Initially, a methodical remark must be made namely that some quantifications in this report are based on partial data only and therefore must be considered estimates. The data…
Abstract
Initially, a methodical remark must be made namely that some quantifications in this report are based on partial data only and therefore must be considered estimates. The data deficiencies in respect of tourism's measurement are generally known. That is particularly true of both availibility and comparability of tourism statistics recorded and compiled in some developing countries.
Pour tenter de faire une synthèse claire du travail intensif, ce rapport se divisera en trois parties:
Vincent Planque, Monique Dacharry and René Baretje
Comme pour les années précédentes, on voudra bien considérer que la participation au Congrès de l'AIEST des Experts Français s'inscrit dans la perspective d'une réflexion en…
Abstract
Comme pour les années précédentes, on voudra bien considérer que la participation au Congrès de l'AIEST des Experts Français s'inscrit dans la perspective d'une réflexion en commun à propos du thème choisi.
A successful hotelman once said that there are only three rules for profitable hotel operation: location, location, location. Although we may regard this as a somewhat over…
Abstract
A successful hotelman once said that there are only three rules for profitable hotel operation: location, location, location. Although we may regard this as a somewhat over simplified prescription for success in the hotel business, it draws our attention to the prirnary importance of location in a business with a high investment in fixed capital, which cannot transport its product to the market. An hotel is an outstanding example of location in relation to the market; once an hotel is built, it cannot change its location or follow its customers, as the principal product it sells—hotel accommodation—has to be bought and consumed at the place of production.
La doctrine du tourisme et son enseignement. La demande des services du tourisme s'étant accrue, la satisfaction en est devenue très compliquée aussi bien du point de vue…
Abstract
La doctrine du tourisme et son enseignement. La demande des services du tourisme s'étant accrue, la satisfaction en est devenue très compliquée aussi bien du point de vue d'organisation que du point de vue économique.
Simon J. Davies and Paul Robert van der Heijden
The chapter provides an overview of the book and addresses the rationale for the selection of cases reflecting teaching and research in major areas of SDG14. For example, the…
Abstract
The chapter provides an overview of the book and addresses the rationale for the selection of cases reflecting teaching and research in major areas of SDG14. For example, the impact of increasing global sea temperature, ocean acidification, and pollution on aquatic life and biosciences. Fisheries and aquaculture for seafood and marine ingredients and marine protected areas (MPAs) that favour the assemblage of fish, crustaceans, alga, coral, and mussels to enhance and stimulate biodiversity. New products derived from marine biotechnology are viewed to conserve and sustainably use the seas and oceans whilst promoting wealth creation and employment. Marine parks allow scientists to better study the marine environment and explore sustainable balances between tourism, work, and recreation in harmony with the Life Below Water – SDG14 mandate. Finally, the aspects of governance and roles of stakeholders and societal involvement are advocated in achieving the safe and effective use of marine resources. Throughout, the role of higher education in providing educated scientists and multidisciplinary specialists for future generations to come is highlighted.
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Keywords
Feng-Xia He, Li Dai, Qisen Chen, Yu Liu and Zhong Luo
Since robot’s structural stiffness is usually less than 1 N/µm, mode coupling chatter occurs frequently during robotic milling process, and chatter frequency is close to the…
Abstract
Purpose
Since robot’s structural stiffness is usually less than 1 N/µm, mode coupling chatter occurs frequently during robotic milling process, and chatter frequency is close to the natural frequency of the robot itself. Chatter not only affects the surface quality but also damages the robot and reduces the positioning accuracy. Therefore, it is necessary to predict chatter in robotic machining process.
Design/methodology/approach
A three-dimensional dynamic model for robot’s spatial milling plane is established, and a corresponding stability criterion is obtained. First, the cutting force in milling plane is transformed into the coordinate system of the robot principal stiffness direction based on homogeneous transformation matrix. Then the three-dimensional stability criterion under milling process can be obtained by using system stability analysis. Furthermore, the circle diagram of mode coupling chatter stability is drawn. Each feeding direction’s stability under the two processing forms, referred as spindle vertical milling and spindle horizontal milling, is analyzed.
Findings
The experimental results verify that the three-dimensional stability criterion can avoid chatter by selecting machining feed direction in stable area.
Originality/value
This paper established a three-dimensional dynamic model in robot’s spatial milling plane and proposed a three-dimensional stability criterion according to the Routh criterion. The work is also expected to be an efficient tool in the development of robotic milling technology.
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A. Hamidi‐Noori and Andrew Templer
The lagging growth in productivity of many western industries has at last captured public attention. Many observers attribute the problem, at least in part, to management…
Abstract
The lagging growth in productivity of many western industries has at last captured public attention. Many observers attribute the problem, at least in part, to management reluctance to invest in the capital equipment necessary to automate production systems at fully competitive levels. Not all such investments, however, result in equivalent benefits. This article presents the findings of a recent survey on robotisation plans, and based on these findings, a conceptual model is developed which attempts to set out the different factors which should be considered when introducing industrial robots. In addition, some attention is given to the related literature on the reasons for automation in general, and robotisation in particular.
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S. Sarath and P. Sam Paul
A new cutting tool is always well-defined and sharp at the onset of the metal cutting process and gradually losses these properties as the machining process advances. Similarly…
Abstract
Purpose
A new cutting tool is always well-defined and sharp at the onset of the metal cutting process and gradually losses these properties as the machining process advances. Similarly, at the beginning of the machining process, amplitude of tool vibrations is considerably low and it increases gradually and peaks at the end of the service period of the cutting tool while machining. It is significant to provide a corresponding real-time varying damping to control this chatter, which directly influences accuracy and quality of productivity. This paper aims to review the literature related to the application of smart fluid to control vibration in metal cutting and also focused on the challenges involved in the implementation of active control system during machining process.
Design/methodology/approach
Smart dampers, which are used as semi-active and active dampers in metal cutting, were reviewed and the research studies carried out in the field of the magnetorheological (MR) damper were concentrated. In smart materials, MR fluids possess some disadvantages because of their sedimentation of iron particles, leakage and slow response time. To overcome these drawbacks, new MR materials such as MR foam, MR elastomers, MR gels and MR plastomers have been recommended and suggested. This review intents to throw light into available literature which exclusively deals with controlling chatter in metal cutting with the help of MR damping methods.
Findings
Using an MR damper popularly known for its semi-active damping characteristics is very adaptable and flexible in controlling chatter by providing damping to real-time amplitudes of tool vibration. In the past, many researchers have attempted to implement MR damper in metal cutting to control vibration and were successful. Various methods with the help of MR fluid are illustrated.
Research limitations/implications
A new cutting tool is always well-defined and sharp at the onset of metal cutting process and gradually losses these properties as the machining process advances. Similarly, at the beginning of the machining process, amplitude of tool vibrations is considerably low and it increases gradually and peaks at the end of service period of cutting tool while machining. Application of MR damper along with the working methodology in metal cutting is presented, challenges met are analyzed and a scope for development is reviewed.
Practical implications
This study provides corresponding real-time varying damping to control tool vibration which directly influences accuracy and quality of productivity. Using an MR damper popularly known for its semi-active damping characteristics is very adaptable and flexible in controlling chatter by providing damping to real-time amplitudes of tool vibration.
Social implications
This study attempts to implement smart damper in metal cutting to control vibrations.
Originality/value
It is significant to provide corresponding real-time varying damping to control tool vibration which directly influences accuracy and quality of productivity.