Showing papers on "Water environment published in 1984"

Rescue support member

Abstract: The invention relates to an improved inflatable and buoyant rescue-support member for use and co-operation with a JORDAN stretcher (lifting) frame, for carrying or transporting a patient from a water environment.

Marine seismic acoustic source

Abstract: An acoustic source for seismic exploration in a water environment consists of an elongated cylindrical housing, closed at both ends and containing laterally disposed exhaust ports. A reciprocable piston and piston follower are slidably mounted within the housing for reciprocal movement. Pressurized hydraulic fluid is admitted to one end of the housing, forcing the piston follower to contact the piston and move towards the opposite end of the housing. A pneumatic latching device retains the piston proximate opposite cylinder end and pressurizes the system. The hydraulic fluid is drained, allowing the piston follower to return to its original position. During the return trip of the piston follower, water is ingested through the exhaust ports to the chamber between the piston and the piston follower. A triggering mechanism then releases the piston that is accelerated towards the piston follower, to impulsively expel the contained water. The ejected water creates a momentary cavity in the surrounding water. The cavity implodes, generating the acoustic signal.

Underwater detection of hydrocarbons

Abstract: Method and apparatus for detecting the presence of hydrocarbons and other substance that fluoresces or absorbs light within a body of water which utilizes a controlled submersible vehicle scanning at or near the water bottom. The method utilizes a selected frequency light source as carried by the submersible to scan the water bottom, and the returned light energy, either at the wavelength of oil fluorescing in water or the source frequency backscatter, is detected and processed for the water bottom as well as a water region that is a selected distance above the water floor. Alternative forms of apparatus are disclosed for carrying out the functions of both oil fluorescence detection, and for obtaining differential absorption readings as to light source backscatter energy that is created by the ambient water and other factors in the water environment such as marine life, turbidity, etc.

Bolt material excellent in stress, corrosion, cracking resistance

Abstract: PURPOSE:To enhance the stress corrosion cracking resistance of a bolt under a high temp. water environment, by preparing the bolt used under a gap and stress acting condition in the high temp. water environment from an Ni-alloy. CONSTITUTION:The bolt used under a gap and stress acting condition in a high temp. water environment within a boiling water type or pressure water type nuclear reactor is fabricated from an Ni-alloy containing, on a wt. basis, 15- 25% Cr, 1-8% Mo, 0.4-2% Al, 0.7-3% Ti, 0.7-4.5% Nb, less than 40% Fe and more than 40% Ni. In this case, contained Al, Ti and Nb are contained in the range shown by the relation of 3.5%<=2Al+Ti+0.5Nb<=5.5%. This Ni- alloy contains one or more of a gamma'-phase and a gamma''-phase in the austenite phase base of the structure thereof and suitable for a bolt material showing excellent stress corrosion cracking resistance used in a high temp. water environment.

Improving Dynamic Positioning Performance in the Deepwater, High-Current, Rough Water Environment

Abstract: Several modifications were made to the Discoverer Seven Seas dynamic positioning system in preparation for drilling in the Atlantic Baltimore Canyon, an area noted for severe winter storms, two knot currents and water depths to 7,500 feet. The modifications included the addition of long-baseline acoustic position measurement, active current and cross force compensations and a Kalman filter with optimum state vector estimation based upon simultaneous input of all available position data. The system's improved accuracy, stability and reliability of position measurement, higher permitted gain, and active forces compensation have produced highly stable and accurate position control, particularly when making quick turns to put the vessel's bow into a storm. An added benefit is a significant reduction in fuel consumption. The baseline transponder deployment, grid calibration and recovery are all accomplished without adding rig time to the drilling operation.

Evolution de la communaute bacterienne heterotrophe de l'eau de mer lors d'une experience d'aquaculture de crevettes peneides en systemes clos

Abstract: The quantitative and qualitative evolution of the heterotrophic bacterial community of sea water was studied throughout an experimental rearing of Penaeus japonicus in closed systems. Cluster analysis was realised on 417 strains coming from water sampled at different moments of the experiment. This strains collection include 40 strains coming from a mussel used fordiel and 40 strains coming from the digestive tract of one prawn alter six month rearing. Quantitative and qualitative studies have both shown a similar evolution of heterotrophic microflora whatever the initial animal load was. The dendrogram obtained led to describe characteristics of the various populations constituying the heterotrophic bacterial community of the water environment considering the increasing number of bacteria brought in the system by breeding activities