Dongliang Sun, Jinliang Xu and Peng Ding
Based on the numerical research on the relationship between the flow pattern transition and the condensation heat transfer in circular microchannels, the purpose of this paper is…
Abstract
Purpose
Based on the numerical research on the relationship between the flow pattern transition and the condensation heat transfer in circular microchannels, the purpose of this paper is to bring forward a concept of external separation circular microchannel to regulate and control the flow pattern for enhancing the condensation heat transfer.
Design/methodology/approach
The numerical research is based on the volume of fluid method and the vapor-liquid phase change model proposed by the present authors.
Findings
By numerical research on the condensation process of water in a general circular microchannel, it is discovered that, with the increase of the inlet velocity and the reduction of the temperature difference between the saturation temperature and the channel wall temperature, the bubble detachment frequency is raised and the water vapor condensation length is extended, representing an exponential growth. Therefore, for the condensation process with low temperature difference and high mass flow rate, it is in urgent need to regulate and control the flow pattern.
Originality/value
To prevent the flow pattern in the general circular microchannel converted from annular flow to slug flow and then to bubble flow, this paper brings forward a concept of external separation circular microchannel, which regulates and controls the flow pattern by discharging partial liquid from the annular wall opening. After regulation and control, the flow pattern is converted from original periodic annular flow/slug flow/bubble flow to current stable annular flow. Accordingly, the heat transfer performance is enhanced and the condensation length is lowered remarkably.
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Duo Shang, Dongliang Yuan, Xinmei Wu and Dehui Li
The aim of this paper is to explore the relationship between digital transformation and corporate fraud.
Abstract
Purpose
The aim of this paper is to explore the relationship between digital transformation and corporate fraud.
Design/methodology/approach
This paper uses panel data of Chinese listed corporations from 2010 to 2021 and captures digital transformation from the perspectives of awareness and investment by extracting related content from annual reports. Our work investigates whether and how digital transformation influences corporate fraud and examines the moderating effects of the legal environment, media environment and privacy concerns.
Findings
Our findings show that digital transformation, captured either from awareness or actual investment, can significantly alleviate corporate fraud. Our results are robust in a set of endogeneity tests and robustness checks. Additionally, we confirm that digital transformation alleviates corporate fraud through two mechanisms: improving internal monitoring and boosting information flow. Additionally, this alleviating effect is more pronounced for corporations with fewer privacy concerns and in worse legal and media environments.
Practical implications
Our findings provide insights for policymakers to motivate corporations to engage in digital transformation for fraud prevention. We also offer guidelines for corporations to improve their awareness and actual investments in digital transformation and take advantage of its governance effect in preventing corporate fraud.
Originality/value
Overall, we highlight the governance role of digital transformation in alleviating corporate fraud and provide policy implications for regulators in emerging economies to regard digital transformation as an effective tool for fraud prevention.
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Yu Zhou, Jiaxin Liu and Dongliang Lei
This paper aims to investigate whether the two dominant financial reporting regimes, US Generally Accepted Accounting Principles (US GAAP) and International Financial Reporting…
Abstract
Purpose
This paper aims to investigate whether the two dominant financial reporting regimes, US Generally Accepted Accounting Principles (US GAAP) and International Financial Reporting Standards (IFRS), are associated with audit pricing and audit report lags.
Design/methodology/approach
In 2007, the US SEC eliminated the requirement for foreign registrants to reconcile their financial statements to US GAAP from IFRS. In this post-reconciliation setting in the USA, the authors use panel ordinary least square regressions to examine a sample of foreign firms cross-listed in the USA reporting under IFRS and US domestic firms reporting under US GAAP during the fiscal year 2007–2019.
Findings
The authors find that the firms reporting under IFRS have longer audit report lags than firms reporting under US GAAP. In addition, the authors find that firms reporting under IFRS pay higher audit fees than their US GAAP counterparts. The results are robust after controlling for the firm- and country-specific characteristics as well as using propensity-score matching.
Originality/value
To the best of the authors’ knowledge, this study is the first to provide empirical evidence that the differences between the two reporting regimes are associated with auditor behavior, possibly through additional audit efforts and audit complexity associated with auditing the principle-based IFRS relative to the rule-based US GAAP.
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This paper aims to examine the relation between managerial ability and stock price crash risk, conditional on managerial overconfidence. In addition, conditional on managerial…
Abstract
Purpose
This paper aims to examine the relation between managerial ability and stock price crash risk, conditional on managerial overconfidence. In addition, conditional on managerial overconfidence, the authors investigate the effect of managerial ability on firms’ choice of bad news hoarding channels, which result in a stock price crash.
Design/methodology/approach
Using a sample of 24,289 firm-years from companies listed on Compustat and CRSP from 1994 to 2018, the authors conduct panel regression analysis.
Findings
The authors find that managerial ability is positively associated with stock price crash risk only when managerial overconfidence is high. Furthermore, the authors find that managerial ability seems to exacerbate (attenuate) the bad news withholding by the overconfident managers using the earnings guidance (earnings management) channel. The authors find limited evidence that high-ability managers are likely to withhold bad news through the overinvestment channel and “other channels” when managers are overconfident. Finally, the authors find that the joint effect of managerial overconfidence and managerial ability on firms’ crash risk is more pronounced when there is a material weakness in firms’ internal controls, high investor belief heterogeneity and high information asymmetry. However, this effect appears to dissipate during the recent financial crisis in 2008.
Originality/value
This research reveals that managerial ability is costly to firms by engendering bad news hoardings and stock price crash risk when managers are overconfident. It also sheds light on how managerial overconfidence and managerial ability affect managers’ choice of bad news withholding channels and stock price crash risk. Finally, the paper is of practical value to the board of directors in selecting the prospective executives.
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Yongtao Zhao, Weili Li, Xiaoyang Xuan, Jianbang Gao, Jue Wang, Liang Dong, Dawei Zang, Mingjian Wang and Xiankang Zhong
This study aims to evaluate the protection performance of zinc as sacrificial anode for ABS A steel in the presence of H2S under different temperatures, pH and salinities.
Abstract
Purpose
This study aims to evaluate the protection performance of zinc as sacrificial anode for ABS A steel in the presence of H2S under different temperatures, pH and salinities.
Design/methodology/approach
In this paper, weight loss measurements and electrochemical measurements are used to evaluate the corrosion degree of zinc and ABS A steel.
Findings
Under the conditions involved in this work, it is shown that zinc is a nice sacrificial anode with the reason of its stable potential and excellent anode current efficiency according to the relevant standard. And it is also found that the hydrogen evolution does not occur on ABS A steel specimens. The potential difference between cathode and anode is suitable; thus, it can be concluded that each steel is well protected.
Originality/value
To the best of the authors’ knowledge, no other study has analyzed the protection mechanism and effect of zinc as sacrificial anode in H2S-containing environments under high temperature at present.
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Dilong Chen, Qiang Lu, Dongliang Peng, Ke Yin, Chaoliang Zhong and Ting Shi
The purpose of this paper is to propose a receding horizon control approach for the problem of locating unknown wireless sensor networks by using a mobile robot.
Abstract
Purpose
The purpose of this paper is to propose a receding horizon control approach for the problem of locating unknown wireless sensor networks by using a mobile robot.
Design/methodology/approach
A control framework is used and consists of two levels: one is a decision level, while the other is a control level. In the decision level, a spatiotemporal probability occupancy grid method is used to give the possible positions of all nodes in sensor networks, where the posterior probability distributions of sensor nodes are estimated by capturing the transient signals. In the control level, a virtual robot is designed to move along the edge of obstacles such that the problem of obstacle avoidance can be transformed into a coordination problem of multiple robots. On the basis of the possible positions of sensor nodes and virtual robots, a receding horizon control approach is proposed to control mobile robots to locate sensor nodes, where a temporary target position method is utilized to avoid several special obstacles.
Findings
When the number of obstacles increases, the average localization errors between the actual locations and the estimated locations significantly increase.
Originality/value
The proposed control approach can guide the mobile robot to avoid obstacles and deal with the corresponding dynamical events so as to locate all sensor nodes for an unknown wireless network.
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Qingqing Song, Xudong Wang, Boyang Pan and Lei Wan
The purpose of this paper is to obtain the environmental factor, which has the greatest effect on the corrosion rate of Q235 carbon steel under thin electrolyte layer, and to…
Abstract
Purpose
The purpose of this paper is to obtain the environmental factor, which has the greatest effect on the corrosion rate of Q235 carbon steel under thin electrolyte layer, and to analyze the effect of this factor on the corrosion morphology, corrosion products and polarization process of Q235 carbon steel.
Design/methodology/approach
An electrochemical device, which can be used under thin electrolyte layer is designed to measure the corrosion current in different environments. Response surface methodology (RSM) is introduced to analyze the effect of environmental factors on corrosion rate. Scanning electron microscope (SEM) and X-ray diffraction (XRD) technique are used to analyze the results. The Tafel slopes of anode and cathode in different humidity and solution are calculated by least square method.
Findings
The three environmental factors are ranked according to importance, namely, humidity, temperature and chloride ion deposition rate. In a high humidity environment, the relative content of α-FeOOH in the corrosion product is high and the relative content of β-FeOOH is low. The higher the humidity, the lower the degree of anodic blockage, whereas the degree of cathodic blockage is independent of humidity. The above experiments confirm the effectiveness and efficiency of the device, indicating it can be used for the screening of corrosive environmental factors.
Originality/value
In this paper, an electrochemical device under thin film is designed, which can simulate atmospheric corrosion well. Subsequent SEM and XRD confirmed the reliability of the data measured by this device. The introduction of a scientific RSM can overcome the limitations of orthogonal experiments and more specifically and intuitively analyze the effects of environmental factors on corrosion rates.
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Kunal Arora, Mohit Kumar and Varun Sharma
The paper aims to fabricate shape memory composites using polylactic acid (PLA) matrix and graphite. Shape memory polymers are a promising family of materials for biomedical…
Abstract
Purpose
The paper aims to fabricate shape memory composites using polylactic acid (PLA) matrix and graphite. Shape memory polymers are a promising family of materials for biomedical applications because of their favourable mechanical properties, fast reactions and good biocompatibility. For most SMPs, however, achieving controllable sequential shape change is challenging.
Design/methodology/approach
In the present work, 4D printing technology is used to fabricate shape memory composites using polylactic acid (PLA) matrix and graphite. A comparative study of pure PLA and graphite’s different weight % composition has been done.
Findings
By carefully managing the deformation state, PLA with graphite shape memory composites produced controllable sequential deformation with an amazing shape memory effect. Surface morphology, thermal properties, melt flow index and shape recovery tests have all been carried out to assess the qualities of manufactured samples.
Originality/value
This is a one-of-a-kind to fabricate shape memory composites using graphite and a PLA matrix. Thus, this research attempts to deliver the possible use of PLA/graphite composites fabricated using 4D printing in robotics and biomedical devices.