Hussein Bazzi, Cong Tam Nguyen and Nicolas Galanis
This work is concerned with the problem of the transient behaviours of the axisymmetric thermocapillary laminar flow occurring inside a half zone subjected to a variable thermal…
Abstract
This work is concerned with the problem of the transient behaviours of the axisymmetric thermocapillary laminar flow occurring inside a half zone subjected to a variable thermal boundary condition during a heating process. The molten liquid with its deformable free surface is considered incompressible with constant physical properties except for its density in buoyancy forces where Boussinesq’s approximation has been applied. The system of governing equations has been successfully solved by using the modified‐SIMPLE method, while the instantaneous position of the free surface was determined by employing a special procedure. Numerical simulations have been carried out for both NaNO3 and Silicon float zones operating under 1‐g and μ‐g conditions. The transient behaviours as well as the influence of the Marangoni number and the aspect ratio have been investigated.
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Catalin Viorel Popa, Cong Tam Nguyen, Stéphane Fohanno and Guillaume Polidori
In the present work, a theoretical model based on the full Navier-Stokes and energy equations for transient mixed convection in a vertical tube is extended to nanofluids with…
Abstract
Purpose
In the present work, a theoretical model based on the full Navier-Stokes and energy equations for transient mixed convection in a vertical tube is extended to nanofluids with nanoparticle volume fraction up to 5 percent to ensure a Newtonian fluid behaviour. The paper aims to discuss these issues.
Design/methodology/approach
The nanofluids considered, alumina/water and CuO/water, flow inside a vertical tube of circular cross-section, which is subjected to convective heat exchange at the outer surface. The transient regime is caused by a sudden change of nanofluid temperature at the tube inlet. The range of the Richardson number (1.6=Ri=2.5) investigated in this study corresponds to classic cases of mixed convection flow.
Findings
Results have shown a significant reduction in the size of the recirculation zone near the wall when the particle volume fraction increases. This may be attributed to the viscosity increase with the volume fraction. Moreover, the flow structure clearly changes when the convective heat transfer coefficient is modified. A decrease of the wall temperature along the tube was found when increasing the convective heat transfer coefficient imposed at the tube external surface.
Research limitations/implications
The problem formulation in 2D axisymmetric geometry includes the continuity, the Navier-Stokes and energy equations and is based on the stream function and vorticity; the numerical solution of equations is carried out using a finite difference method.
Practical implications
From an economic point of view, this research paper is innovative in the sense that it considers nanofluids as a new and more efficient way to transfer heat. This paper could find applications for heat exchange purposes of compact systems with high thermal loads.
Originality/value
Across the world, a still growing number of research teams are investigating nanofluids and their properties. Investigations concern several aspects such as the preparation of the nanofluids, as well as the applications of these nanofluids for convective heat transfer purposes. The dynamical study will consist in the instantaneous and spatial characterization of the dynamic flow field for different nanoparticle volume fractions.
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Sidi El Bécaye Maïga, Cong Tam Nguyen, Nicolas Galanis, Gilles Roy, Thierry Maré and Mickaël Coqueux
To study the hydrodynamic and thermal behaviors of a turbulent flow of nanofluids, which are composed of saturated water and Al2O3 nanoparticles at various concentrations, flowing…
Abstract
Purpose
To study the hydrodynamic and thermal behaviors of a turbulent flow of nanofluids, which are composed of saturated water and Al2O3 nanoparticles at various concentrations, flowing inside a tube submitted to a uniform wall heat flux boundary condition.
Design/methodology/approach
A numerical method based on the “control‐volume” approach was used to solve the system of non‐linear and coupled governing equations. The classical κ‐ε model was employed in order to model the turbulence, together with staggered non‐uniform grid system. The computer model, satisfactorily validated, was used to perform an extended parametric study covering wide ranges of the governing parameters. Information regarding the hydrodynamic and thermal behaviors of nanofluid flow are presented.
Findings
Numerical results show that the inclusion of nanoparticles into the base fluid has produced an augmentation of the heat transfer coefficient, which has been found to increase appreciably with an increase of particles volume concentration. Such beneficial effect appears to be more pronounced for flows with moderate to high Reynolds number. In reverse, the presence of nanoparticles has induced a rather drastic effect on the wall shear stress that has also been found to increase with the particle loading. A new correlation, Nufd=0.085 Re0.71 Pr0.35, is proposed to calculate the fully‐developed heat transfer coefficient for the nanofluid considered.
Practical implications
This study has provided an interesting insight into the nanofluid thermal behaviors in the context of a confined tube flow. The results found can be easily exploited for various practical heat transfer and thermal applications.
Originality/value
The present study is believed to be an interesting and original contribution to the knowledge of the nanofluid thermal behaviors.
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Tin Trung Nguyen, Tony Cat Anh Hung Nguyen and Cong Duc Tran
During the challenging time of lockdown and isolation due to the coronavirus disease (COVID-19), contact-tracing apps have played a critical role in health communication and…
Abstract
Purpose
During the challenging time of lockdown and isolation due to the coronavirus disease (COVID-19), contact-tracing apps have played a critical role in health communication and preventive healthcare. This study proposed and tested an extended technology acceptance model (TAM) with key health factors (i.e. health risk perception from COVID-19, health information orientation to COVID-19 and health consciousness) to understand individuals' adoption of COVID-19 contact-tracing apps.
Design/methodology/approach
A two-stage online survey was conducted to collect data on US individuals’ intention and actual use of COVID-19 contact-tracing apps. The sample comprises 288 valid responses. Partial least squares structural equation modeling (PLS-SEM) and fuzzy set/qualitative comparative analysis (fsQCA) were employed as the complementary approaches.
Findings
The findings from PLS-SEM revealed that health risk perception, health information orientation and perceived usefulness have positive net effects on behavioral intention, which, in turn, affects actual use. The results from fsQCA highlighted the explanatory power of the extended TAM to COVID-19 contact-tracing app adoption.
Originality/value
Although TAM is considerably effective in measuring technology acceptance, the phenomenon is highly context-driven. How technological and health factors simultaneously motivate the use of contact-tracing apps has not been well documented. The present study offers some implications for practitioners concerned about fostering the adoption of mobile health services in the time of COVID-19. Methodologically, this study is among the first to blend PLS-SEM and fsQCA to measure the explanatory power of a structural model.
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Cong Doanh Duong, Thanh Hieu Nguyen, Thi Viet Nga Ngo, Thi Thu Phuong Pham, Anh Trong Vu and Ngoc Su Dang
This study aims to investigate what drives tourists to continue using ChatGPT for travel purposes. This study focuses on the impact of parasocial interaction on tourists’…
Abstract
Purpose
This study aims to investigate what drives tourists to continue using ChatGPT for travel purposes. This study focuses on the impact of parasocial interaction on tourists’ intention to continue using ChatGPT. It also examines how satisfaction mediates this relationship and the role of technology anxiety as a moderating factor.
Design/methodology/approach
Using a sample of 606 tourists in popular Vietnamese tourist destinations, this study used the SPSS PROCESS macro (Model 4 and Model 14) to estimate the research model.
Findings
The study found that tourists’ satisfaction and parasocial interactions positively influenced their intention to continue using ChatGPT for travel purposes. The tourists’ satisfaction was found to play a partial role in mediating the relationship between parasocial interactions and their intention to continue using ChatGPT. Technology anxiety was found to be a negative moderator of the direct effect of satisfaction and the indirect impact of parasocial interaction on this intention.
Originality/value
This study stands out as a pioneering exploration into the novel intersection of parasocial interaction, satisfaction, and technology anxiety and their influence on tourists’ intention to persist with using ChatGPT for travel-related purposes.
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Long Phi Nguyen, Dung Phuong Hoang and Thong Huy Vu
Travel destinations worldwide are seeking smart ways to reduce the negative impact of tourism, and the public bike rental service (PBRS) is one of them. To investigate the usage…
Abstract
Purpose
Travel destinations worldwide are seeking smart ways to reduce the negative impact of tourism, and the public bike rental service (PBRS) is one of them. To investigate the usage intention of this service among visitors, the author of this research employs an integrated approach consisting of two psychological frameworks: the Norm Activation Model (NAM) and the Technology Acceptance Model (TAM).
Design/methodology/approach
The integrated NAM-TAM model is implemented to conduct a survey (sample n = 777) with visitors to Hanoi, Danang, and Ho Chi Minh City regarding the factors underlying their intentions to continue using the PBRS TNGo.
Findings
Structural equation models suggested that: (1) the NAM-TAM can explain behavioural intention to use a smart PBRS. Perceived Usefulness (PU), Perceived Ease of Use (PE), and Awareness of Consequences (AC) have positive and significant impacts on Attitude Towards Using (AT) and, thus, on Behavioural Intention to Use (BI). Also, Personal Norms (PN) positively influence BI. (2) Among the four independent variables, tourists' AC produces the most potent effect on the intention to continue using a PBRS.
Research limitations/implications
This study can start a new research direction of combining the NAM with other theoretical frameworks to explain customer behaviour in the field of sustainable tourism practices. Future research should explore the proposed model based on comparisons of different tourists’ backgrounds, including nationality, length of stay, spending level, visiting purpose, etc.
Practical implications
This research provides strategic implications for destination management organisations in boosting the use of PBRS amongst tourists, contributing to the environmental sustainability targets of the tourism industry.
Originality/value
This study responds to the existing gap by examining both functional value (indicated by PU and PE) and perceived environmental/social value (proxied by AC) in forming tourists’ attitudes towards PBRS and their usage intention. Our study, therefore, actively contributes to the research stream of tourist behaviour in the field of sustainable tourism practices from the altruistic behavioural perspective.
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Vu Minh Ngo, Hiep Cong Pham and Huan Huu Nguyen
Digital transformation in supply chains (SCs) has emerged as one of the most effective ways to minimize SC disruption risks. Given the unprecedented impact of the COVID-19…
Abstract
Purpose
Digital transformation in supply chains (SCs) has emerged as one of the most effective ways to minimize SC disruption risks. Given the unprecedented impact of the COVID-19 pandemic on global SCs, this study aims to identify and provide empirical evidence about the drivers of digital SC transformation, considering the interactivity between environmental dynamism, technology, and organizational capabilities during the pandemic era.
Design/methodology/approach
Using partial least squares structural equation modeling (PLS-SEM), this study examines 923 firms in Vietnam to ascertain the drivers of digital SC transformation between small- and medium-sized enterprises (SMEs) and large enterprises, based on the technology–organization–environment (TOE) as an overarching framework.
Findings
This study finds that greater digital SC transformation adoption could be achieved under the interactivity between the TOE components of firms' technological competencies, learning capabilities, and disruptions in socioeconomic environments due to the COVID-19 pandemic. Moreover, a multigroup analysis shows that the drivers of digital SC transformation differ between SMEs and large enterprises. SMEs were found to be more motivated by the COVID-19 disruption risk when adopting digital SC models.
Originality/value
This study represents an original and novel contribution from Vietnam as an emerging market to the literature on the impact of COVID-19 on the global value chain. Apart from the unique dataset at the firm level, the analysis of interactions between external and internal drivers of digital SC transformation could provide crucial managerial implications for SMEs to survive major disruptions, such as those caused by the COVID-19 pandemic.
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This chapter provides information on the development of Vietnamese education under the influence of global forces based on the analysis of relevant education research and policies…
Abstract
This chapter provides information on the development of Vietnamese education under the influence of global forces based on the analysis of relevant education research and policies using Wolhuter’s frameworks. In the process of coming up with ways to develop education in the face of different influences of globalization, besides having reactions with patterns commonly found in countries around the world, Vietnam also has responses that reflect its own political, sociocultural and economic characteristics. The state still plays a controlling role in education at all levels and many culture-related features that have existed throughout the country’s history have hardly changed, namely aspects related to teachers, learners and teaching and learning methods. To sustain its education in the globalized era, Vietnam must make more efforts in various aspects such as the link between education and employment, the logic of education objectives, the feasibility and appropriateness of curricula, quality of education, especially of higher education and equality in education for underprivileged groups.
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Online knowledge sharing is a popular activity worldwide and can be leveraged by organisations to innovate, create and sustain competitive advantage. Although there have been a…
Abstract
Purpose
Online knowledge sharing is a popular activity worldwide and can be leveraged by organisations to innovate, create and sustain competitive advantage. Although there have been a number of studies examining knowledge sharing to encourage employees to convey their skills and experiences to others in an organisation, few attempts have been made to investigate the key motivators of online knowledge sharing in an organisation. Based on the theory of planned behaviour and technological acceptance model, this study aims to review the literature to establish a conceptual framework examining motivators of online knowledge sharing in organisations.
Design/methodology/approach
Previous studies that investigated motivators of online knowledge sharing in organisations in the literature were reviewed to propose a conceptual framework.
Findings
Four-dimensional model, which includes four types of key motivators of online knowledge sharing, namely, individual, social, organisational and technological, was established.
Originality/value
The model serves as a roadmap for future researchers and managers considering their strategy to enhance online knowledge sharing in organisations.
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Thinh Nguyen-Duc, Linh Phuong Nguyen, Tam To Phuong, Hanh Thi Hien Nguyen and Vinh Thi Hong Cao
This study aims to address the reliability and construct validity of the Individual Work Performance Questionnaire (IWPQ) in a Vietnamese context. Using the IWPQ as a measurement…
Abstract
Purpose
This study aims to address the reliability and construct validity of the Individual Work Performance Questionnaire (IWPQ) in a Vietnamese context. Using the IWPQ as a measurement tool, this research also examined whether demographic features (such as gender, education level, work experience and position in a company) influenced employees’ work performance.
Design/methodology/approach
The Vietnamese IWPQ was validated via a two-step process of factor analysis, including an exploratory factor analysis (EFA) and confirmatory factor analysis (CFA). The data collected were randomly divided into two subsamples to independently serve the EFA (n = 341) and CFA (n = 342). ANOVAs and t-tests were also used to examine the differences in individual work performance (IWP) among different demographic categories.
Findings
The results of the current study confirmed the applicability of the three-dimensional IWPQ in a Vietnamese context. In addition, they also indicated several demographic features that impacted employees’ patterns of responses to IWPQ dimensions.
Research limitations/implications
This study focused on the construct validity of the IWPQ, without taking the content, face or criterion validity into consideration. Thus, future research should be conducted to yield a more comprehensive validation of the instrument, to measure the relationship between human resource development (HRD) practices and employee performance and to examine the relationship between strategic HRD and IWP and firm outcomes. In addition, the validated Vietnamese version of the IWPQ may inspire comparative studies on individual performance within and between units in an organization and among organizations and industries.
Practical implications
HRD practitioners can now use the validated IWPQ in the Vietnamese language to assess fluctuations in and analyze current staff performance, thereby facilitating human resource management and development. This study also offers recommendations for business leaders and HRD practitioners striving to implement strategic HRD aimed at reducing disparities in gender and between educational qualifications and job assignments at workplace, with the overarching goals of enhancing staff performance. These recommendations prove instrumental in improving staff performance, strengthening organizational efficiency and ultimately tackling the issue of low productivity in Vietnam and neighboring countries.
Social implications
This study findings underscore the significance of embracing strategic HRD while taking into account individual, organizational and contextual factors that influence IWP. This approach serves to bridge current gaps related to IWP, including Vietnam’s comparatively lower productivity compared to neighboring nations, educational qualifications and role allocations within the workplace, as well as the prevailing work standards and strategic objectives.
Originality/value
To the best of the authors’ knowledge, this rigorously validated Vietnamese version of the IWPQ is the first of its kind in Vietnam, making a significant contribution to inclusivity initiatives and offering substantial evidence to affirm the IWPQ’s relevance across diverse contexts.