bluuebunny/crossref_metadata_2025_split huggingface dataset:
The "stump" A New Dimension In Dredging
Authors: Batchelder George W. 
Published: October 2008

ABSTRACT
Hydraulic dredging equipments has changed little since Liddy, Von Schmidt and others started pumping dredged spoil about one hundred years ago. The basic elements of the hydraulic dredge are simply a barge or ship's hull, a dredge pump, power plants, maneuvering spuds and lines or engine propulsion, suction line (cutterhead) and ladder, and a discharge line. In spite of various refinements and innovations, hydraulic dredges are about the same as they were when the Panama Canal was built.
Approximately one hundred hydraulic dredges are manufactured each year. Their sizes vary from the small six-inch portables to the 36"- 42" superdredges. Modern dredges have more compact power plants, more efficiently designed pumping systems, swell compensating equipment and space-age electronic equipment for controls and navigation - but this is not enough. Although both the venerable old dredges and the modern dredges have tremendous capacity and are the most efficient earth-moving equipment in the world, they are not capable of meeting the great bulk of today's dredging requirements. Today's requirements include working in the pen sea to cut, clear, and deepen channels and harbors to depths of eighty feet or more. There is a recognized need for dredges to work offshore in ocean mining projects, in land reclamation, and on beach nourishment projects. Planners and engineers have designed offshore nuclear plants, airports, artificial islands, and deep-water ports, taking for granted that the dredging industry was keeping abreast of the times and their requirements and that costs would be nominal. The truth is that there are not enough dredges capable of doing this type of work, and the price is not nominal. It is too expensive. These facts will no doubt be brought out in the National Dredge Study now being completed for Congress by the Arthur D. Little Company.
In the past dredge owners have been able to modify and make innovations to their existing fleet, incorporating the best available technology, in order to tackle various types of projects, most of which were in safe, sheltered waters. A dredge owner therefore has not only a large initial investment in the dredge, but the additional cost of upkeep and renovation. In his own best interest he must operate, maintain, and modify that dredge as long as he can keep it operational. However, many of these dredges are becoming really obsolete, and their owners cannot compete with operators of modern specialized equipment.
Both modern and specialized dredges have profit and performance advantages over the old dredges, which have consequently remained idle. Inflated costs and high interest rates make it too costly to upgrade many of the old dredges to competitive levels. The technology in dredge design that is evolving allows the dredge longer wearing time on replaceable parts and easier and faster servicing. This allows a dredge to work continuously for a greater percentage of the time and to use smaller crews, thus reducing project costs and increasing profits and competition.
Field Testing and Analysis of Laterally Loaded Piles om Stiff Clay
Authors: Reese Lymon C. , Cox William R. , Koop Francis D. 
Published: October 2008

Abstract
Two nominally 24-in. diameter piles, instrumented for measuring bending moments, were driven into stiff clay and subjected to lateral loading. A nominally 6-in. diameter pile was also instrumented for measuring bending moments. It was driven at the same site, loaded, pulled, redriven, and reloaded. Short-term static and cyclic loading was employed on both 24-in. diameter and 6-in. diameter piles. The water table was maintained a few inches above the ground surface during the testing program. The results of the tests were analyzed to obtain families of curves showing soil resistance p as a function of pile deflection y. Based on the experimental p-y curves and on theory for the behavior of soil, procedures for predicting p-y curves for stiff clay were developed. The procedures were used and predictions of pile behavior at the site were made. The predictions compared favorably with actual behavior.

Foreword
The research described in this paper was sponsored by Amoco Production Company, Chevron Oil Field Research, Exxon Production Research Company, Mobil Oil Corporation, and Shell Development Company. Shell Development Company was the operator of the project.

Location of Test Site
The field studies on which this paper is based were made at a location five miles to the northeast of Austin, Texas adjacent to US Highway 290. The surface soils in this area consist of stiff, preconsolidated clays of marine origins. These clays are referred to as the Taylor group and studies showed that unconfined compressive strengths of 2 to 10 tons/ sq ft were not uncommon in zones near the surface. These clays have a secondary structure, such as fissures, joints or slickensides, that was desirable because of the wide occurrence of this type of soil in nature. The secondary structure was expected to result in a less favorable behavior of the clay; therefore, a possibly critical soil condition could be investigated.

Preparation of Test Site
On December 15, 1966, a pit 45 ft wide by 50 ft long by 3 ft deep was excavated at the test site. A plan of the test area is shown in Fig. 1 with the locations of all soil borings and test piles. After the excavations was completed the pit was flooded with water to saturate the near surface clays and to simulate conditions that would exist in clays on the ocean floor. This initial inundation was done some five months before the installation of the first test piles and some six months before lateral loading of test piles. In April 1967, two soil borings, borings 5 and 6, were made to investigate the influence of some four months of ponding on the water content of the clay. These borings indicated an increase in water content with an accompanying decrease in shear strength for clays in the first few feet below the pit bottom. After borings 5 and 6, the pit was lowered an additional 2-1/2 ft. This additional excavation was done on April 21, 1967 and the pit was again inundated.
A 4000-Foot Riser
Authors: Heuze Louis A. 
Published: October 2008

I. ABSTRACT
TOTAL-Compagnie Francaise des Petroles (C.F.P.) has developed, in association with Institut Francais du Petrole (I.F.P.) and ELF-Aquitaine, a dynamic and some static calculation programs for studying the behavior of part, or the totality, of a drilling riser.
This paper:–gives the conclusions of the theoretical studies about the relative influence of every parameter necessary for full determination of a riser,–gives some qualitative test results about different equipment proposed by manufacturers and liable to solve one of the most important problems that are–lastly, presents three systems that have not yet been realized and that could represent solutions for some problems examined in this study.

II. INTRODUCTION
Let it immediately be pointed out that the value 4,000 feet in the title only refers to the magnitude of the water depth now aimed at, not only by TOTAL, but also by all the major oil companies.
At the present time, many wells have been drilled over a water depth between 500 and 1,000 feet, the present record is held by SHELL at 2,000 feet, and about twenty drill ships or semi-submersibles have been ordered and should be equipped for depths between 2,000 and 4,000 feet.
This paper focuses on the risers for this latter category of drilling supports.

III. STATEMENT OF THE OBJECTIVE OF THE STUDY
It is understandable that the riser is one of the most important problems to be solved for deep sea drilling, and that the solution, if any, is to satisfy every condition of security, on pain of seeing the whole project fall into jeopardy.
That is why all the French companies joined together to spend several tens of thousands of dollars for creating very sophisticated static and dynamic calculation programs, for testing equipment such as buoyancy materials or riser connectors, and for developing new technology where existing techniques could not be extended.

IV. MEANS AND CONCLUSIONS OF THE THEORETICAL STUDY OF THE RISER

Dynamic Calculation Program
This program is bi-dimensional and calculates, statically or dynamically, the forces exerted and the stresses inside the riser, whether connected to the well head or disconnected.
Appendix A describes:–the external actions that are considered by the program,–the simulation of the connections at the top and at the bottom of the riser,–the hypotheses and the principle of the calculation.
The riser is defined as the assembly of several stumps of which it is necessary to specify:–the length of each one,–the O.D. and thickness of the resistant section, that is, the section considered for calculating the stresses,–the mass per meter of length, the hydrodynamic diameter D that is considered for calculating the drag forces,–the diameter D considered for calculating the buoyancy,–the modulus of elasticity.
Inertially-Aided Dynamic Positioning
Authors: Buechler David L. , Hanna Jonn. T. 
Published: October 2008

ABSTRACT
Integration of a commercial inertial navigation unit into a dynamic positioning control loop for offshore drilling rigs will provide improved operation and a self-contained backup in the event of signal loss from the primary acoustic or taut wire systems. Tests have demonstrated an average position error buildup of less than two feet per minute for up to one hour of pure inertial operation.

INTRODUCTION
The accuracy and reliability of the dynamic positioning system for deep water drilling rigs are strongly dependent upon the sensors in the control loop which measure the rig position and velocity. The prime reference for position control of the rig is an acoustic beacon, mounted near the well head, whose signals are picked up by receivers under the rig. This reference is usually augmented by taut wire angle sensors which are also tied to anchors on the ocean floor. Other more remote position references, such as Loran C or navigation satellites, are unreliable and less accurate, and therefore not normally considered for primary reference control. While the riser itself is a potential reference, its dynamic motion in deep water needs to be better understood.
As the drilling rigs begin to operate in depths of 2, 000 to 6,000 feet, the ocean bottom acoustic and taut wire references become less reliable because of transmission noise and the increased possibility of their complete loss. There is a strong desire by the operators of the dynamically positioned rigs to have a 'sky hook' available to provide a temporary reference should these signals be completely lost, and to provide a smoothing medium to suppress their high frequency measurement noise. An inertially stabilized platform can provide such a reference when integrated properly with other position references.
An inertial reference unit and digital computer together form a dead reckoning navigation system. The velocity is determined through the integration of accelerometer outputs; another integration determines the system position. The constants of integration, which are the initial velocity and position, must be supplied to the system. In addition, the platform alignment with respect to the earth must be known by the computer in order to establish a reference coordinate system in which to make the measurements and perform the computations.
On board the drilling rig, the inertial reference unit (IRU) platform can be leveled to the local gravity vector to provide a vertical reference to the acoustic pickups.
Wave Characteristics As Revealed By Aerial Photography
Authors: McClenan C.M. , Harris D. Lee 
Published: October 2008

Abstract
Aerial photos of coastal regions generally show complex but well organized wave patterns. It appears that the concept of a "random sea" may be the result of making most wave observations from too Iowan elevation, and thus with a too-limited field of view. The photos reveal several commonly overlooked wave phenomena.

Introduction
- The most common sources of information about waves are:
- visual observations from shipboard or shore,
- mathematical analyses, and
- instrument records that provide a time history of the water surface elevation or of the pressure due to waves.
These sources do not provide the dependable information about wave direction needed for the solution of many engineering problems. Records from an array of instruments and mathematical analyses, combined with assumptions about the two-dimensional wave pattern may provide a unique solution to the problem of determining the direction of wave propagation. The validity of the solution, however, depends on the .validity of the assumptions.
Aerial photography can provide the clearest available information about the validity of many common assumptions used in the analyses of wave records, whether for determining wave directions or for the solution of other engineering problems.

IMPORTANCE OF ELEVATION IN WAVE PHOTOGRAPHY
A few examples of wave photos will show their value as a source of information about waves. Fig. 1, from Harris,5 is an enlargement of a portion of a photo taken with a hand-held camera aboard Apollo 7, at an elevation of about 100 miles.
The diagonal lines are waves, generated by a hurricane about 1,400 miles distant from this scene. The waves appear to be monochromatic and long crested as assumed in the most elementary wave theory.
Fig. 2 was obtained from an airplane at an elevation of 65,000 ft (19,800 m) near Huntington Beach, Calif. Two distinct wave trains may be identified. In deep water these intercept with an angle near 90 degrees. In shallow water both wave trains show refraction and the crests are more nearly parallel.
From these two examples one might suspect that photos of the sea tend to display more regularity as the elevation of the camera, and thereby the field of view, is increased. The next two photos have been selected to illustrate this point. These photos were obtained near an oil well platform a few miles offshore from the Corpus Christi Water Exchange Pass, Tex. Fig. 3 was obtained from an elevation of 500 ft. The term "confused sea" appears to provide an accurate description. Fig. 4, which includes the area of Fig. 3, was obtained a few minutes later from an elevation of 5,000ft. This tendency for photographs of the sea to display more regularity of the surface waves as the elevation of the camera is increased, displayed by these two photographs, is also noted by Kinsman.6
Until about 1950, most reports of actual wave conditions were expressed in terms of significant wave height, period and direction as though the real sea could be adequately represented as a uniform monochromatic wave field similar to Fig. 1.
Wave Induced Oscillations of Tension-Leg Single Buoy Mooring System
Authors: Kirk C.L. , Jain R.K. 
Published: October 2008

ABSTRACT
This paper presents analysis of the response of a tension-leg single buoy mooring system subjected to regular wave excitation. The buoy consists of a cylinder anchored to the sea bed by parallel chains. The nonlinear equations of swaying and pitching motion are derived from Morison's formula with the addition of the dynamic pressure force acting on the base of the buoy. A numerical solution is achieved by assuming that the swaying motion influences the pitching motion but not vice versa Time histories of the response of three sizes of buoy are given and the conditions under which pitching motion will lead to slackening of the anchor chains is determined.

INTRODUCTION
A tension leg single buoy mooring system (S.B.M.) is essentially a cylindrical buoy anchored to the sea bed by pre-tensioned chains or cables. A tanker moored to the buoy is able to transfer. oil from a submarine pipeline through a rubber underwater hose to the buoy's swivelling cargo manifold and finally through a floating surface hose to the tanker. The swivelling arrangement on the buoy permits the tanker to swing freely through 360 degrees thus preventing any twisting of the underbuoy hose.
The design of an S.B.M. for operation in severe sea conditions like those of the North Sea requires reliable estimates to be made of the maximum expected dynamic response of the buoy, the dynamic loads imposed on the anchor chains and their points of attachment with the buoy, and the stretching of the underbuoy hose. In addition to extreme wave loading cases the response of the buoy to smaller waves is of interest from the point of view of 1atigue of the anchor-buoy linkages and wear of eye connections as mentioned in Ref.1. Swaying motion is an important parameter in tanker mooring operations and in landing helicopters on manned buoys. Sway will also be the primary cause of stretching of the underbuoy hose whereas pitch may give rise to slackening of the anchor chains. In tensioned chains which slacken and then snap tight, dynamic loads may occur which are considerably greater than the maximum static loads. Goeller and Laura, Ref. 2, in tests on stranded steel cables found that forces greater than nine times the static load were developed in the snap condition.
The aim of this paper is to describe the mathematical model that was developed to study the response of an S.B.M. in sway and pitch to linear waves in deep water. Since a tanker does not remain moored to an S.B.M. in rough sea, the forces induced by tanker motion are not considered. The nonlinear equations of motion are derived by using D'Alembert's principle. It is assumed in the analysis that pitching motion does not affect swaying motion, but not vice-versa. This partial uncoupling facilitates the numerical solution. The justification for this procedure is based on the fact that the primary motion of the buoy is sway, with the secondary pitching motion occurring at a higher frequency.
A Submersible Diving System for Science
Authors: Fike John W. , Dolan Robert B. 
Published: October 2008

ABSTRACT
As a result of the inventive ambitions of Edwin A. Link, Trustee and Vice President of Harbor Branch Foundation, Inc., a unique observation submersible with diver lock-in/lock-out capabilities has been developed. A second generation submersible christened the JOHNSON-SEA-LINK II in January 1976, it exhibits the characteristics of versatility, simplicity, safety, fast turn around between missions, ease of operation and comparatively low cost.
Framework, pressure hull, mechanical, electrical and pneumatic controls, as well as life support equipment, are divided into separate modular sub-systems. In all cases the removal of a module or a system for routine maintenance or repair is accomplished in minutes. Overlapping, cross-connecting or unitizing between systems has been avoided. The use of off the shelf components, when possible, and standardization of hardware helps to satisfy the five requisites. Extensive human engineering has provided a top to bottom, left to right logic to all control functions.
The objective of the submersible JOHNSON-SEA-LINK II is to provide the scientific staff of Harbor Branch Foundation, Inc. with a sophisticated oceanographic tool that will be operational 365 days a year. This paper discusses how that objective was met.

INTRODUCTION
The drive to preserve and improve our environment and the need to deal with the pollution problems created by prolific industrial technology are two of the major issues facing the United States today. Deterioration of the environment either real or within the realm of real possibility has generated concern and demand by a public that is growing increasingly aware of the threats. If it is accepted that the rivers and streams of the nation act, in part, as sinks, then it stands to reason the oceans are the ultimate sink, the final receptacle for the nation's unrecovered, untreated and unwanted waste and byproducts. What effect has it had, what are the capacities of these great bodies of water? Consider the importance attached to these questions by the Biological Oceanographers concerned with the oceanic eco-system. To measure the quantity of life and catalog the variety of life in the water column and on the ocean floor, there must be a base line with which to compare it. Since the eco-system can be rapidly altered by the introduction of an unnatural substance, sampling and observation must be by highly mobile means. The problems associated with the procurement of accurate in situ biological and physiological sub-surface data is well documented. It follows then that an important aspect of the requirements of the oceanographer and scientist is a means of rapid in situ investigation. Often the use of manned submersibles can offer many advantages for a quick and relatively inexpensive method of obtaining the much needed information.
A High Load Moderate Speed Deployment System for a Deep Ocean Bottom Working Vessel
Authors: Person Abraham 
Published: October 2008

ABSTRACT
A working vessel for deploying and retrieving heavy loads in deep oceans is now operational. This is accomplished by lengthening or shortening a load-connected pipe string and by two pair of yoked, hydraulically powered cylinders that alternately support and transport the pipe string and load. This paper describes the deployment and retrieval system.
The system, known as the Heavy Lift System, contains four 19-foot stroke hydraulic cylinders and their power units and 8500-ton capacity connecting yokes for each pair of cylinders. Ancillary hydraulic equipment includes a pipe string engaging latch on each yoke, a 450,000 ft-lb pipe string torquing/ detorquing device on one yoke, a stationary support for "parking" and rotating the load and the hydraulic power units for these elements. In addition, the system includes an instrumentation and control suit to automatically or manually operate the complete deployment and retrieval functions.
The system has a stall load capacity of 8500 tons. It has been fully tested and successfully used to deploy and retrieve up to 7500 tons at 6 feet/minute in 17,000 foot depths.

INTRODUCTION
The GLOMAR EXPLORER is the surface support vessel for an operational system designed to work the ocean bottom. It transports the bottom equipment and provides the work platform from which the bottom equipment is operated, deployed and retrieved. Design parameters for deploying/retrieving were much greater than anything previously done from a vessel, and unique equipment had to be devised, tested, installed and operated. The resulting subsystem is called the Heavy Lift.
The mechanical link between the Heavy Lift and the bottom equipment is a rigid pipe string. Deploying/retrieving is similar to current offshore riser and drill string operations, i.e., add/remove a pipe stand then lower/raise the pipe string to the next tool joint. Initial pipe string design payload and depth was up to 4,000 tons and 17,000 feet. To minimize pipe string stress and thereby its weight, the work platform for the Heavy Lift was gimballed and heave compensated1. Platform space was limited and any equipment on the platform added to the gimbal-heave compensator loads. Compact and light Heavy Lift components were needed.
The design weather window for deploying/retrieving was' small and the necessary lowering/ raising rates could only be achieved by automation which, in turn, requires remotely controllable components. Finally, pipe stands weighed up to 40,000 lbs each, tool joint torque was up to 450,000 ft-lbs and, in spite of the gimbal-heave compensator refinement, the design payload for the Heavy Lift became 8,500 tons at 17,000 ft depths. High rates and high loads necessitated high powered Heavy Lift components.
Compact, low weight, remotely controllable and high power components were achieved by designing hydraulically powered mechanical equipment. These were integrated with an electronic control system to meet the Heavy Lift subsystem functional requirements during automated operations.