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Date 6-8 Sept. 1978

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Displaying Results 1 - 25 of 141
  • [Front cover and table of contents]

    Publication Year: 1978 , Page(s): 0
    Save to Project icon | PDF file iconPDF (1277 KB)  
    Freely Available from IEEE
  • Evolution of Buoy Electronics and Telemetry

    Publication Year: 1978 , Page(s): 1 - 9
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (931 KB)  

    In November 1967, the National Data Buoy Development Project was established by the United States Coast Guard. The primary purpose of this organization was to verify and standardize the design and performance of environmental data buoys by establishing an extensive network of sophisticated buoys capable of delivering a wide variety of data, supplemented by smaller buoys of simpler design for special user needs. In 1972, user needs were reevaluated and the program was redirected to be more responsive to these needs. Consequently, the goal of establishing a network of multipurpose buoys was discarded. In January 1973, the project was designated the NOAA Data Buoy Office (NDBO) and was sanctioned by the National Weather Service as a prime user of data. A major NDBO mission is to develop the technology required to gather and report environmental data from marine areas on an accurate, reliable, and synoptic basis. The provisioning of this data would enable improved weather forecasting, including warnings of impending catastrophies. The essential ingredient in meeting the objective involves the deployment of a number of buoys moored in various gulfs and oceans. This paper will review the evolution of sensors, electronics, and communication hardware applicable to NDBO programs. We will also present an overview of our major programs so that buoy technology can be better appreciated in terms of the NDBO missions. View full abstract»

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  • New Mooring Design for a Telemetering Offshore Oceanographic Buoy

    Publication Year: 1978 , Page(s): 10 - 17
    Cited by:  Papers (1)  |  Patents (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (756 KB)  

    A new buoy system has been developed for the U. S. Bureau of Land Management to gather, process, and telemeter oceanographic data from the Georges Bank area of the New England outer continental shelf. The buoy system incorporates a taut-moored subsurface sphere 6 m below mean water connected to an anchor by an instrument string using an oil-filled synthetic rubber hose as the strength member. Three main sensor packages on the string measure current speed components, magnetic reference heading, conductivity, and temperature. The bottom sensor package is connected to the anchor by an acoustic release. The anchor consists of a 4500 kg free-flooding storage battery which supplies power to the system for up to four months. The air-sea interface is pierced with a 12.2 m fiberglass mast attached to the subsurface sphere. Mounted on top of the mast is the antenna for transmitting data via the GOES satellite telemetry system. Operational systems were deployed in the fall of 1977. View full abstract»

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  • A Successful Meteorological Drifting Buoy

    Publication Year: 1978 , Page(s): 18 - 21
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (221 KB)  

    The development of a successful meteorological drifting buoy has been undertaken. Buoys which measure sea surface temperature and barometric pressure have been built, tested and successfully deployed. A description of this buoy is given, with details of the sub-systems. View full abstract»

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  • An Analog Wave Spectrum Analyzer System for Operational Buoys

    Publication Year: 1978 , Page(s): 22 - 30
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (574 KB)  

    In 1975, the NOAA Data Buoy Office (NDBO) began deploying a data acquisition system identified as the Prototype Environmental Buoy (PEB) payload on their operational buoys. This payload could report environmental data from remote ocean areas to shore through radio telemetry, but could only receive data inputs in the form of analog voltages. Digital data could not be accommodated. NDBO subsequently developed a wave measurement system specially designed to interface with the PEB payload. This Wave Spectrum Analyzer (WSA) system consisted of 12 parallel analog filters, each of which produced an output voltage related to the spectral density in the vicinity of the center frequency of the filter. Duplicates of this WSA system have since been deployed on a number of operational deep-ocean buoys and have produced wave data routinely. View full abstract»

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  • A GOES--Reporting Waverider Buoy

    Publication Year: 1978 , Page(s): 31 - 36
    Cited by:  Papers (8)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (525 KB)  

    A NEW INSTRUMENT FOR MEASURING AND REPORTING OCEAN WIND WAVES HAS BEEN CONSTRUCTED, TESTED AT SEA, AND PUT TO USE IN FIELD STUDIES OF THE TRANSFER FUNCTION OF OPERATIONAL WAVE MEASURING SYSTEMS ON LARGE DATA BUOYS. THE PROTOTYPE WRANSAC WAS INTEGRATED FROM AN EXISTING MICRO-COMPUTER, A SATELLITE RADIO TRANSMITTER, AND A WAVERIDER. TWENTY MINUTES OF WAVE DATA ARE PROCESSED AND PRODUCE HOURLY REPORTS OF MEAN WAVE HEIGHT, MAXIMUM CREST, MINIMUM TROUGH, AND 150 LAGS OF THE AUTOCORRELATION FUNCTION. THE INTERNATIONAL NETWORK OF SYNCHRONOUS METEOROLOGICAL SATELLITES PROVIDES A RELAY CAPABILITY PERMITTING WRANSAC TO BE USED ALMOST ANYWHERE IN THE WORLD OCEAN. THE DEVELOPMENT OF THE WRANSAC PROTOTYPE IS DESCRIBED AND DATA FROM THE DECEMBER 1977 DEPLOYMENT IS PRESENTED. View full abstract»

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  • Wave Direction Measurement by a Single Wave Follower Buoy

    Publication Year: 1978 , Page(s): 37 - 41
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (379 KB)  

    This paper describes a system for measuring the direction of ocean wave propagation, as well as wave height and period. The system employs a conventional wave follower buoy, modified so as to provide compass, pitch and roll signals in addition to the vertical component of buoy acceleration. The modifications are indicated in the paper, and the buoy was tested in two sea state conditions in Narragansett Bay. The pitch, roll, compass, and heave acceleration signals were all processed on the computer in the laboratory to provide a variety of results. One test condition was ideal in that the wind and wave conditions were changing steadily throughout the data recording process. The second test was exactly opposite, with small waves and a consistent wind direction. The results presented in the paper include the wave height power spectral density, a polar tilt histogram for the buoy motion, and a family of polar plots of the average tilt angle in each 5\deg sector of azimuth of the buoy pitch/roll. View full abstract»

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  • A Digital Survey Fathometer® Providing a Chart Display and a Digital Output

    Publication Year: 1978 , Page(s): 42 - 47
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (423 KB)  

    The Digital Survey Fathometer®(DSF- 600) is a portable, dual frequency recording depth sounder with a permanent chart display, digital output, and features automatic phase changing of the chart display. Operating at frequencies of 40kHz and 200kHz (frequency switch selected), the DSF-600 provides high resolution, quality bathymetric profiles in water depths to 310 fathoms. By interconnecting it with position finding equipment and a suitable digital tape recorder or data logger, depth and position data is generated in permanent digital form for precision bathymetric survey operations. The DSF-600 system is offered with several options, allowing the user to choose the combination that best meets his surveying needs. View full abstract»

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  • A Deterministic and Random Error Model for a Multibeam Hydrographic Sonar System

    Publication Year: 1978 , Page(s): 48 - 53
    Cited by:  Papers (4)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (442 KB)  

    The expanding and increasing affluent world population has brought about a growing need for commodities and energy on a global scale. Two major marine activities affected by this are shipping and mining. The shipping industry, because of its up to 30 meter draft superships, and the mining industry (particularly the hydrocarbon sector), both require timely and accurate bathymetric charts for safe and economical operation. To meet these needs the Bathymetric Swath Survey System (BS3) is being developed. The BS3is a 21 beam mapping sonar designed to accurately and efficiently portray the seabed directly beneath and to the port and starboard side of an underway hydrographic ship. This paper examines the effects of four major inherent error sources on system accuracy. These sources are uncompensated ship roll, sound velocity errors, pulse stretching and noise. View full abstract»

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  • Portable Acoustic Tracking Systems (PATS)

    Publication Year: 1978 , Page(s): 54 - 59
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (434 KB)  

    A portable acoustic tracking system has been developed for the Navy to track underwater construction teams in water depths to 300 ft. The tracking system can be deployed and operated by the divers and is intended for use in remote areas and for nearshore survey, maintenance, and construction work. A self-calibrating system provides a geographically justified track for up to eight divers. Diver position coordinates are computed from acoustic measurements at periodic intervals and displayed for control purposes. The positions are also recorded for future reference. View full abstract»

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  • Swept Carrier Acoustic Underwater Communications

    Publication Year: 1978 , Page(s): 60 - 65
    Cited by:  Papers (3)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (418 KB)  

    This paper describes a novel idea of reducing multipath interference in underwater acoustic communication systems. The proposed idea is based on the observation that the time separation between direct and multipath waveforms can be utilized to suppress the multipath interference. A proposed system employs a carrier with instanteous frequency swept periodically in time over a broad frequency range. This frequency range is much larger than the bandwidth occupied by a message signal. On the other hand the reciprocal of sweeping rate is much smaller compared to the message bandwidth. The carrier is modulated by a message resulting in a time varying instantaneous narrow-band spectrum of the transmitted signal. The received signal is demodulated by a band-pass tracking receiver and suppression of the out-of-band multipath spectrum is accomplished. A simple model for the multipath channel has been proposed and related to the system operation and performance. Some results and conclusions from tests performed on the prototype are presented. View full abstract»

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  • Small Submersible Acoustic Communications System Design

    Publication Year: 1978 , Page(s): 66 - 71
    Cited by:  Papers (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (445 KB)  

    A design is presented for a system providing highly reliable command and control acoustic communications between a mother ship and a number of small, fast submersibles. The small submersibles may be employed for underwater mining, exploration, bottom mapping, or military surveillance. Modulation and coding design is presented; the techniques discussed provide multiple protection against multipath and fading, high reliability, acceptable transmitted signal total time duration, simplicity, and economy. The required decision point signal-to-noise ratio (SNR) for Rayleigh fading conditions is derived for the modulation and coding design. Particular attention is paid in the receive signal processing to the initial doppler and message doppler variation problems inherent in a scenario with mobile end points. A Figure-of-Merit calculation is provided for typical geometrical and environmental parameters. It is shown for a realistic source level that the required SNR can be achieved at long range with extreme end point motion. View full abstract»

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  • Frequency Shift Arrival Time Determination of Acoustic Signals

    Publication Year: 1978 , Page(s): 72 - 75
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (210 KB)  

    In the demodulation of underwater acoustic signals, timing determination is usually based on the leading edge of a pulse, and is therefore subject to errors that are functions of pulse rise time and signal level. This paper describes a system using a phase-locked loop demodulator to determine the time of arrival of a frequency-shifted pulse. In this system, timing is shown to be essentially independent of signal strength, and timing jitter is shown to be low. View full abstract»

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  • Shipboard Evaluation of Drag Coefficients for the Marine Regime

    Publication Year: 1978 , Page(s): 76 - 81
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (332 KB)  

    A considerable amount of overwater dissipation and wind profile data obtained from shipboard measurements were interpreted relative to the representation of the drag coefficient. Drag coefficients were interpreted relative to wind speed, wave and hydrostatic stability influence. It was noted that at all wind speeds and particularly at low wind speeds, drag coefficient values are larger when large waves are present. Likewise, it was noted that in unstable conditions drag coefficient values increase as neutral conditions are approached. View full abstract»

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  • The Mechanical Properties of Chitosan Membranes

    Publication Year: 1978 , Page(s): 82 - 86
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (277 KB)  

    The mechanical properties of chitosan membranes have been investigated as a function of several processing variables. Chitosan, the deacetylated derivative of chitin (N-acetyl-D-glucosamine), was processed from blue crab shells from Virginia. Various chitosans, which had been deacetylated under different conditions, were dissolved in weak acetic acid and then cast into clear, flexible membranes about 50 \mu m thick. The stress-elongation curves exhibited a fairly constant elastic modulus, a yield point, and a high tensile strength (avg. 135 MPa). The mechanical properties were not greatly affected by the deacetylation procedures investigated here, although a small decrease in yield strength and an increase in elongation were observed at the highest temperature used ( 100\deg C). View full abstract»

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  • Sediment as a Cause of MACROCYSIS Gametophyte Non-Survival

    Publication Year: 1978 , Page(s): 87 - 91
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (431 KB)  

    Survival of Macrocystis spp. gametophytes is a function of sediment depth on the surface to which they attach. Relative survival varies as an exponential function of calculated mean depth in all cases. If spores attach to a surface prior to sediment settlement, no survival is noted after four days at depths above 500 microns. If spore inoculation occurs after settlement, no survival is noted for calculated mean depths above 40 microns. Microscopic examination of silt dispersal patterns showed that below 40 micron depths the percentage of non-occluded surface was also an inverse exponential function of mean sediment depth. We infer that motile zoospores cannot pass through even the finest silt particles. Comparatively better survival is noted with attachment prior to deposition. View full abstract»

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  • Navy Research on Marine Borers and the Laboratory Culturing of Limnorians

    Publication Year: 1978 , Page(s): 92 - 98
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (699 KB)  

    The Naval Research Laboratory's investigation of the protection of wood in marine service which began with an in depth study of creosote, is now concentrating on a study of the active antiborer constituents of naturally bioresistant woods. This work is now focussing on woods which are resistant to limnorians, marine crustacean isopods, because most current protective measures are inadequate against these pests. In order to study the effect of the natural wood extractives on the physiology of these marine borers under controlled conditions, a laboratory culture of Limnoria tripunctata has been established using a closed recirculating aquarium system. The usual invertebrate closed aquarium culture techniques have been modified to fit our needs. This includes the redesign of the biological filter bed, and its location outside each aquarium. A full description of our closed recirculating aquarium system and the procedures for its maintenance are given. View full abstract»

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  • The Motility of the Cells and the Extracellular Matrix of Labyrinthula -- A Colonial Organism Found on Zostera Marina

    Publication Year: 1978 , Page(s): 99 - 104
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (498 KB)  

    Labyrinthula is a saprophytic colonial marine protist found on Zostera marina. It consists of cells which move only within an elastic matrix thought to be synthesized and secreted by the cells themselves. Although they have no visible means of locomotion, that is, no cilia, flagella or podia, the cells exhibit movements at velocities up to 200 \mu /min. The extracellular matrix also exhibits motility. We have found, with the help of time lapse cinemicropraphy, lamellipodia-like extracellular processes which exhibit rapid translocation and appear to form the extracellular corridors within which the cells move. Indirect antibody staining shows antimyosin specific rails extending through the extracellular corridors and branching into the lamellipodia-like processes. The rails appear to correspond to regions of birefringence observed with polarized light. Our observations have led us to construct a model which attempts to explain Labyrinthula motility. View full abstract»

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  • A Non-Acoustic Long Distance Underwater Communications System

    Publication Year: 1978 , Page(s): 105 - 108
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (331 KB)  

    An underwater communications system is described which utilizes Technology Development Corporation's (TDC) Hydrocom coupled to a Radio Retransmission Buoy. Hydrocom is nonacoustic, utilizing instead an electric current field which is not adversely affected by thermoclines, reverberation, or interferometer effects. It can be operated in noisy and confined environments where acoustic systems are severely degraded and even when objects, such as reefs or man-made structures, lie between the communicators. The Radio Retransmission Buoy enables telephone clarity communications to exist between divers or a submerged vehicle and a ship several miles distant. Suitable radio patch or satellite relay will extend the communications link to any place on Earth, enabling real-time laboratory overview of distant onsite underwater inspection or data gathering. View full abstract»

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  • Lift Line Dynamics: A Technique Tailored for the User

    Publication Year: 1978 , Page(s): 109 - 114
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (315 KB)  

    A technique is proposed as an aid to the marine salvage master at sea and the ocean engineer. The aid may be used to find line size, factors of safety, maximum operating conditions, salvage object parameters and other useful information relating to the lifting or lowering of heavy objects at sea. A computer program based on Arthur D. Little, Inc. equations for maximum dynamic line force is used to generate a number of parametric curves for a specific ship lift point and line type which are then collapsed into one simple equation--the key formula--for dynamic factor of safety. This is combined with the easily obtained static factor of safety, and the results displayed on a set of homographs and charts. The paper explains the need for such a scheme, what the basic equations mean, their limitations, and how the charts and homographs are used. View full abstract»

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  • External Work of Breathing of Demand-Air Underwater Breathing Apparatus

    Publication Year: 1978 , Page(s): 115 - 121
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (502 KB)  

    Underwater breathing apparatus can be effectively evaluated by measuring the external work of breathing. This paper reviews the existing and the proposed standards for demand-air breathing apparatus and recommends improvements to the Bentley-Reimers criterion. An automated method of collecting data on the external work of breathing is also described along with test results of various demand-air breathing apparatus. The test and evaluation data in this paper support the proposed, modified Bentley-Reimers criterion. View full abstract»

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  • Underwater Repair of Nuclear Reactors

    Publication Year: 1978 , Page(s): 122 - 124
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (203 KB)  

    An innovative approach to maintenance and repair inside reactor vessels without dewatering has been accomplished by the utilization of underwater technicians. The presence of water provides shielding to the workers thereby reducing both the radiation dosage and the dose rate and permits much longer stay time in the repair area. This provides several distinct benefits: (1) the number of people exposed to radiation during a repair operation is reduced by an order of magnitude or more; (2) the overall duration of the repair operation is usually shortened drastically; (3) quality standards are more easy to maintain; and (4) the individual radiation dosage is reduced to unprecedented levels for repair operations. Present experience with underwater technicians indicates clearly that virtually all kinds of Jobs can be accomplished under water. This includes determination of the problem, repair, and quality assurance check up which are all done with greater safety because of the shielding effect of the coolant. View full abstract»

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  • Underwater Stud Welding

    Publication Year: 1978 , Page(s): 125 - 129
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (367 KB)  

    Stud welding is a simple process which requires no skill of the operator. Experiments were conducted to determine whether underwater stud welding could be made. Most experiments were made with mild-steel studs 3/4 inch in diameter. Base plates used were mild steel and HY-80 steel, 1/2 and 1 inch (6.4 and 25.4 mm) thick. It was found that stud welding could be made successfully under water. In the mechanical and metallurgical examinations, including tensile tests, bend tests, examinations of macro-structures, and micro-hardness tests, underwater welded specimens exhibited properties comparable to those of welds made in air. An effort is being made to develop an integrated stud welding unit which can be used for various applications in underwater fabrication and repair. View full abstract»

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  • Development of a Design Baseline for Remotely Controlled Underwater Work Systems

    Publication Year: 1978 , Page(s): 130 - 136
    Cited by:  Papers (3)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (586 KB)  

    The Work Systems Package (WSP), following two years of at-sea testing and evaluation, has completed an extensive laboratory time-motion analysis. This analysis, designed to simulate remote operation, provided a controlled evaluation of the system. Instrumentation was installed to provide time-motion and power consumption data on system components. The work tasks were divided into numerous subtasks and behavior motions which would be representative of the WSP's diverse capabilities. A computer analysis was performed on the data to provide a quantitative description of the WSP, its capabilities and the parameters effecting them. Thus, the effect of system modifications on mission time and power requirements can be easily simulated to assist the designer in system optimization. The operational evaluation of the WSP has, for the first time, provided a quantitative data base on which to base future underwater work system designs. View full abstract»

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  • Coastal Demographic Changes in the United States, 1950-1974

    Publication Year: 1978 , Page(s): 137 - 142
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (497 KB)  

    The present paper compares the demographic developments which have characterized the coastal zone in conterminous United States. The population changes in the coastal counties are analyzed for the two census periods 1950-1960 and 1960-1970, and population estimates made in 1974. The coastal counties are grouped into three classes: coastal urban, non coastal urban, which are part of coastal SMSAs and coastal rural. Three objectives are sought. The first describes the demographic changes which have taken place nationally during the past 24 years. The second objective analyzes the demographic differences in the three types of settlements discussed above. The final objective compares regional, urban/exurban differences in the demography within the coastal zone. The findings of these are discussed in light of the urban/ suburban migration and competing uses for the nation's shoreline. View full abstract»

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