Deep Submergence Research Articles

単組成ガス燃料吸入時におけるディーゼル機関の燃焼と性能

s Summary Among many nominated papers, five technical papers have been published in this volume. However, there are excellent papers in the unselected ones, some of them, hereafter, are summarized for readers reference. Research on Combustion of Marine Heavy Fuels (Differential Thermal Analysis and Droplet Burning) By Takashi Mineyana and Nobuyuki Awai An experimental research is performed to clarify the combustion characteristics of the present bunker fuels by the methods mentioned above subtitle. The sample fuels are several kinds of base oils taken out from the conventional and some recent refiner process, these mixture oils on trail and several bunker fuels in practical use. The main result are showed as fol1ows: (1) The thermal analysis makes possible to predict the original components of bunker fuels by comparing the burning profile with it of the base oil. (2) Two correlation formulas on droplet burning were obtained by the method of multple regression analysis. The ignition lag and the burning rate on droplet burring are able to be predicted by these formulas. (3) The sample fuels are able to be classified by the characteristic component on the diagram between the ignition lag and the burning rate. (4) On the same diagram, bunker fuels which were reported troubles happened in use, are distributed the characteristic range. The recent low grade bunker fuels have caused to increase troubles on combustion in the marine diesel engines. Troubles on combustion are able to be predicted by adapting the analysis result above mentioned to these low grade bunker fuels. ―― Reprinted from Journal of the MESJ, Vo1. 24. No.1 ――Deep Submergence Vehicle By Hideyuki Morihana, Nobuhiko Watanabe The features of the new Japanese two deep submergence vehicles are presented. Shinkai 6500, a manmed research submergence vehicle for Japan Marine Science and Technology Center (JAMSTEC), is being built by MHI Kobe shipyard. The vehicle can dive to 6500m deep and explore the s1opes of trenches around Japan. That is very important to the geophysical study of the deep ocean floors. The vehicle is small in size and light in weight and has advanced capability in research and observation system, comparing to the predecessor Shinkai 2000. MARCAS 2500, a remotely operated vehicle, was built by MHI Kobe shipyard and delivered to Kokusai Denshin Denwa. Co., Ltd. (KDD) in 1987. The vehicle can dive to 2500m deep and operate for the construction and maintenance of under water communication cables. ―― Reprinted from Journal of the MESJ. Vo1. 24. No.2 ―― (58) Bulletin of the M.E.S.J., Vol. 18, No.1

Wave forces on hemicylinders

Potential solutions describing the flow about two-dimensional marine structures on or near the ocean bottom are formulated, based on Airy's wave model. The solutions for a half-cylinder and semicircular shell are considered in detail and evaluated in the case of deep submergence. The formulation with and without flow underneath the structure is given and, in particular, the existence of a large difference between the two cases in the vertical forces is shown. The effect of introducing vorticity at the edges of the shell is investigated. Numerical results for hemicylinders resting on the bottom and slightly raised off the bottom are presented. The results obtained for the wave forces are compared with experimental results obtained for a slightly raised, open hemicylinder.

Hydrothermal activity on the Gorda Ridge

Were port our discovery of the first hydrothermal field on the northern Gorda Ridge located only 200 km off southern Oregon within the proclaimed U.S. Exclusive Economic Zone (Figure 1). The discovery was made with the U.S. Navy Deep Submergence Vehicle Sea Cliff and her support ship the DSVSS Laney Chouest on a dive series between September 15 and 30, 1988.The northern Gorda Ridge is characterized by an intermediate spreading rate (2.8 cm/yr half‐rate), although the high relief of the sediment‐free rift valley a n d distribution of volcanic rock types resemble the slow‐spreading Mid‐Atlantic Ridge more than other intermediate‐ to fast‐spreading centers in the Pacific. The hydrotheral field extends several hundred meters along the east wall at water depths between 2700 and 2800 m, about 300 m above the floor of the rift valley.

A Study on Propeller Cavitation Noise

Studies on reducing propeller noise from the supporting ship for a deep submergence research vehicle are described. The propeller investigated was a controllable pitch propeller (CPP). The studies included noise measurements on a full scale propeller; noise measurements on a model propeller in a cavitation tunnel; and a theoretical analysis of what CPP operating conditions might result in least noise. It was found that there are optimal combinations of propeller blade angle and propeller revolutions that do minimize noise. The model tests showed these phenomena to be strongly related to the occurrence of propeller cavitation.

The development of a deep submergence, airbacked transducer

The development of a deep submergence, airbacked transducer

Inelastic response of deeply submerged stiffened shells subjected to transient loads from explosions

The large deflection elastoplastic response of stiffened cylindrical shells subjected to transient loadings from explosions is considered. Because the cylinders are located at deep submergence, the effects of initial stress distributions due to hydrostatic pressure are included in the analysis. A large deflection elastoplastic shell theory is utilized in the analysis. This shell theory defines a yield surface at each cross section of the shell in terms of the moment and direct force components at the section. An associated flow rule is utilized to define the plastic‐strain rate. The EPSA (elastoplastic shell analysis) code is utilized in the analysis of the shell response to the dynamic loadings. Results obtained from the analysis have compared well with the results of experiments.

Evaluation of PbTiO3‐based piezoelectric ceramics for hydrophone applications

PbTiO3‐based ceramics recently developed by Toshiba scientists have interesting implications for conventional hydrophone design. They exhibit virtually no coupling in the 31‐mode while the 33‐mode is strongly coupled, yielding a high hydrostatic voltage coefficient (gh). The possible application of this material in hydrophones was investigated by comparing the theoretical performance of a PZT‐5H cylinder with capped ends to a PbTiO3 disk. Particular attention is paid to calculating the signal‐to‐noise performance because of the low permittivity of this material. It was found that this parameter is only slightly affected in the presence of a low‐noise preamplifier, but it will probably not be acceptable for measuring water noise levels. Sensitivity measurements obtained from a PbTiO3 disk suspended in a rubber boot filled with castor oil gave predictable results. The responses were flat to within ±2 dB up to the thickness resonance. It is indicated that the PbTiO3‐based hydrophone generally compares favorably with the conventional PZT designs. The PbTiO3‐based hydrophone offers the advantages of a superior wideband performance and a very simple construction. It should also be ideally suited to deep submergence applications.

Research on Fabrication Procedure of Spherical Pressure Hull Made from Titanium Alloy for Deep Submergence Research Vehicle (2 nd Report)

Following “Shinkai 2000”, as Japanese deep research project, a 6000 m class deep submergence research vehicle is under planning. For the research vehicle of this class, from the maneuverability and operationability, of utmost importance is the reduction of weight. As for a pressure hull, which houses crew members, the authors have carried out a series of research for the application of titanium alloy (Ti-6 Al-4 V ELI) considering the strength-weight ratio, and anti-corrosion capability against sea water. In the 1 st report, the authors have made a full scale model of the pressure hull of Ti-6 Al-4 V ELI for the 6000 m class submersible to establish the manufacturing procedure. In this report, by disassembling the model, the authors have investigated the material characteristics for the application of a deep submergence research vehicle. The research covered the fields of mechanical properties, fracture toughness, fatigue strength, stress corrosion cracking, hardness distribution, micro-structure, and residual stress. As a result, 6 A1-4 V titanium alloy was confirmed to be one of the most effective material for the pressure hull of a deep submergence research vehicle.

Forces and moment on a horizontal plate due to wave scattering

Wave reflection and transmission from a fixed horizontal plate have been widely studied but theoretical solutions are only available for certain limiting conditions. A general solution for this wave scattering problem is presented using the finite-element method, covering the whole range of relative depth ratio from shallow to deep water limits and submergence depth ratio from the water surface to the bed. Existing long-wave solutions for the surface plate and the submerged plate have been extended to obtain the hydrodynamic forces and overturning moment exerted on the plate. Results from the finite-element program compare well with these solutions. Variations of the reflection coefficient, wave forces and moment, with the plate width to wave length ratio, relative depth ratio and submergence depth ratio are discussed.

Effects of water depth on choice of spatially separated prey by Notonecta glauca L.

In laboratory experiments, the predator, Notonecta glauca L., was exposed to varying densities of surfacedwelling culicine mosquito larvae and the bottom-inhabiting isopod, Asellus aquaticus L., in either shallow or deep water at 20° C. At this temperature N. glauca spends most of the time at the water's surface, so, by changing water depth the accessibility of Asellus to the predator was manipulated relative to a consistent Culex presence.All N. glauca spent more time submerged in shallow (75 mm) than in deep (275 mm) water but submergence times were independent of exposure to different prey combinations. Mature females made more descents and remained submerged longer than males.All N. glauca captured more Asellus in shallow than in deep water but males and newly-moulted females captured Culex predominantly, in all treatments, regardless of water depth or prey availability. Mature females captured mostly Asellus in shallow water and Culex in deep water. When presented with small rather than large Asellus, mature females spent an equivalent amount of time submerged as in the large Asellus treatments and ate the same number of Asellus but more Culex.By foraging on Culex larvae, male and newly moulted female N. glauca maximise their rate of energy intake. In contrast, mature females may actively select Asellus to optimise something other than energy (e.g. specific nutrients). Alternatively their predation on Asellus may be simply a consequence of a high encounter rate with this prey type, reflecting habitat use determined by factors that do not concern prey capture directly.

Research on Fabrication Procedure of Spherical Pressure Hull Made from Titanium Alloy for Deep Submersible

As the new project of a deep submergence research vehicle following “SHINKAI 2000”, 6000 m vehicle is now under contemplation in Japan. One of the essential themes for a 6000 m vehicle is how to reduce the weight of the vehicle in order to achieve excellent maneuverability and operational efficiency. A pressure hull material with a high strength to density ratio is indispensable for this application.Some of the authors of this paper have been studying the material properties and fabrication procedure for both ultra-high strrength steel (10 Ni-8 Co Steel) and titanium alloy (6 Al4 VELI). As to 10 Ni-8 Co steel, the pressure hull fabrication procedure have already been established. As to titanium alloy, it was utilized for the small pressure vessels of SHINKAI 2000.In this paper, the authors have constructed the full-scale model of a titanium alloy (6 Al4 VELI) pressure hull, and established the fabrication procedure of the titanium alloy pressure hull.

New tender for Alvin

This month the Atlantis II will become the new tender ship for the Deep Submergence Research Vehicle (DSRV) Alvin. The Woods Hole Oceanographic Institution's 64‐m refitted ship replaces the 32‐m catamaran Lulu, which has been Alvin's tender and escort for 19 years. Originally constructed as a temporary support vessel from two surplus mine sweeping pontoons, Lulu cannot move quickly enough or traverse the large distances required to support priority research. In the next three months, two workshops will review letters of intent to use the new ship/submersible team.

Early Cretaceous Drowning and Recovery of a Carbonate Continental Margin, Eastern Arabia: ABSTRACT

The eastern margin of the vast Mesozoic carbonate platform which underlies much of Arabia is exposed in the mountains of Oman and the United Arab Emirates. Outer platform and margin facies occur as autochthonous windows in the Oman Mountains and as allochthonous terrane in the Musandam Mountains to the north. These strata are in turn surrounded by westward-thrust nappes of contemporaneous deep-water strata and oceanic lithosphere. Inundation or drowning of the platform occurred in earliest Cretaceous time and is reflected by Jurassic reef limestones overlain directly by Lower Cretaceous pelagic carbonates. In Oman the outer platform strata are buried by over 250 m (820 ft) of these radiolarian lime mudstones. The abrupt upward transition in middle Cretaceous time to ooid grainstones and then muddy fossiliferous limestones interbedded with rudist biostromes documents buildup to sea level and eastward progradation of first high-energy facies and then lower energy interior facies. In the Musandam Mountains to the north, however, where the Jurassic margin proper was drowned, deep submergence was accompanied by flexure and the Lower Cretaceous limestones are slope deposits as indicated by numerous turbidites, debris flows, and slope unconformities. These strata are also transitional upward into shallow water facies so that by Middle Cretaceous time the high-energy facies were once more at the shelf edge. These events, which are reflected along the length of this extensive continental margin, occurred during a time of apparant eustatic sea level rise. End_of_Article - Last_Page 549------------

Research on Heat Treatment Procedure of Deep Submergence Research Vehicle's Pressure Hull using Full Scale Model

In order to make oceanographic research activity more extensive, deep submergence research vehicle diving to the depth of 6000 m is being required in these days.A pressure hull of the vehicle requires the material of high strength/weight ratio and good ability of manufacturing. In this point, 10 Ni-8 Co steel with the yield strength of 120 kgf/ mm2 can be said the most promising candidate for the pressure hull at present.To give 10 Ni-8 Co steel enough strength and toughness, heat treatment (double-quenching and tempering) is indispensable.From this respect, the authors conducted experimentally heat-treatment of 10 Ni-8 Co spherical shell using a full scale model.The report presents the description on the heat-treatment procedure, including the experimental results, which are necessary to establish the whole manufacturing procedure of a pressure hull being combined with the welding procedure already established.

Discussion of sea water sound-speed determinations

Available data on the speed of sound in sea water are examined to arrive at a basis for deriving simple equations suitable for most ocean areas. Extant laboratory data are compared. In situ measurements aboard deep submergence vehicles are presented, and convergence zone ranges discussed. Del Grosso and Mader [J. Acoust. Soc. Am. 52, 961–974 (1972)] equations appear superior, after numerous intercomparisons, to serve as a foundation for generating simple sound-speed equations.

Broadband free-flooding magnetostrictive scroll transducer

A free-flooding, deep submergence cylindrical magnetostrictive transducer ving a plurality of identical, coaxial, ring-shaped scrolls, surrounded by a toroidal coil, the scrolls being vibration isolated from each other and from the coil, and having ring resonance frequency sufficiently close to cavity resonance frequency for broadband operation, i.e. approximately one octave at the 6 db down points.

Study on Electron Beam Welding Procedure for Pressure Hull of Deep Submergence Research Vehicle

The pressure hull for deep submersible has to cope with the trade-off subject of load carrying capacity and minimum weight at the same time. For this reason, spherical shell has been normally adopted for the pressure hull. Besides this, high yield strength materials and high-precision manufacturing are indispensable for it.The authors have already confirmed that GTA welding is effective for the pressure hull of 6, 000 m class of 10 Ni-8 Co steel. However recently, electron beam welding, which has the possibility to reduce welding distortion in comparison with GTA welding, has come to withstand this objective.The authors, in this paper, have estabilished the effectiveness of EBW for the pressure hull of 6, 000 m class of 10 Ni-8 Co steel.

深海潜水調査船耐圧かく用高じん性高張力鋼の溶接に関する研究 ＩＩ

For pressure hulls of Deep Submergence Vehicle (DSV) operating in seas of 2000 m depth, the most important point is the maximum load carrying capacity under the minimum weight. For this reason, spherical shell made of high strength steel is adopted for pressure hulls.The authors investigated heat treatment conditions and GTAW welding conditions of HT 100 steel (5Ni-Cr-Mo-V QT steel with a yield strength of 90 kgf/mm2) in report. 1.In this report, a procedure of decision of welding conditions for high strength steel like HT 100 is proposed. And using this procedure the full scale model of spherical pressure hull was fabricated. After completion of this model, the weld metal was proved to satisfy the requirements of the destructive and non-destructive tests.

深海潜水調査船耐圧殻用高靱性高張力鋼の溶接に関する研究(第1報)

For pressure hulls of Deep Submergence Vehicle (DSV) operating in seas of 2000 m depth, the most important point is the maximum load carrying capacity under the minimum weight. For this reason, spherical shell made of high strength steel is adopted for pressure hulls. Spherical shape is an optimum shape for external hydrostatic pressure loading and the most suitable steel for this shape is HT100 steel (5 Ni-Cr-Mo-V quenched and tempered steel with a yield strength of 90 kgf/mm2).However, in the application of HT100 steel to spherical pressure hulls, there are some difficult problems from the view point of fabrication; that is, (1) quenching and tempering procedure of hemisphere. (2) welding procedure of two hemispheres and penetrate joints. Then heat treatment conditions and TIG welding conditions were investigated.The results obtained are summarized as follows:(1) The quenching cooling rate of HT100 is needed over 3°C/sec for satisfying required property.(2) The mean quenching cooling rates of hemisphere (thickness: 60 mm, diameter 2320 mm) are 5.7-6.2°C/sec. Then it is possible to fabricate hemisphere by hot forming method.(3) It is necessary to preheat over 100°C for preventing cold crack.(4) The cooling rate (at 540°C) of weld metal is required over 20.5°C/sec for guarantee 90 kgf/mm2 proof stress.

Design and Fabrication of Pressure Hull of Deep Submergence Research Vehicle

Design and Fabrication of Pressure Hull of Deep Submergence Research Vehicle