Hao Li, Haipeng Geng and Hao Lin
The misalignment is generally inevitable in the process of machining and assembly of rotor systems with gas foil bearings, but the exploration on this phenomenon is relatively…
Abstract
Purpose
The misalignment is generally inevitable in the process of machining and assembly of rotor systems with gas foil bearings, but the exploration on this phenomenon is relatively less. Therefore, the purpose of this paper is to carry out the thermo-elastohydrodynamic analysis of the foil bearing with misalignment, especially the inhomogeneous foil bearing.
Design/methodology/approach
The rotor is allowed to misalign in two non-rotating directions. Then the static and dynamic performance of the inhomogeneous foil bearing is studied. The thermal-elastohydrodynamic analysis is realized by combining the Reynolds equation, foil deformation equation and energy equation. The small perturbation method is used to calculate the dynamic coefficients, then the critical whirl ratio is obtained.
Findings
The gas pressure, film thickness and temperature distribution distort when the misalignment appears. The rotor misalignment can improve the loading capacity but rise the gas temperature at the same time. Furthermore, the rotor misalignment can affect the critical whirl ratio which demonstrates that it is necessary to analyze the misalignment before the rotordynamic design.
Originality/value
The value of this paper is the exploration of the thermo-elastohydrodynamic performance of the inhomogeneous foil bearing with misalignment, the analysis procedure and the corresponding results are valuable for the design of turbo system with gas foil bearings.
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Hui-Chun Chang, Yung-Kai Lin, Chia-Hua Liang, Hsin-Wei Huang, Yung-Hao Lin, Yung-Hsiang Lin, Wei-Chun Hu and Chi Fu Chiang
Population aging was a global trend, and the most obvious thing after aging was the change in skin appearance. Therefore, the active ingredients that delay skin aging were…
Abstract
Purpose
Population aging was a global trend, and the most obvious thing after aging was the change in skin appearance. Therefore, the active ingredients that delay skin aging were particularly noticed. Past studies had pointed out that Chinese herbal extracts can improve skin elasticity, reduce wrinkles and melanin precipitation. The purpose of this paper is to explore whether combining hydrolyzed collagen with Chinese herbal extracts can improve skin conditions and achieve anti-inflammatory effects.
Design/methodology/approach
Fifty subjects were randomly divided into collagen or placebo groups, and one bottle of collagen or placebo drink was used every day for four weeks, after which skin and inflammatory factors were tested.
Findings
In comparison with the baseline results, the skin parameters were improving after four-week intervention. In addition, the IL-6, IL-8, TNF-a were significantly decreased and tissue inhibitor matrix metalloproteinase 1 (TIMP-1) was increased after four-week hydrolyzed collagen intervention.
Originality/value
This study showed that hydrolyzed collagen combined with Chinese herbal extracts can improve the condition of the skin, and can also reduce inflammatory associated factors, thereby achieving anti-aging effects.
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Hsiu-Yuan Tsao, Ming-Yi Chen, Hao-Chiang Koong Lin and Yu-Chun Ma
The basic assumption is that there is a symmetric relationship between review valence and rating, but what if review valence and rating were linked asymmetrically? There are few…
Abstract
Purpose
The basic assumption is that there is a symmetric relationship between review valence and rating, but what if review valence and rating were linked asymmetrically? There are few studies which have investigated the situations in which positive and negative online reviews exert different influences on ratings. This study considers brand strength as having an important moderating role because the average rating of existing reviews for a particular product is a heuristic cue for decision makers. Thus, the purpose of this paper is to argue that an asymmetric relationship between review content valence and numerical rating will depend on brand strength.
Design/methodology/approach
The authors have conducted a sentiment analysis via text mining, using self-developed computer programs to retrieve a data set from the TripAdvisor website.
Findings
This study finds there is an asymmetric relationship between review valence (verbal) and numerical rating. The authors further find brand strength to have an important moderating role. For a stronger brand, negative review content will have a greater impact on numerical ratings than positive review content, while for a weaker brand, positive review content will have a greater impact on numerical ratings than negative review content.
Practical implications
Marketers could adopt sentiment analysis via text mining of online reviews as a valid measure or predictor of consumer satisfaction or numerical ratings. Strong brands should direct more attention to negative reviews, because in such reviews the negative impact transcends the positive. In contrast, weak brands should aim to exploit as many positive reviews as possible to minimize the impact of any negative reviews.
Originality/value
This study finds there is an asymmetric relationship between review valence (verbal) and numerical rating and considers brand strength to play an important moderating role. The authors have used real data from the TripAdvisor website, which allow people to express themselves in an unsolicited manner, and linked these with the results from the sentiment analysis.
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Hao Li, Peng Hai Geng and Hao Lin
The normal operation of a rotor system is generally vulnerable to misalignment between gas foil bearing (GFB) and rotor. However, most theoretical and experimental researches…
Abstract
Purpose
The normal operation of a rotor system is generally vulnerable to misalignment between gas foil bearing (GFB) and rotor. However, most theoretical and experimental researches about the characteristics of GFBs have ignored this phenomenon. Therefore, the main purpose of this paper is to evaluate the static and dynamic performance of GFBs considering misalignment.
Design/methodology/approach
The shaft is allowed to misalign in two directions. Then the variations of bearing load, friction force, restoring moment, stiffness and damping coefficients are thoroughly explored. The hydrodynamic pressure on the gas film is modeled with compressible Reynolds equation, and the deformation of the flexible bearing is calculated with finite element method. Small perturbation method is used to obtain the displacement and moment dynamic coefficients.
Findings
The film thickness and pressure distribution distort when misalignments appear. The inclination of GFBs can enhance the restoring moment to withstand the imposed misalignment. Furthermore, the simulation phenomenon demonstrates the misalignment around load direction should be avoided as much as possible, while a small value misalignment around another direction is allowed.
Originality/value
The value of this paper is the exploration of the influence of misalignments on the static and dynamic performance of the Generation II journal GFB.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-10-2019-0418/
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Yu-Ming Chung, Shao-Yu Lee, Yung-Kai Lin, Yung-Hao Lin, Mohamed El-Shazly, Yung-Hsiang Lin and Chi-Fu Chiang
Rambutan (Nephelium lappaceum), a ubiquitous fruit in Southeastern Asia, was rich in vitamins and phytochemicals, which were beneficial for improving of skin conditions. The…
Abstract
Purpose
Rambutan (Nephelium lappaceum), a ubiquitous fruit in Southeastern Asia, was rich in vitamins and phytochemicals, which were beneficial for improving of skin conditions. The fermentation process increased phytochemicals and antioxidant capacity. Thus, the purpose of this paper is to examine whether phytochemicals can be increased through the fermentation process of rambutan extracts to improve skin aging.
Design/methodology/approach
In this study, the authors used the three stages of fermentation with Saccharomyces cerevisiae, Lactobacillus plantarum TCI028 and Acetobacter aceti under red light to develop a fermented rambutan extract.
Findings
The level of polyphenols of red-light-based fermented rambutan extract (RLFRE) were significantly increased 108.9% (p < 0.01) and 97% (p <0.01) compared with fermented rambutan extract (FRE) and pure rambutan extract (RE), respectively. The human skin fibroblasts treated with 0.03 or 0.06% of RLFRE can significantly decrease reactive oxygen species (ROS) levels by 0.74- (p <0.001) and 0.84-fold (p <0.001) compared with H2O2 group, respectively. And 0.03% of RLFRE can significantly increase in elastin content by 1.13-fold (p <0.05). Also, ten compounds were identified including one new phenolic compound and nine known compounds from RLFRE. Moreover, red light could enhance the levels of compounds 4, 9 and 3 by 5, 2.5 and 2.5-fold, respectively, relative to the results of FRE. The last, RLFRE isolated compounds significantly facilitated the elastin content on fibroblast (compound 1, 7, 9, 10 compared with control: p <0.001, compound 2 compared with control: p <0.001).
Originality/value
In short, this was the first study to unveil that the red-light-based fermentation can enrich the antioxidant content in a rambutan extract and its product had the potential to be developed a functional product for health-promoting effects such as skin aging.
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Jia-Bo Guo, Hao-Chieh Lin and Yi-Hsien Wang
Because of the interest of enterprises and unions are often conflicting. For unions, how to promote union instrumentality is a critical issue. This study aims to apply the…
Abstract
Purpose
Because of the interest of enterprises and unions are often conflicting. For unions, how to promote union instrumentality is a critical issue. This study aims to apply the resource dependence theory to examine the role of cooperative approach to conflict in the relationship between union–enterprise guanxi and union instrumentality under the moderation of union leader humility.
Design/methodology/approach
A questionnaire survey was undertaken to collect data from enterprise human resource (HR) manager and union stewards in Taiwanese firms using a dyadic approach. Hierarchical regression analysis and bootstrapping with a mediation model and moderated-mediation model were used to test the hypotheses.
Findings
The results show that cooperative approach to conflict is a prominent mediator between union–enterprise guanxi and union instrumentality, while union leader humility strengthens the positive association between cooperative approach to conflict and union instrumentality. Moderated-mediation analysis further demonstrates that the influence of the cooperative approach to conflict is stronger when there is a higher level of union leader humility.
Originality/value
The study offers an integrated picture about how union–enterprise social relationships promote union instrumentality.
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This chapter is a review and discussion of the experience of becoming an Electric Vehicle (EV) owner, with a focus on the importance of online EV communities on social media…
Abstract
This chapter is a review and discussion of the experience of becoming an Electric Vehicle (EV) owner, with a focus on the importance of online EV communities on social media platforms in providing informal support to new owners during the transition into EV ownership and use.
Becoming an EV owner represents a significant disruption to drivers’ very established and comfortable driving practices. Electric cars force their owners to re-think long-habitual aspects of the driving experience, including driving behaviour, refuelling (practicalities and etiquette), route planning, and the extent of the car’s ‘sphere of access’.
Because of this disruption, new EV owners regularly encounter challenges, including charging, range, new technology, route planning, etiquette, and more. People often need support to overcome these challenges, and EV owner groups on social media are an important source of such support; new owners can receive advice on a range of issues. This chapter presents data extracted from EV owner social media group posts, analysing the discussions and advice that EV owners offer one another, and exploring the various forms of important support available to new owners/drivers.
This chapter shows how online EV communities are very actively used by EV owners and are of particular importance for new owners. These communities welcome new owners/drivers, offer support and advice, respond to questions, give recommendations, and encourage socialising and a form of group identity/bonding. With EV ownership rapidly increasing in many countries, online EV communities have a very important role to play in helping facilitate the international transition to electric mobility.
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Graham Parkhurst and William Clayton
The chapter draws on the key findings from across the previous chapters in this book with a view to reaching a synthesis which responds to the key question that motivated the…
Abstract
The chapter draws on the key findings from across the previous chapters in this book with a view to reaching a synthesis which responds to the key question that motivated the book: ‘to what extent does a shift to electric automobility suggest a sustainable future for the passenger car?’ Across the chapters is found evidence for a clear and apparently unstoppable transition to electric mobility, but this does not mean it is harmonious and smooth; the transition itself faces potential disruption, as well as being disruptive to the status quo through creating new forms of conflict over space and material resources. Nonetheless, meanwhile internal combustion engine vehicle (ICEV) sales continue to exceed electric vehicle (EV) sales, even if the margin reduces, and there is the enormous problem of inertia presented by the established global ICEV fleet.
Considering the current dynamics of consumer demand for electric cars, a complex set of factors and preferences have been shown to have influence, but the interrelated factors of range and total cost of ownership stand out as the key ones. Prospects for accelerating the rate of transition are identified, but a further important dynamic is the slow rate of turnover in an established vehicle fleet dominated by ICEs: consideration is therefore given to the potential for retrofit EV conversions.
Looking to the future, the cost and performance of battery technology remains a critical and uncertain factor in the rate and depth of the transition to EVs, but the wider context of mobility practices and policies in which that change occurs is also fundamental. The EV transition sits entwined with other novel and substantial changes to our long-established systems of automobility that are becoming visible on the horizon. Relatively expensive to buy but cheap to use, and also hard to tax, EVs will necessitate a shift away from pay-up-front to pay-as-you-go road use, while the development and full realisation of Mobility-as-a-Service (MaaS) systems could herald a fundamental change in the basis of owning and using cars. In conclusion, a sustainable future for the car implies not just a new way of powering it, but a different role for the car in both the economy and society.
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Axial field flux-switching permanent magnet machine (AFFSPMM) can be applied in the field of electric and hybrid electric vehicles because of short axial size, large torque…
Abstract
Purpose
Axial field flux-switching permanent magnet machine (AFFSPMM) can be applied in the field of electric and hybrid electric vehicles because of short axial size, large torque density, and high-power density. The purpose of this paper is to improve the reliability of AFFSPMM itself, the design parameters have to be considered for attaining high self-inductances and reduced mutual-inductances.
Design/methodology/approach
The original parameters of E-core AFFSPMM are designed with reference to a 600 W prototype, on the basis of which the 3-D model of the original AFFSPMM is established, and the inductances are calculated by finite element method. The influence of these parameters on the inductances, including combinations of stator and rotor pole numbers, spilt ratio, stator side tooth width, magnet thickness, and rotor pole width etc., are respectively investigated and analyzed under the constant copper loss.
Findings
The relationships of rotor pole numbers and inductances are deduced on the condition of the fixed stator poles. It is found that the rotor pole numbers has significant effects on the ratio of mutual-inductance to self-inductance, and the self-inductance is mainly affected by the rotor pole numbers, the split ratio, the stator tooth width, and the rotor pole width. The asymmetry of back-EMF can be largely reduced by optimizing the rotor tooth width. In this paper, the static characteristics are compared and analyzed for the original and optimal 6/14-pole AFFSPMM. Meanwhile, the open-circuit and short-circuit fault are investigated by transient analysis. The results show that the optimized E-core AFFSPMM has good fault tolerance.
Originality/value
The research of inductance characteristics for E-core AFFSPMM is valuable to design the fault-tolerant machine, by which the cost of control and manufacture can be largely saved.
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Javad Rahmani Fard and Mohammad Ardebili
The purpose of this paper is to propose a novel axial field flux-switching machine with sandwiched permanent magnets. It is one of the most efficient machines which is appropriate…
Abstract
Purpose
The purpose of this paper is to propose a novel axial field flux-switching machine with sandwiched permanent magnets. It is one of the most efficient machines which is appropriate for high-torque and low-speed direct-drive applications. The proposed model is equipped with an advanced phase-group concentrated-coil winding to obtain a unity displacement winding factor. Two configurations of the proposed motors with 6-stator-slot (S)/10-rotor-pole (P) and 12S/19P are investigated. These two structures are compared with optimized a conventional axial-field flux-switching permanent-magnet (CAFFSPM) machine. Unity displacement winding factor increases the back-EMF and electromagnetic torque. Moreover, the prototype 12S/19P motor is built to verify the design.
Design/methodology/approach
The torque equation is obtained and the dimensions of the two proposed motors are determined. Some specific design issues, including the stator/rotor pole sandwiching pole angle, the stator tooth angle and the rotor pole angle have been optimized to minimize the cogging torque while maintaining the high torque density by means of response surface methodology (RSM) and 3-D finite element model of the machine.
Findings
To improve the performance, especially at high torque density, low cogging torque and high level of fault-tolerant capability, the 12S/19P axial field flux-switching sandwiched permanent-magnet (AFFSSPM) motor is proposed. Based on the optimized design, a prototype of the 12S/19P AFFSSPM motor is fabricated and tested. It is found that the experimental results validate the 3-D finite element method (FEM) simulation results.
Originality/value
The AFFSSPM motor is one of the most efficient motors, but the 12S/19P AFFSSPM motor with sandwiched permanent magnet and unity displacement winding factor has not been specially reported to date. Thus, in this paper, the authors report on optimal design of a novel axial flux-switching sandwiched permanent-magnet machine for electric vehicles and fabricate a prototype of the 12S/19P AFFSSPM motor.