bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental and Numerical Determination of Thermal Radiative Properties of ZnO Particulate Media
Authors: Coray P. , Lipiński W. , Steinfeld A.
Published: November 2009

The radiative characteristics of dependently scattering packed-beds of ZnO particles, applied in the design of high-temperature solar thermochemical reactors, were investigated experimentally. ZnO samples of varying thickness were exposed to a continuous beam of near monochromatic thermal radiation in the 0.5–1 μm wavelength range. The overall transmitted fraction measured as a function of sample thickness s obeys an exponential trend exp(−As), with the fit parameter A ranging from 4000±100 m−1 at 555 nm to 2100±100 m−1 at 1 μm. In the forward directions, the measured intensity distribution is approximately isotropic, whereas in the backward directions it is well approximated by a Henyey–Greenstein equation with asymmetry factors g≈−0.4 at 555 nm and g≈−0.1 at 1 μm. A Monte Carlo ray-tracing model of the experimental setup is employed to extract the extinction coefficient and the scattering albedo for the case of a nongray absorbing-scattering medium.
Three-Dimensional Magnetic Fluid Boundary Layer Flow Over a Linearly Stretching Sheet
Authors: Tzirtzilakis E. E. , Kafoussias N. G.
Published: November 2009

The three-dimensional laminar and steady boundary layer flow of an electrically nonconducting and incompressible magnetic fluid, with low Curie temperature and moderate saturation magnetization, over an elastic stretching sheet, is numerically studied. The fluid is subject to the magnetic field generated by an infinitely long, straight wire, carrying an electric current. The magnetic fluid far from the surface is at rest and at temperature greater of that of the sheet. It is also assumed that the magnetization of the fluid varies with the magnetic field strength H and the temperature T. The numerical solution of the coupled and nonlinear system of ordinary differential equations, resulting after the introduction of appropriate nondimensional variables, with its boundary conditions, describing the problem under consideration, is obtained by an efficient numerical technique based on the common finite difference method. Numerical calculations are carried out for the case of a representative water-based magnetic fluid and for specific values of the dimensionless parameters entering into the problem, and the obtained results are presented graphically for these values of the parameters. The analysis of these results showed that there is an interaction between the motions of the fluid, which are induced by the stretching surface and by the action of the magnetic field, and the flow field is noticeably affected by the variations in the magnetic interaction parameter β. The important results of the present analysis are summarized in Sec. 6.
Exergy Study of Fouling Factors in Heat Exchanger Networks
Authors: Jin Zunlong , Dong Qiwu , Liu Minshan
Published: November 2009

Selection of fouling factors is somewhat arbitrary in heat exchanger networks (HENs) synthesis. Fouling factors were reconsidered in this article for heat exchanger networks design. An objective function based on exergoeconomic analysis was introduced to assess optimal less conservative fouling factors. The objective took account of exergy consumption expense and heat exchanger capital cost at the same time. The exergy consumption of heat transfer in HENs was calculated using subsection integral on balanced composite curves. The proposed method was applied to an industrial case. Numerical results indicated that the optimal less conservative fouling factors were 80% of the original values and the heat transfer area of the system saved 350 m2 compared with root design. So it is necessary to reconsider the values of fouling factors for HENs design and that exergoeconomic analysis is useful in determining the optimal less conservative fouling factors.
Subcooled Boiling Heat Transfer for Turbulent Flow of Water in a Short Vertical Tube
Authors: Hata Koichi , Masuzaki Suguru
Published: November 2009

The subcooled boiling heat transfer and the critical heat flux (CHF) due to exponentially increasing heat inputs with various periods (Q=Q0 exp(t/τ), τ=22.52 ms–26.31 s) were systematically measured by an experimental water loop flow and observed by an infrared thermal imaging camera. Measurements were made on a 3 mm inner diameter, a 66.5 mm heated length, and a 0.5 mm thickness of platinum test tube, which was divided into three sections (upper, mid, and lower positions). The axial variations of the inner surface temperature, the heat flux, and the heat transfer coefficient from nonboiling to critical heat flux were clarified. The results were compared with other correlations for the subcooled boiling heat transfer and authors’ transient CHF correlations. The influence of exponential period (τ) and flow velocity on the subcooled boiling heat transfer and the CHF was investigated and the predictable correlation of the subcooled boiling heat transfer for turbulent flow of water in a short vertical tube was derived based on the experimental data. In this work, the correlation gave 15% difference for subcooled boiling heat transfer coefficients. Most of the CHF data (101 points) were within 15% and −30 to +20% differences of the authors’ transient CHF correlations against inlet and outlet subcoolings, respectively.
Thermal Properties for Bulk Silicon Based on the Determination of Relaxation Times Using Molecular Dynamics
Authors: Goicochea Javier V. , Madrid Marcela , Amon Cristina
Published: November 2009

Molecular dynamics simulations are performed to estimate acoustical and optical phonon relaxation times, dispersion relations, group velocities, and specific heat of silicon needed to solve the Boltzmann transport equation (BTE) at 300 K and 1000 K. The relaxation times are calculated from the temporal decay of the autocorrelation function of the fluctuation of total energy of each normal mode in the ⟨100⟩ family of directions, where the total energy of each mode is obtained from the normal mode decomposition of the motion of the silicon atoms over a period of time. Additionally, silicon dispersion relations are directly determined from the equipartition theorem obtained from the normal mode decomposition. The impact of the anharmonic nature of the potential energy function on the thermal expansion of the crystal is determined by computing the lattice parameter at the cited temperatures using a NPT (i.e., constant number of atoms, pressure, and temperature) ensemble, and are compared with experimental values reported in the literature and with those computed analytically using the quasiharmonic approximation. The dependence of the relaxation times with respect to the frequency is identified with two functions that follow the functional form of the relaxation time expressions reported in the literature. From these functions a simplified version of relaxation times for each normal mode is extracted. Properties, such as group and phase velocities, thermal conductivity, and mean free path, needed to further develop a methodology for the thermal analysis of electronic devices (i.e., from nano- to macroscales) are determined once the relaxation times and dispersion relations are obtained. The thermal properties are validated by comparing the BTE-based thermal conductivity against the predictions obtained from the Green–Kubo method. It is found that the relaxation times closely resemble the ones obtained from perturbation theory at high temperatures; the contribution to the thermal conductivity of the transverse acoustic, longitudinal acoustic, and longitudinal optical modes being approximately 30%, 60%, and 10%, respectively, and the contribution of the transverse optical mode negligible.
Measurement of the Heat Capacity of Copper Thin Films Using a Micropulse Calorimeter
Authors: Yu Jun , Tang Zhen’an , Zhang Fengtian , Ding Haitao , Huang Zhengxing
Published: November 2009

This paper presents a micropulse calorimeter for heat capacity measurement of thin films. Optimization of the structure and data processing methods of the microcalorimeter improved the thermal isolation and temperature uniformity and reduced the heat capacity measurement errors. Heat capacities of copper thin films with thicknesses from 20 nm to 340 nm are measured in the temperature range from 300 K to 420 K in vacuum of 1 mPa. The specific heat of the 340 nm Cu film is close to the literature data of bulk Cu. For the thinner films, the data shows that the specific heat increases with the decreasing of film thickness (or the average crystalline size).
Design and TEM Simulation of a MEMS Based Microcantilever Cardiac Marker Sensor
Authors: Vidhya Sree , Kumar Gideon Praveen , Mathew Lazar
Published: November 2009

Piezoresistive actuation of a microcantilever induced by biomolecular binding such as DNA hybridization and antibody-antigen binding is an important principle useful in biosensing applications. As the magnitude of the forces exerted is small, increasing the sensitivity of the microcantilever becomes critical. In this paper, we are considering to achieve this by geometric variation in the cantilever. The sensitivity of the cantilever was improved so that the device can sense the presence of antigen even if the magnitude of surface-stresses over the microcantilever was very small. We consider a “T-shaped” cantilever that eliminates the disadvantages while improving the sensitivity simultaneously. Simulations for validation have been performed using INTELLISUITE software (a micro-electromechanical system design and simulation package). The simulations reveal that the T-shaped microcantilever is almost as sensitive as a thin cantilever and has relatively very low buckling effect. Simulations also reveal that with an increase in thickness of the cantilever, there is a proportional decrease in the sensitivity.
Nonzero Finite Wall Resistance Solution With Constant Dialyzate for Various Mass Transfer Quantities
Authors: Abdalla Wassf Isaac A. S.
Published: November 2009

This article deals with the theoretical investigations into dialytic mass transfer in parallel-plate hemodialyzers. The theoretical solutions presented are closed-form analytical solutions involving only exponential and algebraic polynomial functions, and are simple, economical, and convenient to use. With the help of Laplace transforms and the Galerkin method, the expressions for mixed mean concentration, local fluid-wall Sherwood number, logarithmic fluid-wall Sherwood number, local fluid Sherwood number, logarithmic fluid Sherwood number, clearance, and local concentration have been obtained. Data obtained in the present contribution are compared with earlier results and are found to be in the excellent agreement. Two solutes, urea and vitamin B12, were considered. It is observed from the above-mentioned comparison that the effect of variable dialyzate concentration on various mass transfer quantities is significant in the case of uremic small molecules. In the case of uremic middle molecules, the nonuniform concentration distribution in the dialyzate channel is only slightly affected.
Effects of AlCl3 Additive on Cutting Forces and Diamond Wear Rate While Cutting Granite With a Single Diamond
Authors: Appl F. C. , Rao B. N. , Walker B. H.
Published: November 2009

The effects of surfactant solution aluminum chloride on cutting granite rock with a diamond were investigated experimentally. Tests were conducted by cutting on the cylindrical surface of a granite cylinder in a lathe with a single spherically shaped diamond cutting tool. The cutting fluid consisted of various concentrations of aluminum chloride in deionized distilled water. The cutting force components were determined by means of a tool post dynamometer and were recorded continuously during the tests. Diamond wear was determined by periodically photographing the wear flat through an optical miscroscope. Results indicate that cutting forces and diamond wear rate are influenced by the additive. The normal cutting force is maximum at a concentration of 7 × 10−6 molar, and the tangential cutting force is maximum at 3 × 10−6 while the diamond wear rate is minimum at 3 × 10−6 molar. It is also found that there is an effect of concentration on relative tool life for constant depth cutting, but that maximum life occurs at higher levels of concentration.
High and Low-Cycle Fatigue Behavior of Prestressed Concrete in Offshore Structures
Authors: Gerwick B. C. , Venuti W. J.
Published: November 2009

The expanding use of prestressed concrete in offshore structures, both fixed and floating, in ever more hostile environments has generated intense interest in its fatigue endurance capabilities, even though, as far as it is known, no fatigue problems have arisen in actual structures. Although concrete does suffer progressive loss of strength with increasing number of cycles, a comparison of the Wo¨hler curves developed on the basis of laboratory tests with the probable distribution of compressive stresses during a service life in an environment such as the North Sea shows extremely low cumulative usage at the high-cycle end of the spectrum. However, significant damage can occur at the low-cycle, high-amplitude end of the spectrum under a relative small number of cycles of very high magnitude. This damage is displayed by a reduction in stiffness and by rapidly increasing axial and lateral strains that lead to cracking and spalling. Repeated cycling into high compressive ranges causes a substantial increase in creep, reducing the effective prestress. Confining reinforcement resists lateral deformation and delays compressive fatigue failure. Cycling into the tensile range a large number of times can produce cracking due to tensile fatigue at about half the static tensile strength. Cracking also can occur due to overload, accident, construction procedures, and thermal strains. Repeated excursions of submerged concrete into the crack opening range leads to pumping of water in and out of the crack and hydraulic wedging, leading to splitting of the concrete. Cracking subjects the reinforcing and prestressing steel to cyclic tension. Loss of bond ensues and may lead to eventual fatigue failure. Adequate endurance can be ensured by prestressing, so as to avoid a large number of cycles extending into the crack opening range, and by the provision of adequate percentages of steel across the section plus transverse and confining steel. Cyclic membrane shear may produce diagonal tension cracking at about half the static strength. Conventional reinforcing in an orthogonal grid pattern is very inefficient in resisting such cracking. Crack widths grow rapidly. Repeated loading may lead to abrasion of concrete surfaces and failure of the steel due to combined axial force and bending. Vertical prestress is an efficient and practical method of resisting high-amplitude cyclic shear. For the typical concrete sea structure, high-cycle, low-amplitude, cumulative fatigue is not a significant problem. However low-cycle, high-amplitude fatigue requires consideration, expecially when there are numerous cycles into the tensile cracking range. In this latter case, fatigue of the steel and/or concrete may occur unless adequate amounts of steel are provided to ensure that crack widths and steel stresses are kept within allowable values.
Bending of Tubular Bundles Attached to Marine Risers
Authors: Huang T. , Dareing D. W. , Beran W. T.
Published: November 2009

Individual tubulars attached to marine risers are modelled as continuous axially loaded multiple-spanned beams. Traditional methods for solving continuous beam-column problems require the solution to many simultaneous equations. The calculation procedure in this paper requires that only two equations be solved simultaneously; intermediate support reaction loads are obtained by using recursion formulas.
Design of Hydrostatically Supported Sand Islands for Arctic Drilling
Authors: Dowse B. E. W.
Published: November 2009

The search for oil and gas has already extended to the Arctic areas of the world. To date conventional sand islands have been used for exploration drilling purposes in water depths of up to 43 ft. In deeper water exploration has only been possible using floating drilling equipment which can only operate during the short summer season of open water. This paper briefly outlines the geotechnical principles and development to date of hydrostatically supported sand islands. This construction technique, which utilizes hydrostatic water pressure to stabilize dredged sand at near vertical underwater slopes, would allow sand islands to be quickly and economically built in water depths of up to 200 ft. The hydrostatically supported sand island is a gravity structure and, therefore, is only suitable for use on competent seabed soils. This paper presents two different designs which are currently proposed for use as drilling structures in such areas as the Beaufort Sea. One design is intended for use as a movable exploration structure and the second for a permanent production island that would remain on location for 30 to 50 yr. The near vertical side slopes of the hydrostatically supported sand islands reduce the amount of sand required to manageable amounts, and allow the construction on location to be safely completed during the short Arctic summers. The sand provides sufficient mass to resist ice pressures.
Conversion of Refuse to Electrical Energy at the St. Louis-Union Electric Refuse Fuel Demonstration Project
Authors: Fiscus D. E. , Gorman P. G. , Wiles C. C.
Published: November 2009

At the Union Electric Meramec power plant in St. Louis, tests in which refuse-derived fuel was co-fired with pulverized coal in a tangential suspension-fired coal boiler have been conducted. Data obtained were used to calculate the megawatt-hours of electrical energy produced by refuse-derived fuel. The experimental method used, the results obtained, and a discussion of these results are presented in this report.
Structural Design of Production Risers and Offshore Production Terminals
Authors: Wolfram W. R. , Gunderson R. H.
Published: November 2009

Offshore production terminals and deepwater risers are seeing increasing use by the offshore oil industry. The structural design of these units presents a unique challenge compared to other offshore systems. Development of design loading conditions and fatigue histories is especially interesting due to the complex interaction of nonlinear riser and vessel dynamics, the statistical nature of maximum loads and the need to consider directionality as well as the magnitude of environmental loading. This paper presents a complete procedure for predicting design loads and fatigue histories for production risers and offshore terminals. The emphasis will be on systems wherein a dedicated vessel is connected to the riser by a rigid mooring arm. A number of structural design configurations will be surveyed. Techniques for preliminary sizing, dynamic analysis, model testing and fatigue analysis will be discussed. The application of this procedure to several specific design cases will be summarized.
Mooring with Multicomponent Cable Systems
Authors: Ansari K. A.
Published: November 2009

Relative to the present-day need for offshore operations involving the use of moored vessels, mooring system design has become quite complex. Since a proper choice of mooring line components in the form of anchors, clump weights, chains and cables is vital for vessel station-keeping and mooring system survival, the adequacy of the mooring system under consideration must be checked out by suitable analysis techniques. This paper gives a general discussion of the various mooring line components available for use, presents an analysis tool to determine the stiffness characteristics of a multicomponent cable including the effect of line stretch, and demonstrates how these could be included in the dynamic analysis of an offshore construction vessel moored by a multileg anchoring system. The maximum limiting tension of the mooring line considered, which is a combination of anchors, clump weights, chains and cables is determined from the several breaking strengths and anchor capacities associated with the various cable configurations that can occur. Finally, in order to illustrate a practical application, the dynamic response of a moored production barge subjected to external environmental forces is examined.
An Approach to Determining the Economic Feasibility of Refuse-Derived Fuel and Materials Recovery Processing
Authors: Gershman H. W.
Published: November 2009

This paper presents an approach for determining the economic feasibility of refuse-derived fuel production and the recovery of various materials. The information presented here is based largely upon data developed for [1] the metropolitan Washington, D. C. area1 as input for the consideration of a regional resource recovery program which would eventually encompass some 4000 t per day (3628.8 Mg per day) of municipal solid waste. The initial facility would process 650 t per day (589.7 Mg per day). The facility is designed to recover refuse-derived fuel (RDF), light and heavy ferrous metals, aluminum and other nonferrous metals, flint glass cutlet, color-mixed glass cullet, color-mixed glass fines, and handpicked waste newspapers and corrugated. For the most part, advance commitments for the sale of these products have been obtained. An early stage in the planning process requires recovery product revenues to be estimated and the feasibility of the process to be analyzed. Since materials revenues can be predicted with a higher degree of certainty than RDF revenues, it becomes necessary to determine what revenues will be required from the sale of the RDF in order that projected economics can at least be the same as the alternative disposal practice. A technique is described here which will assist the decisionmaker to evaluate the economic feasibilty of the proposed project by determining what is termed here the RDF “Indifference Value [3].”
Measurements of Sea-Ice Stresses Near Grounded Obstacles
Authors: Sackinger W. M. , Nelson R. D.
Published: November 2009

Stresses were measured in multiyear sea ice near a grounded floe island. Compressive stresses as high as 250 psi (1.72 MPa) were observed, in the form of impulses. A second installation in annual sea ice near a grounded pressure ridge showed tensile stress of 100 psi (0.69 MPa), followed by crack formation. These stresses were localized to a range of the order of 100 m. Localized compressive stresses in multiyear ice near grounded offshore structures may exceed 250 psi (1.72 MPa), and impulsive loading should be expected.
Prediction of Annulus Pressure Gradients in Pumping Wells
Authors: Schmidt Zˇ. , Brill J. P. , Beggs H. D.
Published: November 2009

Experimental data on pressure gradients were obtained for gas bubbling through static liquids in various concentric annulus configurations with eight different liquids. Although a definite liquid physical property effect exists, the Gilbert “S” curve gave an adequate representation of the data. A more accurate correlation was developed, together with a physical model that separates hydrostatic and friction components of the pressure gradient.
Higher Order Approximations in Stress Analysis of Submarine Pipelines
Authors: Konuk Ibrahim
Published: November 2009

A unified three-dimensional formulation of the pipeline or riser problems is developed by following the rod theories. A rigorous singular perturbation technique is used to solve the associated two-dimensional nonlinear problem. The results can be used with a programmable calculator.
Proposed External Pressure Design Rules for Pressure Vessels for Human Occupancy
Authors: Maison J. R. , Briggs E. M.
Published: November 2009

The safety of externally pressurized manned diving bells, submersibles and underwater work systems resides in the ability of the system to rise to the surface in case of an emergency. Use of the ASME Boiler and Pressure Vessel Code Section VIII design rules, lead to unacceptably heavy structures, and thus substantially compromise the sought-for safety in underwater manned systems. A recognition on the part of the diving industry of the inherent limitations in using the ASME Boiler and Pressure Vessel Code for design of underwater pressure vessels, motivated the formation of the ASME Safety Code Committee on Pressure Vessels for Human Occupancy (PVHO) in 1974. A subcommittee of the PVHO Safety Code Committee was formed to address the specific problems of external pressure vessel design. The mathematical development which provided the basis for the proposed rules are presented. The restrictions imposed by the External Pressure Subcommittee are also presented.
Practice of Heat Utilization from Refuse
Authors: Martin W. J. , Weiand H.
Published: November 2009

Many European refuse incinerators utilize the heat derived from refuse incineration for steam or hot water supply to district-heating systems or to certain industries for generation of electricity, for sludge drying, etc. The design of five typical incinerators with heat recovery is outlined and the value of recovered energy in terms of fuel oil savings is tabulated.
Experience with Solid Waste as a Supplementary Fuel
Authors: Marshall J. E.
Published: November 2009

The introduction covers the historical development of the Imperial Metal Industries Ltd. Power Plant and the psychology behind that development. The investigation into the concept of firing solid waste into boilers is detailed, as well as the final design parameters. Details are given of the performance achieved so far, including the problems that had to be overcome. Finally, the author gives his opinion of advantages to the energy industry and the community.
Analysis of Motions of a Semisubmersible in Sea Waves
Authors: Sun F. Z.
Published: November 2009

The forces acting on a three-dimensional cylinder with arbitrary symmetrical cross section are derived taking into account viscous effect and applying linear-processing techniques. Then general expressions for the hydrodynamic forces, motion equation and its solution for a semisubmersible platform in regular waves are obtained. Based on linear theory of statistical analysis, it is proposed to employ the concept of “equivalent wave height” for the calculation of transfer functions with which both the short-term and long-term distribution and statistical characteristics of the motion of a semisubmersible may be estimated. A computer program has been developed. Comparison between model experimental and theoretical data has shown satisfactory agreement.
Some Recent Studies of Vortex Shedding With Application to Marine Tubulars and Risers
Authors: Griffin O. M. , Ramberg S. E.
Published: November 2009

Many types of marine structures are susceptible to vortex-excited oscillations. These include the risers and conductor tubes that are employed in offshore drilling and production, deep water pipelines, and members of jacketed structures. Deepwater pile installation and driving operations also have been hampered by problems arising from vortex shedding. A discussion is given in this paper of the problems caused by vortex shedding from flexible, bluff cylinders in steady current flows. In particular, recent measurements of the steady and unsteady deflections caused by the vortex-excited drag and lift forces are discussed. Various approaches that have been developed for the suppression of vortex-excited oscillations are reviewed. A classification and a comparison are made of the effectiveness of several suppression devices, and some practical examples of their application are presented.
The Inertial Pressure Concept for Determining the Wave Forces on Submerged Bodies
Authors: Horton T. E. , Feifarek M. J.
Published: November 2009

A new concept is presented which is aimed at improving the methodology for determining the wave forces on offshore structures. The Inertial Pressure Concept (IPC) is based on a direct, empirical approach to calculating forces. The resulting method can be formulated to include realistic sea state wave kinematics while not being dependent on a particular kinematic representation. Futhermore, the method should be as easy to apply as the Morison equation, but will allow diffraction and three-dimensional aspects to be considered.
“The Spiral Arrester”—A New Buckle Arrestor Design for Offshore Pipelines
Authors: Kyriakides S. , Babcock C. D.
Published: November 2009

If a pipeline buckles in the presence of sufficiently large external pressure, a propagating buckle is initiated. The buckle propagates along the pipeline until it encounters a region of low pressure or an arresting device. This paper suggests a new buckle arrestor design. It is comprised of a rod tightly wound around the pipe to form a number of turns. Its main characteristic is that it can be used in continuous pipelaying methods (reel pipelaying). It can also be used in the case of pipes coated with concrete where it can be inserted into the concrete. Due to its design, it restricts the stress concentration at the discontinuity when bending is applied to the pipe arrestor assembly. Experiments have shown that its efficiency is comparable to other arrestors. An empirical expression for the arrestor efficiency is presented.
Pressure Behavior During Polymer Flow in Petroleum Reservoirs
Authors: Ikoku Chi U. , Ramey H. J.
Published: November 2009

This paper presents solutions of the nonlinear partial differential equation using the Douglas-Jones predictor-corrector method for the numerical solution of nonlinear partial differential equations. The results are presented in tabular form and as semilogarithmic and log-log type-curve graphs. Graphs of dimensionless pressure versus dimensionless radius also are presented. Compared to results from analytical solutions of the linear partial differential equation, the graphs have the same shape. The error introduced by the linearizing approximation is small for many values of the flow behavior index, n, and decreases as n tends to unity. Dimensionless pressure is a linear function of dimensionless radius to the power (1–n), near the well, as predicted by the steady-state equations. Also radius of investigation equation derived analytically agrees with results from numerical solutions.
Application of Production Systems Analysis to Determine Completion Sensitivity on Gas Well Production
Authors: Mach J. , Proano E. A. , Brown K. E.
Published: November 2009

A completely new approach is presented to show the effect of completion parameters on high volume gas wells typical of the Gulf Coast. The solution can be summarized in graphical form and it will consider the following sections of the total producing system: 1) flow in the porous media, 2) effect of completion, and 3) flow conduit performance. The result is that the controlling parameter in the total production system can be determined. Many wells are capable of producing very high rates but are restricted due to very restricted gravel pack parameters, while wells with very efficient gravel pack completions are tubing-dominated. The procedure presented approaches the completion sensitivity analysis from a complete production system concept.
The Manufacture of Composite-Holed, Safety-Rupture Diaphragms
Authors: Beese J. G.
Published: November 2009

A modified method of producing composite-holed, safety-rupture diaphragms is suggested. The influence of the proposed manufactring approach on predoming, bursting pressure, and venting action is examined.
Missed Opportunities—Strategy and Procedures for Testing Alarm and Shutdown Devices
Authors: Koelle P. S.
Published: November 2009

Loop testing of safety devices during operation improves plant performance, reduces downtime of process-dependent rotating equipment, and enhances training of personnel. Designers, manufacturers, staff engineers, and plant personnel are always concerned with improving the efficiency and reliability of process equipment. An unscheduled shutdown caused by breakdowns or accidents involving machinery may result in millions of dollars in unrecoverable losses, because the capacity of rotating equipment has increased to a point where temporary replacements to enable the plants to continue their production are hard, or even impossible, to find. The paper will discuss how accidents may be prevented and outline a systematic approach to checking alarm and trip circuits.
Minimum Spacing of Thermally Induced Cracks in Brittle Solids: Addendum
Authors: Nemat-Nasser S. , Oranratnachai A.
Published: November 2009

Sharper lower bounds for the minimum spacing of thermally induced tension cracks in brittle half-planes are presented, and four previous [1] numerical estimates are improved.
Frost and Ice Formation in the Air Convection Pile Permafrost Protection Device
Authors: Reid R. L. , Hudgins E. H. , Onufer J. S.
Published: November 2009

Experimental studies on frost and ice growth under simulated summer conditions were performed on a 3.0-m (10-ft) model of an air convection pile. The air convection pile is a thermosyphon-type permafrost protection device which has been considered for use in arctic construction projects. The device consists of an outer tube, usually 45.75 cm (18 in.) in diameter, extending 3.05 to 18.3 m (10 to 60 ft) into the permafrost. This outer tube contains a shorter concentric 25.4-cm- (10-in.) dia inner tube. Data was taken for typical arctic temperatures and humidities and for simulated above-ground heights of 0.153, 1.373, and 2.88 m (0.5, 4.5, and 7.5 ft). The results have shown that the ice growth is governed by the concentration gradient in the annulus of the pile.
Heat Transfer in an Air Thermosyphon Permafrost Protection Device
Authors: Evans A. L. , Reid R. L.
Published: November 2009

Velocity and temperature profiles were measured in a prototype air thermosyphon permafrost protection device. This device, known as the air convection pile, consists of an 18-in. (0.46-m) outer tube containing a shorter concentric 10-in. (0.25-m) tube extending from 10 to 60 ft (3 to 18 m) into the permafrost. Measurements showed a low frequency oscillating flow in both the annulus and inner tube. Heat removal rates compared favorable with an analytical model and previous experimental results, but the annulus velocity profiles were significantly different, possibly due to the oscillation in the flow.
A High-Pressure Swivel for Natural Gas Service and Oscillating Motion in a Marine Environment
Authors: Herbert J. T. , Ortloff J. E.
Published: November 2009

A joint development program has produced a unique flowline swivel for high-pressure natural gas service under continuous, small degree rotation, oscillating service. The swivel uses an elastomeric bearing element made up of alternate, frusto-conical shaped rings of metal and rubber (elastomer) to absorb continuous small degree rotary oscillations or flexures of the swivel. It accommodates larger oscillations, including complete 360-deg rotations, by locking the elastomeric element at its maximum design flexure capability and permitting the entire shaft assembly to rotate relative to the housing. A 6-in. (152.4-mm), 6000-psig (41,370-kPa) prototype successfully passed a rigorous qualification test program. The swivel should be useful in offshore marine production riser systems and loading terminals.
Optimum Design and Control of Self-Supported Wave Energy Systems
Authors: Abuelnaga A. , Seireg A.
Published: November 2009

In a previous paper by the authors [1] a procedure is given for the optimum design of single mass, anchored wave energy generators. The anchoring problem is generally regarded as one of the major obstacles of developing practical systems due to the high cost of implementation. This paper presents a procedure for the design of supporting platforms for wave generators which are essentially self-positioned and require minimum anchoring. The optimum design and control for such systems is given for a selected ocean condition. The study shows that an unanchored platform in an optimally designed two-mass system can provide appropriate support for the wave generator without any significant loss of conversion efficiency.
Underwater Cargo Vessel Utilizing Variable Buoyancy System for Gliding Propulsion
Authors: Qi Z. K. , Seireg A.
Published: November 2009

This study deals with investigating the feasibility of an underwater glider capable of carrying cargo for long distances by alternately employing gravity and buoyancy forces for forward propulsion. The parameters controlling the vessel design, stability and control are investigated.
Automatic Position Control of a 300,000-Ton Ship Ocean Mining Systems
Authors: Brink A. W. , Chung J. S.
Published: November 2009

Extensive computer simulation and performance analysis and assessment have been carried out for the dynamic positioning control of a large, commercial ocean mining ship / pipe system, and selective results are presented. It is tentatively concluded that automatic position control, with a manual override option, of a 300,000-ton ship with 18 thrusters of 4500 hp and an 18,000 ft long lift pipe system would be feasible for commercial operations of a preliminary mining system in the Pacific Ocean. The preliminary system employs a self-propelled miner. For the feasibility study, we have performed the following: the thruster power estimate, a subsequent selection of an azimuthing ship thruster system configuration, steady-state and dynamic motion of the ship-pipe system, track-keeping, turning and station-keeping control, design of an automatic control system, and nonlinear control simulation during mining operations and selective contingency situations. For the development of commercial systems, the small-size, test-mining system does not provide all the design data. It is much larger, and subsequently, requires development of more sophisticated technology and engineering capabilities. The present method of analysis and simulation can be applied to many other mining system analyses, and to the position keeping control of deepsea drilling systems, and deepsea piplaying.
Impact—Response Behavior of Offshore Pipelines
Authors: Bergan P. G. , Mollestad E.
Published: November 2009

A method for analyzing the dynamic behavior of marine pipelines subjected to impact loads or sudden forced movements is outlined. Inertia forces (also from hydrodynamic mass), hydrodynamic drag forces as well as friction and lift effects for a pipe at the sea bottom are accounted for. An extensive nonlinear formulation is used for the pipe itself; it includes large displacements and elasto-plastic material behavior. Aspects of the numerical formulation of the problem and the solution of the nonlinear dynamic equations are discussed. The examples show computed dynamic response for pipelines lying on the sea floor and for a pipe section freely submerged in water when subjected to various force and displacement histories.
The Action of Irregular Waves on Ships Moored on Terminals
Authors: Li Yu-Cheng
Published: November 2009

For the analysis of the dynamic characteristics of ships moored at the offshore terminals under the action of wind waves, the moored ship system may be simplified to be linear. Introducing the transfer function Ye(ω), the impact energy of a moored ship on the terminal resulting from a random sea may be obtained from the spectrum of the ocean waves. Furthermore, by using the directional function of impact Y2(α), the directional spectrum of the impact by ships can also be estimated. The results show that there is a significant relationship between the spectrum of the ocean waves and the impact energy of the ship.
Nonlinear Static Analysis of Deep Ocean Mining Pipe—Part II: Numerical Studies
Authors: Chung J. S. , Felippa C. A.
Published: November 2009

This part applies the modeling and solution techniques discussed in Part I to the computerized steady-state deflection analysis of deep ocean mining pipe systems. For accurate analysis, a realistic representation of drag forces along the pipe is required. This is affected by three major factors. First, in a temperature-stratified ocean, the viscosity and consequently the Reynolds number (Re) and drag coefficient vary significantly along the depth. Second, three-dimensional subsea current velocity distribution must be combined with ship velocity data and pipe configuration in the calculation of relative pipe-fluid velolcities. Finally, the drag coefficient versus Re, which varies between experiments and becomes very sensitive in the transition region, has to be properly characterized. Several cases that illustrate these parametric effects are presented for an 18,000-ft pipe modeled by three-dimensional beam elements which include coupled axial, bending and torsional deformations. The sensitivity of the results to environment characterization suggests that, for deep-ocean applications, a review of many current modeling and analysis practices is necessary.
Dynamic Response of a Cantilever Pile to Vortex Shedding in Regular Waves
Authors: Zedan M. F. , Yeung J. Y. , Salane H. J. , Fischer F. J.
Published: November 2009

This paper summarizes an experimental investigation of cantilever pile dynamics in response to wave excitation under vortex-shedding “lock-in” conditions. The study was carried out in regular waves for two conditions of wave length in relation to water depth. Pile response was measured in terms of top accelerations and bottom strains in both the in-line and transverse directions. Vortex-shedding lock-in is shown to produce substantial dynamic amplification of deflection not only in the transverse direction, but also in the in-line direction. Results indicate that the Morison equation is inadequate to describe the in-line force under vortex-shedding lock-in.
Evaluation of Tensile Failure of Girth Weld Repair Grooves in Pipe Subjected to Offshore Laying Stresses
Authors: Wilkowski G. M. , Eiber R. J.
Published: November 2009

The repair procedure for removal of a girth weld defect in offshore pipelines involves arc-gouging a groove into the defective area. Since high bending stresses in the pipes exist at the repair station, the concern was whether the weld repair groove may cause failure of the pipes. An experimental research program was conducted to determine the critical length and depth of repair grooves. Experiments were conducted on 100, 150, and 762-mm-dia pipes. A plastic instability failure criteria was developed and verified to predict the failure stresses for carbon steel pipes. The failure criterion is given as a function of three nondimensional parameters. These parameters are groove depth to pipe thickness ratio, groove length to pipe circumference ratio, and longitudinal stress to flow stress ratio. Stable versus unstable (i.e., leak versus break) behavior is also predicted from the failure criteria.
Experimental Study of Oil-Water Flow in Inclined Pipes
Authors: Mukherjee H. , Brill J. P. , Beggs H. D.
Published: November 2009

Pressure loss and water holdup data were measured for oil-water flow in 1.5-in-dia inclined pipe with inclination angles from ± 30 deg to ± 90 deg from horizontal. Pressure losses were higher than calculated with available techniques, with maximum values near the phase inversion. Effects of input liquid fraction and inclination angle on friction pressure gradient are presented. Water holdup correlations for predicting in-situ liquid fractions are given.
Approximate Solution to Neumann Problem for Soil Systems
Authors: Lunardini V. J. , Varotta R.
Published: November 2009

An approximate solution to the Neumann problem has been obtained by using the heat balance integral method. The accuracy of the solution is shown to be very good for all practical soil system cases. The thermal properties of soil systems are also expressed in terms of only the liquid volumetric fraction and combine with the approximate solution to give a rapid, accurate solution for freeze / thaw problems without using graphs, tables, or transcendental equations. A simple relation is also given for the analogous problem in cylindrical coordinates, but its range of validity is somewhat limited.
Experimental Study on Moving Loads on a Floating Sea Ice Road
Authors: Haspel R. A. , Masterson D. M. , Goff R. J. , Potter R. E.
Published: November 2009

On a 14.5-km (9-mi) floating sea ice road at the North Slope of Alaska dynamic load tests were performed with a 68-tonne (75-ton) gravel truck. The results were in good agreement with the theory of moving loads on floating ice and with the design concept of floating ice structures. In tests over a road with and without bumps, values for dynamic amplification were measured as high as 1.9 for deflections and 1.5 for flexural stresses. Vehicle test speeds ranged between 16 and 50 km/h (10 and 30 mph), the water depth from 3 to 8 m (10 to 27 ft) and the ice thickness from 2 to 2.9 m (6.6 to 9.5 ft). The test results represent a definite advancement of the state-of-the-art in design and use of floating ice for transportation.
Oil Shale Retorting in a Bottom-Burning Retort
Authors: Udell K. S. , Jacobs H. R.
Published: November 2009

An experimental study of a bottom-burning oil shale retort is described. It is shown that for a constant oxidizer flow the combustion front moves at a uniform velocity through the bed. This leads to the use of a moving coordinate system attached to the combustion front in evaluating the various thermal processes occurring in the retort. It is shown that the high quality of oil produced can be tied to a thermal refluxing not present in other retort processes.
Design and Evaluation of Evaporating Lens Direct Contact Heat Exchangers
Authors: Kodres C. A. , Jacobs H. R. , Boehm R. F.
Published: November 2009

An explicit procedure for analyzing a superheated, evaporating lens direct contact heat exchanger has been developed. This method is based upon the application of a dimensional analysis derivation of a relationship for the heat flux from a single evaporating lens. Several suggestions are offered for use in the design of these devices. To estimate the error introduced by extrapolating a single lens model to represent a system of lenses, the method is used to “design” two operating geothermal heat exchangers. A difference of about 16 percent is observed between the calculated and measured overall heat flux.
Propagation and Extinction of Combustion Fronts in Crushed Oil Shale
Authors: Nguyen K. , Branch M. C.
Published: November 2009

The effects of oil shale particle size and Fischer assay on the extinction air flux, the air flux at which the combustion front cannot operate, were studied using a small laboratory-scale retort. It was found that for runs with air consisting of 21 percent oxygen by volume, the extinction air flux is strongly dependent on the particle size and Fischer assay. The smaller oil shale particle sizes led to higher observed extinction air flux, while the leaner shale resulted in lower observed extinction air flux.
Model Capabilities for In-Situ Oil Shale Recovery
Authors: Hommert P. J. , Tyner C. E.
Published: November 2009

The extensive oil shale reserves of the United States are now under development as an energy source. One of the approaches for extracting oil from shale is the so-called modified in-situ retort. The operation of such retorts for maximum yield requires an understanding of oil loss mechanisms so that operating strategies that minimize these losses can be developed. The present modeling capabilities for describing the behavior and yield from a modified in-situ retort are discussed. Two models that have been subject to comparison with laboratory retorts are described. The first is a one-dimensional model that treats the retort as a packed bed reactor; the second is a quasi-two-dimensional examination of block retorting. Both models are capable of predicting retorting rates, off-gas composition and oil yield losses to coking and combustion. The major need for modeling now is expansion to multi-dimensional simulation.