4,389 research outputs found
Development of high performance composite bend-twist coupled blades for a horizontal axis tidal turbine
Development of a design methodology for a composite, bend-twist coupled, tidal turbine blade has been undertaken. Numerical modelling was used to predict the response of the main structural member for the adaptive blade. An experimental method for validation is described. The analysis indicates a non-linear blade twist response
Use of cryogenic buoyancy systems for controlled removal of heavy objects from the seabed
The concept design of a lightweight cryogenic marine heavy lift buoyancy system has been investigated. The approach makes use of a novel cryogenic system for provision of buoyancy within the ocean environment. The objective is to be able to lift or lower large displacement objects under full remote control. The nature of subsea lifting and lowering operations requires a high degree of precise control for operational safety, reasons and to preserve the structural integrity of the load. The lift operation occurs in two phases: Development of lift to overcome seabed suction, and then rapid reduction of buoyancy to maintain a controlled ascent. Descent involves controlled release of the buoyancy. The proposed buoyancy system consists of a buoyancy chamber and an integral cryogenic gas generation unit. The application of an on-board gas generation unit allows the removal of the engineering challenges associated with use of compressors and the concomitant complex manifold of connecting umbilical pipe work. It provides for a fully remote system completely eliminating all risk associated with extensive physical surface to subsea connection throughout the entire lift operation.
The opening stages of the project work include the development of a system that will operate efficiently and effectively to a depth of 350m. An initial general arrangement for the buoyancy system has been developed. A number of these systems involve considerable design and development, these include: structural design of the buoyancy chamber, mechanical systems to control and connection to the lift device, the cryogenic system itself and overall process control systems. As part of the design process for such an arrangement, numerical simulation of the complete system has been undertaken in order to develop mechanical, cryogenic and process control systems efficiently and effectively. This system simulation has been developed using Matlab Simulink. This paper considers the overall design concept and associated system development issues. These are illustrated through use of the time accurate simulation of alternative design configurations that confirm the viability of the concept. A main conclusion is that minimisation of the dry weight of the system is critical to cost-effective operation of the project
Measuring intermodalism at European port cities: An employment-based study
Paper presented at Challenges and Trends in Shipping: Markets, Investments and Policies, International Association of Maritime Economists (IAME) Conference, Athens, Greece, 4-7 July 2007. Journal website: http://www.inderscience.com/browse/index.php?journalID=194International audienceThis paper proposes a continental approach to the combination of transport functions within European port cities. It reviews a number of concepts and theories, regarding with transport chain integration and urban centrality in the case of ports. While many studies on intermodalism face a lack of quantifiable data, this research proposes an original methodology based on employment. The data is collected for 76 port cities, 9,000 companies and more than one million employees in all transport modes. By bringing together employment figures and basic urban and port indicators, results of the factor analysis show the different functional and spatial trends. There is a recurrent opposition between freight and passenger-oriented specializations among port cities, which are also influenced by the European core-periphery spatial pattern. In addition, a benchmarking of port cities in terms of their intermodal potentials is provided as a means for policy implicationsCet article propose une étude de la combinaison des fonctions de transport au sein des villes portuaires en Europe. Le recours aux données sur l'emploi, pour 76 villes et à partir de 8000 établissements, permettent de contourner l'absence d'informations détaillées sur les trafics. L'analyse montre notamment l'influence de l'organisation centre-périphérie européenne sur les spécialisations modales des ville
Frontline soldiers of globalisation: port-city evolution and regional competition
International audienceThis paper is an empirical attempt to measure the relative concentration of port-city functions in the context of globalisation. It reviews a number of urban and port issues regarding their complementary and contradictory aspects about the evolution of port cities. The main purpose is to verify how port function is more or less important to local economies, compared to other functions, through a temporal and global approach. Based on a matrix of port-city centrality and intermediacy, the main indicators available for international comparison are urban population and container throughput. An analysis of 653 places between 1970 and 2005 period is provided, using the relative concentration index proposed by Vallega. The appropriate geographical scale to measure the relative evolution of port cities at a global level is discussed. Results tend to question previous models which consider functional and spatial separation between the city and its port as an ineluctable process. The port-city evolution appears to be gradual rather than linear or chaotic, and in many cases largely influenced by regional factors and local strategie
Open Inflation With Scalar-tensor Gravity
The open inflation model recently proposed by Hawking and Turok is
investigated in scalar-tensor gravity context. If the dilaton-like field has no
potential, the instanton of our model is singular but has a finite action. The
Gibbons-Hawking surface term vanishes and hence, can not be used to make
nonzero. To obtain a successful open inflation one should introduce
other matter fields or a potential for the dilaton-like fields.Comment: 10 pages.1 figure. Some comments and references are improved. to be
published in PR
Waterfront redevelopment and territorial integration in Le Havre (France) and Southampton (UK)
This paper propose policy directions for waterfront redevelopment in Busan, Korea's largest port city. A comparative approach is proposed, based on the relation between waterfront area and the overall structure of the port city in European cities. A spatial model of the European port city is discussed and applied to the Busan case, in order to highlight the major stakes
Local strength and global weakness: A maritime network perspective on South Korea as Northeast Asia's logistics hub
Paper presented at the International Conference on Shipping, Port, and Logistics Management, 3rd Asian Logistics Round Table (ALRT), Inha University, Incheon, April 2-3 (2009)Port development in South Korea has taken advantage of the country's remarkable situation and economic growth during the past decades. However, the governmental âtwo-hub port strategy' is currently at stake because of fierce competition from Chinese ports. Based on a global database on the daily movements of containerships, this paper proposes an evaluation of the position of South Korean ports within Northeast Asian liner networks in 1996 and 2006. Main results show that although Chinese ports have increased substantially their position in the maritime system, South Korean ports (notably Busan) still keep a dominant hub function in this region. However, a multi-scalar analysis shows the limited global radiance of South Korean ports. Implications for policy and further research are addresse
Network Position and Throughput Performance of Seaports
ISBN 978 90 5487 858 2The determinants of throughput volume at a given set of ports have rarely been approached from a network perspective. This paper proposes a set of novel indicators describing the relative situation of seaports in the worldwide maritime network of container shipping in 2006, which are distinguished among five categories: circulation (calls, vessels, and operators), foreland (distance to other ports and distribution of connections), connectivity itself (number of connections to other ports), centrality (betweenness and eccentricity), and neighbourhood (strength and clustering indices). Main results help to classify ports according to their location and function in the network, while they stress which parameters most influence throughput volumes. Although centrality indicators highly correlate with throughput, the latter seems to be influenced mostly by the geographic parameter of the maximum distance link to another port
The Influence of Experimental Conditions on the Results of In Vitro Tests for Antifungal Action (With Special Reference to the Effect of Maintaining Solubility of the Agents)11From the New York Skin&Cancer Unit, New York Post-Graduate Medical School and Hospital, Columbia University, and Wallace Laboratories, Inc., New Brunswick, New Jersey.
Smart technology for healthcare: Exploring the antecedents of adoption intention of healthcare wearable technology
© The Author(s), 2019. Technological advancement and personalized health information has led to an increase in people using and responding to wearable technology in the last decade. These changes are often perceived to be beneficial, providing greater information and insights about health for users, organizations and healthcare and government. However, to date, understanding the antecedents of its adoption is limited. Seeking to address this gap, this cross-sectional study examined what factors influence usersâ adoption intention of healthcare wearable technology. We used self-administrated online survey to explore adoption intentions of healthcare wearable devices in 171 adults residing in Hong Kong. We analyzed the data by Partial least squares â structural equation modelling (PLS-SEM). The results reveal that perceived convenience and perceived irreplaceability are key predictors of perceived useful ness, which in turn strengthens usersâ adoption intention. Additionally, the results also reveal that health belief is one of the key predictors of adoption intention. This paper contributes to the extant literature by providing understanding of how to strengthen usersâ intention to adopt healthcare wearable technology. This includes the strengthening of perceived convenience and perceived irreplaceability to enhance the perceived usefulness, incorporating the extensive communication in the area of healthcare messages, which is useful in strengthening consumersâ adoption intention in healthcare wearable technology
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