes) processed by organic vapor phase deposition (OVPD). The performance of combining Zrq4 and EI-111 is analyzed in unipolar devices and compared to devices with configurations of Zrq4/Cs2CO3, TPBi/EI-111 and TPBi/Cs2CO3. Current density-voltage (J-V) measurements are performed and correlated to different carrier injection and transport properties. The investigated material combinations are implemented in the simplified OLED structures and compared to each other. To account for the high HOMO level of Zrq4, 5 nm of TPBi are added to confine holes and excitons in the emissive layer (EML) and to improve device performance. After tailoring the organic stack for OLED with Zrq4, a remarkable boost in device efficiency is observed. The luminous efficacy increased from 3.0 to 21.9 lm/W and the EQE from 2.1 to 11.0 % for a device with Zrq4/EI-111. Furthermore, OLED having Zrq4/Cs2CO3 show an even greater enhancement to 26.3 lm/W and 11.7 %.

Using push-pull winescape attributes to model Australian wine tourist segmentation

Purpose The study aims to introduce a comprehensive segmentation instrument that incorporates the push–pull winescape attributes, providing a new perspective of the wine tourist profile and explaining their behavioural intentions in the Australian winescape. Design/methodology/approach A literature review, focus groups and expert panels generated an extensive list of push–pull winescape attributes. Pen-and-paper surveys conveniently sampled 739 wine tourists at three wineries across three wine regions in Australia. Adopting push–pull winescape attributes as the segmentation base, cluster analysis identified four segments, namely, inspireds, self-drivens, market-drivens and inerts, and their behavioural intentions were examined. Findings Inspireds demonstrate both self- and market-motivation. Self-drivens exhibit self-motivation but limited market-motivation, whereas Market-drivens characterise market-motivation but limited self-motivation. Inerts are limited in both market- and self-motivations. At the Swan Valley, all four segments were identified, with Inspireds being the most willing to revisit and recommend to others and Inerts, the least willing. At the Barossa Valley, only two segments emerged. Again, Inspireds and Inerts were the most and least willing to revisit and recommend to others respectively. Finally, at the Yarra Valley, three segments were identified. Market-drivens were most willing to revisit and recommend to others, followed by self-drivens and lastly, by inerts. Research limitations/implications A comprehensive push–pull winescape segmentation base of wine tourists is introduced, which provides a more sophisticated profile of wine tourist segments than otherwise would be attained with conventional measures. Practical implications New insights into who the wine tourist is and what it is they seek from the winescape are vital to smaller wine producers whose best access to the domestic retail and export markets is through direct selling at the cellar door. Originality/value The empirically tested 18-item push–pull winescape instrument presents a comprehensive segmentation approach, which profiles wine tourists and predicts their behavioural intentions based on an extensive investigation of push–pull winescape attributes.