Eryong Liu, Yuan Xue, Yaping Bai, Jibin Pu, Shuangming Du and Huiling Du
The purpose of this paper is to improve the tribological properties of aluminum cylinder liner. Higher martensite contents were closely related to the higher hardness and…
Abstract
Purpose
The purpose of this paper is to improve the tribological properties of aluminum cylinder liner. Higher martensite contents were closely related to the higher hardness and excellent wear resistance of Fe-based coatings. Furthermore, the grain size of the Fe-based coating was approximately 40 nm, which provides an excellent fine grain strengthening effect.
Design/methodology/approach
To improve the tribological properties of aluminum cylinder liners, a Fe-based martensite coating was prepared by internal plasma spraying technology, whose microstructure and tribological properties were then investigated.
Findings
Sprayed Fe-based coating possessed a low contact angle and strong adhesion with lubricating oil. In a simulated engine condition, Fe-based coating exhibited a decreased friction coefficient and increased wear resistance under oil lubrication, which was dominated by a stronger adhesive force with lubricating oil, higher martensite contents on the worn surface, higher hardness and higher H/E value than those of the reference HT 200 and Al-19Si cylinder material.
Originality/value
Nanostructure Fe-based martensite coating was sprayed on an aluminum cylinder liner, which demonstrated remarkable advantages over the reference cylinder material.
Details
Keywords
Shaw Chen, Bing-Xuan Lin, Yaping Wang and Liansheng Wu
The effectiveness of corporate governance is a major factor in forecasting firm performance. We examine the relationships among cross-listing, corporate governance and firm…
Abstract
The effectiveness of corporate governance is a major factor in forecasting firm performance. We examine the relationships among cross-listing, corporate governance and firm performance for a sample of Chinese cross-listed companies. We show that cross-listed firms display higher overall quality of corporate governance compared to non-cross-listed firms. Consequently better corporate governance results in higher operating performance. Our results support the bonding hypothesis of cross-listing. Furthermore, we also illustrate that the cross-listing status encapsulates the higher quality of corporate governance that leads to higher operating performance. When forecasting performance of cross-listing companies, it is therefore important to recognize the substitute effect between cross-listing and corporate governance.
Yaping Zhao, Xiangtianrui Kong, Xiaoyun Xu and Endong Xu
Cycle time reduction is important for order fulling process but often subject to resource constraints. This study considers an unrelated parallel machine environment where orders…
Abstract
Purpose
Cycle time reduction is important for order fulling process but often subject to resource constraints. This study considers an unrelated parallel machine environment where orders with random demands arrive dynamically. Processing speeds are controlled by resource allocation and subject to diminishing marginal returns. The objective is to minimize long-run expected order cycle time via order schedule and resource allocation decisions.
Design/methodology/approach
A stochastic optimization algorithm named CAP is proposed based on particle swarm optimization framework. It takes advantage of derived bound information to improve local search efficiency. Parameter impacts including demand variance, product type number, machine speed and resource coefficient are also analyzed through theoretic studies. The algorithm is evaluated and benchmarked with four well-known algorithms via extensive numerical experiments.
Findings
First, cycle time can be significantly improved when demand randomness is reduced via better forecasting. Second, achieving processing balance should be of top priority when considering resource allocation. Third, given marginal returns on resource consumption, it is advisable to allocate more resources to resource-sensitive machines.
Originality/value
A novel PSO-based optimization algorithm is proposed to jointly optimize order schedule and resource allocation decisions in a dynamic environment with random demands and stochastic arrivals. A general quadratic resource consumption function is adopted to better capture diminishing marginal returns.
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Keywords
Ali Ghasemi, Farzin Shama, Gholamreza Karimi and Farshad Khosravi
The purpose of this paper is to provide appropriate methods for reducing the abnormalities on the extracted fetal heart signal from the maternal electrocardiogram (ECG).
Abstract
Purpose
The purpose of this paper is to provide appropriate methods for reducing the abnormalities on the extracted fetal heart signal from the maternal electrocardiogram (ECG).
Design/methodology/approach
In this regard, the extracted signal of the fetal heart from the mother, improved using an active noise cancelation (ANC) system. It uses commonly adaptive algorithms of normalized least mean squares (NLMS). In the present paper, fetal extraction and denoising methodology are proposed. This methodology uses a combination of the NLMS algorithm with Savitzky–Golay (S-G) filter.
Findings
The obtained results show that a combination of NLMS algorithm with filter coefficient of 15 and µ = 0.02 and S-G filter has a better qSNR (qSNR = 3.6727) and good performance for fetal ECG extraction in comparison with the other works for average fmSNR in the range of −30 to −15 dB. Also, with considering the SNR value of −24.7 dB before filtering and SNR = 3.1861 dB after filtering; the SNR improvement of 27.8861 dB has been obtained.
Originality/value
A new method in the extract and noise reduction of fetal ECG from maternal ECG by the combination of NLMS algorithm and S-G filter is proposed.