bluuebunny/crossref_metadata_2025 huggingface dataset:
The Uses and Morphology of Atmospheric Fluidized Bed Combustion Wastes From Canada’s First Industrial AFBC Boilers
Authors: Berry E. E. , Anthony E. J. , Kalmanovitch D. P.
Published: November 2009

The literature of FBC solid wastes has been critically evaluated and solid wastes from Canada’s first atmospheric fluidized bed combustion (AFBC) boilers at the Canadian Forces Base (CFB) Summerside, Prince Edward Island have been investigated in order to determine possible uses for AFBC wastes. Scanning electron microscopy (SEM), electron microprobe, and chemical and physical tests were employed to determine the suitability of the material for pollution control, construction, and other uses. SEM and ancillary techniques have shown that the chemical and physical properties of the bed material and the elutriated streams are significantly different. Agricultural use, pollution control, soil stabilization (where freezing and thawing are not significant problems), asphaltic concrete, and specialized construction applications such as low strength backfill appear to be potential uses for FBC solid wastes.
On the Vortex-Induced Oscillation of Long Structural Elements
Authors: Iwan W. D. , Jones N. P.
Published: November 2009

Previous solutions to the vortex-induced vibration of structures have been primarily based on modal analysis, using a one or two-mode approximation. Such an analysis is generally meaningful only when the vortex shedding frequency is locked onto a natural frequency of the structure. In very large structures, typical of those found in some ocean engineering applications, modes are closely spaced, and it is not reasonable to assume total spanwise correlation in the fluid forces or response. The approach used herein avoids the limitations associated with the modal solution of such problems by implementing a solution based on the traveling wave nature of the response. Results presented indicate that the amplitude of response of a long cable is smaller than is predicted by a conventional modal analysis. The drag forces on such a structure may therefore be overestimated by current design approaches.
The Performance of Fabric Filters in a Pilot Baghouse During Coal Water Fuel Combustion Trials
Authors: Thanisch M. R. , Rankin D. M. , Read P. J. , Whaley H.
Published: November 2009

Energy, Mines and Resources, Canada, together with the New Brunswick Electric Power Commission (N.B. Power) and Cape Breton Development Corporation have undertaken a program in eastern Canada to demonstrate coal-water fuel (C.W.F.) technology for electric utility boilers. The successful results of the C.W.F. demonstration in N.B. Power’s Chatham Generating Station led to a continuation of the program in a 20-MWe compact oil-designed utility boiler in Charlottetown, P.E.I. during the latter part of 1986 and early 1987. Based upon the results of the Charlottetown demonstration an evaluation of C.W.F. for a larger utility boiler (in the 90–150-MWe range) is planned. An essential feature of the Charlottetown demonstration, and any subsequent use of C.W.F., is the containment of the particulate emissions which arise from use of coal in the boiler. This paper describes tests which were undertaken at Chatham, using a pilot-scale baghouse, in order to be able to specify equipment, materials and operating procedures for the Charlottetown C.W.F. demonstration.
A Mechanistic Model for Two-Phase Vertical Slug Flow in Pipes
Authors: Sylvester N. D.
Published: November 2009

This paper presents the formulation of a mechanistic model for slug flow in vertical pipes. The equations required to determine holdup, the relevant velocities and pressure loss are presented. The model is fully deterministic and the pressure drop predictions of the model are compared to experimental field data for oil and gas and gas and water wells. For the 143 data points, the model shows an average percent difference of 4.83 percent, which is felt to be excellent.
Correlating the PVT Properties of Nigerian Crudes
Authors: Obomanu D. A. , Okpobiri G. A.
Published: November 2009

Existing correlations for predicting solution gas oil ratio, Rs, and oil formation volume factor, Bo, gave standard deviations as high as 50 and 12 percent, respectively, for Nigerian crudes. New correlations developed using 503 Pressure-Volume-Temperature (PVT) data points from 100 Nigerian crude oil reservoirs of the Niger Delta Basin are presented. The correlations for Rs and Bo predict values from different reservoirs within 6 and 2 percent standard deviations, respectively, and will apply to crudes of specific gravity range 0.811 to 0.966. These correlations are applicable to other crudes with characteristics similar to those of Nigerian crudes.
An Improved Model for Predicting Heat Losses and Pressure Changes in Steam Injection Wells—Part 2: Model Evaluation
Authors: Yao S. C. , Sylvester N. D.
Published: November 2009

The improved model developed in Part 1 for predicting heat losses and pressure changes in steam injection wells is evaluated. It shows good agreement with limited field data. The improved model is used to predict the effects of steam injection time, rate and pressure, well depth and tubing diameter on heat losses, bottomhole pressure and downhole steam quality. A design example is presented to illustrate the solution method for a common field operations problem.
Experimental and Analytical Investigation of the Convective Diffusion of Methane Into Air
Authors: Karim G. A. , Lam H. T. , Petela R. , Rowe R.
Published: November 2009

The concentration changes with time and space of methane gas were examined following its release into air at atmospheric pressure within a long smooth cylindrical tube of 2.5 in. (63.5 mm) diameter, taking into account the combined effects of molecular diffusion and natural convection. The concentration profiles as a function of diffusion time at specified regions of the tube was determined by measuring the velocity of sound in the medium along a tube diameter using an ultrasonic gas analyzer. Comparative tests involving carbon dioxide, neon and helium were also made. It was shown that the experimental concentration profile for the diffusion of methane observed may be reproduced using the simple one-dimensional classical diffusion equation when the molecular diffusivity was replaced by a very much larger effective eddy diffusivity that appeared to depend on the diffusion time and local concentration gradient.
Tension Fatigue Model for Helically Armored Cables
Authors: Knapp R. H. , Chiu E. Y. C.
Published: November 2009

A fatigue model which predicts cycles-to-failure for helically armored cables subjected to fluctuating axial tension is proposed. Electrical-optical communication cables, power cables, and bridge and track strands normally derive structural strength from two or more layers of round steel wires contrahelically laid around a cylindrical core. In cases where wires are laid in direct contact with wires in adjacent layers, Hertz contact stresses produce wire failures leading to ultimate cable failure at tensions well below the static breaking strength. The proposed model treats cross-wire Hertz contact stresses as equivalent geometric notches in conjunction with the numerical solution of the governing helical wire cable equations. Model and physical test results show good agreement.
Thermal Characteristics of Damp Hydrophobic, Microfibrous Batt
Authors: Steele K. A.
Published: November 2009

The thermal characteristics of damp, hydrophobic insulating material used primarily in underwater dry suit applications were investigated. Testing was performed in a Rapid-K Thermal Conductivity Instrument manufactured by Dynatech, Inc. A mathematical model of the process was proposed, and the results obtained using this model were compared to experimental results. The two agreed well except in the higher temperature range, where the model predicts higher thermal conductivities than those observed. However, for the region of interest agreement was good, and the model should be considered valid for the preliminary design of dry suits using hydrophobic batting as an insulator.
The Integration of Synthesis and Optimization for Conceptual Designs of Energy Systems
Authors: El-Sayed Y. M. , Gaggioli R. A.
Published: November 2009

The evolutionary process of system synthesis and the mathematical process of system optimization are integrated in one do-it-yourself software. A large number of flowsheet arrangements can be conveniently evaluated and optimized. The interactions among dissipations and dissipators can be monitored and analyzed to establish leading indicators to optimal configuration. The software is briefly described. An example problem demonstrates the integration of synthesis and optimization. The distribution of dissipations of the considered solutions to the problem are discussed.
Second Law Efficiency and Costing Analysis of a Combined Power and Desalination Plant
Authors: Gaggioli R. A. , El-Sayed Y. M. , El-Nashar A. M. , Kamaluddin B.
Published: November 2009

Flow diagrams for exergy have been made for Unit 2 at the Umm Al Nar West power plant in Abu Dhabi. This unit is one of six in a combined power and desalination facility, each delivering 60 MW of electricity and 18000 metric tons per day of freshwater at design conditions. The diagrams show the rates of exergy flow between all of the components in the facility as well as the consumption in each. For the desalination facility, diagrams were developed for both summer and winter operation, at design conditions. The steam generation and power plant diagrams were made for full and three-quarter electrical loads, and full-load delivery of steam to the desalination plant. Furthermore, detailed exergy costing diagrams have been constructed for the steam/power facility, at both full and three-quarter electrical load conditions. Conclusions are drawn regarding means for improving the existing plant and future designs.
A Theoretical Analysis of Predrying of Solid Fuels With Flue Gas
Authors: Kinoshita C. M.
Published: November 2009

Combustion efficiency and flue-gas drying of solid fuels are analyzed. A simple, universal arithmetic expression for combustion efficiency is developed. This expression involves four primary dimensionless parameters which relate to (and are fixed for given) fuel and ambient conditions, and three secondary dimensionless parameters which relate to (and vary with) fuel moisture content, excess air, and flue-gas temperature. Additional expressions involving the same primary parameters are developed to calculate the decrease in fuel moisture content due to flue-gas drying with and without entrainment of air into the dryer system and the decrease in flue-gas temperature with air entrainment. Values for the four primary parameters are presented for various fuels; their values do not vary much for most biomass fuels.
Improved Modeling of Pulverized Coal Combustion in a Furnace
Authors: Jang D. S. , Acharya S.
Published: November 2009

A comprehensive computer code is developed for the calculation of pulverized coal combustion and is evaluated against a series of IFRF experimental data. An improved stochastic model for turbulent particle dispersion is implemented together with a phenomenological fast chemistry eddy breakup model for coal-off gas combustion. The predicted and measured values show good agreement with each other. However, model deficiencies are noted in the prediction of nonequilibrium phenomena such as local flame extinction and minor species (e.g., CO) formation.
Double Pipe Ensures Reliable Insulation of Offshore Pipelines
Authors: Bruschi R. , Gambelli L. , Pierangeli P. , Raffaeli E.
Published: November 2009

At the beginning of the eighties, the offshore technology relevant to thermally insulated pipelines did not offer a cost-effective and technically challenging solution. Nowadays, the oil industry requires an ever-increasing use of thermally insulated pipelines with improved reliability in the offshore and, more particularly, for the exploitation of arctic fields. The present solution has been developed on the basis of easy handling, conventional laying procedures and long-term integrity criteria adopting a special field joint connector. This type of connector allows the two coaxial pipes to be assembled in a workshop and the individual double pipe sections to be connected in the field by means of a standard butt weld. This paper includes: the presentation of the DPIS (Double Pipe Insulated System) concept, which deals with the structural and thermal insulation aspects relevant to this new system; and a brief description of the first application of the DPIS for a pipeline connecting an unloading terminal for heavy oils to onshore plants.
Approaches to Acoustic Backscattering Measurements From the Deep Seafloor
Authors: de Moustier C.
Published: November 2009

Because the average ocean depth is four kilometers, seafloor investigations are mostly remote sensing operations. The primary means to determine the morphology, the structure, and the texture of the seafloor are acoustic. This paper considers the current seafloor remote sensing approaches involving acoustic backscattering. The physical constraints imposed by the ocean as a propagation medium, by the seafloor as a backscattering boundary, and by the measuring instruments are briefly reviewed. The sonar systems currently used by the oceanographic community for deep seafloor acoustic backscattering measurements deal with these constraints differently, depending on their specific application and on whether they are towed behind a ship or mounted on her hull. Towed sidescan systems such as Gloria II (U.K.), the Sea Mapping and Remote Characterization (Sea MARC) I and II, the Deep Tow system of the Marine Physical Laboratory (MPL), and hull-mounted systems, such as Swathmap all give a qualitative measure of backscattering by converting echo amplitudes to gray levels to produce a sidescan image of the seafloor. A new approach is presented which uses a Sea Beam multibeam echo-sounder to produce similar acoustic images. Quantitative measurements of backscattering have been attempted in recent experiments using the Deep Tow system and Sea Beam. Such measurements provide some insight into the geological processes responsible for the acoustic backscatter, with useful applications for geologists as well as designers and operators of bottom-interacting sonars.
A Mathematical Model for Predicting Concentration Profiles in Liquid-Solid Fine Slurry Pipe Flows
Authors: Satchwell R. M. , Sharma M. P. , Miller R. L.
Published: November 2009

Radial solid concentration profile distributions are often present in pipe flows of fine particle slurries, and play a dominant role in controlling the behavior of the flow. This paper presents a mathematical model for predicting such profiles from actual pressure drop data. The model is based on the concepts of “layered pseudo-homogeneous non-Newtonian fluids.” Preliminary results of studies with this model are discussed.
The Behavior of Tar Sand Fragments in Steady Streams of the Products of Combustion of Lean CH4-Air or H2-Air
Authors: Karim G. A. , Ishola G. , Hanafi A.
Published: November 2009

The behavior of tar sand fragments, molded into either slabs or spheres, was examined when exposed to low-velocity streams of the products of combustion of lean CH4-air mixtures, at temperatures of 700 K to 1200 K or lean H2-air mixtures at temperatures of 700 K to 1000 K. The processes of volatilization followed by slow oxidation were identified at low temperatures while autoignition and subsequent combustion of the volatiles complemented and enhanced the volatilization stage at higher temperatures. Some gross kinetic parameters of the processes involved are then evaluated using the mass loss and ignition delay data obtained.
The Design and Engineering of Cross-Country Hydrogen Pipelines
Authors: Mohitpour M. , Pierce C. L. , Hooper R.
Published: November 2009

Design of cross-country hydrogen pipelines is still uncommon. No industry-accepted codes and standards have been developed to guide the engineering and design of such facilities. A hydrogen pipeline was required to connect a hydrogen purification plant to an anhydrous ammonia production facility. Since no pipeline standards were available, special considerations were required during the design and engineering stages. The small molecular size and reactivity of hydrogen presented unique problems. So do the hydrogen embrittlement/attack/delayed failure phenomena, inverse Joule-Thomson effects and special concerns for commissioning, operation and maintenance. This paper will review world experience, the research, economics, design and safety considerations for hydrogen gas pipelines, as well as the engineering, design and construction methods which were considered necessary by Novacorp International Consulting Inc. for successful completion of the project.
Seismic Response of Buried Submarine Pipelines
Authors: Datta T. K. , Mashaly E. A.
Published: November 2009

Submarine pipelines are many a time buried into a jet-blasted channel in the seabed. Seismic response of such buried pipelines are investigated in this paper. The earthquake is considered as a partially correlated stationary random process characterized by a power spectral density function (PSDF). The cross-spectral density function between two random inputs along the length of the pipe is defined with the help of the local earthquake PSDF, which is the same for all points, and a frequency-dependent, exponentially decaying function (with distance). A lumped-mass model with 2-D beam elements is used to write the equation of motion. Soil resistance to dynamic excitation along the pipe length is obtained in an approximate manner with the help of frequency-independent impedance functions derived from half-space analysis and Mindlin’s static stresses within the soil due to point loads. The responses are obtained by a spectral analysis for horizontal ground motions in two principal directions, which are assumed to coincide with pipe axis and the perpendicular to it. Using the proposed method of analysis, a parametric study is conducted. The results of the study help in understanding the behavior of buried submarine pipelines under seismic forces and its differences from that of the buried pipelines on land.
Terminal Slugcatchers for Two-Phase Flow and Dense-Phase Flow Gas Pipelines
Authors: Oranje L.
Published: November 2009

Slugcatchers are installed at the end of two-phase pipelines and dense-phase pipelines. The technical specifications of a slugcatcher for a two-phase pipeline are based on the gas-liquid flow behavior at the various operating conditions. For a dense-phase pipeline these specifications are derived from the flow behavior in the pipeline during depressurization. These flow studies, which are carried out in the design stage of a transmission system, should be sufficiently accurate to provide proper sizing of the transmission line and slugcatcher. The paper deals with: • the methods and the quality of these methods for calculating the flow behavior in a two-phase pipeline and in a dense-phase pipeline—a comparison of both types of transmission systems is given; • the basic design of a terminal slugcatcher, including some causes of possible malfunctioning—an optimal design of a terminal slugcatcher is also discussed.
Vortex Tube-Assisted Environmental Control of Hyperbaric Chambers
Authors: Baz A. , Gilheany J.
Published: November 2009

Model predictions of time histories of the temperature and humidity ratio within a hyperbaric chamber under conditions of compression and decompression are presented with and without vortex tube-assisted environmental control. The effects of ventilation and ascent and descent rates on the environment within the chamber and the power required by the environmental control system, with and without vortex tube assist, are also presented. Results demonstrate that the vortex tube assist system is an effective means of more precisely controlling the environment within hyperbaric chambers with substantial savings in power. The model used incorporates a complete description of the pyschrometric properties of the humid gas mixture within the chamber, plus the sensible and latent heat loads produced by the occupants and wet porch.
Formulas for Variation of Stress Concentration Around Intersection in Tubular Joints
Authors: Sundaravadivelu R. , Hariharan M. , Ganapathy C.
Published: November 2009

Many of the offshore structures used for oil exploration and exploitation are built of tubular members. The repeated damages in tubular joints have clearly shown that the safety of these structures depends on the safe fatigue design of the joints. The fatigue life of the joint depends very much on the Stress Concentration Factor, SCF. The current practice is to use semi-empirical formulas proposed by various investigators to determine SCF. While some of the formulas give the maximum SCF, others give the SCFs at both the crown and saddle points. The design of fatigue life using the value of maximum SCF is conservative, while using SCFs at crown and saddle is unsafe. The main aim of this paper is to propose a set of formulas for T and Y-joints, which gives not only the magnitude of maximum SCF as in the presently available formulas, but also the variation of SCF around intersection.
Stress Concentration Factors in T and K-T Tubular Joints Using Finite Element Analysis
Authors: Dijkstra O. D. , Puthli R. S. , Snijder H. H.
Published: November 2009

Stress concentration factors (SCFs) in a T and a K-T tubular joint have been determined using the finite element method (FEM). The SCFs are determined for basic load cases (axial load or bending moment) in one of the braces or in the chord. The results of the FEM are compared with available experimental data and with parametric formulas. The T-joint results for brace loadings agree reasonably with the parametric formulas. The K-T joint results for in-plane bending agree reasonably with the parametric formulas.
Heat Transfer in the Flow of Gases Around Oil Sand Spheres
Authors: Abdrabboh M. A. , Karim G. A.
Published: November 2009

An experimental study was conducted for the combined free and forced convection heating of preshaped molded spherical particles of Athabasca oil sands in hot gaseous streams of air at low Reynolds numbers. Based on a quasi-steady system, the lumped-heat-capacity approximation was employed to estimate the heat transfer coefficient of the transient convective system for each prescribed set of experimental stream conditions. Correlation of the results was made in terms of the dimensionless Nusselt number as a function of the particle Reynolds number and a dimensionless temperature difference. The simple closed-form analytical expression of the correlation was shown to fit the experimental data well.
Discontinuities in the Orkiszewski Correlation for Predicting Pressure Gradients in Wells
Authors: Brill J. P.
Published: November 2009

The Orkiszewski correlation is used extensively in the petroleum industry for predicting pressure gradients when gas and liquid flow simultaneously in wells. Unfortunately, the correlation contains a parameter called the liquid distribution coefficient, Γ, that can be discontinuous at a superficial mixture velocity of 10 ft/sec. The liquid distribution coefficient is used to predict both the elevation and friction components of the pressure gradient for slug flow. The accepted trial and error method for integrating the pressure gradient to obtain pressure loss in wells can fail to converge when pressure gradients are discontinuous. Examples of discontinuities in Γ for oil as the continuous phase are presented for several liquid viscosities ranging from 0.3 to 200 cp and for pipe diameters of 1.049, 2.441 and 6.049 in. It was found that a constraint recommended for Γ when mixture velocity <10 ft/sec was essentially useless. It was also found that a constraint for velocities >10 ft/sec could actually increase the magnitude of pressure gradient discontinuity. Convergence of pressure loss calculations when the discontinuity was encountered was possible only if the convergence tolerance was temporarily relaxed.
Phase Change Heat Transfer During Melting and Resolidification of Melt Around Cylindrical Heat Source(s)/Sink(s)
Authors: Sasaguchi K. , Viskanta R.
Published: November 2009

Melting and resolidification of a phase change material around two cylindrical heat exchangers spaced vertically have been investigated experimentally. Experiments have been performed to examine the effects of the cylinder surface temperatures on heat transfer during the melting and freezing cycle. The processes have been clarified on the basis of observations of timewise variations in the solid/liquid interface and of temperature distribution measurements in the phase change material. The results show that the solid/liquid interface contour during the melting and resolidification of the liquid from the upper cylinder is greatly affected by the surface temperature of the lower cylinder. The results show that multiple liquid regions may develop in the phase change material around the embedded heat sources/sinks, and the temperature swings and melting and freezing periods need to be selected properly in order to effectively utilize the phase change material in a latent heat energy storage unit.
Forced Vibratory Motion of a Circular Disk on an Infinite Transversely Isotropic Medium
Authors: Tsai Y. M.
Published: November 2009

The forced vertical vibratory motion of a rigid body with a circular base on the surface of a transversely isotropic material is investigated by using the method of Hankel transform. The total dynamic contact force is obtained through a complete contour integration in terms of the Rayleigh surface waves. The real-valued displacement functions are expressed in terms of the frequency factor and the anisotropic material constants. The resonant amplitudes of vibration are shown to depend significantly on the anisotropic material constants, the mass ratio, and the vibration frequency.
A Critical Review of Second Law Costing Methods—II: Calculus Procedures
Authors: Gaggioli R. A. , El-Sayed Y. M.
Published: November 2009

The following article completes the review of the development and state of engineering economic applications of the Second Law of Thermodynamics, which was begun in Part I (El-Sayed and Gaggioli, 1989). We began with a historical review, followed by a brief discussion of the relevant cost accounting concepts and, in turn, general descriptions of the different exergy costing methods which are in existence. Then, the various algebraic techniques of exergy costing were analyzed and critiqued, generally by considering successive publications developing and/or based on a technique. This paper, on the other hand, is devoted primarily to calculus methods. Of course the algebraic and calculus techniques do relate to each other, and those relationships are developed here. Furthermore, general concepts, discussion and conclusions which are relevant to both algebraic and calculus methods are presented, along with suggestions regarding further research.
The Flammability of Fuel Mixtures in Air Containing Propane and Butane
Authors: Wierzba I. , Karim G. A.
Published: November 2009

The behavior of the lean and rich flammability limits of various fuel mixture combinations involving propane, n-butane, propylene and ethylene, which feature prominently in a variety of industrial and natural fuel gases such as liquefied petroleum gases (LPGs), was examined. It was found that the lean limits of such mixtures can be predicted well by using Le Chatelier’s Rule. This rule can also predict the rich flammability limits of propane-n-butane mixtures. However, its application to calculate the rich limits of mixtures such as propane-propylene, propane-ethylene, butane-ethylene, propylene-ethylene mixtures carries a significant error with certain mixtures composition. The effect of the dilution of such fuel mixtures with nitrogen or carbon dioxide was also investigated and a predictive procedure is described.
Volatilization and Ignition of Oil Sand Samples During Intermittent Exposure to Hot Low-Velocity Air Streams
Authors: Karim G. A. , Hanafi A. , Mehta S. A.
Published: November 2009

The behavior of small oil sand samples was monitored experimentally when subjected repeatedly to low-velocity heated air streams, with either prompt quenching or slow cooling of the samples to their initial temperatures between these exposures. The stream temperature was either in the range of 300°C to 500°C in air or at higher temperatures of up to 760°C, while being exposed to the products of combustion of very lean hydrogen-air mixtures. This was done in relation to understanding better the associated processes in some in-situ recovery trials where stoppage of the combustion front and/or the flow of the injected fluids can occur. A variety of multi-exposure-cooling schemes was considered and their effects on the extent of volatilization and ignition established. Comparison to the corresponding behavior of similar samples under uninterrupted exposure to the heated streams was made throughout.
Vortex Load Reduction: Experiments in Optimal Helical Strake Geometry for Rigid Cylinders
Authors: Wilson J. F. , Tinsley J. C.
Published: November 2009

Vortex-induced lift loads and their energy spectra were measured on laboratory-scale models of isolated, rigid, right circular cylinders subjected to steady, transverse currents. The control cylinder was smooth and the others were fitted with right-handed or left-handed, constant angle helical strakes that protruded one-tenth the cylinder diameter. For Reynolds numbers of the order of 104, the results clearly show that, compared with the smooth cylinder counterpart, the geometry that most effectively reduces both the lift coefficient and also the peaks of the lift load energy spectra in the low frequency band is three evenly spaced strakes at a 60-deg angle with the cylinder’s transverse axis.
An Analytical Framework for Preliminary Evaluation of Space Conditioning Systems
Authors: Bullard C. W.
Published: November 2009

This paper introduces a methodology for comparing three advanced space and water heating technologies whose higher second-law efficiencies promise to offset their increased capital costs: 1) onsite cogeneration; 2) centralized cogeneration with district heating; and 3) electric heat pumps. The competing technologies are compared within a single-system boundary that includes the electric utility system, because cogeneration systems produce electricity and heat pumps consume it. This approach eliminates the electric rate structure from the equations, allowing the analysis to focus on cost rather than price. The results are intended to inform a longer term perspective, over which modern metering technology will enable utility rate structures to reflect the real duration-dependent cost of electricity generation.
SUPERTARGETING: Optimum Synthesis of Energy Management Systems
Authors: Linnhoff B. , Ahmad S.
Published: November 2009

Thermodynamically based procedures that guarantee minimum energy levels in the design of integrated systems have recently been reported in the chemical engineering literature. These procedures—generally summarized as pinch technology—apply to heat exchanger networks, heat pumps, combined heat and power cycles, and utility systems. The procedures are based on Second Law Analysis. They have proven successful in over 500 industrial applications worldwide and the cost benefits have been significant. This paper describes recent developments in pinch technology aimed at the optimization of energy and capital. An overall method has now emerged which brings together energy and capital costs. It virtually guarantees near global optimality for integrated process plant and energy systems. This guarantee even applies for complex and highly constrained industrial problems. A key concept is that of supertargeting.
Application of Sonic Nozzles in Field Calibration of Natural Gas Flows
Authors: Shen J. J. S. , Ting V. C. , Jones E. H.
Published: November 2009

This paper presents Chevron Oil Field Research Company’s operating experience using the sonic nozzle as a proving device for measuring natural gas flows in field tests. The nozzle reference flow rate was used for calibrating orifice, turbine, and vortex meters in three tests with a pipeline quality gas and an unprocessed natural gas as the working fluid. For pipeline gas, the field calibration results show good agreement between the sonic nozzle reference and a turbine meter while the accuracy of orifice metering is size dependent. The 4-in. (102-mm) orifice meter flow rates agree well with the nozzle reference, but the 16-in. (406-mm) orifice flow measurements are up to 2 percent lower. Deviations between the test meters and the sonic nozzles are generally larger for the unprocessed gas. These field projects demonstrate that sonic nozzles can be operated successfully as a prover for processed natural gas, while more work is needed to study the critical flow in nozzles for unprocessed natural gas.
Influence of Variable Fluid Density on Free Convection in Rectangular Porous Media
Authors: Marpu D. R. , Satyamurty V. V.
Published: November 2009

Free convection in rectangular porous media has been numerically investigated incorporating the dependence of fluid density on temperature in all the conservation equations. The fluid density dependence on temperature is described through a parametric equation which can be used for different fluids. The method of successive accelerated replacement scheme has been employed to obtain numerical results for a wide range of Rayleigh numbers, 50 to 1000, aspect ratio, 0.1 to 10 and density difference ratio of 0 to 0.75. The increase in the average Nusselt number at a Rayleigh number of 100 and an aspect ratio of unity is 9.57 percent when density difference ratio is 0.25, whereas it is as high as 19.88 percent when the density difference ratio is 0.5.
Modeling of a Magma Energy Geothermal Open Cycle Power Plant
Authors: Boehm R. F. , Berg D. L. , Ortega A.
Published: November 2009

We are currently investigating the engineering feasibility of drilling into an active magma body at a depth of roughly 5 km from the earth’s surface, establishing a downhole heat exchange region, and extracting thermal energy from the magma body by circulating fluid through this heat exchange region. In the present paper, we evaluate the overall thermodynamic performance of a conceptual magma energy system in which energy is added as heat to the fluid within the magma region and is converted to useful work in a power conversion cycle at the surface. Unusually high return temperatures and pressures may be available at the wellhead of such a circulating well. Investigated here is an open Rankine power system in which heated water from the magma well is circulated directly through a power conversion cycle. The downhole heat exchange region is established during the drilling process. As drilling proceeds into the magma, a solidified layer forms about the drilling tube due to heat exchange to the fluid. This solidified layer thermally fractures because of large temperature gradients between the cooled inner region and the heater outer region, thereby opening secondary flow paths. Two models of the downhole behavior have been used. In the simplest approach, denoted as the “infinite area model,” the water entering the pipe to return to the surface is assumed to be always at the temperature of the magma, independent of mass flow rate and other parameters. The other model is more detailed and the fractured heat exchange region is modeled as a cylindrical porous layer through which fluid flows vertically. The net power and other performance aspects for the systems are investigated in terms of various parameters, including the characteristics of the downhole heat transfer. It is concluded that the open Rankine cycle probably will not be appropriate for this application; however, the analysis provides the first insights into possible characteristics of this energy resource.
Unified Iso-Response Curves for Orthotropic Plates Under Lateral Pressure Pulse
Authors: Ari-Gur J. , Kenig M. J.
Published: November 2009

General nondimensional iso-deflection and iso-bending moment curves for the elastic response of orthotropic rectangular plates under lateral pressure pulse are presented. Similarities of loads and plate properties are employed to develop the curves, which represent the peak response for various combinations of orthotropy, density, geometry and loading. The presented curves are valid within the elastic small deflection theory of plates, and their usefulness and limitations are discussed in the paper.
A Rate-Dependent Interpretation of the Taylor Impact Test
Authors: Jones S. E. , Gillis P. P. , Foster J. C. , Wilson L. L.
Published: November 2009

A new one-dimensional theory for estimating the dynamic yield strength of materials, based on post-test measurements of Taylor impact specimens, has been developed by the authors. This theory offers the advantage of mathematical simplicity, while requiring only measurements of final specimen length, final undeformed length, and impact velocity as experimental data inputs. It is observed that the theory can accommodate a variety of material constitutive relations while preserving its basic simplicity. In particular, the dynamic material strength on impact, Y, can be directly correlated with impact velocity V through the relation Y = − Y0 − BV2. Here Y0 is the static yield strength and B is a material constant. This relation provides a rate-dependent constitutive law that is potentially useful in situations such as rod penetration, for example.
Creep Parameters for Pile Settlement Equations
Authors: Stelzer D. , Andersland O. B.
Published: November 2009

Friction pile settlement in frozen ground is tyically predicted on the basis of a creep equation relating shear stresses at the soil/pile interface to pile displacement rates. Creep parameters are used to characterize soil type, soil/ice structure, temperature, and loading conditions. Experimental tests involving model steel piles embedded in frozen sand provided data showing that change in a given test variable can alter the numerical value for some of the creep parameters. The test variables included static, incremental, and dynamic loading; pile surface roughness; soil ice content; and sand particle size. Changes observed included the apparent effect on creep rate when a small dynamic load was superimposed on the static load. A tabulation of observed creep parameter changes is included.
Griffith’s Strength Loci for Jointed Rock Masses
Authors: Chappell B. A.
Published: November 2009

Stress distribution in a rock material containing cracks, without thickness, and joints, with thickness, is controlled by two basic principles, namely equilibrium and compatibility. Two deformation models representing these two basic requirements are used to construct the rock mass’ local composite moduli that are then combined to obtain the rock mass’ global moduli. Deformational modes in the form of compliances give upper and lower value moduli representing the constraints of compatibility and equilibrium, respectively. In a loaded rock mass there is no stress redistribution involved in the application of the equilibrium model, while for the compatibility model there are stress redistributions. For cracks, with no thickness, only the equilibrium model defines the deformation moduli, whereas for joints both the equilibrium and compatibility models are required because of the joint’s volume effects. Using both the joint’s shear strength and the Griffith’s crack initiation criteria, the Griffith’s strength loci for firm-hard and soft rock masses are produced. The strength loci representing normal and shear failure modes for the firm-hard rock mass are significantly different, whereas for the soft rock mass they are similar.
Parameter Estimation for Hyperbolic Decline Curve
Authors: Ayeni B. J.
Published: November 2009

The problem of estimating the nonlinear parameters associated with the hyperbolic decline curve equation is considered in this paper. Estimation equations are developed to estimate these nonlinear parameters. The condition under which the results can be used to predict future oil productions is examined using actual field data. An approximate linear term is obtained from the nonlinear hyperbolic equation through Taylor’s series expansion, and the optimum parameter values are determined by employing the method of least squares through an iterative process. The estimated parameters are incorporated into the original hyperbolic decline equation to provide realistic forecast function. This method does not require any straight line extrapolation, shifting, correcting and/or adjusting scales in order to estimate future oil and gas predictions. The method has been successfully applied to actual oil production data from a West Cameron Block 33 Field in South Louisiana. The results obtained are provided in Fig. 1.
Iron Oxide Magnetic Nanotubes and Their Drug Loading and Release Capabilities
Authors: Chen Linfeng , Xie Jining , Aatre Kiran R. , Varadan Vijay K.
Published: November 2009

Iron oxide magnetic nanomaterials are among the most widely used nanomaterials in nanomedicine. Due to their magnetic and structural properties, iron oxide magnetic nanotubes are extremely attractive for biomedical applications. This paper presents the synthesis of iron oxide magnetic nanotubes, and their potential applications in drug delivery. Three types of iron oxide magnetic nanotubes, i.e., hematite, maghemite, and magnetite, were synthesized using template and hydrothermal methods, and the effects of synthesis methods on the morphological and crystalline properties of the synthesized magnetic nanotubes were analyzed. The magnetization properties of the three types of synthesized magnetic nanotubes and their responses to external magnetic fields were studied. To explore their applications in drug delivery, the drug loading and release capabilities of the synthesized magnetic nanotubes were investigated. The final part of this paper discusses several important issues related to the applications of iron oxide magnetic nanotubes for drug delivery, especially the controlled release of drugs.
A Type I–Secreted, Sulfated Peptide Triggers XA21-Mediated Innate Immunity
Authors: Lee Sang-Won , Han Sang-Wook , Sririyanum Malinee , Park Chang-Jin , Seo Young-Su , Ronald Pamela C.
Published: November 2009

Bacterial Trigger of Plant Protection

Innate immunity can be rapidly activated to defend a host plant against a microbial pathogen. The rice protein XA21, which is thought to be a cell surface–located receptor with a kinase domain, activates the plant's defenses in response to infection by certain strains of
Xanthomonas
bacteria.

Lee
et al.

(p.
850
) have now identified the bacterial gene that encodes the protein, AvrXA21, to which the plant receptor XA21 responds. The 194–amino acid protein needs to be secreted and sulfated to trigger the rice plant defense responses. Similarities exist between the receptor XA21 and other immune response receptors in both plants and animals.
Peatland Response to Global Change
Authors: Dise Nancy B.
Published: November 2009

Peatlands can buffer the impact of external perturbations, but can also rapidly shift to a new ecosystem type, with large gains or losses of stored carbon.
Bacterial Community Variation in Human Body Habitats Across Space and Time
Authors: Costello Elizabeth K. , Lauber Christian L. , Hamady Micah , Fierer Noah , Gordon Jeffrey I. , Knight Rob
Published: November 2009

Growing on You

The human gut and skin harbor diverse microbial communities that are known to vary strikingly among individuals. Here,

Costello
et al.

(p.
1694
, published online 5 November) analyzed microbial diversity among several distinct body habitats (including the gut, mouth, inside the ears and nose, and skin) of the same person at different times. They found that body habitat had more influence on microbial community composition than temporal differences and variation among people. Some skin locations, such as the index finger, back of the knee, and sole of the foot, on occasion harbored higher microbial diversity than the gut or oral cavity.
Activation of a Bacterial Virulence Protein by the GTPase RhoA
Authors: Christen Matthias , Coye Lisette H. , Hontz Jill S. , LaRock Doris L. , Pfuetzner Richard A. , Megha  , Miller Samuel I.
Published: November 2009

An enzyme essential for the virulence of
Salmonella
in mammals is activated by the GTP-bound form of RhoA.
Increased MKK4 Abundance with Replicative Senescence Is Linked to the Joint Reduction of Multiple MicroRNAs
Authors: Marasa Bernard S. , Srikantan Subramanya , Masuda Kiyoshi , Abdelmohsen Kotb , Kuwano Yuki , Yang Xiaoling , Martindale Jennifer L. , Rinker-Schaeffer Carrie W. , Gorospe Myriam
Published: November 2009

Replicative senescence is associated with the decreased abundance of four microRNAs that target the mRNA encoding the kinase MKK4.
The Rfx4 Transcription Factor Modulates Shh Signaling by Regional Control of Ciliogenesis
Authors: Ashique Amir M. , Choe Youngshik , Karlen Mattias , May Scott R. , Phamluong Khanhky , Solloway Mark J. , Ericson Johan , Peterson Andrew S.
Published: November 2009

Rfx4 regulates the formation of primary cilia, thereby playing a crucial role in central nervous system development.
Quality Killing
Authors: Foley John F.
Published: November 2009

Strong stimuli are required to trigger the efficient killing of targets by cytotoxic T cells.
A Smooth(ened) Path to Drug Resistance
Authors: Kiberstis Paula A.
Published: November 2009

A mutation that prevents binding of a promising drug lead to its target protein confers resistance in a human brain tumor.
Toward Neuronal Regeneration
Authors: Hines Pamela
Published: November 2009

Mouse neurons that lack a receptor for inhibitory proteoglycans show improved regeneration.
Confronting Morphogen Gradients: How Important Are They for Growth?
Authors: Hamaratoglu Fisun , Basler Konrad , Affolter Markus
Published: November 2009

A graded distribution of Wingless is not required for growth of the fly wing.
IRF-3 and Ubiquitin
Authors: Foley John F.
Published: November 2009

The ubiquitin-conjugating enzyme Ubc5 is required for the activation of interferon regulatory factor 3 during the mitochondrial antiviral response.
The Hippo Tumor Suppressor Pathway: A Brainstorming WorkshopA report on the research meeting “The Hippo Tumor Suppressor Pathway: A Brainstorming Workshop” sponsored mainly by the Regina Elena Cancer Center and the Nicola Foundation and held in Rome, Italy, on 22 and 23 April 2009.
Authors: Blandino Giovanni , Shaul Yosef , Strano Sabrina , Sudol Marius , Yaffe Michael
Published: November 2009

Researchers of flies and mammals met to discuss components of the Hippo signaling pathway.