On the dynamics of the collapse of a diffusion-flame hole

The collapse dynamics of a diffusion-flame hole in the presence of a counterflow are studied. We construct unsteady solutions of the one-dimensional edge-flame model of Buckmaster (1996), in which heat and mass transverse losses are algebraic. The flame structure is determined in the classical limit of large activation energy. Solutions for both planar and axisymmetric strain geometry are considered for the particular case of unity Lewis number. It is shown that the final stage of the edge-flame collapse is determined by a dominant balance between the time rate of change of the mass fractions (and temperature) and diffusion, giving a self-similar structure in which the size of the edge-flame hole approaches zero, to leading (zeroth) order, as a 1/2-power of time. This solution suggests an expansion of the full model equations in 1/2-powers of time that allows detailed analysis of the effects of side losses and flow distribution in the edge-flame collapse process. It is found that side loss effects are apparent at the first order, whereas convection by the counterflow is first felt during collapse at the second order in the fractional-time expansion. Numerical integrations of the governing equations are found to verify the analytic results

Exploring the origin of retail stores in Europe: evidence from Southern Italy from the 6th century BCE to the 3rd century BCE

Retail literature reports considerable research on the role that technology has played in retailing as an enabler of change, with emphasis on the shifting of power from retailers to consumers. While scholarly attention has been paid mainly to investigating the current scenario in order to predict future trends and preview retail settings for the coming years, the origins of the retail process, in terms of physical space for selling activities and history of retailing as discipline of business history, is less investigated. Using qualitative data gathered through historical documents and archaeological findings, the present study goes back beyond modern retail settings to explore the origins of points of sales as early as the Magna Graecia period (600 BCE – 300 BCE). Such historical analysis not only offers an insight into the origin of the modern retailing, but also cast broader questions about the degree to which historical interpretations of the growth of retailing have been evolved, by emphasising that after 2000 years, there are still similarities. To the authors’ knowledge, this current study is the first to extend the baseline for such an understanding back a further millennium or so

The effect of mobile retailing effect on consumption experiences: a dynamic perspective

The emerging retail culture is characterized by the extensive use of mobile technologies, high connectivity, ubiquitous computing and contactless technologies, which enable consumers to experience shopping differently. In fact, innovative mobile technologies provide new tools (apps) which are able to separate the moment of purchase from the moment of effective consumption, by allowing consumers to make purchases by mobile phone and collect them at home or at a store (a pick-up boutique or collection point), in addition to the traditional in-store service (purchase in the store and collect/consume in the store). The aim of this paper is to understand the extent to which mobile technologies have an impact on consumer behaviour, with emphasis on the drivers motivating consumers to adopt the consumer experience of mobile shopping. To achieve this goal we used a qualitative approach involving 29 consumers in the Italian market, where mobile shopping is still at an early stage. The findings shed a light on the extent to which consumers are moving from e-channels to mobile channels and take into account the effect of these technological innovations in retail settings from a cognitive standpoint, where studies are limited. The implications for researchers and practitioners are then discussed, with emphasis on retailers need to develop new mobile service competences, and integrate and synthetize physical retail settings with mobile opportunities and functionalities

Large-eddy simulation and multiscale modelling of a Richtmyer–Meshkov instability with reshock

Large-eddy simulations of the Richtmyer–Meshkov instability with reshock are pre- sented and the results are compared with experiments. Several configurations of shocks initially travelling from light (air) to heavy (sulfur hexafluoride, SF6) have been simulated to match previous experiments and good agreement is found in the growth rates of the turbulent mixing zone (TMZ). The stretched-vortex subgrid model used in this study allows for subgrid continuation modelling, where statistics of the unresolved scales of the flow are estimated. In particular, this multiscale modelling allows the anisotropy of the flow to be extended to the dissipation scale, eta, and estimates to be formed for the subgrid probability density function of the mixture fraction of air/SF6 based on the subgrid variance, including the effect of Schmidt number

Store buildings as tourist attractions: mining retail meaning of store building pictures through a machine learning approach

The aim of this paper is to understand the extent to which a store building can function as a tourism attraction, using a large luxury department store as case research. The study draws upon the idea that people complete a hermeneutic circle to create an extraordinary tourism experience to share with others. The data gathering is based on the collection of pictures posted online on Flickr and and analysed using a machine learning approach. A sample of 1,557 pictures related to a specific area in London (UK) were collected and analysed by means of a cluster analysis in order to determine which objects are most photographed. Findings reveal that the store building of a luxury department store is the central object in the majority of pictures within a 1km radius of the store main entrance, which demonstrates the role of store building attractiveness in tourism experience. The theoretical contribution is that this is the first paper adding the exterior of the building as attribute of the department store, and demonstrating the role of department stores in place attractiveness

A new approach to retailing for successful competition in the new smart scenario

Purpose- This study develops the idea of smart retailing, exemplified in innovative, technology-enriched retail services as part of service-oriented strategies. In particular, the aim is to provide a new integrated framework to understand the emerging retail scenario based on the smart usage of technologies to improve retail service and develop innovation management strategies. This framework will provide a comprehensive understanding the basic forms of smart retailing as the current competitive scenario. Design/ Methodology/approach- As a viewpoint, this paper employs an interdisciplinary approach, drawing upon the actual challenges in retailing, to propose a new perspective, the smart retailing one, to describe the new competitive scenario and formulates an emerging research agenda. Findings- The present paper contributes to research on innovation and technology management for retailing by examining the key dimensions of smart retailing, which aims to enhancing retail service quality and retailers’ performance. Originality- The paper explains how current retailing is moving to a smart perspective, and how retail management should be adapted to successfully perform in the current service-dominant logic scenario, as a consequence of increasing consumer involvement in service co-production and the rapid growth of digital technologies

Reconstruction subgrid models for nonpremixed combustion

Large-eddy simulation of combustion problems involves highly nonlinear terms that, when filtered, result in a contribution from subgrid fluctuations of scalars, Z, to the dynamics of the filtered value. This subgrid contribution requires modeling. Reconstruction models try to recover as much information as possible from the resolved field Z, based on a deconvolution procedure to obtain an intermediate field ZM. The approximate reconstruction using moments (ARM) method combines approximate reconstruction, a purely mathematical procedure, with additional physics-based information required to match specific scalar moments, in the simplest case, the Reynolds-averaged value of the subgrid variance. Here, results from the analysis of the ARM model in the case of a spatially evolving turbulent plane jet are presented. A priori and a posteriori evaluations using data from direct numerical simulation are carried out. The nonlinearities considered are representative of reacting flows: power functions, the dependence of the density on the mixture fraction (relevant for conserved scalar approaches) and the Arrhenius nonlinearity (very localized in Z space). Comparisons are made against the more popular beta probability density function (PDF) approach in the a priori analysis, trying to define ranges of validity for each approach. The results show that the ARM model is able to capture the subgrid part of the variance accurately over a wide range of filter sizes and performs well for the different nonlinearities, giving uniformly better predictions than the beta PDF for the polynomial case. In the case of the density and Arrhenius nonlinearities, the relative performance of the ARM and traditional PDF approaches depends on the size of the subgrid variance with respect to a characteristic scale of each function. Furthermore, the sources of error associated with the ARM method are considered and analytical bounds on that error are obtained

A low-numerical dissipation, patch-based adaptive-mesh-refinement method for large-eddy simulation of compressible flows

This paper describes a hybrid finite-difference method for the large-eddy simulation of compressible flows with low-numerical dissipation and structured adaptive mesh refinement (SAMR). A conservative flux-based approach is described with an explicit centered scheme used in turbulent flow regions while a weighted essentially non-oscillatory (WENO) scheme is employed to capture shocks. Three-dimensional numerical simulations of a Richtmyer-Meshkov instability are presented

'You will like it!' Using open data to predict tourists' responses to a tourist attraction

The increasing amount of user-generated content spread via social networking services such as reviews, comments, and past experiences, has made a great deal of information available. Tourists can access this information to support their decision making process. This information is freely accessible online and generates so-called “open data”. While many studies have investigated the effect of online reviews on tourists’ decisions, none have directly investigated the extent to which open data analyses might predict tourists’ response to a certain destination. To this end, our study contributes to the process of predicting tourists’ future preferences via MathematicaTM, software that analyzes a large set of the open data (i.e. tourists’ reviews) that is freely available on tripadvisor. This is devised by generating the classification function and the best model for predicting the destination tourists would potentially select. The implications for the tourist industry are discussed in terms of research and practice