Haigang Gu, Guang Feng, Yonggang Lin and Chaozhu Wang
This paper aims to analyze fatigue failures of a typical marine gearbox under harsh ocean conditions, and these failures are reasonably attributed to the bearing fretting fatigue…
Abstract
Purpose
This paper aims to analyze fatigue failures of a typical marine gearbox under harsh ocean conditions, and these failures are reasonably attributed to the bearing fretting fatigue damages.
Design/methodology/approach
Two typical FAG cylindrical roller bearings mounted on this marine gearbox are particularly used for analysis, as they are most vulnerable to these failures. A series of simulations have also been conducted to verify the analysis results and failure reasons by reproducing the fretting fatigue damages for the same shaft-bearing system under the same manufacturing error conditions.
Findings
The analysis results indicate that manufacturing errors are the most possible reasons for the bearing failures, and these errors have more effects on the FAG cylindrical roller bearing as compared to other bearings mounted on the same shaft system. The simulations results are in good agreement with the theoretical analysis results and test results and hence validate that manufacturing errors are the dominant reasons for bearing fretting fatigue damages in this typical marine gearbox.
Originality/value
Fatigue failures of a typical marine gearbox. Manufacturing errors are the most possible reasons for the bearing failures. A series of simulations have been conducted to verify the analysis results and failure reasons. The simulations results are in good agreement with the theoretical analysis results and test results.
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Dunying Deng, Yunfan Liao, Meichao Lin, Xiaxuan Xiong and Yonggang Tong
The purpose of this paper is to develop advanced materials with outstanding mechanical properties and high-temperature oxidation performance for their potential application in…
Abstract
Purpose
The purpose of this paper is to develop advanced materials with outstanding mechanical properties and high-temperature oxidation performance for their potential application in high-temperature structural components.
Design/methodology/approach
The alloy ingots with high-purity Co, Cr, Ni, Al and Y metals (= 99.9 Wt.%) were prepared in a vacuum arc melting furnace under an argon atmosphere.
Findings
This study investigated the impact of the Y content on the microstructure and oxidation behavior of CoCrNiAl medium entropy alloys at 1,200°C. All alloys exhibit a combination of ß and γ phases, with CoCrNiAlY 0.11revealing the presence of obvious sub-micron γ phase precipitates within the ß phase. The oxidation behavior of CoCrNiAlYx (x = 0.05, 0.08, 0.11) at 1,200°C demonstrates the formation of a dense oxide scale on the alloy surface. The surface with aluminum oxide accompanied by yttrium oxide exhibits improved adhesion between the matrix and oxide scale. The CoCrNiAlY0.11 alloy, with a decreased oxidation rate of 7.8 × 10–6 mg2 cm−4s−1, displays the best oxidation resistance among these alloys with varying Y content.
Originality/value
The study examines the optimal content of Y in the CoCrNiAl medium alloy and its superior oxidation behavior at 1,200°C.
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BaoJun Dong, Wei Liu, Fei Wu, JiaQi Zhu, Banthukul Wongpat, Yonggang Zhao, Yueming Fan and TianYi Zhang
The salinity of the oilfield produced water has a significant effect on steel corrosion. The purpose of this paper is to study the influence of salinity on corrosion behavior of…
Abstract
Purpose
The salinity of the oilfield produced water has a significant effect on steel corrosion. The purpose of this paper is to study the influence of salinity on corrosion behavior of X60 steel and it also provides basic for material selection of gas wells with high salinity.
Design/methodology/approach
The weight loss experiment was carried out on steel with high temperature and high pressure autoclave. The surface morphology and composition of corrosion scales were studied by means of scanning electron microscopy, energy dispersive spectroscopy and X-ray diffractometry.
Findings
The results show that as salinity increases, the corrosion rate of X60 steel will gradually experience a rapid decline stage and then a slow decline stage. X60 steel is mainly exhibiting uniform corrosion in the first rapid decline stage and pitting corrosion in the second slow decline stage. The increase in salinity reduces gas solubility, which, in turn, changes the morphology and density of the corrosion scales of X60 steel. At low salinity, loose iron oxides generated on the surface of the steel, which poorly protects the substrate. At high salinity, surface of the steel gradually forms protective films. Chloride ions in the saline solution mainly affect the structure of the corrosion scales and initiate pitting corrosion. The increased chloride ions lead to more pitting pits on the surface of steel. The recrystallization of FeCO3 in pitting pits causes the corrosion scales to bulge.
Originality/value
The investigation determined the critical concentration of pitting corrosion and uniform corrosion of X60 steel, and the new corrosion mechanism model was presented.
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Shuwen Deng, Yili Cai, Longpan Xie and Yonggang Pan
Unsafe behavior is a major cause of safety accidents, while in most management measures for unsafe behavior, the construction workers are generally managed as a whole. Therefore…
Abstract
Purpose
Unsafe behavior is a major cause of safety accidents, while in most management measures for unsafe behavior, the construction workers are generally managed as a whole. Therefore, this study aims to propose group management of construction workers' unsafe behavior considering individual characteristics.
Design/methodology/approach
A cognitive process model with ten cognitive factors was constructed based on cognitive safety theory. The questionnaire was developed and validated based on the cognitive model, and the results showed that the questionnaire had good reliability and validity, and the cognitive model fitted well. Latent class analysis was used to classify the unsafe behaviors of construction workers.
Findings
Four categories of cognitive excellent type, cognitive failure type, no fear type and knowingly offending type were obtained. Workers of cognitive excellent type have good cognitive ability and a small tendency for unsafe behaviors. Workers of cognitive failure type have poor cognitive ability and the potential for cognitive failure in all four cognitive links. Workers of no fear type have weak cognitive ability, and cognitive failure may occur in discovering information and choosing coping links. Workers of knowingly offending type have certain cognitive abilities, but cognitive failure may occur in choosing coping link.
Originality/value
This study formulates targeted management measures according to the potential characteristics of these four types and provides scientific theoretical support for the personalized management of unsafe behavior.
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Yonggang Ye and Bote Chen
The purpose of this paper is to analyse the implications of exchange rate fluctuations on China's national macro‐financial stability and evaluate current renminbi (RMB…
Abstract
Purpose
The purpose of this paper is to analyse the implications of exchange rate fluctuations on China's national macro‐financial stability and evaluate current renminbi (RMB) appreciation speed and magnitude.
Design/methodology/approach
The contingent claims analysis method is used to construct the financial risk indicator and evaluate the macro‐financial risk. The paper also implemented computer simulations to generate different scenarios in the macro‐scenario analysis.
Findings
The main conclusion is that there is claims‐based currency mismatch in China's four major economic sectors. The simulation results show that faster appreciation leads to wide fluctuations on asset prices, the size of the base currency and foreign debt in China. In the current risk level, steady speed appreciation style is better than the accelerated appreciation style.
Social implications
The results of this paper imply that current appreciation speed and magnitude are favorable to control macro‐financial risks within safe status, but China needs to promote the reform of RMB exchange rate formation mechanism in the future.
Originality/value
The paper is of historical value in applying the contingent claims analysis method to analyse the implications of exchange rate fluctuations. It provides a new way to measure whether the exchange rate is reasonable.
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Entrepreneurship in most cases can provide new products and services to the market and play an active role in an industry. Nowadays, colleges entrepreneurship education is…
Abstract
Purpose
Entrepreneurship in most cases can provide new products and services to the market and play an active role in an industry. Nowadays, colleges entrepreneurship education is becoming more of a “business incubator” for future entrepreneurship. This paper reviews the relative literature with entrepreneurship education in China and USA's colleges, aims to identify Chinese colleges' issues, then develops suggestions of Chinese colleges' entrepreneurship education and illustrated its future trends.
Design/methodology/approach
It revealed the theoretical framework of American main entrepreneurship education modes, analyzing three representative entrepreneurship modes in American colleges, its spirit, capability of innovation, entrepreneurship ability contribute to the basic frame of entrepreneurship education in American colleges, then by comparative research between American and Chinese colleges.
Findings
This paper is based on discussing the differences between US and Chinese colleges with entrepreneurship education as well as the enlightenment. Meanwhile, it was pointed out the disadvantages relating to our colleges' entrepreneurship education and its future trends.
Originality/value
By introducing the entrepreneurship modes of US colleges and analyzing the modes together with Chinese colleges entrepreneurship education, it draws out the conclusion to carry out practical activities and establish a good entrepreneurship environment, to strengthen teacher training in entrepreneurship education and entrepreneurial consultant team building and to deploy entrepreneurship research.
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Junyu Shi, Shengli Ling, Yinjie Kuang, Yonggang Tong, Yongle Hu and Dunying Deng
The purpose of this paper is to reveal the effect of microstructure on the corrosion behavior of CoCrNi alloy in 3.5 Wt.% NaCl solution.
Abstract
Purpose
The purpose of this paper is to reveal the effect of microstructure on the corrosion behavior of CoCrNi alloy in 3.5 Wt.% NaCl solution.
Design/methodology/approach
The as-cast CoCrNi alloy was prepared by arc melting, and the cold-rolled and annealed alloys were prepared by processing the as-cast alloy.
Findings
The experimental results showed that a protective passivation film was formed on the surfaces of these CoCrNi MEA, and the stability and compactness of alloys increased in the sequence of cold-rolled, as-cast and annealed CoCrNi alloys. The annealed CoCrNi alloys had the best pitting resistance.
Originality/value
This study proposes the effect of the microstructure of CoCrNi alloy on corrosion resistance.
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Fabio Santagata, Jianwen Sun, Elina Iervolino, Hongyu Yu, Fei Wang, Guoqi Zhang, P.M. Sarro and Guoyi Zhang
The purpose of this paper is to demonstrate a novel 3D system-in-package (SiP) approach. This new packaging approach is based on stacked silicon submount technology. As…
Abstract
Purpose
The purpose of this paper is to demonstrate a novel 3D system-in-package (SiP) approach. This new packaging approach is based on stacked silicon submount technology. As demonstrators, a smart lighting module and a sensor systems were successfully developed by using the fabrication and assembly process described in this paper.
Design/methodology/approach
The stacked module consists of multiple layers of silicon submounts which can be designed and fabricated in parallel. The 3D stacking design offers higher silicon efficiency and miniaturized package form factor. This platform consists of silicon submount design and fabrication, module packaging, system assembling and testing and analyzing.
Findings
In this paper, a smart light emitting diode system and sensor system will be described based on stacked silicon submount and 3D SiP technology. The integrated smart lighting module meets the optical requirements of general lighting applications. The developed SiP design is also implemented into the miniaturization of particular matter sensors and gas sensor detection system.
Originality/value
SiP has great potential of integrating multiple components into a single compact package, which has potential implementation in intelligent applications.
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This chapter reviews the role of industrial parks (IP) as drivers of export-led industrialisation in Ethiopia. For several decades, IPs or special economic zones have been…
Abstract
This chapter reviews the role of industrial parks (IP) as drivers of export-led industrialisation in Ethiopia. For several decades, IPs or special economic zones have been promoted as policy instruments to attract investment, create jobs and promote exports of manufactured goods. However, their popularity as policy instruments has been mainly associated with the successful export-led industrialisation of emerging economies in East Asia where IPs have played a critical role not only in attracting investment and promoting export-led growth but also transferring technology, promoting technological learning and industrial development and jump-starting the process of economic diversification and structural transformation. Ethiopia, along with other African countries, is among the latest to introduce IPs as major drivers of economic diversification and export-led industrialisation. As a newcomer, Ethiopia can learn many valuable lessons from more successful cases. This chapter explores some of the lessons that Ethiopia can draw from other countries’ experience as it continues to build additional parks to attract investment and push its industrialisation agenda.
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A.E.‐S.I. Ahmed, A.M. El‐Masry, A. Saleh and A. Nada
The purpose of this paper is to prepare and optimize the preparation conditions of some new hydrogels and in addition, evaluate their water absorbance at different mediums and…
Abstract
Purpose
The purpose of this paper is to prepare and optimize the preparation conditions of some new hydrogels and in addition, evaluate their water absorbance at different mediums and their ability to remove ions from aqueous solutions.
Design/methodology/approach
Cellulose was extracted from depithed bagasse at two different pulping conditions; 3 and 6 hours cooking times, pulp (I) and (II), respectively. These pulps, in addition to cotton linter for comparison, were grafted with acrylamide followed by cross‐linking with glutaraldehyde. The networks were partially hydrolyzed and the structures of products (before and after hydrolysis) were studied using FTIR, SEM, TGA and X‐ray. The optimum preparation conditions were identified, before and after hydrolysis, to achieve maximum absorbance and the ability of prepared hydrogels to remove ions from solutions was investigated.
Findings
Maximum level of absorption was recorded using hydrogels prepared with monomer concentration =0.8 mol/l, cross‐linker concentration =0.01 mol/l, reaction time =2 hours and temperature =65°C. Hydrogels prepared using pulp (I) showed the best absorbance behavior and a tendency to remove ions from water.
Research limitations/implications
The ability of the prepared gels to remove ions from water could be further investigated to evaluate the ability of their use in a multi‐filtration system for water treatment.
Practical implications
This piece of work has suggested a simple way to convert an agricultural waste to hydrogel able to remove metal ions from water.
Social implications
Consuming this type of waste reduces the risks resulting from its burning in some countries, such as Egypt, that produce large amounts of it.
Originality/value
In this paper, low cost hydrogels, with expected value in water treatment, were prepared using agricultural wastes. They have shown better reactivity than gels prepared using pure cellulosic materials (cotton linter).