Search results

The purpose of this paper is to propose a bolt loosening detection approach which integrates piezoelectric ceramics with active sensor technology.

When the ultrasonic wave propagates across the contact surface at the bolted joints, because of the existence of imperfect interface, only part of the ultrasonic wave energy is passed through it. According to the Hertz contact theory, the passed energy depends on the true contact area which is decided by the bolt pretension. Hence, by measuring the received energy with the sensing piezoelectric material, the bolt pretension or bolt loosening can be detected.

The experiment revealed that the wave energy propagated across the interface is strongly correlated to the torque level. This relationship will be a good indicator to detect the status of bolted joints. The presented method has a potential application for the monitoring of bolt load loss in-site. Moreover, some factors which will affect the propagation of ultrasonic wave across the bolted joints are discussed in this paper.

This paper provides a good criterion to detect bolt load loss.

The purpose of this study is to investigate the influence of green finance on human well-being in China in the context of urbanization and aging population. It aims to explore the contributions of green finance in such demographic scenarios.

This study innovates and optimizes the calculation of the carbon intensity of human well-being (CIWB) index and strengthens the integrity of the assessment model for green finance development. It uses the serial multiple mediator model and moderation effect analysis to address the impact of green finance on human well-being in China on the provincial level from 2009 to 2020.

Green finance has a significant, positive and direct impact on human well-being. Simultaneously, it influences human well-being indirectly through three transmission channels. Urbanization and an ageing population are significant individual mediators through which green finance contributes to human well-being improvement. Notably, these two mediators also work together to transfer the promotional impact of green finance to human well-being.

The government can perfect the regulations to strengthen the market ecosystem to accelerate the development of green finance. Reforms on the administrative division to expand the size of cities with the implementation of ageing friendly development strategy is also necessary. Attracting incoming foreign direct investment in sustainable projects and adjusting public projects and trade activities to fulfil the sustainable principles are also regarded as essential.

The findings challenge traditional views on the impact of aging populations, highlighting the beneficial role of green finance in improving well-being amidst demographic changes. This offers a new perspective on economic and environmental sustainability in aging societies.

A multi-dimensional well-being indicator, CIWB and the serial multiple mediator model are used and direct and indirect impacts of green finance on human well-being is exhibited. It offers novel insights on the transmission channels behind, identifies the mediating role of urbanization and ageing population and offers empirical evidences with strong academic and policy implications.

The purpose of this paper is to develop a new oil‐in‐water (O/W) emulsion used for alpha phase brass, which can increase the antiwear and anti‐galling abilities of the rollers, and improve the surface quality of the rolled brass sheet. The aim is to evaluate the tribological performance of new kind of O/W emulsion for the hot rolling of alpha brass, which provides the fundamental information for the selecting of new chemical group, and to understand the lubrication mechanism of the used rolling emulsion and to correlate the laboratory findings with those of industrial rolling of alpha phase brass.

According to the hydrophile‐lipophile balance theory and the evaluation results of friction, wear and lubrication using a four‐ball tribometer, a novel O/W emulsion was developed for the hot rolling process of CuZn₃₂(ASTM C26200) and CuZn₃₀(ASTM C26000) alloys by controlling the composition of the emulsion, such as emulsifying, antiwear, extreme pressure, antirust and so on. By scanning electron microscope (SEM), energy‐dispersive X‐ray (EDX), and roughness profile the tribological mechanism were studied.

The production result proved that it was easy to control the accuracy and size of the brass sheet because of the emulsion‐jet to the roller surface directly and in succession. Polyol with hydroxyl group is found to provide better lubrication and lower coefficient of friction. The actual hot rolling results proved that it was easy to control the accuracy and size of the brass sheet with the emulsion jet. The morphologies and roughness profile of the copper sheet surface were observed and measured by SEM and topographic meter under different lubricant conditions. The in situ results supported the selection of compositions of O/W emulsion. The suitable temperature of feed emulsion is over 20°C.

The tribological mechanism of friction modified emulsion is not still clear. The thermal mechanical properties of rollers under this kind of emulsion are also worth studying in the future.

Understanding the tribological behaviour of O/W emulsion, will be useful for emulsion chemists, tribologists and rolling mill users.

The current study shows new compositions of O/W emulsion used for hot rolling of alpha phase brass.