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This paper aims to study analytically and numerically the problem of transient natural convection heat transfer in a trapezoidal cavity with spatial side-wall temperature variation.

The governing equations subject to the initial and boundary conditions are solved numerically by the finite difference scheme consisting of the alternating direction implicit method and the tri-diagonal matrix algorithm. The left sloping wall of the cavity is heated to non-uniform temperature, and the right sloping wall is maintained at a constant cold temperature, while the horizontal walls are kept adiabatic.

It is shown that the heat transfer rate increases in non-uniform heating increments, whereby low wave number values are more affected by the convection. The best heat transfer enhancement results from larger side wall inclination angle; however, trapezoidal cavities require longer time compared to that of square to reach steady state.

The study of natural convection heat transfer in a trapezoidal cavity filled with nanofluid and heated by spatial side-wall temperature has not yet been undertaken. Thus, the authors of the present study believe that this work is valuable.

This paper aims to investigate the fluid structure interaction analysis of conjugate natural convection in a square containing internal solid cylinder and flexible right wall.

The right wall of the cavity is flexible, which can be deformed due to the interaction with the natural convection flow in the cavity. The top and bottom walls of the cavity are insulated while the right wall is cold and the left wall is partially heated. The governing equations for heat, flow and elastic wall, as well as the grid deformation are written in Arbitrary Lagrangian–Eulerian formulation. The governing equations along with their boundary conditions are solved using the finite element method.

The results of the present study show that the presence of the solid cylinder strongly affects the transient solution at the initial times. The natural convection flow changes the shape of the flexible right wall of the cavity into S shape wall due to the interaction of the flow and the structure. It is found that the increase of the flexibility of the right wall increases the average Nusselt number of the hot wall up to 2 per cent.

To the best of the authors' knowledge, the unsteady natural convection in an enclosure having a flexible wall and inner solid cylinder has never been reported before.

Purpose: The purpose of the present study is to synthesize and organize existing literature on contagious diseases and tourism. This systematic mapping of the literature helps to identify various mature and emerging themes around the research domain in the literature.

Design/Methodology/Approach: The study uses systematic methodology along with bibliometric and content analysis. Using a combination of electronic database searching and forward and backward references searching, the study identifies 160 suitable published studies.

Findings: Initial bibliometric analysis reveals that Tourism Geographies and Tourism Management are most influential journals and Law and Lee are most influential authors working on this field. The Hong Kong Polytechnic University and Universiti Sains Malaysia are among the top contributing educational and research organizations. Further, the content analysis reveals that literature on contagious diseases and tourism industry revolves around three prominent themes namely SARS and other contagious diseases, crisis management and tourism forecasting.

Research Limitations/Implications: The study does not consider ‘grey literature’ and conference proceedings.

Originality and Value: Present study is one of the early attempts that analyzes the literature on contagious diseases and tourism using bibliometric analysis and contributes to the literature by identifying various mature and emerging on contagious diseases and tourism literature. These insights provide a robust map for future investigation in this field and also offer implications for practitioners.

Like many social media trends, the romantic craze charms Egyptian youth. Romantic Facebook crush pages popped up locally in the past few years among university students particularly. They expressed a new aspect of online social interaction that has raised red flags with some adults, while thought to be a new healthy way to pour youth’s hearts out anonymously in a so-called a conservative society for others. Some crush pages, in particular, drew concerns of several parents for they are more vulgar and aggressive submissions. Laying between the two arguments, this study aims to examine the extent to which Facebook users make use of it to pursue romance, if Facebook’s characteristics and social context reflected in users’ perceptions of romantic relationships, the implications of being in a romantic relationship on Facebook and if such FB practices could pose a state of moral panic or a public concern.

A survey of 200 Facebook users between 18 and 25 years was gathered. Furthermore, a content analysis of three Egyptian universities’ “crush pages” posts was applied.

The study highlighted the conflicting ideals of today’s Egyptian youth moral lives. Ultimately, there is an evidence that practices of using Facebook online crush pages have been creating new contested but delightful moral normative rules around love.

Crushes pages have been sweeping across Egyptian colleges and faculties; however, almost no Arabic study was done to figure out its impact. Furthermore, the study takes into account the socio-cultural background of the Egyptian society.

Under the sunlight of social commerce, few concepts have blossomed like value co-creation. But when blurred strategies are implemented, the opportunity to wilt a brand is high. To avoid the miscues and the controversies, an ascendant step is to engage consumers with social commerce sites. The purpose of this paper is to propose three antecedents to engage consumers with social commerce sites, namely, social support, social commerce value and social commerce information sharing, and the effect of brand engagement on the intention of brand co-creation.

This study used survey data from 234 Iranians with experience using social commerce sites. Variance-based structural equation modeling using the partial least squares path modeling approach was adopted to analyze the structural model.

The authors found that social support, social commerce value and social commerce information sharing positively foster brand engagement. The study also revealed that brand engagement is a significant predictor of brand co-creation intention.

The study is the first study that considers and explains brand engagement from social support theory, social commerce value theory and social commerce information exchange. Also, the study shows how consumers can be an integral part of a brand. Unlike other studies which were done in industrialized countries, this study was employed in Iran.

This paper aims to propose a mathematical model for describing and clarifying the relationships among the indicators governing the social values of special customers in business-to-consumer (B2C) e-commerce systems. This mathematical model is also able to describe the degree of adaptability of e-commerce systems to the social values of specific clients, and commercial firms are able to use the parameters described in this paper to increase the versatility and has the power to trade with special customers in different areas.

In this paper, while analyzing the issue of trading from the point of view of the customer as an element of trading, the affecting factors the trading space have been extracted. These affecting factors are categorized in three major groups: culture, technology and customers. This classification is based on the e-commerce and developing the traditional commerce. Using the mapping functions, the effects of each element in these three spaces on the concept of social values have been analyzed. The result of this analysis is the mathematical model governing each parameter and its semantic relation with the concept of social value.

The presence of a mathematical model between the indicators influencing the model adaptability and social values space allows e-commerce system designers to be able to make decisions on the adaptability of the model with a quantitative approach. To examine the proposed mathematical models, important frameworks and patterns in the field of e-commerce have been analyzed with an Islamic approach, as one of the adaptations of B2C e-commerce model.

Regarding the innovation of the work, the case has been made, and the concept of social value and the model governing the elements of social values in this paper, in a B2C e-commerce model, has been discussed in general; the problem is parametric solved.

One of the key concepts in commerce is the ability of the commerce model to adapt to the requirements of special customers. This is more important in costumer-based e-commerce models. In these types of systems, if the commerce cannot match the customer’s characteristics, it will not be accepted and used by customers. This is especially more important in the field of social values for customers.

In this paper, a mathematical model is presented to examine the adaptability of e-commerce systems to the social values of special customers. In examining this model, the relationship between each element affecting the social value of specific customers and the factors affecting trade has been studied.

This study aims to investigate the latest breakthroughs in social commerce by examining the characteristics of consumers' social self-identity factors in the food and beverage sector. The objective is to examine how social self-identities factors contribute to exchanging information on social commerce platforms for food and beverage products.

This study employed partial least squares structural equation modeling (PLS-SEM) to test the measurement and structural model. A total of 238 food and beverage website and apps users were questioned using a structural survey.

Contrary to expectations, one self-inner driver does not influence consumers' intentions to exchange social commerce information, while up-to-date information, validation and like-minded discussion have a strong impact on the social commerce exchange model.

The findings of this research offer new insights into the brand's abilities to induce social commerce. The findings also assist marketing managers in better managing brand content on these websites.

In the digital era, business-to-business (B2B) salespersons are encouraged to communicate with buyers on social media platforms and shape customer loyalty. However, the effect of social media usage and its mechanism remain unexplored. The purpose of this paper is to investigate how salespersons’ social media usage influences B2B buyers’ trust beliefs and purchase risk, and therefore, customer loyalty.

The authors conduct an online-survey, use partial least squares structural equation modeling to analyze the data, and adopt SPSS PROCESS macro 2.13 to test mediation effects.

Salespersons’ social media usage can enhance buyers’ trust beliefs on salespersons’ ability, integrity and benevolence, but only the latter two can improve customer loyalty. Social media usage does not directly affect purchase risk, and only benevolence can reduce purchase risk. Serial mediation models reveal that the effect of social media usage on customer loyalty is mediated by buyers’ trust beliefs on salespersons’ integrity/benevolence and purchase risk.

First, the authors confirm the effect of social media usage on customer loyalty in B2B context and refute the fallacy of social media uselessness in B2B practices. Second, the research shows that buyers’ trusting beliefs on salesperson’s ability and integrity do not significantly influence perceived risk. The finding is different from the stereotypical judgment in B2C scenarios. Third, the authors distinguish differently weighted influences of buyers’ trusting beliefs on salesperson’s ability, integrity and benevolence, and highlight the role of salespersons’ altruism attributes in shaping customer loyalty.

Internationalization and financial deregulation have caused market participants and policymakers to consider the significance of financial connectedness and the spillover effects of shocks. In this context, this research is a pioneering effort to investigate the direction and magnitude of return volatility spillovers between Pakistan’s financial markets and those of its key trade partners. This paper examines the relationship between return and volatility spillover in the financial markets of Pakistan and its major trading partners.

Ten countries are selected for empirical examination of dynamic connectedness among Pakistan and its major trading partner’s stock markets. This study utilizes a spillover index approach model and considers daily, weekly and monthly datasets spanning 25 years from 1995 to 2019.

The results indicate that stock markets provide efficient channels for return and volatility spillovers. Moreover, it is found that the intensity of spillovers during the financial crisis is more intense as these crises are major determinants of contagion; consequently, investors, speculators and policymakers use these events for their respective purposes.

Researchers, practitioners, policymakers and investors may all benefit from the findings in areas including risk management, portfolio diversification and trading methods.

This paper aims to investigate the sources of variation in aluminum profiles hot extrusion process for the purpose of process capability improvement at National Aluminum and Profiles Company (NAPCO) in Palestine. The critical-to-quality characteristics (CTQ) have been determined as base variables to measure the process capability.

The DMAIC (Define, Measure, Analyze, Improve, and Control) Lean Six Sigma (LSS) approach has been adopted to conduct this study. More specifically, historical data analysis and PARETO charts have been employed. The defects' root causes have been determined using the cause-and-effect diagram and decision matrix. A course of suggested actions has been established to help in improving extrusion process capability. Minitab-18 software was used for conducting inferential statistical analysis. A case study considering a geometry CTQ of D3 dimension of bottom sash aluminum profiles 4,332 was selected for analysis.

The results indicated a reduction in DPMO from 89,649 to 15,659, sigma level was improved from 2.84 to 3.65, process yield was improved from 91.04% to 98.43% and cost was reduced from U$75,972 to U$13,250.9 (i.e. a saving of U$62,721). Studying and improving the sigma level of the extrusion process would yield fewer defective products and consequently fewer customer complaints. A validation process which has been conducted during the year 2019 showed a consistent improvement that aligns with the first stage of improvement made on October 1, 2018.

This study focuses on only one critical quality characteristic (CTQ), namely, a geometry CTQ of D3 dimension of bottom sash aluminum profiles 4,332 produced by NAPCO was selected for analysis.

This study would be useful for researchers and practitioners to improve the process capability in aluminum profiles manufacturing industries in general and hot extrusion processes in particular.

Many previous studies on applying LSS-DMAIC methodology have been conducted in aluminum industries in developed countries. According to the literature, it is highly recommended to have more case studies of applying LSS-DMAIC in different industries in developing countries. NAPCO is the only aluminum manufacturing plant in Palestine that hotly extrudes and coats aluminum profiles. Hence, the present study is the first of its kind in NAPCO and in Palestine. Projecting the assessment of the impact of process improvement opportunities and capability analyses into monetary measures are also innovative.