Fuzzy delphi method: Issues and challenges
The Fuzzy Delphi Method (FDM) is the modified and enhanced version of the classical Delphi technique. Improvement was made to rectify the imperfection of traditional Delphi Method (DM) that leads to low convergence in retrieving outcomes, loss of important information, and long progress of investigation. Nevertheless, this approach has been employed in various application domains, including humanities, management, business, physical science, and engineering. Furthermore, the literature has exposed numerous key issues in relation to the existing FDM that need to be resolved with regard to the classical DM. Hence, the analysis obtained from the existing literature highlighted two key issues, which were; i) most FDM ignored certain important characteristics of DM, and ii) lack of explanation on how FDM obtained controlled feedback with the lack of iteration process. Additionally, it was observed that there had been lack of comparison between decision outcomes obtained based on FDM and the decision outcomes obtained from the traditional DM.
Applying the fuzzy Delphi method to analyze the evaluation indexes for service quality after railway re-opening: using the old mountain line railway as an example
The railway tourism has become a trend due to cultural heritage preservation. There have been voices calling for re-opening of the Old Mountain Line Railway. The service quality controlled by the management will have a great influence on tourists' intention to use the railway again. Therefore, the service quality after the railway re-opening is the key issue to be considered when it comes to management strategies. This study explored the indexes for service quality after railway re-opening from the viewpoints of some experts and scholars. Through literature review and interviews with experts, preliminary indexes were determined. Then the fuzzy Delphi method was applied to select proper ones from them, to discuss the key factors needed to be improved based on the current service quality. The result of this study shows that the most important factor was safety. With a safe foundation, tourists would trust the management more. The second important thing was to preserve features of scenic spots and heritage, a key factor of heritage tourism. Then with service facilities, sanitation facilities, and medical facilities, tourists' needs in comfort and emergency medical services could be satisfied, to create a service standard for the overall management. The achievement of this study helps the management to improve service quality after the railway re-opening and to facilitate future tourism management.
Numerical and experimental investigation on air distributor design of fluidized bed reactor of sawdust pyrolysis
Abstract An improved biomass conversion in a lab-scale fluidized bed reactor (FBR) is achieved by optimizing the air distributor orifice size and number. Two approaches for introducing air were numerically and experimentally examined. These included perforated plate and downward orifice sparger. 3 mm and 5 mm orifice diameters, and 7, 9 and 13 holes were simulated at flow velocities of 2, 4, 6, and 8 times the minimum fluidization velocity, Umf. The simulation results revealed that increasing the orifice number has a positive effect on gas holdup, particularly for the perforated plate, which showed a uniform distribution of bubbles. The sparger configuration produced larger bubbles sizes, which could lead to better recirculation of solid flux, while stagnant particle zones were observed at the lower section of both distributors. A pyrolysis unit is also inserted at the top of freeboard of the FBR. For perforated plate with 6Umf, the pyrolysis process achieved thermal and cold gas efficiencies of 82.91% and 52.03%, respectively, while combustible gases with 41.6%mol CO, 8.7%mol CH 4 and 2.17%mol HC, were obtained. For sparger pipe and 6U mf _sp, 35.33 ppm NOx and 111 ppm SO 2 were measured in flue gas from combustion process at bed region.