1,721,554 research outputs found
Basic Naval Architecture: Ship Stability
No full textThis textbook provides readers with an understanding of the basics of ship stability as it has been enacted in international law. The assessment of ship stability has evolved considerably since the first SOLAS convention after the sinking of the HMS Titanic, and this book enables readers to familiarise themselves with the most up-to-date modern day methodology, as well as looking ahead to the effects on ship design over the next fifty years. The author not only explains the methodology of probabilistic ship damage as required by the International Maritime Organisation (IMO), but also details the new requirements to assess certain sizes and classes of ships to the seven second-generation ship stability requirements. Many textbooks that are currently used by undergraduates focus on the geometric-centric deterministic approach to the assessment of ship stability, whereas this book also includes material on the classes of ships that are now required to have probabilistic ship damage assessment, as has only recently been agreed by the IMO
Arqueología marítima en la UNAM: transdisciplina y colaboración internacional en el proyecto arqueología marítima de la Guerra de Intervención (1846-1848)
No full textTransactions of the Royal Institution of Naval Architects: International Journal of Maritime Engineering
No full textMysticism, esotericism and translation
No full textA study of how our understanding of translation can be deepened by examining the ways that translation has interacted with writings from mystical and esoteric tradition
A new design concept for a fully actuated unmanned surface vehicle
No full textTo be effective in their roles, unmanned surface vehicles (USVs) need to be capable of performing a variety of distinct manoeuvres, including trajectory tracking and station keeping. Conventional fully-actuated actuator configuration permits an accurate station-keeping ability at the expense of the hydrodynamic efficiency which may be a critical factor for long-range high-speed operation. This paper presents a new USV design that is optimised for both manoeuvring styles. This attributes to the reconfigurable design that transforms between the under-actuated mode which suits high-speed operation and the fully-actuated mode which is effective for station keeping. In addition, the trimaran design offers wide deck space and great roll stability which is beneficial for a wide range of potential applications. The possible control system is also suggested for utilising multiple actuators that are equipped on the vehicle in the most energy efficient way. Regarding the simulation studies, the propose design has shown to enhance the station-keeping performance even when the USV is subjected to the sway disturbance.<br/
Hydrodynamics of high-performance marine vessels, vols 1 and 2
No full textHydrodynamics of high-performance marine vessels, vols 1 and 2Doctors Lawrence J . Hydrodynamics of high-performance marine vessels, vols 1 and 2. Charleston, SC: CreateSpace Independent Publishing Platform, 2015. ISBN: 1514839431; ISBN: 978151489430.This Magnum Opus runs to two volumes over a total of 836 pages, so it covers a huge area of research spanning from papers written in 1874, by Froude, to the date of publication of the book. This work is an essential guide to anyone new to the area of high-performance craft as well as died in the wool researchers. The list of references, chapter 19, contains 76 pages of papers! To be able to track these down for a new doctoral student would be difficult, but Professor Doctors have now achieved that. It is noted that the use of American spelling persists throughout, no doubt reflecting the award of an ONR grant, which supported the production of the work. It must be said that the quality of the pictures is outstanding and that applies to the figures, which are all produced in a uniform clear and precise manner. The attention to detail is first class; there are nearly 50 pages of contents, lists of symbols, tables, and graphical representations. Rather give a general overview of this large work I have summarised the each chapter
Numerical investigation of an influence of square cylinder crossovers on twin bare hulls in close proximity
No full textThis paper investigates the influence of two crossovers on twin bare spheroids in close proximity. Firstly, to examine the impact of the crossovers to the flow behaviour and overall drag coefficient of spheroids. Secondly, to compare the drag coefficient for various speeds. The CFD RANS-SST with a commercial code ANSYS CFX simulation is performed for the fully submerged twin spheroids with transverse separation (S/D) of 1.02; where S is the distance between centreline to centreline and D is the maximum diameter of a spheroid. The Reynolds Numbers used are 2 × 106, 3 × 106, and 4 × 106. The results show that each spheroids experience an additional 20% drag which is dominated by crossovers. The drag coefficient of small volume crossovers between spheroids is 10 times higher than the drag of each spheroids, consequently, the total drag of system is increased by 11 times compares to twin bare spheroids system. Increasing speed results in the drag reduction. At the Reynolds Number 2 × 106 shows the highest drag coefficient of twin hulls for both cases (with or without crossovers). The result suggests the use of twin bare hulls without crossovers in the fleet, an application; for example, a fleet of small autonomous underwater vehicles
Modelling using neural networks and dynamic position control for unmanned underwater vehicles
Full text linkUnderwater construction, maintenance, and mapping all use autonomous underwater vehicles (AUVs) for path planning, path following, and target tracking operations. However, dynamic position management and localization of AUVs are critical issues. Correct localization and dynamic position management to prevent drifts can be used to acquire information on energy efficiency, another crucial topic. In this paper, the AUV’s dynamic modelling using experimental data and position control is studied. The experiments were implemented on Delphin2 scaled AUV model belonging to the Engineering and Environment Faculty, University of Southampton, UK. Hover and flight style motions according to different speeds of Delphin2 were implemented in the test tank. Nonlinear coupled mathematical models were studied using Shallow Neural Networks (SNNs). The models are formed into depth-pitch and heading motion black-box models using the SNNs algorithm. PID control of heading motions and depth-pitch motions simulation studies were applied to the SNNs model
The ecology and conservation of rare arable weed species and communities
No full textSIGLEAvailable from British Library Document Supply Centre- DSC:DX97142 / BLDSC - British Library Document Supply CentreGBUnited Kingdo
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