bluuebunny/crossref_metadata_2025 huggingface dataset:
Transmission of Solid Particulates Using a Two-Phase Medium
Authors: Kundu N. , Peterson G. P.
Published: November 2009

The ability of water to hold solid particulate matter in suspension, together with its fluidity, make it a desirable medium for use in the transportation of solid material in slurry pipelines. However in some areas, the vast amount of water required for this type of system may not be readily available. Presented here is a discussion of the technical and economic advantages of a slurry transport system, in which foam is used as the transport medium. Also included are the results of an experimental investigation designed to determine the feasibility and transport capacity of such a system. The results of the experimental investigation indicate that the use of foam in the transport of solid particulate material is technically sound, economically attractive and environmentally acceptable.
Acrylic Plastic Spherical Pressure Hull for 2439 m (8000 ft) Design Depth: Phase I
Authors: Stachiw J. D. , Clark A. , Brenn C. B.
Published: November 2009

A program has been initiated to provide the oceanographic community with a manned submersible with panoramic visibility for 2439 m (8000 ft) design depth. The first phase of the program is to validate the design of the acrylic plastic pressure hull utilizing model scale spheres with different diameters and thickness to inside diameter (t/Di) ratios. This papers summarizes 1) the criteria used in the design of the acrylic plastic hull for 2439 m (8000 ft) depth, 2) the experimental test plan for validation of the hull design, and 3) the fabrication, and short-term pressurization to destruction of the first scale model with an aluminum hatch. The 457-mm (18-in.) o.d. acrylic sphere with t/Di ratio of 0.2 successfully withstood 1-hr long pressurizations from 0 to 6.9, 13.8, 20.7, 27.6, 34.4 and 41.3 MPa (1000, 2000, 3000, 4000, 5000, and 6000 psi) followed by 1-hr long relaxation periods after each pressurization prior to imploding at 110.2 MPa (16,000 psi) under 4.5 MPa/min (650 psi/min) pressurization. The selected t/Di ratio 0.2 appears to exceed the design depth requirement for 2439 m (8000 ft).
Experimental Studies on Combustion of Cattle Manure in a Fluidized Bed Combustor
Authors: Annamalai K. , Ibrahim M. Y. , Sweeten J. M.
Published: November 2009

Manure from cattle feedlots is a renewable energy source which has the potential of supplementing the existing fossil fuels. But the heat content of manure is rather low. Since, the fluidized bed combustion technology has been used for the energy conversion of marginal fuels, such a technology is being explored for the combustion of feedlot manure. A fluidized bed combustor of 0.15 m (6 in.) diameter was used for the combustion tests on manure. Experiments were conducted with −20 to +20 percent excess air and at bed temperatures ranging from 600°C (1112°F) to 800°C (1472°F). Experimental data revealed that the gasification efficiencies ranged from 90 to 98 percent, while the combustion efficiencies varied from 45 to 85 percent. Higher combustion efficiencies were obtained with decreased volatile solids content of manure. The low combustion efficiencies are attributed to the limited residence time available for the volatiles to burn within the reactor.
An Analytical Study of Heat and Mass Transfer Within an Oil Sand Bed
Authors: Abdrabboh M. A. , Karim G. A.
Published: November 2009

The physical processes that occur typically within an oil sand bed are considered when the bed is subjected to a hot gaseous stream. In this study, the extent of fluid volatilization was obtained from a consideration of the simultaneous heat and mass transfer processes within the oil sands. The resulting system of equations together with the boundary conditions were solved numerically using an implicit finite difference method. The transient fluid concentration and temperature distributions within the oil sand bed were then obtained under a wide range of operating conditions. The resulting theoretical rates of volatilization and temperatures show generally good agreement with corresponding experimental values that were obtained for the purpose.
Volatilization of Packed Beds of Oil Sand Particles
Authors: Abdrabboh M. A. , Karim G. A.
Published: November 2009

Based on a quasi-steady system, published experimental data on mass transfer in packed beds of spherical particles at relatively low Reynolds numbers, were employed to estimate the convective mass-transfer coefficients in the bed in terms of the corresponding values for single particles. The average transient fluid concentrations within the bed of particles were also obtained in terms of the corresponding single-particle concentrations using the lumped-heat-capacity system. Thus, experimental data published on volatilization of single oil sand spheres could then be extended to estimate the rates of volatilization of packed beds of oil sand spheres. A simple analytical expression could, therefore, be derived for estimating the transient mass loss from fixed beds of oil sand spheres in terms of the parameters involved.
Theoretical Thermal Evaluation of Energy Recovery Incinerators—Part I: Modeling
Authors: Kodres C. A.
Published: November 2009

A mathematical model is developed to simulate the thermal characteristics of energy recovery incinerators. This model takes descriptions of the fuel and of the incinerator as inputs then predicts system temperatures, steam generation rate, and energy recovery efficiency. There are options to include primary or secondary water-walls, a water/firetube boiler, or combinations of these heat exchangers. Both starved and excess air operation are considered.
Optimization of Air-Cooled Condensers
Authors: Lau S. C. , Annamalai K. , Shelton S. V.
Published: November 2009

The essential design parameters for determining the optimum configuration of an air-cooled condenser are identified in this paper. For a power plant operating on a Rankine cycle, expressions for (i) the minimum frontal area, (ii) the minimum heat transfer area, and for (iii) the maximum net cycle efficiency, with respect to the condenser temperature and the cooling air velocity are derived. The analyses are carried out with the assumption that the exit temperature of the cooling air is equal to the condenser temperature. All resulting equations are presented in dimensionless form so that they are applicable to any power cycle with a gas-cooled condenser.
Feasibility Study of Ammonia-Water Vapor Absorption Heat Transformer
Authors: Ertas A. , Gandhidasan P. , Luthan J. J.
Published: November 2009

Many industrial sectors reject heat to the atmosphere in the form of hot water with a temperature between 40° and 70°C. This low grade heat can be upgraded by using a vapor absorption heat transformer (AHT). The present study considers a single stage AHT with binary mixture of NH3–H2O as the working fluid. The performance characteristics of the system have been evaluated by solving the governing mass and energy balance equations using a digital computer. It is found that the permissible range of concentration across the absorber is 0.04<ΔX<0.075 for the following operating conditions: Tusefulheat≤120°C,43°≤Twasteheat≤88°Cand10°≤Tsink≤27°C.
Nonlinear Three-Dimensional Dynamic Analysis of Marine Risers
Authors: Kokarakis J. E. , Bernitsas M. M.
Published: November 2009

Marine risers are modeled as thin-walled, slender, extensible or inextensible, tubular beams subject to nonlinear three-dimensional hydrodynamic loads of interactive nature, torsion and distributed couples, inertia forces and varying axial tension. A finite element, time-incremental algorithm is developed which utilizes equilibrium and kinematic constraints to reduce the required computational time. Iterations are used within each increment to assure convergence of deformation, stiffness matrices and external loads. The algorithm is implemented numerically and the developed computer code is used in several numerical applications to show that a structurally linear model may not be accurate enough and may occasionally be nonconservative in predicting the dynamic riser response.
Analysis of Wood Combustion Based on the First and Second Laws of Thermodynamics
Authors: Dadkhah-Nikoo A. , Bushnell D. J.
Published: November 2009

Wood is a highly flexible fuel which can be used in a variety of ways for energy generation. Direct combustion of wood is the oldest method of utilization of this renewable energy source. This paper presents an analysis of wood combustion based on the first and second laws of thermodynamics, using a computer program developed for this study. Since the moisture content of the available wood fuels vary over a wide range, special attention is given to the effects of moisture content on the exergy and energy content of the wood. Because of the wide variation in particle size and moisture content of the wood fuels, different types of combustion systems have been designed and are utilized in industry. Each combustion system uses a certain amount of combustion air and is designed for a certain range of combustion air temperatures and wood fuel moisture contents. The effects of these variables on wood combustion and the efficiencies of the process have been studied and are presented in this paper. To point out the importance and differences between efficiencies that are commonly used, several efficiencies based on the first and the second laws of the thermodynamics are calculated and compared. Based on the results presented in this report, it is concluded that, over the range of variables studied, the most efficient conditions for wood combustion can be achieved by using the minimum amount of excess air at highest permissible temperature. It is also concluded that the lower moisture contents result in higher combustion efficiencies.
Multiphase Flow Field Trials on BP’s Magnus Platform
Authors: Hill T. J.
Published: November 2009

The trend toward offshore oilfield development schemes which utilize relatively long, large diameter, multiphase flowlines has resulted in a need for better design techniques for such systems. In order to validate these new and improved design methods it is necessary to compare them with good quality field data obtained from a variety of different multiphase lines. Therefore trials to determine the characteristics of the multiphase flow through 150 mm NB (6 in. NB) lines from four of the satellite wells in BP’s Magnus field were carried out during October, 1985. Using two gamma ray density gages, the flow regimes, and where possible the characteristics of slug flow, were identified over a range of flowrates in the different lines. Comparison of the data is made with the predictive techniques widely used in the industry.
A Review of Current Approaches to Riser Modeling
Authors: Ertas A. , Kozik T. J.
Published: November 2009

The purpose of this paper is to review the progress made during the past two decades towards the structural modeling and the numerical approaches of a more realistic riser analysis. Two or three-dimensional, linear or nonlinear, either static or dynamic riser modelings are reviewed. Suitable numerical solution techniques for different kinds of modelings are discussed and compared.
Fatigue Loads on the Foundation due to Turbine Rotor Eccentricity
Authors: Ertas A. , Kozik T. J.
Published: November 2009

This paper is concerned with the effect of rotor eccentricity on the turbine behavior and the shaft deflection which affect the load on the foundation and on the turbine bearings. An analytical technique for determining the housing motion and foundation forces for a rotating machine having a prescribed mass center eccentricity distribution is developed and discussed.
Study of Friction Factor and Equivalent Diameter Correlations for Annular Flow of Non-Newtonian Drilling Fluids
Authors: Jensen T. B. , Sharma M. P.
Published: November 2009

Published annular pressure drop field data have been compared with values predicted by the Bingham plastic and power law models. Several different equivalent diameter equations and friction factor correlations were utilized to estimate the frictional pressure gradients. The estimated frictional pressure drop gradients were then compared with the experimental gradients statistically to determine which combination of friction factor correlation and equivalent diameter equation predicted the experimental data best. Finally, new correlations for friction factors were developed. These new correlations predict the field data better than previously published correlations.
An Improved Model for Predicting Heat Losses and Pressure Changes in Steam Injection Wells—Part 1: Model Development
Authors: Yao S. C. , Sylvester N. D.
Published: November 2009

An improved model for predicting heat losses and pressure changes in steam injection wells is presented. The model incorporates a new two-phase, annular-mist flow pressure change model with heat transfer to the surroundings during wet steam injection. The model requires an iterative procedure which is solved numerically using a fourth-order Runge-Kutta method.
Comparison of Measurement Methods for Pore Size Evaluation of Nonwoven Filter Media
Authors: Biswas S. , Gupta P. , Narang S.
Published: November 2009

The pore size characteristics are widely used in specifying and comparing filter media. Several methods of calculation have been prepared by researchers and some of these have formed the basis of well-known standards. In this paper five different methods of calculation have been compared. The experimental work has been performed on a rig fabricated in line with ASTM-F316 standard and results of careful measurements are reported. The results indicate that the values obtained by some methods are in close agreement with specification. The electron micrograph of filters revealed the random distribution of pore sizes and shapes leaving the use of some theories to question. The practicality and limitations of different methods have been discussed.
Finite Element Simulation of Jump-Out Behavior of Threaded Pipe Joints Used in Oil-Producing Wells
Authors: Morita Y. , Kawashima H. , Ishihara K.
Published: November 2009

High tensile strength is one of the most important requirements for threaded pipe joints used in oil or gas-producing wells. If an excessively large tensile load is applied to the joints, a jump-out phenomenon of the pipe from the coupling occurs. The jump-out phenomenon depends largely on the thread profile, the nonlinear material properties and the contact condition at threads. In this paper, as a fundamental study, the jump-out behavior of a one-ring thread model was experimentally investigated and the FEM simulation was conducted considering the material nonlinearity and the contact condition at threads. Here, the penalty function method was applied as a technique of introducing contact condition into a large deformation elasto-plastic FEM code CAPS, which has been developed by the authors. A jump-out test of actual 473.1-mm-(18-5/8-in-) dia joint was carried out, and based on the experimental results, one criterion was proposed for the slide out of helicoidal thread in FEM simulation. As a result, the present FEM simulation method can be applied to the analysis of the jump-out phenomenon of the threaded joint.
Experimental Determination of Formation Damage Pore Blocking Mechanisms
Authors: Wojtanowicz A. K. , Krilov Z. , Langlinais J. P.
Published: November 2009

The process of formation permeability damage due to solids movement and capture was quantitatively modeled by using principles of deep bed filtration and chemical reactions kinetics. The developed theory describes the pore blocking mechanism caused by particles from completion fluids (foreign particles invasion), as well as the mechanism of release and capture of rock fines (in-situ mobilization). For practical applications, this theory was used in the context of pattern recognition, i.e., to examine the experimental data on rock permeability change versus time from the laboratory flow experiments. Thus, a straight line section of data plotted in a certain system of coordinates indicated the type of formation damage occurring. The verification study was performed in two series of laboratory experiments. In the first, a completion fluid, contaminated with drilling mud, was pumped through the simulated synthetic rock. In the second, four typical, solids-free completion brines were pumped through actual samples of water-sensitive, unconsolidated sandstones taken from Adriatic Sea gas fields. The experiments revealed the applicability of the theory and the method of diagnostic plots to describe and analyze formation permeability damage.
Losses in Very Long Insulated Steam Pipelines
Authors: Mitra A. K. , Rouleau W. T.
Published: November 2009

A numerical method has been developed for calculating the losses and property variations in very long insulated steam pipelines. This method is based on the fundamental equations of compressible fluid flow and heat transfer, and utilizes computer software for evaluation of steam properties. Examples illustrate the effects of different inlet conditions, mass flows, and insulation thicknesses. Choking occurs under some conditions.
An Experimental Examination of the Spontaneous Ignition of Fibrous Materials in Heated Air Streams
Authors: Mehta S. A. , Karim G. A.
Published: November 2009

The behavior of a bed of fibrous combustile material, exemplified by pure cotton (ASTM, 1982), when subjected to a controlled stream of heated air, was examined experimentally. The effects of some controlling basic physical parameters, such as sample compactness and ventilation, air stream temperature, and air stream velocity on the spontaneous ignition and combustion characteristics were established. Moreover, the observed spontaneous ignition delay time was correlated in terms of these variables. The effective activation energy during the ignition reactions was derived and shown to be dependent on the compactness of the sample.
Analysis of a Caisson Retained Island
Authors: Evgin E. , Lord S. , Konuk I.
Published: November 2009

The results of the two and three-dimensional, nonlinear analyses of a caisson retained island in the Beaufort Sea are presented. A hyperbolic stress-strain relation for soils has been implemented in a general purpose finite element program, ADINA, to carry out the analysis. Based on the comparisons of the results, conclusions were drawn about whether a two-dimensional analysis can be safely used to replace a three-dimensional analysis.
Finite Element Analysis and Fatigue Evaluation of the Threaded Marine Riser Connector
Authors: Sato T. , Sano S. , Ishikawa K. , Nakano T.
Published: November 2009

Finite element analyses were conducted of the threaded marine riser connector which has the main, internal, and external shoulder seals. The objectives of the analyses are to evaluate the fatigue resistance, strength, and seal capability of the connector under the bending, tensile, internal and external pressure loads. An element which models the bending effect in an axisymmetric body is developed and implemented into the computer program ADINA. Using the program, stress concentration factors at the corner and threaded parts of the connector under these loads are obtained. The large contribution of both shoulders to the reduction of the stress concentration factors is found to be quite clear. The seal mechanism and the stress response of the connectors are also clarified. The fatigue evaluation based on ASME Boiler and Pressure Vessel Code, Sec. III, Rules for Construction of Nuclear Power Plant Components, Division 1, Subsection NB are compared with the experimental results.
Design of the University of New Orleans Ship-Offshore University Laboratory for Offshore Industry Support
Authors: Latorre R.
Published: November 2009

On July 23, 1987, the University of New Orleans (UNO) dedicated its new Engineering Building, which houses a 38.3 m×4.57 m×0–2.134 m deep ship-offshore university laboratory tow tank. This paper covers the initial stages of the project and summarizes the towing tank design for ship-offshore testing. The tank is configured for three purposes: 1) conventional ship research in deep water with calm water or waves; 2) offshore structure testing with provision for observation and anchoring; 3) shallow water research in calm water, current, and waves.
Turbulent Jet Diffusion Flames in Environments Containing Some Premixed Fuel
Authors: Kibrya M. G. , Karim G. A.
Published: November 2009

The blowout limit of a methane jet diffusion flame is extended by adding small concentrations of a fuel to the surrounding air. The improvement is predicted theoretically with a model based on the stoichiometric changes within the jet and in its vicinity due to the presence of this additional fuel. Good agreement was obtained between such a prediction and the corresponding experimental values for a range of gaseous fuels in the surrounding air.
Correlating the Flammability Limits of Fuel-Diluent Mixtures
Authors: Wierzba I. , Karim G. A. , Cheng H.
Published: November 2009

A simple method based on analysis of experimental flammability limits data is described for the calculation of the lean and rich flammability limits in air of common gaseous fuels (e.g., hydrogen, carbon monoxide, ethylene and propane) with the addition of diluents (e.g., nitrogen, carbon dioxide and helium) and various combinations of their mixtures.
Hydrocarbons From U.S. Gulf Coast Geopressured Brines
Authors: Keeley D. F. , Meriwether J. R.
Published: November 2009

U.S. Gulf Coast geopressured brines studied to date contain small amounts of C6+ hydrocarbons which are primarily aromatic in nature. They range from benzene to substituted anthracenes. In addition, the brines contain a variety of ions and light, C1 to C6, aliphatic hydrocarbons. The primarily aromatic hydrocarbon mixture was collected at −78.5°C and is referred to as a “cryocondensate.” It contains at least 95 different compounds and, from the carbon isotropic ratios, appears to be of terrestrial plant origin. For the only U.S. DOE geopressured energy design well studied for an extended period of time, i.e., the Glady’s McCall well, the concentration of the cryocondensate in the brine was observed to increase prior to the onset of oil production. It is postulated that the change in the brine cryocondensate concentration as a function of the cumulative brine volume produced from the wells results from an extraction of additional aromatic components from oil migrating into the production zone from adjacent shale. When sufficient oil has migrated, it is produced along with the brine.
Biodegradation of Oil-Based Drilling Muds and Production Pit Sludges
Authors: Marks R. E. , Field S. D. , Wojtanowicz W. K.
Published: November 2009

Biological degradation of oil-based drilling muds and production pit sludges are examined using batch reactors. Microbial populations from five different cultures were screened as to their capability of survival in degradation of the oils present. Two microorganism cultures, one developed from raw domestic wastewater and the other from a refinery biological treatment system, demonstrated superior acclimation degradative properties based on substrate utilization and oxygen uptake rates. No toxic or inhibitory properties of the wastes were observed. Biological treatment has the potential to satisfactorily biodegrade wastes for disposal according to recently established Louisiana requirements, and also as a preconditioning step prior to conventional dewatering techniques.
Compaction Performance of Geopressured-Geothermal Reservoir Rock
Authors: Fahrenthold E. P. , Gray K. E.
Published: November 2009

The mechanical properties of intact shale samples and reservoir sandstone cored from a Gulf Coast geopressured-geothermal well have been measured in triaxial compaction tests at similar confining pressures. The results suggest that such shales exhibit a reduced Young’s modulus and increased bulk modulus as compared to neighboring sandstone. Additional uniaxial compaction and pore pressure drawdown tests were conducted on the sandstone in order to investigate the significance of rock compaction to reservoir performance predictions. The test data and existing porous media models indicate that, although partial decoupling of the fluid-solid motions is justified for uniaxial compaction conditions, pore volume compressibility can significantly influence the interpretation of well test analyses.
Geology of the Gladys McCall Geopressured-Geothermal Prospect, Cameron Parish, Louisiana
Authors: John Chacko J.
Published: November 2009

The Gladys McCall prospect lies at the western edge of the Rockefeller Wildlife Refuge about 88 km (55 mi) southeast of Lake Charles in Cameron Parish, Louisiana. The test well is 4825 m (15,831 ft) deep and was drilled in 1981 under the U. S. Department of Energy geopressured-geothermal research program. The well was shut in at the end of October 1987 after it had produced over 27 million barrels of brine and 676 MMscf gas, without any significant pressure decline. The stratigraphic section seen in this test well consists of alternating sandstones and shales with about 350 m (1150 ft) of net sand between 4393 m (14,412 ft) and 4974 m (16,320 ft). The producing reservoir is bounded on the north and south by faults. The east-west dimension is poorly defined due to lack of deep well control. Eleven prospective production zones have been identified. The pressure maintenance and the continuous high brine yield from the reservoir may be due to laterally overlapping and connected sandstones, communication between overlying and/or underlying reservoirs, growth faults acting as passageways for brine, shale dewatering, or possible communication of zones behind the casing.
Gladys McCall Geopressured Reservoir Analysis—June 1987
Authors: Riney T. D.
Published: November 2009

The Gladys McCall geopressured reservoir consists of an interbedded sequence of relatively thick sands and thin shales. The lateral extent of the reservoir is not well defined. Gladys McCall Well No. 1 produced approximately 4.0×106 m3 (25×106 barrels) of brine from Sand Zone No. 8 from October 7, 1983 through May 1987. Analysis of the flow data from the well has led to the development of a conceptual model of the reservoir, which depends on cross-flow from sands overlying/underlying Sand Zone No. 8 for the observed pressure maintenance. The fluid source is remote from the well in the sense that the fluid from the neighboring sands must flow a long distance to find a vertical pathway around the intervening shale stringers in order to recharge Sand Zone No. 8. A reservoir simulation model based on the conceptual model provides an excellent match to the detailed downhole pressure buildup measurements made during the original Reservoir Limits Test and two subsequent short-term buildup tests. The model has also been employed to match the production history of the Gladys McCall No. 1 well and to predict future reservoir response. Nevertheless, the reservoir model employed is not unique and alternate models for pressure maintenance are also being investigated.
Mediator-Assisted Electrochemical Desulfurization of Coal
Authors: Lalvani S. B. , Ramaswami K.
Published: November 2009

A bituminous coal from Illinois (Colchester No. 2) in acid slurry was electrolyzed anodically at 1.2–1.3 V versus SCE (saturated calomel electrode) and 65–75°C. Hydrogen gas was observed to evolve at the cathode with almost 100 percent Faradaic current efficiencies, while simultaneous desulfurization of coal was noted in the anode compartment. In order to enhance sulfur removal, the cations of Ce (IV) and Fe (III) were added to coal slurries. Up to 80 percent reduction in sulfur content of the coal was observed.
Mass Transfer in Oil Sand Fluidized Beds—A Simplified Model
Authors: Abdrabboh M. A. , Karim G. A.
Published: November 2009

Experimental data obtained previously relating to the behavior of single spherical particles of oil sands in hot uniform velocity oxidizing gaseous streams were employed and extended to estimate in a preliminary fashion the extent of mass transfer from oil sand fragments in a fluidized bed. This has been done through employing experimental correlations published in the literature on fluidization. A simple closed-form analytical expression was derived for estimating the transient rates of mass transfer in fluidized beds of oil sands in terms of the main controlling parameters.
Field Calibration of Orifice Meters for Natural Gas Flow
Authors: Ting V. C. , Shen J. J. S.
Published: November 2009

This paper presents the orifice calibration results for nominal 15.24, 10.16, and 5.08-cm (6, 4, 2-in.) orifice meters conducted at the Chevron’s Sand Hills natural gas flow measurement facility in Crane, Texas. Over 200 test runs were collected in a field environment to study the accuracy of the orifice meters. Data were obtained at beta ratios ranging from 0.12 to 0.74 at the nominal conditions of 4576 kPa and 27°C (650 psig and 80°F) with a 0.57 specific gravity processed, pipeline quality natural gas. A bank of critical flow nozzles was used as the flow rate proving device to calibrate the orifice meters. Orifice discharge coefficients were computed with ANSI/API 2530-1985 (AGA3) and ISO 5167/ASME MFC-3M-1984 equations for every set of data points. The uncertainty of the calibration system was analyzed according to The American National Standard (ANSI/ASME MFC-2M-A1983). The 10.16 and 5.08-cm (4 and 2-in.) orifice discharge coefficients agreed with the ANSI and ISO standards within the estimated uncertainty level. However, the 15.24-cm (6-in.) meter deviated up to − 2 percent at a beta ratio of 0.74. With the orifice bore Reynolds numbers ranging from 1 to 9 million, the Sand Hills calibration data bridge the gap between the Ohio State water data at low Reynolds numbers and Chevron’s high Reynolds number test data taken at a larger test facility in Venice, Louisiana. The test results also successfully demonstrated that orifice meters can be accurately proved with critical flow nozzles under realistic field conditions.
Thermal Hydraulics of Wellbores and Surface Lines During Steam/Hot Water Injection—Part I: Theoretical Model
Authors: Jensen T. B. , Sharma M. P.
Published: November 2009

A mathematical model is proposed for analyzing the thermal hydraulic behavior of wellbores and surface lines. The model discusses two-phase pressure drop and heat transfer for a variety of practical wellbore boundary conditions and includes theoretical formulations for calculating effects of geothermal gradient, transient heat flow to the surroundings of the wellbore, and radiation and convection heat transfer in the annulus. The model has been applied to evaluate the effects of insulation thickness, injection rate and injection time on steam temperature and quality. Some interesting performance behaviors are noted. The predictions of the model are compared with the results of other models [1, 2] and a field case [29].
A Note on the Existence of a Solution for Two-Phase Slug Flow in Vertical Pipes
Authors: Vo D. T. , Shoham O.
Published: November 2009

This note discusses the existence of a solution for gas-liquid slug flow in vertical pipes. The analysis presented here is based on the slug model that has been originally developed by Fernandes et al., and later modified by Sylvester. An iterative scheme is presented which not only is convenient numerically, but also provides an analytical criterion for the existence of a solution for a given set of input flow conditions.
A Study of Mass Transfer Around Oil Sand Fragments in High Temperature Atmospheres
Authors: Abdrabboh M. A. , Karim G. A.
Published: November 2009

An approximate approach was formulated to estimate the coefficient of convective mass transfer from small preshaped rectangular fragments of oil sands when subjected to hot streams of products of combustion of lean mixtures to hydrogen in air at low Reynolds number and at temperatures up to 1000 K. A simple expression which was derived to correlate the mass transfer coefficient in terms of the connective stream temperature was shown to fit the experimental data well.
A Decomposition Strategy for Thermoeconomic Optimization
Authors: El-Sayed Y. M.
Published: November 2009

An optimal thermal design of a considered system configuration is conveniently decided when the system is modeled as made up of one thermodynamic subsystem and of the essential number of design subsystems. The thermodynamic subsystem decides the performance of the components and the design subsystems decide their best matching geometry and costs. An optimizer directs all decisions to an extremum of a given objective function. This decomposition strategy is illustrated by investigating the optimal values of seven decision design variables for a regenerative gas turbine power cycle when a cost-objective function is minimized. The results seen from the point of view of second law analysis and costing are discussed.
Pinch Technology for the Synthesis of Optimal Heat and Power Systems
Authors: Linnhoff B.
Published: November 2009

Over recent years a new methodology for the analysis and design of heat exchanger networks, called pinch technology, has led to significant energy savings in the chemical and process industries. The methodology has later been extended to apply to integrated heat and power systems (Townsend and Linnhoff, 1983). This paper shows that pinch technology is firmly based in Second Law Analysis. In contrast to conventional Second Law Analysis, however, it does not require a base case design. Rather, it performs true synthesis. Also, it is capable of a methodical distinction between “inevitable” and “avoidable” exergy losses.
Energy Optimization Through Exergy-Economic Evaluation
Authors: Hua B. , Yin Q. , Wu G.
Published: November 2009

This paper deals with total system optimization for energy use in complex process systems based on the premise that the sub-systems or local schemes have been optimally designed. The problem, however, has not been solved so far. Based on the three-links-model established for the energy structure of process systems, this paper advances an evolving optimization strategy, in which the results of quantitative exergy-economic evaluation of the sub-systems are taken as the criteria to guide trade-off among them and lead the total scheme gradually towards optimum. The general concepts, evaluation equations, applying procedure, and examples are presented. Notable economical and energy-saving benefits can be (have been) obtained when used on actual industrial plants.
A Second-Order Marginal Costs Approximation for Energy Storage Charging and Discharging Price Functions
Authors: Vadasz P.
Published: November 2009

A second-order technique is presented for the evaluation of peak/off-peak price functions, based on marginal costs methods, in energy storage technologies. This method is particularly useful in statical optimization of the fundamental parameters required for planning energy storage plants. Its applications permits to transform the original dynamic optimization problem into its statical equivalent, thus reducing considerably the computing time needed. This transformation introduces two additional parameters to be optimized using statical optimization methods, i.e., charging and discharging duration.
Cost-Effective Sulfur Control Strategies for the Great Plains Gasification Project
Authors: Doctor R. D. , Wilzbach K. E.
Published: November 2009

The Great Plains gasification plant in Beulah, North Dakota, uses 14 Lurgi gasifiers to produce 152×106 scf/d (4.1×106 Nm3/d) of pipeline-quality gas from lignite. Since start-up in mid-1984, the plant has provided a serious challenge to the reliable operation of the Stretford sulfur recovery system. To address this challenge, over forty options for mitigating sulfur emissions wre evaluated on an economic and technical basis, beginning at the emissions source (the stack) and working back through the plant. Although this study was directed toward providing a timely solution to the sulfur dioxide emissions problem, the status and opportunities for a number of emerging technologies were brought into focus. Specifically, technical challenges of liquid reduction-oxidation chemistries (such as Sulfolin and Stretford), Claus technologies, and the internal handling of coal-derived liquids need to be met for future synfuels facilities.
An Experimental Study of the Performance of the Counter-Rotating Wave Energy Conversion Turbine
Authors: McCormick M. E. , Surko S. W.
Published: November 2009

Results of an experimental study of a counter-rotating turbine operating on a pneumatic wave energy conversion system are presented. The vertical capture chamber of the water column of the system has a down-facing water intake. An electrical generator (d-c) is coupled to the turbine by a ten-gear-ratio drive train. Tests of the pneumatic wave energy conversion system were conducted with the mouth at two depths in order to vary the natural oscillating frequency of the water column. The maximum electrical power output of the system was approximately 90 W in the monochromatic waves. This value corresponds to a 36-percent efficiency based on the incident wave power in a wave crest width equal to the diameter of the capture chamber. The theoretical maximum efficiency of such a system has been shown to be 50 percent by several investigators.
Analytical Simulation of the Composite Ice Wall
Authors: Corder P. , Kozik T.
Published: November 2009

A system of linear, closed-form stress equations for a steel-concrete-steel sandwich configuration, i.e., the “Composite Ice Wall,” was derived incorporating a formulation of classical beam theory. The stress terms include the longitudinal normal stress, the transverse shear stress and the transverse normal stress. These equations were programmed using Pascal and a parametric study was conducted. Some of the results are included herein. The analytical model produces principal stress contours and centerline deflections very similar to those in the classical beam for comparable pressure loadings.
The Effect of Inclination on Flow Regime Boundaries and Slug Flow Characteristics
Authors: Wood D. G.
Published: November 2009

Multiphase schemes for oil and gas production systems are becoming more common as the development of marginal fields necessitates a reduction in capital costs. Prediction of flow regime within these pipelines and the characteristics of the flow, especially within the slugging regime, is required in order to design the pipeline and the downstream separation and processing facilities. Test rig studies have been carried out at BP’s Sunbury Research Centre on the effect of small changes in pipeline inclination on both the flow regime and the characteristics of slug flow. Results from tests on a 2-in. rig are quoted.
A Valveless Pulse Combustor With Wide Operation Range and Low Noise Level
Authors: Ohiwa N. , Yamaguchi S.
Published: November 2009

The possibility of a valveless pulse combustor with wide range and low noise level was experimentally examined by introducing two practical approaches simultaneously: one is the rich mixture supply outside the flammability limit, instead of the ordinary fuel supply without any primary air; the other is forced secondary air ventilation. An overall evaluation of pulsation limits was also made in terms of the volumetric efficiency of the pulse combustor. Fuel used was a commercial grade gaseous propane. The results showed that, under a constant total of equivalence ratios of 0.9, a large turn-down ratio of 9.4–11.5 and a high combustion intensity of 55–67MW/m3 could be obtained by setting the rich mixture equivalence ratio equal to 3.0. Also, the proposed valveless pulse combustor could operate more silently than the flapper-valved one by 3-8dB (A), being indicative of noise radiation due to valve flapping.
Examination of the Formation of Combustible Mixtures by Diffusional Mass Transfer
Authors: Badr O. A. , Karim G. A.
Published: November 2009

The approximate prediction of the concentration profiles following the release of a fuel into air, typically within a confined space at constant pressure and temperature is presented using generalized charts based on the one-dimensional diffusion equation and an effective eddy diffusivity. It is suggested that such generalized plots can be employed to establish the size and changes with time of the associated flammable zones, including when convective diffusion may be involved. Examples for some typical common fuels are presented.
Flame Initiation and Spread Characteristics Within Homogeneous Streams of Methane-Air Mixtures
Authors: Karim G. A. , Sarpal G.
Published: November 2009

The flame initiation and spread characteristics following spark ignition within a subsonically flowing homogeneous stream of methane and air inside a smooth cylindrical long tubular reactor were examined experimentally. The effects of the imposition of flow pulsations of known frequency and amplitude on the combustion processes and the extent of variations observed in the combustion processes when tests were repeated under otherwise identical conditions were also established.
Stochastic Response of Tension Leg Platform to Wave and Current Forces
Authors: Ertas A. , Lee J.-H.
Published: November 2009

The linear analysis in the frequency domain is presented for the surge motion of a tension leg platform (TLP) in the case of random waves only and random waves with constant current. A single-degree-of-freedom model of a TLP is employed for response. The superposition method, one of the simulation techniques, is applied to random sea wave, and the response analysis of TLP in time is developed with wave velocity and wave acceleration simulations. Wave-induced forces are calculated using the modified Morison equation, which takes into account relative motion. Computational methods for both analyses are developed, and the results of stochastic, dynamic response of the TLP, with and without the presence of current, are presented and compared.
The Design and Performance Optimization of Thermal System Components
Authors: von Spakovsky M. R. , Evans R. B.
Published: November 2009

A general analytical approach which directly determines the optimum thermodynamic and economic behavior of thermal systems and which is described in detail in von Spakovsky and Evans (1987) and von Spakovsky (1986) is briefly discussed here in the context of establishing a “stable economic environment” around each cycle component. Such environments allow for isolated, individual component optimizations which need not to be performed at the time the system is optimized, but which nonetheless correspond to some overall system optimum. In these environments, very “detailed” thermoeconomic component models can be optimized without the added complications resulting from a consideration of all the other system variables. The development and optimization of these “detailed” models is illustrated using the example of a feedwater heater. Utilizing the Second Law and typical Second Law costing techniques, the method presented here provides for the creation of mathematical models which balance operating costs and capital expenditures. Such models can be solved numerically for the optimum design point or the optimum operating point of a thermal system and each of its components.
Shear Stability, Instability and Localization of Materials Exhibiting Thermal Softening, Strain Rate Sensitivity and Strain Hardening
Authors: Charalambakis N.
Published: November 2009

We consider the test-problem of simple shearing of a thermoviscoplastic solid subject to steady or time-dependent boundary velocities or shear forces. Previously derived stability and nonlocalization criteria are presented. The influence of boundary conditions on the time-asymptotic “solution,” the role of nonuniformities and the localization of plastic deformation are discussed. Finally, a perturbation analysis of homogeneous solution under steady boundary velocities or stresses of a material with a gradient-dependent flow stress is presented and “shear-banding” criteria are derived.
Biocompatible Bacterial Cellulose Composites for Biomedical Application
Authors: Kim Jaehwan , Cai Zhijiang , Chen Yi
Published: November 2009

This paper reports bacterial cellulose composites made by blending chitosan, poly(ethylene glycol) (PEG), and gelatin for potential biomedical application of tissue-engineering scaffold and wound-dressing material. The bacterial cellulose composites were successfully prepared by immersing a wet bacterial cellulose pellicle into chitosan, PEG, or gelatin solutions followed by freeze-drying. The products look like a foam structure. Scanning electron microscopy images show that chitosan molecules penetrated into bacterial cellulose forming a multilayer and a well interconnected porous network structure with a large aspect surface. The morphology of the bacterial cellulose/gelatin scaffold indicates that the gelatin molecules could penetrate well between the individual nanofibers of the bacterial cellulose. Cell adhesion studies for these composites were carried out using 3T3 fibroblast cells. They showed much better biocompatibility than pure bacterial cellulose. Preparation and material characterization of these composites are explained.
Mechanistic Study of Self-Assembling Peptide RADA16-I in Formation of Nanofibers and Hydrogels
Authors: Zhang Hangyu , Luo Hanlin , Zhao Xiaojun
Published: November 2009

The biophysical and biochemical properties of RADA16-I, the representative of a class of self-assembling peptides, were studied to elucidate the molecular mechanism of nanofiber and hydrogel formations. We found that self-assembly occurs in the solution at low pH (pH 4), rather than the popular belief that it occurs in the physiological environment. Actually, the peptide lost its β-sheet structure and formed irregular aggregates in the condition around pH 7. Our results demonstrated that the extended conformation of peptide backbone caused by the electrostatic repulsive force in acid solution is crucial for the peptide to self-assemble into nanofibers. Importantly, we have proposed a mechanism for the peptide to form nanofiber hydrogel in the physiological condition, which is not propitious for nanofiber formation. Hypothetically, it is by virtue of the tendency of fibers to collapse and form irregular aggregates at pH 7 that we could obtain stable hydrogels by introducing phosphate buffered saline into the system.
Potassium Ion Sensing With Nanowire Electrodes on a Flexible Substrate for Early Detection of Myocardial Ischemia
Authors: Ramachandran Vasuda , Yoon Hargsoon , Varadan Vijay K.
Published: November 2009

An increase in extracellular potassium levels is a physiological sign of myocardial ischemia and timely sensing with an implantable potassium sensing biosensor could play a significant role in detecting and expediting care. In this paper, unique fabrication techniques for both planar and nanowire structured gold microelectrodes are described along with data showing the enhanced charge transfer capabilities of the nanowire design. Optimization is required for the electrodeposition of polypyrrole onto gold nanowires and processing details along with characterization data are provided for both the polypyrrole layer and ion selective membrane. Cyclic voltammetry and electrochemical impedance spectroscopy results show that the polypyrrole coated gold nanowire electrodes provide stable charge transfer, showing the potential as a potassium sensing device for the early detection of myocardial ischemia applications.
An Atypical CNG Channel Activated by a Single cGMP Molecule Controls Sperm Chemotaxis
Authors: Bönigk Wolfgang , Loogen Astrid , Seifert Reinhard , Kashikar Nachiket , Klemm Clementine , Krause Eberhard , Hagen Volker , Kremmer Elisabeth , Strünker Timo , Kaupp U. Benjamin
Published: November 2009

The ability of a single molecule of cGMP to activate the K
+
-selective cyclic nucleotide–gated channel allows sea urchin sperm to find an egg.
Toll 2 Interferon Production
Authors: Wong Wei
Published: November 2009

Certain viruses trigger interferon production through a Toll-like receptor 2−dependent mechanism in inflammatory monocytes.
A Ready Supply
Authors: Adler Elizabeth M.
Published: November 2009

Constitutive internalization of CX
3
CL1 prevents its proteolytic degradation and may enable its rapid deployment when needed.