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To explore the effect of storage time on the flavor and quality of white peony tea, sensory evaluation and volatile and non-volatile composition analysis of 12 white peony tea samples made from three different varieties: Fudingdahao (FDDH), Zhenghedabai (ZHDB) and Fujiangshuixian (FJSX) were carried out, and the resulting data were analyzed by multivariate statistical analysis combined with multivariate statistical analysis. The results showed that during the storage process, the content of tea polyphenols and free amino acids decreased, and the ratio of polyphenols to amino and the contents of soluble sugar, flavonoids and thearubigin increased, so that the taste of white peony tea was sweet, mellow, sweet after taste and stale. The large decrease in the content of alcohol substances resulted in a reduction in the refreshing and floral aroma of white peony tea. Totally 12 differential volatiles were key to changing the aroma types of white peony tea. α-Farnesene, linalool oxide II, methyl salicylate, linalool, cis-2-pentene-1-alcohol and hexanal were the key components responsible for the floral, pekoe-like and refreshing aroma. cis-Linalool oxide and neryl oxide were also positively related to the formation of the floral aroma, and the latter was also key to the formation of the pekoe-like aroma. cis-3-Hexen-1-ol and phenethyl alcohol were also positively correlated with the formation of the refreshing aroma. In addition, 4-isopropyltoluene was the key component responsible for the honey-like and herbal aroma. Linalool oxide II and neryl oxide were the key components responsible for the jujube-like aroma. cis-Linalool oxide was the key component responsible for the plum-like aroma. The 4-isopropyltoluene and isobutyraldehyde were the key components contributing to the woody aroma. This study provides scientific insights into the formation of the differences in the flavor and quality of white peony tea of different ages, which could provide a reference for the improvement of tea flavor.

The electro-mechanical brake is a new advancement in railway train braking. Ball-screws are important components of electro-mechanical braking units (EMBUs), and their wear can cause EMBUs to degrade in performance or even fail to function. In this paper, we present a framework for prediction of ball-screw wear with discrete operating conditions as inputs, taking into account the time-varying characteristics of EMBUs. The framework includes determining the contact type, analyzing relative motion, calculating contact deformations, and estimating wear. The contact type is determined based on the quasi-static approach of Hertz theory. A dynamics model using multiple coordinate systems is established to analyze how balls and raceways move in relation to each other. The contact deformations of the ball–raceway contact are determined using numerical calculation. Then, the wear depth increment is calculated using the Archard model. The results of the calculation and the endurance test indicate that the wear on the screw raceway is greater than that on the nut raceway. The effect of velocity is greater than the effect of axial force. The presented calculation framework is reasonable and can be used for predicting EMBU ball-screw wear. [ABSTRACT FROM AUTHOR]

The wheel slide protection control system for rail vehicles plays a crucial role in ensuring a consistent braking performance in all operating environments, making it a vital factor in the safety and efficiency of rail transportation. In this paper, a hybrid approach to wheel slide protection control is presented, which combines the rule-based control strategy and the model-based control methods using adhesion force estimation. Model-based control usually relies on mathematical models to characterize the vehicle dynamics, requiring online estimators to be designed or extra sensors to be added for practical application. Rule-based control operates on predefined rules and thresholds and the available data from vehicles in service. A comparative test was conducted between the traditional rule-based control strategy and the proposed combined control strategy using a semi-physical simulation test bench. The performance differences of the control strategies were analyzed from two perspectives: adhesion utilization and air consumption. It was observed that among the traditional 2-phase, 3-phase, 4-phase and the optimized 4-phase combined control method, the combined control strategy has the best adhesion utilization and the traditional 4-phase control strategy has the least air consumption. [ABSTRACT FROM AUTHOR]

Employees' participation in corporate social responsibility (CSR) is a channel that not only helps corporations convey their social responsibility messages but also, in the long run, enhances stakeholder-organization relationships and builds corporate image. Given the important role employees play in CSR, inadequate attention is paid to their motivation to engage in voluntary CSR activities, and there is a research gap in the literature in terms of a lack of a systematic view of that motivation. Therefore, this study seeks to narrow this gap by exploring the factors influencing individual employees' motivation to take part in voluntary CSR activities, using a qualitative approach, with empirical data collected from employees of leading CSR companies in Vietnam. Through grounded theory analysis, our findings lead to the proposal of a personal characteristics – CSR capacity – organizational reinforcing model, revealing different intrinsic and extrinsic elements, categorized into personal characteristics, CSR capacities and organizational reinforcement, that motivate employees to participate and engage in voluntary CSR activities. Our findings and the proposed model offer a significant contribution to the CSR literature and organization management theories, and also provide insights and practical implications for those involved in CSR endeavors, including human resource (HR) managers in organizations. Supplemental data for this article is available online at https://doi.org/10.1080/09585192.2021.1967422. [ABSTRACT FROM AUTHOR]

The electromechanical braking is a novel braking mode, which is the development direction of the electrification and intelligent train braking system. In this paper, a coupled-rigid-flexible model of the EMB unit is developed, and dynamic characteristics of the EMB unit are analysed based on the model. Firstly, assumed mode method is used to describe the axial and torsional vibration of the screw in nut-screw assembly, and lumped mass method is used to describe motions of other components in the EMB unit. Secondly, the EMB unit model is established and simulated in Matlab/Simulink software based on electro-mechanical and rigid-flexible coupling characteristics. Then the model parameters are calibrated by experiment. Finally, the simulated model is studied to analyse the influence of various factors on the dynamic characteristics of the EMB unit. The results indicate that an increment in viscous damping flats the fluctuation of the pushout force. The maximal pushout force decreases and the changing trend of force is different along with the rotational structure damping increases. The flexible vibration of the screw results in higher pushout force, meanwhile the fluctuation of the force is greater with higher braking instruction current value. When the ratio of the screw length to the screw cross-sectional diameter is 30, the pushout force varies along with the friction pairs wear under vibration. The study can provide references for structure design, control design and fault diagnosis of EMB units. [ABSTRACT FROM AUTHOR]

Social enterprises, as a typical type of hybrid-identity organization, face identification tensions among members, arising from the divergent identities. Prior research has focused on how hybrid identities can be managed at the organizational level. However, the process through which identification emerges in hybrid-identity social enterprises remains relatively unexplored. This study addresses these gaps and aims to contribute to identity and identification theory. This research has taken a qualitative (case study) approach, with in-depth interviews and archival data from nine social enterprises in Taiwan. Our findings reveal three different types of responses to hybrid identities of social enterprises: synthesis, integration, and deletion. It is observed that different hybrid identities management and organizational identification management practices will lead to members' identification and dis-identification. This research proposes an attraction-selection-socialization model, suggesting that, to foster identification, social enterprises need to manage their hybrid organizational identities and embed the new common identity into members' daily work through attraction, selection, and socialization processes. [ABSTRACT FROM AUTHOR]