Wei Zhu, Chunze Yan, Yunsong Shi, Shifeng Wen, Changjun Han, Chao Cai, Jie Liu and Yusheng Shi
Semi-crystalline polymers such as polyamide-12 can be used for selective laser sintering (SLS) to make near-fully dense plastic parts. At present, however, the types of…
Abstract
Purpose
Semi-crystalline polymers such as polyamide-12 can be used for selective laser sintering (SLS) to make near-fully dense plastic parts. At present, however, the types of semi-crystalline polymers suitable for SLS are critically limited. Therefore, the purpose of this paper is to investigate the processibility of a new kind of semi-crystalline polypropylene (PP) with low isotacticity for SLS process.
Design/methodology/approach
The SLS processibility of the PP powder, including particle size and shape, sintering window, degree of crystallinity and degradation temperature, was evaluated. Effects of the applied laser energy density on the surface micromorphology, density, tensile strength and thermal properties of SLS-built PP specimens were studied.
Findings
The results show that the PP powder has a nearly spherical shape, smooth surfaces, an appropriate average particle size of 63.6 μm, a broad sintering window of 21 oC and low crystalline degree of 30.4 per cent comparable to that of polyamide-12, a high degradation temperature of 381.8°C and low part bed temperature of 105°C, indicating a very good SLS processibility. The density and the tensile strength first increase with increasing laser energy density until they reach the maximum values of 0.831 g/cm3 and 19.9 MPa, respectively, at the laser energy density of 0.0458 J/mm2, and then decrease when the applied laser energy density continue to increase owing to the degradation of PP powders. The complex PP components have been manufactured by SLS using the optimum parameters, which are strong enough to be directly used as functional parts.
Originality/value
This paper provides a new knowledge for this field that low-isotacticity PPs exhibit good SLS processibility, therefore increasing material types and broadening the application of SLS technology.
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Iman Harymawan, Fiona Vista Putri, Melinda Cahyaning Ratri and Mohammad Nasih
A company needs to use auditing procedures to ensure the reliability of financial statements while also providing transparency to stakeholders. The extent of risk associated with…
Abstract
Purpose
A company needs to use auditing procedures to ensure the reliability of financial statements while also providing transparency to stakeholders. The extent of risk associated with the company depends on the directors’ involvement in its daily operations. This paper aims to study the relationship between busy chief executive officers (CEOs) and audit fees.
Design/methodology/approach
This study uses 1,037 data samples from companies listed on the Indonesia Stock Exchange from 2010 until 2018. It adopts the ordinary least squares method to test the hypothesis. Furthermore, this study performs robustness tests, such as propensity score matching (PSM) and Heckman’s two-stage least square tests (Heckman, 1979), to address the endogeneity issues.
Findings
This study finds that the appearance of a busy CEO in a company will significantly increase the audit fee. It also concludes that a long tenure of a busy CEO will substantially weaken the positive relationship between the CEO and the audit fee. However, this study discovers that, in a company with a busy CEO, a monitoring mechanism through the independent commissioner and risk management committee will only help to maximize the firm’s practical risk evaluation a little. This result is robust because the PSM and Heckman tests display consistent results, so it is free from endogeneity issues.
Practical implications
This study is valuable for theoretical and practical development in Indonesia. Due to the minimum regulation about multiple positions on boards in Indonesia, the shareholders must be aware of the need to choose a board with more skill and commitment to improve the position of the company. This result also warns the C-level of the company to pay more attention to its risk-monitoring process to make it more effective and efficient.
Originality/value
Indonesia is one of the countries that have implemented the two-tier governance system. With the minimum regulation about multiple directorships in Indonesia, this study offers new insights into how a busy CEO will be related to the audit outcomes.
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Melanie E. Kreye, Linda B. Newnes and Yee Mey Goh
– The purpose of this paper is to explore the information that manufacturing companies have available when competitively bidding for service contracts.
Abstract
Purpose
The purpose of this paper is to explore the information that manufacturing companies have available when competitively bidding for service contracts.
Design/methodology/approach
A semi-structured interview study was undertaken with industrialists in various sectors, which are currently facing the issue of servitisation.
Findings
One of the main findings was that, despite the novelty of the process, the decision makers at the competitive bidding stage have an understanding of the involved uncertainties. In particular, the uncertainty arising from the customer as the user of the product and evaluator of the competitive bids in addition to the uncertainty connected to the competitors were identified as the main influences on the pricing decision.
Research limitations/implications
The research implications show the influences and considerations during the decision-making process at the competitive bidding stage for service contracts. These include the customer and the competitors.
Practical implications
Shortcomings in the current industrial practice were identified such as the approaches used to communicate the cost estimate for the service contract. The approaches currently used contradict research findings in the area of communicating uncertainty information, which means that further research is to be done to identify optimal approaches to displaying the uncertainty connected to the communicated information.
Originality/value
This paper offers a basis for research to understand the challenges industry faces when competitively bidding for service contracts. This can be used to develop novel approaches in supporting the decision maker such as a model that presents the probability of winning in comparison to the probability of making a profit.
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Shengquan Wang, Chao Wang, Yong Cai and Guangyao Li
The purpose of this paper is to improve the computational speed of solving nonlinear dynamics by using parallel methods and mixed-precision algorithm on graphic processing units…
Abstract
Purpose
The purpose of this paper is to improve the computational speed of solving nonlinear dynamics by using parallel methods and mixed-precision algorithm on graphic processing units (GPUs). The computational efficiency of traditional central processing units (CPUs)-based computer aided engineering software has been difficult to satisfy the needs of scientific research and practical engineering, especially for nonlinear dynamic problems. Besides, when calculations are performed on GPUs, double-precision operations are slower than single-precision operations. So this paper implemented mixed precision for nonlinear dynamic problem simulation using Belytschko-Tsay (BT) shell element on GPU.
Design/methodology/approach
To minimize data transfer between heterogeneous architectures, the parallel computation of the fully explicit finite element (FE) calculation is realized using a vectorized thread-level parallelism algorithm. An asynchronous data transmission strategy and a novel dependency relationship link-based method, for efficiently solving parallel explicit shell element equations, are used to improve the GPU utilization ratio. Finally, this paper implements mixed precision for nonlinear dynamic problems simulation using the BT shell element on a GPU and compare it to the CPU-based serially executed program and a GPU-based double-precision parallel computing program.
Findings
For a car body model containing approximately 5.3 million degrees of freedom, the computational speed is improved 25 times over CPU sequential computation, and approximately 10% over double-precision parallel computing method. The accuracy error of the mixed-precision computation is small and can satisfy the requirements of practical engineering problems.
Originality/value
This paper realized a novel FE parallel computing procedure for nonlinear dynamic problems using mixed-precision algorithm on CPU-GPU platform. Compared with the CPU serial program, the program implemented in this article obtains a 25 times acceleration ratio when calculating the model of 883,168 elements, which greatly improves the calculation speed for solving nonlinear dynamic problems.
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Ping Zhang, Wenju Zhu, Md. Yousuf Hossain, Shamima Sarker, Md. Nahid Pervez, Md. Ibrahim H. Mondal, Chao Yan, Yingjie Cai and Vincenzo Naddeo
The conventional textile dyeing process requires various operational characteristics, and determining the most reliable factor in dyeing performance has always been a challenge…
Abstract
Purpose
The conventional textile dyeing process requires various operational characteristics, and determining the most reliable factor in dyeing performance has always been a challenge for the textile industry. Thus, the present paper aimed to evaluate the process sensitivity of C. I. Reactive Blue 194 dyeing of cotton fabric using a statistical technique.
Design/methodology/approach
An L27 orthogonal array-based Taguchi's methodology was used with six parameters and three levels of each parameter. The signal-to-noise (S/N) ratio and analysis of variance were studied using total fixation efficiency (T%) as the response of the process sensitivity.
Findings
Results showed that dyebath pH was the most influential factor on the process and total fixation efficiency (p-value = 0.00 and contribution percentage 45.03%), followed by dye-fixing temperature, dye mass, electrolyte concentration, dye-fixing time and material to liquor ratio.
Originality/value
Overall this study provides a foundation for the determination of dyeing process sensitivity that will be useful in textile industries toward further development.
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Qi Sun, Fang Sun, Cai Liang, Chao Yu and Yamin Zhang
Beijing rail transit can actively control the density of rail transit passenger flow, ensure travel facilities and provide a safe and comfortable riding atmosphere for rail…
Abstract
Purpose
Beijing rail transit can actively control the density of rail transit passenger flow, ensure travel facilities and provide a safe and comfortable riding atmosphere for rail transit passengers during the epidemic. The purpose of this paper is to efficiently monitor the flow of rail passengers, the first method is to regulate the flow of passengers by means of a coordinated connection between the stations of the railway line; the second method is to objectively distribute the inbound traffic quotas between stations to achieve the aim of accurate and reasonable control according to the actual number of people entering the station.
Design/methodology/approach
This paper analyzes the rules of rail transit passenger flow and updates the passenger flow prediction model in time according to the characteristics of passenger flow during the epidemic to solve the above-mentioned problems. Big data system analysis restores and refines the time and space distribution of the finely expected passenger flow and the train service plan of each route. Get information on the passenger travel chain from arriving, boarding, transferring, getting off and leaving, as well as the full load rate of each train.
Findings
A series of digital flow control models, based on the time and space composition of passengers on trains with congested sections, has been designed and developed to scientifically calculate the number of passengers entering the station and provide an operational basis for operating companies to accurately control flow.
Originality/value
This study can analyze the section where the highest full load occurs, the composition of passengers in this section and when and where passengers board the train, based on the measured train full load rate data. Then, this paper combines the full load rate control index to perform reverse deduction to calculate the inbound volume time-sharing indicators of each station and redistribute the time-sharing indicators for each station according to the actual situation of the inbound volume of each line during the epidemic. Finally, form the specified full load rate index digital time-sharing passenger flow control scheme.
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Fei Liu, Chao Bian and Christopher Gan
This paper aims to examine whether government intervention acts as a substitution mechanism for laws and institutions in affecting firms’ long-term debt financing decision and the…
Abstract
Purpose
This paper aims to examine whether government intervention acts as a substitution mechanism for laws and institutions in affecting firms’ long-term debt financing decision and the moderating effect of firm ownership on the relationship between law and finance in Chinese capital market.
Design/methodology/approach
This study uses ordinary least squares with standard errors clustered at the firm level in the regressions. To address the potential endogeneity problem, the authors also use the system generalized method of moments in their estimation.
Findings
The results show that both long-term bank debt and long-term bank debt maturity structure ratios are positively related to government intervention. The results also reveal that with improvement in the legal environment, public non-state-owned firms have more access to long-term bank debt in the regions where the level of government intervention is low.
Research limitations/implications
Government intervention appears to replace laws and institutions in influencing the allocation of financial resources in China.
Originality/value
The finding suggests the necessity of increasing the protection of both creditors and investors, and shows the importance of a free and independent judiciary system in allocating funds to private firms. The results also imply that the non-state-owned Chinese firms also benefit from the improved laws and institutions.
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Chuansheng Wang, Ning Cai, Dewei Zhang, Jinxiu Zhang, Tianhao Chang, Shaoming Li, Yuqi Chao and Jiquan Hu
This purpose of this study was to develop a 3D printer based on powder particle. The best degreasing and sintering process of a blank body was investigated to obtain a metal…
Abstract
Purpose
This purpose of this study was to develop a 3D printer based on powder particle. The best degreasing and sintering process of a blank body was investigated to obtain a metal product with high precision and high surface finish. This process will greatly reduce the difficulty and cost of forming a complex metal product with high application value.
Design/methodology/approach
Stainless steel powder and polymer materials were mixed using a rubber mixing machine. The powders were granulated to prepare a mixed material. A powder feed 3D printer was used at low temperature (about 200°C) to print and degrease the body. A series of sintering experiments were performed to study the different sintering temperatures, and the physical and mechanical properties of the sample sintered under various conditions were compared to determine the best degreasing and sintering process.
Findings
The reaction at 1,370°C was the optimal route for the metal billet degreasing. The resulting metal products had fine structure and stable performance compared with the products with traditional powder metallurgy composition.
Originality/value
Most 3D printed metal powder materials rely on imports, which are expensive and increase the manufacturing cost. These drawbacks limit the application and development of metal 3D printing technology to a certain extent. The successful study of this molding method greatly reduces the difficulty and cost of forming complex metal products with high application value. This report will provide valuable guidance for sintering process and forming methods.
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The conventional pedestrian detection algorithms lack in scale sensitivity. The purpose of this paper is to propose a novel algorithm of self-adaptive scale pedestrian detection…
Abstract
Purpose
The conventional pedestrian detection algorithms lack in scale sensitivity. The purpose of this paper is to propose a novel algorithm of self-adaptive scale pedestrian detection, based on deep residual network (DRN), to address such lacks.
Design/methodology/approach
First, the “Edge boxes” algorithm is introduced to extract region of interests from pedestrian images. Then, the extracted bounding boxes are incorporated to different DRNs, one is a large-scale DRN and the other one is the small-scale DRN. The height of the bounding boxes is used to classify the results of pedestrians and to regress the bounding boxes to the entity of the pedestrian. At last, a weighted self-adaptive scale function, which combines the large-scale results and small-scale results, is designed for the final pedestrian detection.
Findings
To validate the effectiveness and feasibility of the proposed algorithm, some comparison experiments have been done on the common pedestrian detection data sets: Caltech, INRIA, ETH and KITTI. Experimental results show that the proposed algorithm is adapted for the various scales of the pedestrians. For the hard detected small-scale pedestrians, the proposed algorithm has improved the accuracy and robustness of detections.
Originality/value
By applying different models to deal with different scales of pedestrians, the proposed algorithm with the weighted calculation function has improved the accuracy and robustness for different scales of pedestrians.
Details
Keywords
Chao Tan, Honghua Wang and Ling Chen
An improved analytical method for calculating the natural frequencies of a switched reluctance motor (SRM) stator is proposed in this paper. The method is different from…
Abstract
Purpose
An improved analytical method for calculating the natural frequencies of a switched reluctance motor (SRM) stator is proposed in this paper. The method is different from traditional analytical methods, which only consider the influence of mass of the stator poles and windings on the natural frequencies of the SRM stator. This paper aims to consider the influence of stiffness and mass of the stator poles and windings simultaneously and reasonably.
Design/methodology/approach
An innovated analytical method based on the electromechanical analogy method is presented. In the proposed analytical formulae for calculating the natural frequencies, the influence of the windings on natural frequencies is considered by using the springs to simulate the flexible connection between the stator core and windings, and the stator poles are treated as both additional mass and additional equivalent stiffness. Both three-dimensional (3D) finite-element analysis (FEA) and experimental modal analysis results validate the improved method.
Findings
The influence of the mass and stiffness of stator winding is considered by using the springs to simulate the flexible connection between the stator core and windings, and the stator poles are treated as both additional mass and additional equivalent stiffness. The traditional analytical method only considers the influence of mass. Therefore, the calculation results are comparatively lower than 3D FEA results and may lead to a large error. The 3D FEA and experimental modal analysis confirm that the proposed method has good precision for low-order natural frequency calculation of SRMs.
Originality/value
An improved analytical method for calculating the natural frequencies of an SRM stator is proposed. Unlike the traditional analytical method, the proposed method can consider the influence of stiffness and mass of the stator poles and windings. This method is valuable for designers to predict the natural frequencies accurately.