Chien-Hsuan Chang, Hung-Liang Cheng and En-Chih Chang
A typical photovoltaic grid-connection power system usually consists of multi-stage converters to perform multiple functions simultaneously. To simplify system configuration…
Abstract
Purpose
A typical photovoltaic grid-connection power system usually consists of multi-stage converters to perform multiple functions simultaneously. To simplify system configuration, reduce cost and improve conversion efficiency, this paper aims to develop a buck–boost-type inverter. The proposed inverter has both step-up and step-down functions, so that it is suitable for applications with wide voltage variation. As only one power switch operates with high frequency at one time, switching losses can significantly be reduced.
Design/methodology/approach
A step-up/down inverter is developed by adopting a buck-interleaved buck–boost (BuIBB) DC-DC converter and connecting with an H-bridge unfolding circuit with line-commutated operation.
Finding
The proposed circuit can work functionally as either a buck-type or boost-type inverter, so that partial energy can be directly delivered to output to improve efficiency. The input current is shared by two inductors, leading to the reduction of current stresses.
Research limitations/implications
To apply the proposed inverter to micro-inverter applications in the future, developing a step-up/down inverter with a higher conversion ratio will be considered.
Practical implications
A laboratory prototype is built accordingly to verify the feasibility of the proposed inverter. The experimental results are presented to show the effectiveness.
Originality/value
This paper proposes a step-up/down inverter by using the BuIBB converter, which is innovatively studied.
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Chun-Mei Kai, Feng-Jun Zhang, Cong-Liang Cheng and Qian-Bao Chen
The purpose of this paper is to study the influence of different factors on mud performance, find the best conditions and synthesize a new type of anti-collapse drilling polymer…
Abstract
Purpose
The purpose of this paper is to study the influence of different factors on mud performance, find the best conditions and synthesize a new type of anti-collapse drilling polymer mud with higher stability. The anti-collapse mechanism of drilling polymer mud was also suggested.
Design/methodology/approach
Exploring the influence of different molecular weight thickeners, filtrate reducers, soda ash addition and film-forming components on the mud performance, so as to obtain the best ratio of anti-collapse drilling polymer mud.
Findings
The results show that the use of vegetable glue, sulfonate copolymer and vegetable fiber powder can synthesize a high-viscosity, high-stability, collapse-resistant mud. When the mass ratio of vegetable fiber powder: vegetable glue: sulfonate copolymer is 40:1:2, the mud viscosity is 21.2 s, the fluid loss in 30 min is only 12.5 mL, and the mud film thickness is 1.5 mm, which is one ideal anti-collapse polymer mud.
Originality/value
Compared with ordinary polymer mud and bentonite mud, this anti-collapse polymer mud not only uses vegetable glue instead of traditional tackifiers but also effectively uses vegetable fiber powder produced from waste wood, which is environmentally friendly and highly stable specialty. It can effectively improve the safety and quality of construction during drilling in water-sensitive geology.
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Liang Cheng, Qing Wang, Jiangxiong Li and Yinglin Ke
This paper aims to present a modeling and analysis approach for multi-station aircraft assembly to predict assembly variation. The variation accumulated in the assembly process…
Abstract
Purpose
This paper aims to present a modeling and analysis approach for multi-station aircraft assembly to predict assembly variation. The variation accumulated in the assembly process will influence the dimensional accuracy and fatigue life of airframes. However, in digital large aircraft assembly, variation propagation analysis and modeling are still unresolved issues.
Design/methodology/approach
Based on an elastic structure model and variation model of multistage assembly in one station, the propagation of key characteristics, assembly reference and measurement errors are introduced. Moreover, the reposition and posture coordination are considered as major aspects. The reposition of assembly objects in a different assembly station is described using transformation and blocking of coefficient matrix in finite element equation. The posture coordination of the objects is described using homogeneous matrix multiplication. Then, the variation propagation model and analysis of large aircraft assembly are established using a discrete system diagram.
Findings
This modeling and analysis approach for multi-station aircraft assembly reveals the basic rule of variation propagation between adjacent assembly stations and can be used to predict assembly variation or potential dimension problems at a preliminary assembly phase.
Practical implications
The modeling and analysis approaches have been used in a transport aircraft project, and the calculated results were shown to be a good prediction of variation in the actual assembly.
Originality/value
Although certain simplifications and assumptions have been imposed, the proposed method provides a better understanding of the multi-station assembly process and creates an analytical foundation for further work on variation control and tolerance optimization.
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Qing Wang, Yadong Dou, Liang Cheng and Yinglin Ke
This paper aims to provide a shimming method based on scanned data and finite element analysis (FEA) for a wing box assembly involving non-uniform gaps. The effort of the present…
Abstract
Purpose
This paper aims to provide a shimming method based on scanned data and finite element analysis (FEA) for a wing box assembly involving non-uniform gaps. The effort of the present work is to deal with gap compensation problem using hybrid shims composed of solid and liquid forms.
Design/methodology/approach
First, the assembly gaps of the mating components are calculated based on the scanned surfaces. The local gap region is extracted by the seed point and region growth algorithm from the scattered point cloud. Second, with the constraints of hole margin, gap space and shim specification, the optional shimming schemes are designed by the exhaustive searching method. Finally, the three-dimensional model of the real component is reconstructed based on the reverse engineering techniques, such as section lines and sweeping. Using FEA software ABAQUS, the stress distribution and damage status of the joints under tensile load are obtained for optimal scheme selection.
Findings
With the scanned mating surfaces, the non-uniform gaps are digitally evaluated with accurate measurement and good visualization. By filling the hybrid shims in the assembly gaps, the joint structures possess similar load capacity but stronger initial stiffness compared to the custom-shimmed structures.
Practical implications
This method has been tested with the interface data of a wing tip, and the results have shown good efficiency and automation of the shimming process.
Originality/value
The proposed method can decrease the manufacturing cost of shims, shorten the shimming process cycle and improve the assembly efficiency.
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Xinliang Liu, Liang Cheng, Guoning Chen, Xiaolei Wang and Jingqiu Wang
The purpose of this study is to provide a new convolutional neural network (CNN) model with multi-scale feature extractor to segment and recognize wear particles in complex…
Abstract
Purpose
The purpose of this study is to provide a new convolutional neural network (CNN) model with multi-scale feature extractor to segment and recognize wear particles in complex ferrograph images, especially fatigue and severe sliding wear particles, which are similar in morphology while different in wear mechanism.
Design/methodology/approach
A CNN model named DWear is proposed to semantically segment fatigue, severe sliding particles and four other types of particles, that is, chain, spherical, cutting and oxide particles, which unifies segmentation and recognition together. DWear is constructed using four modules, namely, encoder, densely connected atrous spatial pyramid pooling, decoder and fully connected conditional random field. Different from the architectures of ordinary semantic segmentation CNN models, a multi-scale feature extractor using cascade connections and a coprime atrous rate group is incorporated into the DWear model to obtain multi-scale receptive fields and better extract features of wear particles. Moreover, fully connected conditional random field module is adopted for post-processing to smooth coarse prediction and obtain finer results.
Findings
DWear is trained and verified on the ferrograph image data set, and experimental results show that the final Mean Pixel Accuracy is 95.6% and the Mean Intersection over Union is 92.2%, which means that the recognition and segmentation accuracy is higher than those of previous works.
Originality/value
DWear provides a promising approach for wear particle analysis and can be further developed in equipment condition monitoring applications.
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Hang Guo, Xin Chen, Min Yu, Marcin Uradziński and Liang Cheng
In this study, an indoor sensor information fusion positioning system of the quadrotor unmanned aerial vehicle (UAV) was investigated to solve the problem of unstable indoor…
Abstract
Purpose
In this study, an indoor sensor information fusion positioning system of the quadrotor unmanned aerial vehicle (UAV) was investigated to solve the problem of unstable indoor flight positioning.
Design/methodology/approach
The presented system was built on Light Detection and Ranging (LiDAR), Inertial Measurement Unit (IMU) and LiDAR-Lite devices. Based on this, one can obtain the aircraft's current attitude and the position vector relative to the target and control the attitudes and positions of the UAV to reach the specified target positions. While building a UAV positioning model relative to the target for indoor positioning scenarios under limited Global Navigation Satellite Systems (GNSS), the system detects the environment through the NVIDIA Jetson TX2 (Transmit Data) peripheral sensor, obtains the current attitude and the position vector of the UAV, packs the data in the format and delivers it to the flight controller. Then the flight controller controls the UAV by calculating the posture to reach the specified target position.
Findings
The authors used two systems in the experiment. The first is the proposed UAV, and the other is the Vicon system, our reference system for comparison purposes. Vicon positioning error can be considered lower than 2 mm from low to high-speed experiments. After comparison, experimental results demonstrated that the system could fully meet the requirements (less than 50 mm) in real-time positioning of the indoor quadrotor UAV flight. It verifies the accuracy and robustness of the proposed method compared with that of Vicon and achieves the aim of a stable indoor flight preliminarily.
Originality/value
Vicon positioning error can be considered lower than 2 mm from low to high-speed experiments. After comparison, experimental results demonstrated that the system could fully meet the requirements (less than 50 mm) in real-time positioning of the indoor quadrotor UAV flight. It verifies the accuracy and robustness of the proposed method compared with that of Vicon and achieves the aim of a stable indoor flight preliminarily.
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Abdulhakim Adeoye Shittu, Fuat Kara, Ahmed Aliyu and Obinna Unaeze
The purpose of this paper is to mainly review the state-of-the-art developments in the field of hydrodynamics of offshore pipelines, identifying the key tools for analysis of…
Abstract
Purpose
The purpose of this paper is to mainly review the state-of-the-art developments in the field of hydrodynamics of offshore pipelines, identifying the key tools for analysis of pipeline free spans, their applications, their qualifying characteristics and capabilities and limitations.
Design/methodology/approach
These different analytical, numerical and semi-empirical tools available for predicting such hydrodynamic loads and their effects include VIVANA, PIPESIN, VIVSIM, SIMULATOR, FATFREE, amongst others. Inherent in these models are current effects, wave effects and/ or pipe–soil interactions.
Findings
Amongst these models, the most attention was given to the new VIVANA model because this model take into account the vortex-induced effects with respect to free-spanning pipelines (which have dominant effect in the span analysis in deep water) better than other semi-empirical models (such as Shear 7). Recent improvements in VIVANA include its ability to have arbitrary variation in speed and direction of current, as well as the ability for calculation of pure IL and combined IL-CF response. Improvements in fatigue assessments at free spans, i.e. pipe–soil interaction have been achieved through the combined frequency domain and non-linear time domain analysis methodology adopted. Semi-empirical models are still the de facto currently used in the design of free-spanning pipelines. However, there is need for further research on free-span hydrodynamic coefficients and on how in-line and cross-flow vibrations interact. Again, there is still the challenge due to VIV complexity in fully understanding the fluid structure interaction problem, as there is no consolidated procedure for its analysis. It has been observed that there is large scatter between the different codes adopted in the prediction of fatigue damage, as there lacks full-scale test data devoted to determination/validation of the coefficients used in the semi-empirical models. A case study of the preliminary design of a typical 48 in. pipeline has been presented in this study to demonstrate the use of the free-span analysis tool, DNV RP F105. Excel spreadsheet has been applied in the execution of formulas.
Originality/value
This review paper is the first of its kind to study the state-of-the-art development in pipeline free-span analysis models and demonstrate the use of analysis tool, DNV for MAFSL calculation. Hence, information obtained from this paper would be invaluable in assisting designers both in the industry and academia.
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Muhammad Awais Bhatti, Mohammed Alshagawi, Ahmad Zakariya and Ariff Syah Juhari
Globalization has brought many challenges to organizations, namely, in managing the performance of multicultural workforces to achieve organizational objectives. Past researchers…
Abstract
Purpose
Globalization has brought many challenges to organizations, namely, in managing the performance of multicultural workforces to achieve organizational objectives. Past researchers have highlighted many factors that influence the employee’s performance, but the nature and scope of these factors is limited to the conventional setting. Therefore, the purpose of this paper is to develop a comprehensive framework to better understand the role of the psychological diversity climate, HRM practices and personality traits (Big Five) in job satisfaction and performance of the multicultural workforce.
Design/methodology/approach
Data were collected from 258 faculty members working in Saudi Arabia’s higher educational sector. Structural equation modeling was used with Amos 18 to analyze the data.
Findings
The findings of this study suggest that managers should adopt diversity practices to improve the psychological diversity climate among multicultural workforce. In addition, diversity training and unbiased performance appraisal systems also increase the faculty member’s job satisfaction and performance in multicultural settings. Finally, managers should consider openness to culture and sociability traits while selecting faculty members to work in multicultural settings.
Originality/value
This framework has never been tested in higher educational institutions and in multicultural setting.
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Rohit Kumar Singh and Sachin Modgil
The main aim of this study is to explore the relationship between information system flexibility and dynamic capabilities to build sustainable and net zero supply chains under the…
Abstract
Purpose
The main aim of this study is to explore the relationship between information system flexibility and dynamic capabilities to build sustainable and net zero supply chains under the influence of environmental dynamism.
Design/methodology/approach
We have formulated a self-administered survey, with 359 participants contributing responses. Prior to delving into foundational assumptions, such as homoscedasticity and normality, a nonresponse bias analysis was executed. The integrity of the data, in terms of reliability and construct validity, was gauged using confirmatory factor analysis. Subsequent regression outputs corroborated all the proposed assumptions, fortifying the extant scholarly literature.
Findings
The empirical findings of this research underscore a positive correlation between Information system flexibility, dynamic capabilities and a net zero supply chain, especially in the context of environmental dynamism. Data sourced from the cement manufacturing sector support these observations. We also found that environmental dynamism moderates the relationship between data analytics capability and sustainable supply chain flexibility but does not moderate the relationship between Resource flexibility and sustainable supply chain flexibility. Additionally, this research strengthens the foundational principles of the dynamic capability theory.
Originality/value
The conceptual framework elucidates the interplay between information system flexibility, dynamic capabilities, and sustainable supply chain flexibility, emphasizing their collective contribution towards achieving sustainable chain net zero, introducing environmental dynamics as a moderating variable that augments the scholarly discourse with a nuanced layer of analytical depth.
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Liang‐Chieh (Victor) Cheng, Michael L. Gibson, Edward E. Carrillo and Grayson Fitch
This paper seeks to explore the necessity to incorporate technology as a key component in studying business operations of industrial entities.
Abstract
Purpose
This paper seeks to explore the necessity to incorporate technology as a key component in studying business operations of industrial entities.
Design/methodology/approach
Reviews of key management theories that shaped organization‐centric and process‐centric views in industrial management research are conducted. The paper then identifies the limitations of these two schools of thinking and develops a technology‐centric framework that integrates technology, organization, and process in general. A series of case studies that apply the framework at multiple levels of observations are presented. The research concludes with theoretical and managerial implications.
Findings
This paper presents a “trinity” framework that includes three core constructs that can simultaneously develop into variants. Technology as a holistic concept must be taken into consideration when researchers or practitioners take a dynamic view to study business entities. A multi‐dimensional, technology‐centric framework acknowledges technology as the transformational resource and helps the practitioners and researchers to examine technology as potential facilitators for organizational operations.
Originality/value
A review of the cases found that technology, organizational structures, and business processes impact one another. Firms' actions are indicative that in today's technology‐intensive environment, organizational structures and business processes need to be developed or modified in coordination with technological development. In doing so, organizations will gain the potential to harvest benefits from technology‐organization‐process integration.