Seismotectonic, structural, volcanologic, and geomorphic study of New Zealand; indigenous forest assessment in New Zealand; mapping, land use, and environmental studies in New Zealand, volume 2

The author has identified the following significant results. Ship detection via LANDSAT MSS data was demonstrated. In addition, information on ship size, orientation, and movement was obtained. Band 7 was used for the initial detection followed by confirmation on other MSS bands. Under low turbidity, as experienced in open seas, the detection of ships 100 m long was verified and detection of ships down to 30 m length theorized. High turbidity and sea state inhibit ship detection by decreasing S/N ratios. The radiance effect from snow of local slope angles and orientation was also studied. Higher radiance values and even overloading in three bands were recorded for the sun-facing slope. Local hot spots from solar reflection appear at several locations along transect D-C in Six Mile Creek Basin during September 1976

Modelling the induced magnetic signature of naval vessels

In the construction of naval vessels stealth is an important design feature. With recent advances in electromagnetic sensor technology the war time threat to shipping posed by electromagnetically triggered mines is becoming more significant and consequently the need to understand, predict and reduce the electromagnetic signature of ships is growing. There are a number of components to the electromagnetic field surrounding a ship, with each component originating from different physical processes. The work presented in this study is concerned with the magnetic signature resulting from the magnetisation of the ferromagnetic material of the ship, under the influence of the earth's magnetic field. The detection threat arising from this induced magnetic signature has been known for many years, and consequently, warships are generally fitted with degaussing coils which aim to generate a masking field to counteract this signature. In this work computational models are developed to enable the induced magnetic signature and the effects of degaussing coils to be studied. The models are intended to provide a tool set, to aid the electromagnetic signature analyst in ensuring that pre-production designs of a vessel lie within specified induced magnetic signature targets. Techniques presented where also allow the rapid calculation of currents in degaussing coils. This is necessary because the induced magnetisation of a vessel changes with orientation. Three models are presented within this work. The first model represents a ship as a simple geometric shape, a prolate spheroidal shell, of a given relative permeability. Analytical expressions are derived which characterise the magnetic perturbation to a previously uniform magnetic field, the earth's magnetic field, when the spheroid is placed within its influence. These results provide a quantitative insight into the shielding of large internal magnetic sources by the hull. This model is intended for use in preliminary design studies. A second model is described which is based on the finite element method. This is a numerical model which has the capability of accurately reproducing the relatively complex geometry of a ship and of including the effects of degaussing coils. For these reasons this model is intended for detailed quantitative studies of the induced magnetic signature. A method is described to calculate the optimal set of degaussing coil currents required to minimise the induced magnetic signature. The induced signature without and with degaussing is presented. For the successful application of the finite element method the generation of a mesh is of extreme importance. In this work a mesh generation procedure is described which permits meshes to be generated around a collection of planar surfaces. The relatively complex geometry of a ship can be easily specified as a number of planar surfaces and from this, the finite element mesh can be automatically generated. The automatic mesh generation detailed in this work eliminates an otherwise labour intensive step in the analysis procedure. These techniques are sufficiently powerful to allow meaningful calculations for real ships to be performed on desk-top computers of modest power. An example is presented which highlights the application of this model to a hypothetical ship structure. The third model detailed is specifically designed to study the induced magnetic signature of mine countermeasures vessels. Here the induced magnetic signature is no longer dominated by the gross structure of the ship, which is constructed from non-magnetic materials, but arises from the combined effect of the individual items of machinery onboard the craft

Antimatter propulsion, status and prospects

The use of advanced propulsion techniques must be considered if the currently envisioned launch date of the manned Mars mission were delayed until 2020 or later. Within the next thirty years, technological advances may allow such methods as beaming power to the ship, inertial-confinement fusion, or mass-conversion of antiprotons to become feasible. A propulsion system with an ISP of around 5000 s would allow the currently envisioned mission module to fly to Mars in 3 months and would require about one million pounds to be assembled in Earth orbit. Of the possible methods to achieve this, the antiproton mass-conversion reaction offers the highest potential, the greatest problems, and the most fascination. Increasing the production rates of antiprotons is a high priority task at facilities around the world. The application of antiprotons to propulsion requires the coupling of the energy released in the mass-conversion reaction to thrust-producing mechanisms. Recent proposals entail using the antiprotons to produce inertial confinement fusion or to produce negative muons which can catalyze fusion. By increasing the energy released per antiproton, the effective cost, (dollars/joule) can be reduced. These proposals and other areas of research can be investigated now. These short term results will be important in assessing the long range feasibility of an antiproton powered engine

Oceanus.

v. 38, no.1 (1995

A marine geophysical investigation of the continental margin of east Greenland (63(^º)n to 69(^º) n)

During late July and August 1977, a marine geophysical investigation of the continental margin off East Greenland between latitudes 63(^º)N and 69.1(^º)N was undertaken by the University of Durham using the research vessel, R.R.S. Shackleton. Nearly 3500 km of continuously recorded bathymetric, magnetic and gravity data and approximately 2000 km of multi-channel seismic reflection data were recorded in a series of nearly parallel profiles perpendicular to the assumed strike of the continental margin. Disposable sonobuoy work was also carried out. The reduction, processing and interpretation of the geophysical data are described. In particular, the application of the maximum entropy method (MEM) of spectral estimation (using Burg's algorithm) to the problem of estimating the depth to buried magnetic sources is assessed. The principal geophysical results include: 1. The location of the ocean-continent boundary is inferred Fran seismic reflection data and the recognition of marine magnetic anomalies. Oceanic anomalies 22 through 24 are truncated by the continental margin. The marine anomaly sequence 13 through 21 is tentatively extrapolated northwards through the Denmark Straits and stops against the Denmark Straits fracture zone. 2. It is proposed that the Tertiary plateau basalts of the Blosseville coast do not terminate abruptly offshore but are down-faulted and continue eastwards, overlain by a prograded sequence of Tertiary sediments. 3. An interpretation of one processed, GDP stacked seismic section north of the Greenland-Iceland Ridge is presented. Several unconformities are recognised on the basis of seismic stratigraphic analysis. Two seismic horizons showing distinctive of flap against oceanic basement are tentatively dated at 30 Ma and 22 Ma respectively. No evidence is found for the presence of Mesozoic sediments offshore. 4. Gravity modelling indicates that the prograded wedge of Tertiary sediments observed north and south of the Greenland-Iceland Ridge is not isostatically compensated

Acoustic interference fields in the ocean

Two areas of underwater acoustics are investigated: ocean-bottom scattering and acoustic fields in geometrically dispersive sound channels. The purpose is to describe and provide an understanding of the physical mechanisms in these two areas by comparing analyzed results from ocean experiments with theoretical computations. Experiments using directive 19.5-kHz transducers illustrate temporal and spacial behavior of signals scattered from the ocean bottom. The signals fluctuate, as a function of acoustic geometry, in linear relation to source and receiver motion and to signal frequency. Spacial structure of the acoustic field depends on frequency and acoustic geometry and is independent of motion and bottom roughness. Data supporting these observations are included as well as data showing the effects of bottom type on the scattered returns, that is, the existence of subbottom returns in some data. Volume-scattering-strength profiles are also provided from data obtained in these experiments. Continuous-wave (CW) and impulsive sources covering frequencies 5 to 260 Hz were towed and deployed respectively over ranges up to 3000 km, with reception on fixed hydrophones. Analyses of measured propagation losses of these low-frequency acoustic signals in the dispersive channel provide insights into the nature of the propagation and the acoustic channel. Both the CW signals and the arrivals of the impulsive signals are analyzed in terms of transmission loss, convergence-zone structure, source-motion effects, interference structure, and channel characteristics. The systematic variation (internal tides) of the medium and its influence on the interference field are discussed. The state of modeling, both simple and complicated, is reviewed and compared with results of the ocean experiments. Relationships are provided between this work and the broader field of underwater acoustics. Suggested areas for future research are made

Report and preliminary results of RV METEOR Cruise M78/3. Sediment transport off Uruguay and Argentina: from the shelf to the deep sea ; 19.05.2009 – 06.07.2009, Montevideo (Uruguay) – Montevideo (Uruguay)

The waters off Uruguay and Northern Argentina offer the possibility to study sediment transport processes from ‘source-to-sink’ in a relatively small area. Quickly accumulated sediments are potentially unstable and might be transported downslope in canyons and/or on the open slope. Strong contour currents result in along-slope sediment transport. Within the scope of Meteor-Cruise M78/3 we investigated sediment transport and depositional patterns by means of hydroacoustic and seismic mapping as well as geological sampling with conventional coring tools and the new MARUM seafloor drill rig (MeBo). Geotechnical investigations were carried out with the aim to analyze the controlling parameters for the destabilization of the slope and the succeeding failure of a sediment body. Various types of sediment instabilities have been imaged in geophysical and core data, documenting particularly the continental slope offshore Uruguay to be locus of frequent submarine landslides. Apart from individual landslides, however, gravitational downslope sediment transport along the continental slope is restricted to the prominent Mar del Plata Canyon and smaller canyons identified in the bathymetric data. In contrast, many morphological features reveal that sediment transport is predominantly controlled by strong contour bottom currents. This suggests a significant impact of the western boundary currents on the overall architectural evolution of the margin. The investigations are related to projects of the DFG Research Center / Excellence Cluster 'The Ocean in the Earth System', University of Bremen, as well as the Excellence Cluster 'The Future Ocean', University of Kiel

Marine engineering training in Myanmar

The present system of maritime education and training for engineers in Myanmar has existed since 1963, It is very close to the old British system of maritime training. Marine engineers trained in this way have been found to be competent and qualified in their profession. Despite this satisfactory achievement, it is necessary to modify the existing training system to keep abreast with the changing global system and developing standards\u3c The purpose of this study is to highlight the maritime education and training system presently used in Myanmar and to propose some modifications needed to comply with international standards. This paper contains seven chapters. Four of them present the current situation in Myanmar: They cover the Shipping Industry, the implementation of International Conventions and the Training and Examination systems used for maritime personnel. In Chapter 4 a comparison is made between existing training syllabi and STCW 1976 minimum requirements. Chapter 6 deals with the Maritime Education and Training programs of several countries which have modern systems. Recommendations, which are my own views, are made in the last chapter. They come from knowledge gained during my two years of study at the World Maritime University. With the approval of the authorities concerned, this study paper could provide guidance in improving the Myanmar marine engineering training system

Manning and automation of naval surface combatants : a functional allocation approach using axiomatic design theory

Thesis (Nav.E.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2000.Includes bibliographical references (p. 431-432).The design of ships is an inherently complex process. This complexity is significantly increased when the particular ship being designed is a naval surface combatant. The ship design process is traditionally viewed as a highly coupled collection of interrelated physical attributes often determined in an ad hoc fashion. Therefore, lack of understanding and documenting the design progression frequently necessitates modification of a completely developed, functionally acceptable portion of the ship because of its undesirable effect on other functionally unrelated parameters. A methodology based on axiomatic design principles that strives to eliminate the currently accepted iterative nature of concept level ship design is proposed. Specifically, the hierarchical decomposition of a naval surface combatant based on functional requirements mapped into physical design parameters reveals physical couplings. Studying the design at each level of the hierarchy determines the logical order to fulfill each requirement such that these couplings do not adversely impact the design progression. By implementing this methodical approach, the ship design process follows a repeatable structured format in which functional relationships between physical parameters are mapped, documented, and controlled. Since functional design is the key to this methodology, it is extended to assist designers with assigning tasks between shipboard personnel and automated machines. With this proposed approach, functional allocation is not only possible, but also the overall ship effect of each manning and automation decision is readily determined. A case study demonstrating this point is presented.by John J. Szatkowski.S.M.Nav.E