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This paper aims to investigate the temperature dependence of transfer film formation and friction coefficients in NAO friction materials with four different abrasive components, ZrO₂, ZrSiO₄, Al₂O₃ and Fe₃O₄.

8.5% SnS₂ was added as a lubricating component to friction materials. Friction tests comprised 100 times of consecutive braking application for each friction material under constant temperature of 300°C, 400°C, 500°C and 600°C. After the friction tests, the friction surfaces of the counterpart disks were examined by scanning electron microscope to access the formation of transfer film.

Coefficients of friction depended on not only friction temperature but also friction history which is related to development of transfer film. The effect of the transfer film formation was to reduce the friction coefficients for most friction materials. Quantities of the transfer film formation varied with friction materials; at low temperature below 400° the transfer film formation was most active in the Fe₃O₄ materials, while at 600° it was the most active in the Al₂O₃ material. The effect of the lubricating component SnS₂ was to suppress the formation of transfer film, thus enhancing friction coefficients.

The enhancement of friction coefficients with addition of small amount of lubricating components such as SnS₂ is expected to open a new approach in developing high performance-brake pads.

Temperature was the controlling parameter in the present test. Under these test modes, transfer film could be fully developed to access the role of the transfer film.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-10-2019-0427/

The purpose of this paper is to investigate surroundings for transfer film formation and removal, the effect of the transfer film formation on friction coefficients, the effect of four different abrasive components, ZrO₂, ZrSiO₄, Al₂O₃ and Fe₃O₄, on transfer film formation and the effect of lubricating component MoS₂ on transfer film formation and friction coefficients.

Two different MoS₂ contents of 5.5 and 8.5 per cent were added to friction materials with no MoS₂ content, which have four different abrasive components, ZrO₂, ZrSiO₄, Al₂O₃, Fe₃O₄. Friction tests composed of three different stages were conducted for those materials, and the friction surfaces of the counterpart disks were examined by scanning electron microscopy (SEM) to access the formation of transfer film at each stage.

For the transfer film formation, high temperature was a prerequisite, but the magnitude of deceleration rate was not important. The effect of the transfer film formation was to reduce the friction coefficients for most friction materials. Friction coefficients of materials which contain lubricating component MoS₂ were higher than those which contain no MoS₂ for most friction materials. The effect of the lubricating component MoS₂ was to suppress the formation of transfer film, thus resulting in increase in friction coefficients.

The transfer film was rather thin, with thickness of 1-2 µm for most friction materials. That hindered the examination of mechanical properties of the transfer film, such as hardness.

This research explained the surroundings for transfer film formation, and its effect on friction coefficients. The research suggests to suppress the formation of transfer film to make friction materials with high friction coefficient, and the lubricating component MoS₂ can be used for the purpose.

Development of high-friction-brake materials conventionally depends on the use of strong abrasive components, which may induce attacking of counterpart disks. The enhancement of friction coefficients with addition of MoS₂ content is expected to open a new prospect in development of high-performance friction materials, which can be applicable to brake pads for racing cars.

The study is in pursuit of the transfer film formation in successive friction stages, which revealed the conditions for transfer film generation and removal. Specimen preparation for SEM observation of cross section of friction surface was painstaking to not damage the developed friction surface. The study revealed the effect of different abrasive components on transfer film formation and the effect of lubrication contents of MoS₂ on transfer film formation and friction coefficients.

The purpose of this paper is to investigate the friction coefficients of aramid and acrylic fibers on brake pads.

Fiber components used in the present pads are aramid and acrylic fibers, respectively, while keeping other components, such as binders, lubricants, abrasives, fillers the same. Disk FC25 and disk FC17 are used for rotor rubbing test to investigate the friction coefficients with brake pads. The pads are tested by 1/5 scale brake dynamometer, and test mode is modified JASO C406‐P1. The results are analyzed with the friction coefficient and the temperature, transfer film, roughness, and photomicrograph of worn surface on rotors.

The friction coefficient was mainly determined by the pad material rather than the rotor material, and pads made of aramid fiber had high‐friction coefficient, while pads made of acrylic fiber had low‐friction coefficient, especially under high temperature. Temperature change during braking process was directly related to the initial speed only, and was indifferent to materials or decelerations imposed. In the fade test, the reversal of friction coefficients between the aramid fiber and acrylic fiber pads is determined by the amount of remained amount of respective fiber above 520°C.

Effect of different fiber components, aramid and acrylic fibers, on friction characteristics of pad is sought. Reversal of friction coefficients is determined by the thermal stability of fibers used for pads.

This study aims to evaluate the network robustness of major Asian airlines and to explore which airport types have the greatest impact on robustness. We also analyze airports’ specific brokerage roles and their impacts on the robustness of the entire air route network. We select 10 major Asian full-service airlines that operate the main passenger terminals at the top-ranked hub airports in Asia. Data is collected from the Official Airline Guide passenger route dataset for 2017. The results of the network robustness analysis show that Air China and China Eastern Airlines have relatively high network robustness. In contrast, airlines with broader international coverage, such as Japan Airlines, Korean Air, and Singapore Airlines have higher network vulnerability. The measure of betweenness centrality has a greater impact on the robustness of air route networks than other centrality measures have. Furthermore, the brokerage role analysis shows that Chinese airports are more influential within China and Asia but are less influential globally when compared to other major hub airports in Asia. Incheon International Airport, Singapore Changi Airport, Hong Kong International Airport, and Narita International Airport play strong “liaison” roles. Among the brokerage roles, the liaison role has a greater impact on the robustness of air route networks.

This study aims to evaluate the network robustness of major Asian airlines and to explore which airport types have the greatest impact on robustness. We also analyze airports’ specific brokerage roles and their impacts on the robustness of the entire air route network. We select 10 major Asian full-service airlines that operate the main passenger terminals at the top-ranked hub airports in Asia. Data is collected from the Official Airline Guide passenger route dataset for 2017. The results of the network robustness analysis show that Air China and China Eastern Airlines have relatively high network robustness. In contrast, airlines with broader international coverage, such as Japan Airlines, Korean Air, and Singapore Airlines have higher network vulnerability. The measure of betweenness centrality has a greater impact on the robustness of air route networks than other centrality measures have. Furthermore, the brokerage role analysis shows that Chinese airports are more influential within China and Asia but are less influential globally when compared to other major hub airports in Asia. Incheon International Airport, Singapore Changi Airport, Hong Kong International Airport, and Narita International Airport play strong “liaison” roles. Among the brokerage roles, the liaison role has a greater impact on the robustness of air route networks.

The success of an Electronic Health Record (EHR) system is determined by the numerous facilitators and obstacles that influence physicians' intentions toward using these technologies. This study examines physicians' intentions to use EHR by applying the extended technology readiness and acceptance model (TRAM) factors, the result demonstrability, colleagues' opinions, perception of external control, and organizational support.

Convenience sampling was used to collect data from physicians in Egypt (n = 520). To evaluate the model's hypotheses, this study used the partial least squares structural equation modeling (PLS-SEM) method with WarpPLS.7.

The results revealed that positive TR factors (innovativeness and optimism) positively affect perceived usefulness and ease of use, while negative TR factors (discomfort and insecurity) negatively impact perceived usefulness and ease of use. Furthermore, the result demonstrability and colleagues' opinions positively influence perceived usefulness, while the perception of external control and organizational support positively influence perceived ease of use. In addition, significant relationships between perceived ease of use and usefulness and adoption intention were identified.

This is the first study to apply the TRAM to understand physicians' adoption intentions to use EHR systems. Moreover, this study determined the different roles of positive and negative TR affecting physicians' cognition regarding using EHR systems.

The purpose of this study is to describe South Korea’s unique fever for public service jobs (FPSJ) and to critique it from a National Human Resource Development (NHRD) management framework.

This paper reviewed previous studies, news and technical reports related to FPSJ and NHRD to connect FPSJ and NHRD.

This study analyzed FPSJ-related issues based on three areas (development, allocation and utilization) of human resources and four contexts (political, economic, social and educational backgrounds). FPSJ has led to multiple concerns about developing human resources (vocational education and career guidance), allocating human resources (the unbalanced supply-demand mismatch and flawed selection) and using human resources (delayed job entry and low public service ethos).

This study analyzes the challenges related to FPSJ in Korea from a NHRD perspective. Based on the analysis, this study recommends strategies for reducing the over-emphasis on FPSJ.

Social media campaigns by fashion brands typically rely on two types of accounts: official brands' accounts and social media influencers' accounts. The current study investigates relevant mechanisms that explain the effectiveness of Instagram posts contingent upon their account types (commercial brand's Instagram account versus influencer's Instagram account) and content types (the absence versus presence of human figures in the posted contents).

Conducting an online experiment (N Females = 195), it was tested if parasocial interaction (PSI) and feelings of social presence moderate the effects of Instagram accounts' promotional posts on consumers' perceived trustworthiness of the endorsed fashion brand. The experiment employed a 2 (Type of Instagram posts: product-only posts versus product posts with a person content) × 2 (Type of Instagram account: a fashion-brand account versus a a fashion-influencer account) between-subjects factorial design.

Results demonstrate three-way interaction effects among the type of the Instagram account, the type of Instagram posts and PSI/social presence on the perceived trustworthiness of a brand. When the content is coming from a fashion-influencer account, there is no difference between product posts with a person and product-only posts conditions with regard to the positive relationship between PSI/social presence and trustworthiness. In contrast, when the source is a fashion-brand account on Instagram, the positive relationship between PSI/social presence and trustworthiness is stronger for product posts with a person. These findings suggest that Instagram posts that are promoted by fashion influencers would have similar effects of PSI and social presence, even if they do not appear themselves in the branded content.

This research contributes to our understanding of the effective antecedents of trustworthiness in social media-based fashion marketing and fashion brand management. Instagram account types and content types influence the extent to which social media communication allows for the formation of emotional ties with and positive evaluation of the fashion brand.