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This work aims to describe the physical and numerical modeling of a CFD solver for hypersonic flows in thermo-chemical non-equilibrium. This paper is the second of a two-part series that concerns the application of the solver introduced in Part I to adaptive unstructured meshes.

The governing equations are discretized with an edge-based stabilized finite element method (FEM). Chemical non-equilibrium is simulated using a laminar finite-rate kinetics, while a two-temperature model is used to account for thermodynamic non-equilibrium. The equations for total quantities, species and vibrational-electronic energy conservation are loosely coupled to provide flexibility and ease of implementation. To accurately perform simulations on unstructured meshes, the non-equilibrium flow solver is coupled with an edge-based anisotropic mesh optimizer driven by the solution Hessian to carry out mesh refinement, coarsening, edge swapping and node movement.

The paper shows, through comparisons with experimental and other numerical results, how FEM + anisotropic mesh optimization are the natural choice to accurately simulate hypersonic non-equilibrium flows on unstructured meshes. Three-dimensional test cases demonstrate how, for high-speed flows, shocks resolution, and not necessarily boundary layers resolution, is the main driver of solution accuracy at walls. Equally distributing the error among all elements in a suitably defined Riemannian space yields highly anisotropic grids that feature well-resolved shock waves. The resulting high level of accuracy in the computation of the enthalpy jump translates into accurate wall heat flux predictions. At the opposite end, in all cases examined, high-quality but isotropic unstructured meshes gave very poor solutions with severely inadequate heat flux distributions not even featuring expected symmetries. The paper unequivocally demonstrates that unstructured anisotropically adapted meshes are the best, and may be the only, way for accurate and cost-effective hypersonic flow solutions.

Although many hypersonic flow solvers are developed for unstructured meshes, few numerical simulations on unstructured meshes are presented in the literature. This work demonstrates that the proposed approach can be used successfully for hypersonic flows on unstructured meshes.

This paper aims to describe the physical and numerical modeling of a new computational fluid dynamics solver for hypersonic flows in thermo-chemical non-equilibrium. The code uses a blend of numerical techniques to ensure accuracy and robustness and to provide scalability for advanced hypersonic physics and complex three-dimensional (3D) flows.

The solver is based on an edge-based stabilized finite element method (FEM). The chemical and thermal non-equilibrium systems are loosely-coupled to provide flexibility and ease of implementation. Chemical non-equilibrium is modeled using a laminar finite-rate chemical kinetics model while a two-temperature model is used to account for thermodynamic non-equilibrium. The systems are solved implicitly in time to relax numerical stiffness. Investigations are performed on various canonical hypersonic geometries in two-dimensional and 3D.

The comparisons with numerical and experimental results demonstrate the suitability of the code for hypersonic non-equilibrium flows. Although convergence is shown to suffer to some extent from the loosely-coupled implementation, trading a fully-coupled system for a number of smaller ones improves computational time. Furthermore, the specialized numerical discretization offers a great deal of flexibility in the implementation of numerical flux functions and boundary conditions.

The FEM is often disregarded in hypersonics. This paper demonstrates that this method can be used successfully for these types of flows. The present findings will be built upon in a later paper to demonstrate the powerful numerical ability of this type of solver, particularly with respect to robustness on highly stretched unstructured anisotropic grids.

Comparative opinions widely exist in online reviews as a common way of expressing consumers’ ideas or preferences toward certain products. Such opinion-rich texts are key proxies for detecting product competitiveness. The purpose of this paper is to set up a model for competitiveness analysis by identifying comparative relations from online reviews for restaurants based on both pattern matching and machine learning.

The authors define the sub-category of comparative sentences according to Chinese linguistics. Classification rules are set up for each type of comparative relations through class sequence rule. To improve the accuracy of classification, a comparative entity dictionary is then introduced for further identifying comparative sentences. Finally, the authors collect reviews for restaurants from Dianping.com to conduct experiments for testing the proposed model.

The experiments show that the proposed method outperforms the baseline methods in terms of precision in identifying comparative sentences. On the basis of such comparison-rich sentences, product features and comparative relations are extracted for sentiment analysis, and sentimental score is assigned to each comparative relation to facilitate competitiveness analysis.

Only the explicit comparative relations are discussed, neglecting the implicit ones. Besides that, the study is grounded in the assumption that all features are homogeneous. In some cases, however, the weights to different aspects are not of the same importance to market.

On the basis of comparative relation mining, product features and comparative opinions are extracted for competitiveness analysis, which is of interest to businesses for finding weakness or strength of products, as well as to consumers for making better purchase decisions.

Comparative relation mining could be possibly applied in social media for identifying relations among users or products, and ranking users or products, as well as helping companies target and track competitors to enhance competitiveness.

The authors propose a research framework for restaurant competitiveness analysis by mining comparative relations from online consumer reviews. The results would be able to differentiate one restaurant from another in some aspects of interest to consumers, and reveal the changes in these differences over time.

Previous theoretical and empirical literature has advocated growth in the access and use of flexible working arrangements by establishing their link with individual and especially parental subjective well-being. Given this, the current research investigates impact that their own or their partners’ transition to flexitime and teleworking has on parental subjective well-being. The cross-partner dimension has not been explored yet by prior studies. Measures for cognitive, subjective well-being include satisfaction with life overall, satisfaction with the amount of leisure time, and satisfaction with health. Ordered logit longitudinal models are estimated using Understanding Society data from 2009 to 2019. Corroborating prior studies, the current analysis finds that mothers’ transition to flexitime and teleworking has a positive impact on their leisure time and health satisfaction. For fathers, switching to telework improves satisfaction with their amount of leisure time, while adopting flexitime can take a toll on self-reported health satisfaction. However, contrary to expectations, mothers’ move to teleworking can be injurious for fathers’ life satisfaction levels, yet fathers’ adoption of flexitime fosters mothers’ satisfaction with their leisure time amount.

The unanticipated disruption caused by the ongoing coronavirus pandemic led to the extensive use of flexible working arrangements. In such a boundaryless work environment, however there are significant concerns, especially around inclusivity and discrimination. Given the increasing concerns surrounding hybrid and remote work settings, the authors investigated whether the extent of working in substantially flexible working arrangements relates to employees’ perceived ostracism and inequality, distinguishing between working from home, in a hybrid mode or from the office. In addition, the authors theorised that in flexible working arrangements, high-quality leader relationships, such as leader–member exchange (LMX) and servant leadership are likely to reduce perceptions of ostracism and inequality. Based on a survey of 161 professionals, who worked to varying degrees in flexible working arrangements, the authors found that employees who worked extensively in a hybrid mode were less likely to report experiences of ostracism and inequality in comparison to employees who worked mainly from home or in an office. Furthermore, a moderation analysis showed that the effects of LMX and servant leadership on perceptions of ostracism and inequality were much stronger for individuals who work in hybrid working arrangements than those who work at the office or from home. This research makes an important contribution to our understanding of how different degrees of flexible working arrangements affect employees by demonstrating the role of high-quality leader relationships in reducing perceptions of ostracism and inequality at different degrees of work flexibility.

Outsourcing of business-logistics services is a well-established business practice that allows an outsourcer to obtain the services or products from a logistics-service provider (LSP). The outsourcer can order a range of logistics services, including but not limited to warehousing, transportation, and forwarding. The outsourcers had traditionally focused on service-provider selection criteria such as costs, quality, and responsiveness while having devoted considerably less attention to how sustainably the practices are carried out. Past research identified different external and internal motivators that facilitate consideration of sustainability in selection of the service providers, whereas the current study investigates the outsourcers’ perception of importance of environmental sustainability in adoption of green logistics practices and selection of LSPs. We use a vantage point of outsourcers (“buyers”) to conduct the quantitative research based on a survey conducted on large manufacturing companies. The findings reveal a (mis)match between the perception of importance and realized inclusion of environmental-sustainability criteria. Ultimately, this study finds a link between the levels of perception and rate of adoption, and provides recommendations for the future adoption of environmental-sustainability criteria in the selection of the LSPs.

Human group behavior is the driving force behind many complex social and economic phenomena. Few studies have integrated multi-dimensional travel patterns and city interest points to construct urban security risk indicators. This paper combines traffic data and urban alarm data to analyze the safe travel characteristics of the urban population. The research results are helpful to explore the diversity of human group behavior, grasp the temporal and spatial laws and reveal regional security risks. It provides a reference for optimizing resource deployment and group intelligence analysis in emergency management.

Based on the dynamics index of group behavior, this paper mines the data of large shared bikes and ride-hailing in a big city of China. We integrate the urban interest points and travel dynamic characteristics, construct the urban traffic safety index based on alarm behavior and further calculate the urban safety index.

This study found significant differences in the travel power index among ride-sharing users. There is a positive correlation between user shared bike trips and the power-law bimodal phenomenon in the logarithmic coordinate system. It is closely related to the urban public security index.

Based on group-shared dynamic index integrated alarm, we innovatively constructed an urban public safety index and analyzed the correlation of travel alarm behavior. The research results fully reveal the internal mechanism of the group behavior safety index and provide a valuable supplement for the police intelligence analysis.

The purpose of this paper is to comprehend the nature of online reviews received on various social networking sites and internet-based platforms regrading organizational corporate social responsibility (CSR) initiatives.

Given the novelty of this field, a qualitative exploratory research study was carried out. For this research, 28 Indian CSR experts on online CSR reviews were interviewed with a semi-structured open-ended questionnaire for data collection. Thematic and relational content analysis was applied for data analysis. The data was analysed based upon the theoretical anchors of micro foundations approach, organizational egoism (reputational and economic) concept and organizational logic (instrumental and integrative) literature and stakeholder salience.

The study analysis indicated that online CSR reviews that organizations received on various social networking sites and internet-based platforms from different individual and institutional stakeholders were complaints, appreciations, observations and recommendations in nature. Online CSR reviews appreciated more of integrative organizational logic than instrumental organizational logic. CSR reviews present on online platforms valued organizational reputational egoism more than organizational economic egoism. The salience of stakeholders was getting redefines in Web 2.0 based online CSR reviews. Finally, micro foundations approach was becoming a more potent perspective in the CSR narrative.

This research study was anchored in the micro foundations approach of CSR (Hafenbrädl and Waeger, 2017). This study ascertained those individuals did matter in organizational CSR narrative (Maak et al., 2016). Furthermore, how firms were evaluated through online reviews based upon organizational egoism (reputational and economic) (Casali, 2011; Casali and Day, 2015) and organizational logic (instrumental and integrative) (Seele and Lock, 2015; Liu, 2013; Gao and Bansal, 2013; Bansal and Song, 2017) was studied. Finally, in the world of online reviews, the notion of salient stakeholders (Mitchell et al., 2011; Magness, 2008) was getting redefined, and this aspect was also covered in this research study.

Firms have been engaging in CSR initiatives towards provision of social benefits and community engagement. Regarding firm CSR initiatives, CSR managers traditionally used to receive feedback from the stakeholders based upon written and special surveys conducted post or during the late stages of CSR engagement. The advent and ubiquitous presence of digital mobile devices and Web 2.0-enabled internet connections altered the way firms received feedback. This was because increasingly online reviews were received from stakeholders on firm CSR web pages, social networking sites and other online spaces. Many of the online CSR reviews were regarding the compliments and achievements that the CSR initiatives had achieved. However, a significant portion of online CSR reviews were regarding the complaints regarding the CSR initiatives. Online CSR reviews received from an array of stakeholders are inputs for firm managers. Online CSR reviews are thus an asset for an organization. Managers need to develop capabilities towards applying this asset for the expressed purposed. These online CSR reviews could be used as inputs to draw new CSR initiatives, redefine extant CSR initiatives. Furthermore, these online CSR reviews could be used as inputs to alter the organizational resources, capabilities, competencies and process regarding CSR initiatives.

This was one of the first studies that integrated the theoretical aspects of salient stakeholders, organizational logic, organizational egoism through the lens of micro foundations approach in the context of organizational CSR initiatives. To the best of the author’s knowledge, this was indeed a novel contribution, as the same was explored and explicated based upon online CSR reviews on internet-based platforms.

The purpose of this paper is to investigate the effects of minor addition of the rare earth (RE) element cerium, Ce, on the microstructures and creep properties of Sn-Ag-Cu solder alloys.

The pure Sn, Sn-Cu alloy, Sn-Ag alloy and Cu-Ce alloy were used as raw materials. Sn-Ag-Cu alloys with different contents of RE Ce were chosen to compare with Sn-Ag-Cu. The raw materials of Sn, Sn-Cu alloy, Sn-Ag alloy, Cu-Ce alloy were melted in a ceramic crucible, and were melted at 550°C ± 1°C for 40 minutes. To homogenize the solder alloy, mechanical stirring was performed every ten minutes using a glass rod. During the melting, KC1 + LiCI (1.3:1), were used over the surface of liquid solder to prevent oxidation. The melted solder was chill cast into a rod.

It is found that the microstructure exhibits smaller grains and the Ag₃Sn/Cu₆Sn₅ intermetallic compound (IMC) phases are modified in matrix with the addition of Ce. In particular, the addition of 0.03 wt.% Ce to the Sn-Ag-Cu solder can refine the microstructures and decrease the thickness of the IMC layers of Sn-Ag-Cu solder alloys. Meanwhile, thermodynamic analysis showed that these phenomena could be attributed to the reduction of the driving force for Cu-Sn IMC formation due to the addition of Ce. Results calculated using the thermodynamic method are close to the above experimental data. Thus, the optimum content of Ce in Sn-Ag-Cu solder alloys should be about 0.030 percent. Additionally, the effect of Ce on the creep rupture life of Sn-Ag-Cu soldered joints was studied. It was found that the creep rupture life may be increased up to 7.5 times more than that of the original Sn-Ag-Cu alloy, when Ce accounts for 0.030 percent.

This paper usefully investigates the effects of the RE cerium (Ce), on the microstructures and creep properties of Sn-Ag-Cu solder alloys, optimizing the quantity of Ce in the Sn-Ag-Cu solder alloy through a thermodynamic method and by creep-rupture life testing.