Browsing by Issue Date, starting with "2019-08"
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- Parametric study on the performance of an air curtain based on CFD simulations - New proposal for automatic operationPublication . Goncalves, J. C.; Costa, J.J.; Lopes, A.M.G.This paper presents a parametric study on the performance of an air curtain installed over an access door of a refrigerated room. The aim of this work is to quantify, in an integrated way, the influence of the following geometrical and dynamic parameters: door height; temperature difference between rooms, nozzle thickness; initial orientation angle; jet discharge velocity. A numerical model was used to simulate the turbulent non-isothermal 3D airflow generated in the transient period after the door is opened, with the air curtain device turned on or off. Turbulence effects were taken into account with the k-SST model. Results show that the optimum discharge velocity of the air curtain increases with the door height, as well as with the temperature difference between both sides of the air curtain. It was also possible to find an optimum jet nozzle width corresponding to maximum sealing efficiency and lower jet airflow rate. A proposal is made for an empirical correlation to predict the optimum jet discharge velocity as function of the variables used in the parametric study. Additionally, to ensure that the air curtain operates near the optimum conditions, the appropriate air curtain settings are discussed and a new strategy is suggested.
- Competitiveness of the Hotel Industry: A Knowledge Management ApproachPublication . Pinto Gomes Ambrósio, Luís Filipe; Veiga, Pedro; Ribeiro Ferreira, Raúl dos SantosThere is also an emerging research agenda on knowledge management within the hotel sector. Hotels are currently increasingly dependent on their competence to possess internal and external knowledge, making knowledge a critical resource for competitiveness and obtaining competitive advantages for innovation and differentiation of its competitors. Strategies tacit-oriented and explicit-oriented knowledge also has the dominant role in hospitality service operations. The principal goal of this study is to identify the role of knowledge management organizational processes as a determinant of competitiveness in the hotel industry, particularly how knowledge management strategies centered on the source (internal and external) and knowledge (tacit and explicit) have positive an impact on the competitiveness of hotels. We use a quantitative approach based in an email survey applied to 55 Portuguese hotels. Our results show that knowledge management strategies oriented to source and type of knowledge are critical for hotels competitiveness and obtaining competitive advantages.
- Firms’ performance and board size: A simultaneous approach in the European and American contextsPublication . Augusto, Mário; Pascoal, Rui; Reis, PedroThe relation between performance and board size (BS) is analysed in the American and European contexts. It is found that return on assets (ROA) depends on BS defined as an endogenous explanatory variable. This potentially non-monotonous effect is modelled by introducing firm size and number of segments by board member as explanatory variables for ROA. BS net effect after accounting for the indirect effect resulting from these variables is negative. Differences in the results obtained for Tobin’s Q, strategic investors’ weight and equity to total assets, between America and Europe, suggest a more preventive management control in Europe.