Zhengqiang Ding, Li Xu and Yiping Zhang
The purpose of this paper is to investigate the impact of mechanical vibration on the heat transfer and pressure drop characteristics of semicircular channel printed circuit heat…
Abstract
Purpose
The purpose of this paper is to investigate the impact of mechanical vibration on the heat transfer and pressure drop characteristics of semicircular channel printed circuit heat exchangers (PCHEs), while also establishing correlations between vibration parameters and thermal performance.
Design/methodology/approach
By combining experimental and numerical simulation methods, the heat transfer coefficient and pressure drop characteristics of supercritical carbon dioxide (S-CO2) in a semicircular channel with a diameter of 2 mm under vibration conditions were studied. Reinforce the research by conducting computational fluid dynamics studies using ANSYS Fluent 22.0, the experimental results were compared with the numerical simulation results to verify the accuracy of the numerical method.
Findings
The use of vibration has the potential to attenuate the degradation of wall heat transfer caused by buoyancy-induced PCHEs on the upward-facing surface. The heat transfer enhancement (HTE) was maximized by an increase of 18.2%, while the pressure drop enhancement (PDE) was elevated by over 25-fold. The capacity to enhance the heat exchange between S-CO2 and channel walls through increasing vibration intensity is limited, indicating maximum effectiveness in improving thermal performance.
Originality/value
Conducting heat transfer experiments on PCHEs with mechanical vibration enhancement and verifying the accuracy of the vibration numerical model. The relation based on the dimensionless factor is derived. To provide theoretical support for using vibration to enhance the heat transfer capability of PCHEs.
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Hua Fang, Jianyu Zhang, Zhuan Hong, Weizhu Chen, Yiping Zhang and Meijuan Fang
Being interested in developing a natural preservative for the prolongation of shrimp shelf life, this study aims to evaluate the Sargassum horneri extracts for their antioxidant…
Abstract
Purpose
Being interested in developing a natural preservative for the prolongation of shrimp shelf life, this study aims to evaluate the Sargassum horneri extracts for their antioxidant effect, copper reducing power, copper chelating activity and polyphenol oxidase (PPO) inhibitory activity, as well as explored their potential preservative activity in white leg shrimp.
Design/methodology/approach
The antioxidant properties of Sargassum horneri 75% ethanol aqueous extracts were measured by 2,2-diphenyl-1-picryl hydrazyl (DPPH), 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), ferric reducing antioxidant power (FRAP) and PPO inhibitory activity. Sample III displayed the highest antioxidant activity, PPO inhibitory activity, copper reducing power and copper chelating activity, so it was selected for further studying its impact on shrimp's quality changes such as pH value, total volatile basic nitrogen (TVB-N), thiobarbituric acid reactive substances (TBARS), melanosis and sensory score during storage at 4°C.
Findings
Among all three samples, sample III containing 49.88% total phenolic contents was selected for the further study on the prevention of quality loss and melanosis of shrimp, because it yielded the highest antioxidant activity, PPO inhibitory activity, copper reducing power and copper chelating activity than the other two samples (samples II and IV). It was found that shrimp treated with 0.2% sample III had the lowest melanosis scores throughout the storage (p < 0.05). During ten days of storage at 4°C, shrimp treated with 0.2% sample III had a higher score in sensory properties (color, segments, texture and odor), compared with the control, 0.1% kojic acid and 0.1% sample III treated shrimp (p < 0.05). The results indicated that the treatment of shrimp with 0.2% sample III could extend the shelf life to eight days at 4°C.
Social implications
The extracts of Sargassum horneri displayed potent PPO inhibition, antimicrobial and antioxidant properties. Importantly, the 75% extracts of Sargassum horneri could extend the shelf life. Considering these results, the extracts of Sargassum horneri may be used as natural preservatives in the food industry after further evaluation of their other properties such as toxicity, as well as provide a choice target to source natural products intended for cosmetics.
Originality/value
The originality of this paper lies in the development and application of the extracts of edible algae. To extend the shelf life of seafood, the polyphenolic-rich extract of Sargassum horneri provided another possible selection.
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Chengfu Hu, Chong Shi, Yiping Zhang, Xiao Chen and Sha Luo
Cemented conglomerate accumulation is a weak and heterogeneous medium that occurs in western China. It consists mainly of argillaceous cement that loses strength rapidly upon…
Abstract
Purpose
Cemented conglomerate accumulation is a weak and heterogeneous medium that occurs in western China. It consists mainly of argillaceous cement that loses strength rapidly upon contact with water, leading to collapse instability failure. Its deformation failure mechanism is complex and poorly understood. In this paper, the erosion failure mechanism of cemented conglomerate accumulation is investigated.
Design/methodology/approach
The collapse failure process after erosion of the slope foot for typical cemented conglomerate accumulation is studied based on field investigation using the particle discrete element method. And how the medium composition, slope angle and cementation degree influence the failure mode and process of the cemented conglomerate accumulation is examined.
Findings
The foot erosion of slope induces a tensile failure that typically manifests as “erosion at the foot of slope – tensile cracking at the back edge of slope top – integral collapse.” The collapse failure is more likely to occur when the cemented conglomerate accumulation has a higher rock content, a steeper slope angle or a weaker cementation degree.
Originality/value
A model based on rigid blocks and disk particles to simulate the cemented conglomerate accumulation is developed. It shows that the hydraulic erosion at the foot of the slope resulted in a different failure mechanism than that of general slopes. The results can inform the stability management, disaster prevention and mitigation of similar slopes.
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Wei Xia, Lingwen Kong, Jiahuan Zhang, Hui Hao, Yiping Wang, Xiaoqi Ni, Ming Wang and Dongmei Guo
The purpose of this study aims to modify a self-mixing laser mouse as an extremely cost-effective displacement sensor to measure the mechanical oscillation of a commercial shaker…
Abstract
Purpose
The purpose of this study aims to modify a self-mixing laser mouse as an extremely cost-effective displacement sensor to measure the mechanical oscillation of a commercial shaker and a nano-positioning stage.
Design/methodology/approach
This kind of laser mouse, mostly consisting of a pair of vertical cavity surface emitting lasers, two photodiodes and an integrated signal processing unit, is capable of directly giving the x-axis and y-axis components of the measured vibrating displacement. Based on the laser self-mixing interference, the velocity of the object is coded into the Doppler frequency shift of the feedback light, which allows accurate determination of the vibration of the object.
Findings
A commercial shaker has been used to provide standard harmonic oscillation to test the displacement sensor. Within a vibrating frequency range of 110 Hz, the experimental results show that the micrometer scale resolution has been achieved at the velocity of up to 2 m/s, which is much improved compared with the image-based optical mouse. Furthermore, the measurements of the two dimensional displacement of a nano-positioning stage are performed as well. The minimum measurable velocity limit for this sensor has been discussed in detail, and the relative measurement error can be greatly reduced by appropriate selection of the modulation frequency of the triangular injection current.
Originality/value
These results demonstrate the feasibility of this device for the industrial vibration sensing applications.
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Yiping Jiang, Yanhua Chen and Xiaobo Chi
The practice of renovation and construction of university libraries is flourishing, but how to attract readers to use the library is an issue that urgently needs to be explored…
Abstract
Purpose
The practice of renovation and construction of university libraries is flourishing, but how to attract readers to use the library is an issue that urgently needs to be explored. Spatial cognition is a subjective judgment of a person's tendency to take action in the future and implies behavioral intention. Based on the sensory–image–cognition relationship, a theoretical model of university library readers' spatial cognition is conducted, and the influencing factors and mechanisms of spatial cognition are explored based on empirical data to provide theoretical references for spatial practices in university libraries.
Design/methodology/approach
A visual and art-based mental map approach is introduced based on a questionnaire survey. The questionnaire is mainly used for the specific evaluation of spatial use and the breakdown of the detailed elements, while the mental map method is mainly used for the evaluation of readers' spatial cognition. Relevant empirical data are collected from the library of the Zhejiang University of Technology.
Findings
The results indicate that readers' spatial sensory experience and mental imagery have positive effects on readers' behavior via the mediator spatial cognition, readers' spatial sensory experience and mental imagery have a positive effect on readers' spatial cognition and spatial cognition has a significant effect on readers' behavior.
Originality/value
The main contribution of this study is to construct a theoretical model of readers' spatial cognition and to explore the factors that have an impact on spatial cognition and the influence of cognition on behavior. This provides a more rational and in-depth thinking paradigm for the study of university library space and provides theoretical references for library practice.
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Junyan Ma and Yiping Yuan
With the rapid increase in the number of installed wind turbines (WTs) worldwide, requirements and expenses of maintenance have also increased significantly. The condition…
Abstract
Purpose
With the rapid increase in the number of installed wind turbines (WTs) worldwide, requirements and expenses of maintenance have also increased significantly. The condition monitoring (CM) of WT provides a strong “soft guarantee” for preventive maintenance. The supervisory control and data acquisition (SCADA) system records a huge amount of condition data, which has become an effective means of CM. The main objective of the present study is to summarize the application of SCADA data to fault detection in wind turbines, analyze its advantages and disadvantages and predict the potential of future investigations on the use of SCADA data for fault detection.
Design/methodology/approach
The authors first review the means of WT CM and summarize the characteristics of CM based on SCADA data. To ensure the quality of SCADA data, data preprocessing methods are analyzed and compared. Then, the failure modes of the key components are discussed and the SCADA data used for fault detection of each component are compared. Moreover, the fault detection methods for WT are classified and a general framework for fault detection is proposed. Finally, the issues in the WT fault detection method based on SCADA data are reviewed.
Findings
Based on the performed analyses, it is found that although the fault detection accuracy based on SCADA data is relatively poor, it has low capital expenses and low computational cost. More specifically, when there is scarce fault data, the normal SCADA data can be used to detect the fault time. However, the specific fault type cannot be identified in this way. When a large amount of fault data are accumulated in the SCADA system, it can not only detect the occurrence time of the fault but also identify the specific fault type.
Originality/value
The main contribution of the present study is to summarize the pre-processing methods for SCADA data, the data required for fault detection of key components and the characteristics of the fault detection model. Then we propose a general fault detection framework for wind turbines based on SCADA data, where the maintenance workers can choose the appropriate fault detection method according to different fault detection requirements and data resources. This article is expected to provide guidance for fault detection based on time-series sensor signals and be of interest to researchers, maintenance workers and managers.
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Jingjing Shi, Ning Qian, Honghua Su, Ying Yang and Yiping Wang
The electrical properties of piezoelectric vibrators have a crucial influence on the operating state of ultrasonic motors. In order to solve the problem that the current…
Abstract
Purpose
The electrical properties of piezoelectric vibrators have a crucial influence on the operating state of ultrasonic motors. In order to solve the problem that the current piezoelectric vibrator generates a large amount of heat during vibration to degrade its performance, which in turn affects the normal operation of ultrasonic motors, this paper prepares a novel piezoelectric vibrator and tests its maximum vibration velocity under the working condition, which is more than twice as much as that of the current commercial PZT-8.
Design/methodology/approach
The crystal structures of the samples were analyzed by using an X-ray diffractometer. For microstructure observation, samples were observed by scanning electron microscope (SEM). The quasi-static piezoelectric coefficient meter (ZJ-3AN) was used for piezoelectric measurement. Dielectric properties were measured by utilizing an impedance analyzer (Agilent 4294A) with a laboratory heating unit. Ferroelectric hysteresis loops were obtained using a ferroelectric analyzer (Radiant, Multiferroic 100). A Doppler laser vibrometer (Polytec PSV-300F, Germany) and a power amplifier were used for piezoelectric vibration measurements, during which the temperature rise was determined by an infrared radiation thermometer (Victor 303, China).
Findings
The ceramics exhibit enhanced piezoelectric performance at 0.1–0.4 mol% of Yb doping contents. The ceramic of 0.4 mol% Yb reaches the maximal internal bias field and presents a larger mechanical quality factor of 1,692 compared with that of 0.2 mol% Yb-doped ceramic, in spite of a slightly decreased dielectric constant of 439 pC/N, the unit of the piezoelectric constant, which is the ratio of the local charge (pC) to the frontal force (N) and electromechanical coupling coefficient of 0.63. The vibrator with this large mechanical quality factor ceramic displays a vibration velocity of up to 0.81 m/s under the constraint of 20 °C temperature rising, which is much higher than commercial high-power piezoelectric ceramics PZT-8.
Originality/value
The enhanced high-power properties of the piezoelectric vibrator by Yb doping may provide a potential application for the high-performance USM and offer the possibility of long-term stable operation under high power for special equipment like USM. In the subsequent phase of research, the novel PZT-based high-power piezoelectric vibrator can be utilized in the USM, and the motor's performance will be evaluated under aerospace conditions to objectively assess the reliability of the piezoelectric vibrator.
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Wei Zhou, Xiaofei Pan and Yiping Wu
We examine the effectiveness of signaling by disclosing innovation in annual reports in terms of securing R&D subsidies, using a novel text-based measure of firm-level innovation…
Abstract
Purpose
We examine the effectiveness of signaling by disclosing innovation in annual reports in terms of securing R&D subsidies, using a novel text-based measure of firm-level innovation intensity.
Design/methodology/approach
The empirical analysis includes regressions with firm and year-fixed effects and an instrumental variable approach. Both mediation and moderation analysis are conducted to identify the plausible channels.
Findings
We find that firms are likely to receive research and development (R&D) subsidies if their annual reports contain intensive disclosure of information about innovation. We also identify the site visits by government officials as a plausible channel through which innovation disclosure in annual reports can help firms receive R&D subsidies. Additional analysis shows the main effect of innovation disclosure is especially pronounced in firms with severe information asymmetry and those facing a low-trust environment.
Originality/value
Current studies have shown the effectiveness of signaling in capital markets in terms of securing bank loans and venture capital (Cassar et al., 2015; Hoenig and Henkel, 2015; Connelly et al., 2016; Plummer et al., 2016). It is unclear if such a signaling can attract the attention of government officials. Our results suggest that government officials view annual reports as an important means of mitigating information asymmetry, which in turn helps firms to receive external R&D funding.
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Yiping Jiang, Shanshan Zhou, Jie Chu, Xiaoling Fu and Junyi Lin
This paper aims to explore blockchain integration strategies within a three-level livestock meat supply chain in which consumers have a preference for quality trust in livestock…
Abstract
Purpose
This paper aims to explore blockchain integration strategies within a three-level livestock meat supply chain in which consumers have a preference for quality trust in livestock meat products. The paper investigates three questions: First, how does consumers’ preference for quality trust affect blockchain integration and transaction decisions among supply chain participants? Second, under what circumstances will retailers choose to participate in the blockchain? Finally, how can other factors such as blockchain costs and supplier–retailer partnership value affect integration decisions?
Design/methodology/approach
This paper formulates a supply chain network equilibrium model and employs the logarithmic-quadratic proximal prediction-correction method to obtain equilibrium decisions. Extensive numerical studies are conducted using a pork supply chain network to analyze the implications of blockchain integration for different supply chain participants.
Findings
The results reveal several key insights: First, suppliers’ increased blockchain integration, driven by higher quality trust preference, can negatively affect their profits, particularly, with excessive trust preferences and high blockchain costs. Second, an increase in consumers’ preference for quality trust expands the range of unit operating costs for retailers engaging in blockchain. Finally, the supplier–retailer partnership drives retailer blockchain participation, facilitating enhanced information sharing to benefit the entire supply chain.
Originality/value
This study provides original insights into blockchain integration strategies in an agricultural supply chain through the application of the supply chain network equilibrium model. The investigation of several key factors on equilibrium decisions provides important managerial implications for different supply chain participants to address consumers’ preference for quality trust and enhance overall supply chain performance.
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Hanqin Qiu Zhang, York Qi Yan and Yiping Li
This study attempts to demystify the mechanism behind the negative event of the so‐called “zero‐commission” tours that have become synonymous with the booming Chinese outbound…
Abstract
Purpose
This study attempts to demystify the mechanism behind the negative event of the so‐called “zero‐commission” tours that have become synonymous with the booming Chinese outbound tourism in the past decade.
Design/methodology/approach
Utilizing the Atlas.ti computer qualitative analysis software, nine proposed key factors constituting the zero‐tour phenomenon are examined and proven through a content analysis of 30 case studies.
Findings
The validity of the proposed nine factors causing the zero‐tour and their respective degrees of relevance to the phenomenon are also investigated and empirically tested in the study.
Research limitations/implications
The study used the cases from destinations such as Hong Kong and Thailand. It will be better if cases from other destinations such as Malaysia, Japan, Singapore, and Australia can be examined in future studies since the zero‐tour phenomenon also exists in other countries.
Practical implications
This study may serve as a reference for the drafting and implementation of both policy and business countermeasures to curb the zero‐commission tours. Consequently, this would facilitate more positive contributions of the Chinese outbound tourism industry to global tourism development.
Originality/value
No empirical study on the zero‐tour phenomenon was found in the literature. Based on the game theory, the proposed and empirically tested nine factors can serve as the foundation on which future studies on the zero‐commission tour can be conducted.