bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of Plant Maintenance Program Cost-Effectiveness Using ProCost©
Authors: Worledge David H. , Hess Stephen M.
Published: March 2009

This paper discusses use of the ProCost© Maintainability / Reliability / Production / Cost (MRPC) model to assess the cost effective performance of a power plant’s maintenance program. The RMPC model provides an estimate of the economic value added for plant assets. It also provides a summary of production and maintenance costs, generation losses, and revenue losses, and gives a bottom line report on the asset’s economic value to the company. The model accounts for the way in which the maintenance program interacts with the generation process and estimates the leverage provided by expenditures on preventive maintenance. ProCost© is an engineering tool for tracking each asset’s production and cost performance under appropriate engineering approximations. Thus, it provides useful insights into where maintenance resources can be expended most effectively to increase generation and reduce operating costs.
Hybrid Dual-Fuel Combined Cycles: General Performance Analysis
Authors: Petrov Miroslav P. , Martin Andrew R. , Hunyadi Laszlo
Published: March 2009

The hybrid dual-fuel combined cycle concept is a promising technology for increasing the energy utilization of low-grade (solid) fuels. Advantages such as enhanced electrical efficiency, favorable economics, and relative ease of construction and operation have been pointed out by various authors in previous studies. The present investigation aims to assess the performance of natural gas and coal- or biomass-fired hybrid combined cycles, with a gas turbine as topping cycle and a steam boiler as bottoming cycle. A parametric analysis considers the impact of the natural gas/solid fuel energy ratio on the electrical efficiency of various hybrid system configurations. Results show that significant performance improvements (in the order of several percentage points in electrical efficiency) can be achieved by these hybrid configurations when compared to the reference (two independent, single-fuel power plants at the given scales). In large-scale power plants with coal-fired bottoming cycle, efficiencies continuously rise as the share of natural gas fuel is increased up to the cycle integration limits, while an optimum can be seen for the small-scale biomass-fired bottoming cycles (with modest steam parameters) at a certain share of natural gas fuel input.
Fulfilling the Need for Turbine Retrofits Which Match Demand on “Date and Duration” of Outage
Authors: Hesketh Alan , McCoach John
Published: March 2009

Retrofitting has in recent years become established as a major field of activity within the steam turbine industry. Third party upgrades by non-OEM suppliers are frequently part of the scene in these days of modern technological advancement. The main drivers for upgrading of this type are improved performance with reduced emissions, increased reliability overcoming emerging type faults and minimized maintenance for the rest of the life of the plant. The practicability in timing of manufacture and installation of a retrofit module, such as a turbine inner cylinder block, is linked intrinsically with the operation of the existing plant and to the outage schedules of each of the units. These plans may extend over a number of years. The evaluated worth of a proposed project is often decided by how quickly, within the remaining life of the overall unit, the retrofit can be supplied to start generating extra revenue. The delivery constraint of hitting an outage window adds a distinctly different aspect compared to the normal supply of a new machine. Time is required to survey the existing equipment, then design and manufacture — with minimum practical times to obtain rotors and casings, followed by shipment, installation, commissioning and testing — all required to match the date and duration of a planned outage. The whole process demands some expertise and close cooperation with plant operator is needed to ensure the optimum solution. Practical examples are discussed to illustrate the challenges involved with turbine retrofitting within specified timeframes and notable achievements are highlighted.
The Cleaning of Air Cooled Condensers to Improve Performance
Authors: Putman Richard E. , Jaresch Dirk
Published: March 2009

Air-cooled condensers were first introduced into the U.S. power industry in the early 1970’s, but only began to increase in popularity during the last decade. The rising importance of this new and different technology for the condensing of steam has led to the need for a better understanding of the associated design, application, performance monitoring and cleaning requirements. This paper identifies the basic configuration of aircooled condensers in the power industry and some of the problems they encounter, especially fouling problems. Monitoring the performance of air-cooled condensers is an important task and the major criteria involved are identified. To rectify degradations in performance associated with external fouling, a number of cleaning procedures are described. Included among these are details of a new automated cleaning technology that has been successfully applied, and some of the performance improvements that have resulted from the use of this technique are presented.
Predictive Maintenance of Cogeneration Engines Through the Analysis of the Circulating Fluids
Authors: Gonza´lez J. R. , Velayos J. , Comamala M.
Published: March 2009

In this article we present a fluid-based predictive maintenance system based on an expert system which uses fuzzy logic. The programme uses information from the circulating fluids of the machine to provide an evaluation of the maintenance status of the engine. Specifically, the programme is aimed at diesel engines in a half rate cogeneration, and so we will compare our results with other commercial maintenance systems, such as FAMM (Texaco) and ADOC (Repsol), which provide corresponding responses.
Four Large Units at Lakeview Generating Station Achieve 50% NOx Reduction Cost Effectively With a Reduced Schedule
Authors: Raman Kal , Schindler Edmund
Published: March 2009

As part of a much larger Ontario Power Generation NOx reduction program, two separate turnkey contracts were awarded to RJM Corporation to convert the four units at the Lakeview Generating Station located on lake Ontario near downtown Toronto. Lakeview Station Units 1, 2, 5 and 6 are 300 MWe, B&W split furnace, radiant boilers firing bituminous coal. Units 1 & 2 have 24 burners and Units 5 & 6 have 18 burners all located on the front wall. The original B&W register style burners were used as a basis to reduce NOx emissions to the maximum amount possible by means of burner modifications using RJM’s low NOx burner components. This upgrade reduced NOX by more than 50% from the original burner baseline, simultaneously maintained CO below 100 ppm and maintaining a reasonable increase in baseline LOI, with no effect on boiler steam temperatures or performance. RJM Corporation was selected on a competitive bid basis to perform these contracts on a turnkey basis. Stone and Webster prepared the specification and acted as the OPGI engineer throughout the project. The details of the retrofit and the results of the conversion are presented in this paper.
Beyond RAM: What’s It Worth? When Do We Do It?
Authors: Schmidt Michael E. G.
Published: March 2009

Generating facility maintenance strategies are under various stresses. Identifying new strategies is generally easy but determining which strategies, if any, will pay is not. Once strategies that will pay have been identified, how much they pay is often a function of when they are implemented. This paper will briefly discuss ways to measure and manage the present and future risk associated with power plant equipment.
Development of a Low-Power, Low-Cost Remote Pipe Parameters Monitoring Device
Authors: Kurka Paulo R. G. , Quinholi Carlos Geraldo , Laurino Eduardo , Donato Guilherme V. P.
Published: March 2009

The work presents the features and performance of a dedicated system for monitoring stresses in the vicinity of retention valves in a long oil pipe. Monitoring stations that can be numerous and located in remote regions, where no electric power is available, must be operated by batteries which provide a somewhat limited supply of energy. The project of a low-cost low-power consumption device is therefore of great importance for keeping records of strains, or any other engineering parameter that develop remotely on the pipe. The system developed is a simultaneous 5-channel analog data conditioning and recording equipment, that can be programmed to sample data at regular time intervals. The recording device can be any voice/music standard monaural cassette tape recorder. The paper displays project details as well as qualitative results of circumferential and longitudinal stress monitoring in a remote measuring station, with 4 data channels per station, recorded during 7 consecutive days at 15 minutes sampling intervals.
Effect of Material Characteristics on the Properties of a Steel Pipe
Authors: Wiskel J. B. , Rieder M. , Henein H. , Schulz T.
Published: March 2009

The performance of a pipeline is related to both the stress levels to which the pipe is exposed and the characteristics of the pipe material itself. For steel pipe in particular, the grade of skelp used and its deformation history during fabrication can influence both the effective yield strength and subsequent (if any) plastic deformation of the final pipe product. To understand and quantify this relationship between pipe forming and pipe properties, three concurrent areas of study were undertaken: instrumented plant trials to understand and quantify strain history during pipe forming, characterization of the constitutive behaviour of pipe steel deformation under complex loading and the development of a finite element analysis (FEA) stress model to couple the effects of forming history and constitutive material behaviour on the mechanical performance of a steel pipe under an internal pressure. Strain gauge technology and digital imaging were used to measure dynamic strain histories and geometry of the pipe imparted by the forming process. These plant measurements provided unique insight into the dynamics of the forming operation and detailed data for the FEA model verification. A series of tension/compression tests were conducted on X-52 and X-70 steel to quantify the kinematic hardening behaviour of these materials under complex loading conditions. This data was used to formulate the constitutive equations of the steel in the FEA model. The numerical stress model was developed using the commercial finite element package ABAQUS. Loading simulations of the pipe using the FEA model were conducted to illustrate the effect of both steel characteristics and forming history on pipe performance.
Development of a FAD-Based Girth Weld ECA Procedure: Part I — Theoretical Framework
Authors: Wang Yong-Yi , Rudland David , Horsley David
Published: March 2009

Beginning in the late 1970’s and early 1980’s, “alternative defect acceptance criteria” were adopted in various codes and standards in the pipeline industry. These criteria relate the tolerable defect sizes with the magnitude of loads and materials’ resistance to failure. They allow engineers to assess the suitability of the pipes containing defects for intended service conditions, or fitness-for-service. Assessments based on the fitness-for-service principles are often referred to as Engineering Critical Assessment, or ECA. Although most of these codes are based on fracture mechanics principles, the defect tolerance levels vary significantly from code to code. This paper describes a two-year effort funded by PRCI (Pipeline Research Council International) to develop an ECA procedure specifically tailored to pipeline girth welds. The newly developed procedure is in FAD (failure assessment diagram) format. The key features of this procedure are provided in this paper. Based on prior research and extensive experimental data analysis, a modified Miller plastic collapse solution was selected for its rigorous formulation and good agreement with full-scale test results. The effects of weld strength mismatch on plastic collapse load (limit load) were examined and validated through finite element (FE) analysis. Parametric formulae of mismatch correction factors to the plastic collapse solution were adopted. The stress intensity factor solutions of finite-length surface-breaking defects in girth welds were developed and validated. Failure assessment curves (FACs) for girth weld defects were generated. These curves incorporated the effects of material’s strain hardening rate and defect size. They are more accurate than some of the generic material and defect independent FACs, yet easy to use.
A Hazard and Risk Management System for Large Rock Slope Hazards Affecting Pipelines in Mountainous Terrain
Authors: Porter Michael , Baumgard Alex , Savigny K. Wayne
Published: March 2009

Pipelines and other linear facilities that traverse mountainous terrain may be subject to rock fall and rock slide hazards. A system is required to determine which sites pose the greatest hazard to the facility. Once sites are ranked according to hazard exposure, a risk management program involving inspection, monitoring, contingency planning and/or mitigation can be implemented in a systematic and defensible manner. A hazard rating methodology was developed to identify and characterize rock slope hazards above a South American Concentrate Pipeline, and to provide a relative ranking of hazard exposure for the pipeline, an access road and operational personnel. The rating methodology incorporates the geometry of the right-of-way, estimated pipe depth, staff and vehicle occupancy time, failure mechanism and magnitude, and the annual probability of hazard occurrence. This information is used in a risk-based framework to assign relative hazard ratings within rock slope sections of relatively uniform hazard exposure. This paper outlines a general framework for natural hazard and risk management along linear facilities, describes the rock slope hazard rating methodology, and illustrates how the system was applied along a South American Concentrate Pipeline.
Development of the G16CM34 Engine as a High Efficiency Engine for Gas Transmission, Storage and Withdrawal Services
Authors: Gonzalez Bob
Published: March 2009

There is a new large horsepower engine available in North America and supported by a well-established network of authorized factory dealers. The driver is based on a reciprocating engine design delivering 7670 to 8180 HP depending on site conditions. The 16-cylinder prime mover is specially engineered for gas transmission, storage and withdrawal service. Built on a diesel engine designed block, crankshaft, bearings, rods, and gear train, it provides long service intervals and 120,000 hours before major overhaul. Electronic ignition and combustion controls help conserve fuel, minimize emissions and keep the engine operating at peak capability under a variety of ambient and loading conditions. Electronic monitoring protects critical components and systems while greatly simplifying maintenance. The electronic control tightly regulates the combustion process, cylinder by cylinder, to optimize efficiency. It also controls the main cylinder and prechamber fuel delivery. Using sensor data based on ambient and turbocharged-aftercooled air intake temperatures, the microprocessors in the control system continuously monitor available engine power. With this information, the PLC controlling the compressor has the ability to load or unload the compressor to match the available engine output. Fuel efficiency is less than 5900 Btu/bhp-hr and NOx emissions of 0.50 grams/bhp-hr. The mechanical efficiency of the engine is greater than 43%. The mechanical refinements designed into the prime mover, are behind the high efficiency. For instance, the long stroke design maximizes fuel efficiency. A solenoid operated gas admission valve for each cylinder provides precise fuel metering. A calibration ring in the upper part of the cylinder liner helps reduce CO and NMHC emissions. Combustion gases do not collect in the gap between the piston and the liner wall, where most of these gases form. Instead, piston action forces them back into the combustion chamber for complete burning. In the event of a decline in fuel quality, a three-piece connecting rod enables a quick change in compression ratio without changing the piston. The paper will also cover details on maintenance intervals and costs, with additional features on the product along with construction details. Figure 1, illustrates a side view of the engine as Seen from the front.
The Progress of the Greatest Gas Pipeline Project in China
Authors: Huang Zhiqian
Published: March 2009

The Chinese West-East Gas Pipeline project is the greatest gas pipeline in Chinese history. Its construction indicates that the Chinese gas pipeline technology reaches a new level. In this paper, the design, material selection, compression stations, control system, schedule of construction, financing and international cooperation of this project were described.
New Limit State Functions for Determining the Puncture Resistance to External Force
Authors: Liu Jianhui , Francis Andrew
Published: March 2009

Traditionally, a key component of the design philosophy applied to high-pressure pipelines has been the stipulation that the nominal hoop stress is less than some fraction of the specified minimum yield strength (SMYS). However, more recently both designers and operators have recognised that whilst this approach generally leads to conservatively safe designs, there may be some situations in which the conservatism is not adequate. This has resulted in a move towards limit state, and structural reliability based, methods that address actual failure modes, and consequently the contributions to structural integrity of other factors in addition to stress. One such failure mode is the puncture of a pipeline wall due an external force. This situation can arise from the impact of excavating machinery for onshore pipelines or drop objects and anchors for offshore lines. A limit state function describing this failure mode is given in DNV guidelines No 13. However, this function does not take account of the internal pressure. In this paper the influence of pressure on the pipeline indentation is addressed using both theoretical and finite element analyses. A closed-form solution of force-deformation relationship based on a consideration of rigid-plastic deformation theory, that gives a good agreement with results from both FE analyses and experimental tests, is presented. The analytical results show that indentation force, and the maximum stress/strain, required to produce a given dent depth, increase with increasing internal pressure. However, the relationship between indentation force and maximum stress/strain is not sensitive to internal pressure. The analysis therefore shows that an indentation force criterion governed solely by the dent depth, such as that given in DNV guidelines No. 13, may be highly unconservative when the pressure in the pipeline is high. Consequently, a new local denting criterion for puncture of pressurised pipes, which is based the maximum acceptable strain of the pipe material, and thereby removes the above unconservatsim, has been proposed and is presented in this paper.
Dynamic Behaviour of a Turret FPSO in Single and Tandem Configurations in Realistic Sea Environments
Authors: de Souza Junior Jesse´ R. , Morishita Helio M.
Published: March 2009

A comprehensive analysis of the dynamics of ship-type Floating, Production, Storage and Offloading systems anchored through a turret system (Turret-FPSO) is presented. Firstly, the behavior of the FPSO unit alone is examined under the combined action of wind, current and waves. Wave forces are represented by second-order effects such as slow drift forces, as well as wave-current interaction corrections to mean drift forces, namely wave drift damping. The influence of the vessel’s draft and of the longitudinal position of the turret is also assessed. The study of the dynamics of the system is performed by calculating static equilibrium solutions and evaluating their stability properties. Relevant ranges of environmental parameters such as wind and current speeds, wave spectra, and respective angles of incidence are investigated. Numerical results are obtained and shown in bifurcation diagrams depicting the evolution of steady-state responses as a function of environmental parameters. The system displays a variety of different regimes of solutions in which both their number and their stability may change as one or more parameters are varied. The stability analysis of the Turret-FPSO system is extended to include the tandem configuration with a shuttle vessel. The main features of this more intricate scenario are summarized in 3D bifurcation diagrams.
Analytical Study of Appropriate Design for the High-Grade Induction Bend Pipes Subjected to Large Ground Deformation
Authors: Yatabe Hiroshi , Fukuda Naoki , Masuda Tomoki , Toyoda Masao
Published: March 2009

In this study, the deformability of induction bends made out of high-grade line pipe is analytically discussed. In order to clarify the significant parameters for the deformability, 30 cases of finite element analyses simulating the deformation behavior subjected to internal pressure and bending moment were carried out. The effects of the mechanical properties, the geometry of the “bend” part and the properties of the “transition” part on the deformability were investigated. Finally, the change in the integrity of the buried pipeline due to the quality of the induction bend was quantitatively examined. The results showed that the effects of the mechanical properties and geometry of the “bend” part on the deformability were small in the closing mode. On the other hand, the deformability was sensitive to such parameters in the opening mode. Especially, the properties of the “transition” part were significant. Consequently this study indicated that the mechanical properties, the dimensions and tolerance and the properties of the “transition” part should be appropriately designed in proportion to the amount of assumed ground deformation.
Dynamics of a Floating Buoy Under Latching Control
Authors: Korde Umesh A.
Published: March 2009

This paper is an attempt at a deeper investigation of the dynamic behavior of an axisymmetric buoy under latching (switching) control. The bilinear system of equations of motion is integrated analytically for regular wave excitation, assuming pneumatic and hydraulic power take-off mechanisms. The procedure provides, for a prescribed latching sequence, the time variation of the buoy displacement and the pneumatic/hydraulic pressure, and the phase plots for buoy motion. Results are used to investigate the dependence on wave number, of capture factor, peak to peak and mean buoy displacement, and peak to peak and mean pressure. Also examined is the dependence of these quantities on load damping. Overall, the results appear to provide some useful insight that could help with design of the device and the power take-off mechanism when latching control is being considered.
A 3D Computational Fluid Dynamics Analysis of the Wells Turbine
Authors: Daly John , Thakker Ajit , Frawley Patrick , Bajeet Elvis Sheik
Published: March 2009

This paper deals with the application of Computational Fluid Dynamics (CFD) to the turbulent analysis of the Wells Turbine. The objectives of this work were twofold; firstly to develop and benchmark the 3D CFD model and then to use this model to analyse the airflow through the turbine. The model was analysed as fully turbulent compressible flow using the Fluent™ CFD code. The computational model was first benchmarked against previously published experimental and CFD data for two similar turbines. The computational model accurately predicted the non-dimensional torque and non-dimensional pressure drop, while the efficiency predictions were lower than the experimental results. Predicted location of turbine stall also corresponded well with experimental results. Potential causes for differences between the computational and experimental results are suggested. The computational model was then analysed at both high and low tip Mach number settings and also with and without the tip gap, and these results were discussed.
Ductile Fracture Property of Structural Steels With a Surface Flaw Under Large Deformation
Authors: Igi Satoshi , Sumi Hiroyuki , Kurihara Masayoshi
Published: March 2009

Tensile tests using plate specimens with a surface flaw were conducted in order to study the large deformation behavior of steels with a flaw. Steels prepared for examination had tensile strengths of 470–490MPa with different stress-strain relationships. The strain distribution during loading and the maximum strain at fracture were measured in order to investigate the influence of stress-strain properties on ductile fracture. The crack shape changes during ductile crack growth were also examined and compared with empirical formulae for estimating fatigue crack shape change. In order to assess test results, three dimensional elastoplastic finite element analyses were carried out which included detailed analysis of the influence of stress-strain properties on deformation behavior. In addition, a simplified analytical model to estimate fracture strain and critical flaw size was proposed using the stress-strain relationship of Swift’s equation. The results from the model show fairly good agreement with experimental results.
Computer Controlled Capsizing Tests Using Tailored Wave Sequences
Authors: Clauss Gu¨nther F. , Hennig Janou
Published: March 2009

This paper presents a new kind of computer controlled sea-keeping test procedure for investigating large roll motions and capsizing behavior of ship models. In cooperation with the Hamburg Ship Model Basin (HSVA) our research group has carried out computer controlled capsizing tests in steep transient wave groups for two different types of ship models which show typically two different modes of rolling. The parameters of the model seas – transient wave sequences consisting of random seas or regular wave trains with an embedded deterministic high transient wave – are systematically varied to investigate the ship model response with regard to metacentric height, model velocity, and course angle for each of both ship types. The wave elevation at the position of the ship model at any position in time and space is calculated by a semi-empirical method (and controlled by registrations during model tests) in order to relate wave excitation to the resulting roll motion.
Probability of Occurrence of a “Giant” Wave Crest
Authors: Prevosto Marc , Bouffandeau Barbara
Published: March 2009

On January the 1st 1995, a “giant” wave is observed and measured at the Draupner platform in the North Sea. During a sea state with a significant wave height close to 12 meters, the crest of this isolated wave reached 18.5 meters. The question has been often asked if the physics governing such a wave differ from the physics governing the population of typical waves. Before responding more precisely to this question a first step is to use as accurately as possible, in such extreme situations, the physics governing the typical waves. One of the methodologies to furnish statistics of crest height for individual sea states starting from spectral information is based on Monte Carlo techniques. These techniques ask for the simulation of a very large population to estimate accurately the probability of occurrence of extreme events. As an example, in the sea state conditions of the “Draupner wave”, and using a linear irregular wave model, 40,000,000 simulated waves are necessary to calculate accurately the sea state conditional probability of occurrence of crests higher than 14.6 meters. In this context the more complex reasonably usable model is the irregular second order 3D wave model. In this paper we show how more complicated models (and so more time consuming simulators) can be used without loss in the accuracy of the estimation of the probability of occurrence. In that way, Creamer transform is used which gives the Draupner “giant” crest, 10 times more probable than given by second order models.
DNV RP-F201: Recommended Practice for Design of Titanium Risers
Authors: Leinum Bente H. , To̸rstad Elisabeth H.
Published: March 2009

During resent years there has been an increasing interest in titanium as a material for offshore risers. The use of titanium in offshore risers has been considered in several projects in the North Sea over the last decades, namely Heidrun, Visund, Kristin and A˚sgard. Additionally, a significant number of titanium taper joints have been successfully designed and are put into service. The principles of standards such as DNV Offshore Standard for Submarine Pipelines (DNV OS F101) [1] have been utilized for design of titanium risers. However, significant modifications have been necessary in order to use this standard for titanium purposes, introducing extensive demands to the design process. In this connection, DNV is currently developing a recommended practice (RP) for design of titanium risers, DNV RP-F201. The RP is based on a probabilistic foundation using limit state formulations and following the Load and Resistance Design Format. The format is flexible to easily accommodate new technical results from research or future developments. All aspects of the design, including relevant considerations to manufacturing and fabrication, are covered.
Design Requirements for High Temperature Flowline Coatings
Authors: Melve Bjo̸rn
Published: March 2009

It is a challenge to find cost effective insulation systems for subsea flowlines operating at high internal temperatures. Integrated polymeric insulation coatings are susceptible to degradation by hydrolysis or oxidation. Burial of the flowline accelerates the degradation due to the higher outer surface temperature. In addition does the high temperature modify the mechanical properties of the coating materials. It is recommended to include the temperature history of the field in the design basis. Also it is necessary to perform impact test and shear tests of the coating system at the operational temperature. For buried pipelines it is necessary to calculate the insulating effect of the backfill materials on the surface temperature.
Conclusions From the Comparisons of Numerous 2D Airfoil Computations With Experiments
Authors: Bertagnolio F. , So̸rensen N. N. , Johansen J. , Fuglsang P.
Published: March 2009

The aim of this work is two-fold. Firstly, 28 sets of airfoil (widely used for wind turbine applications) measurements were compared with numerical results from a 2D Navier-Stokes solver and a panel method code. These results have been collected into an airfoil catalogue that has been separately published. Secondly, based on the previous results, criterions for evaluating the airfoils are derived. Thereby, the performance of the Navier-Stokes solver is evaluated. Further analysis of the results determines geometrical and flow properties that may cause problems when computing airfoil flows with a Navier-Stokes solver, and some recommendations are given.
Advanced Aerodynamics Methods for Wind Site Selection
Authors: Castellani Francesco , Franceschini Giordano
Published: March 2009

Wind potential — in Italy — has not been completely explored yet, and many investors are still looking into the most promising sites. The interest on the exploitation of a wind site is linked to the possibility of setting up an industrial plan that yields a fast return on investment. The success of this investment depends on the following parameters: • the amount of funding to be spent (cost of the electric lines, roads, turbines, etc.); • the quality of the predicted wind flow; • the price of the electric energy produced. To select a wind site in a fast and convenient way some of the traditional methods of aerodynamics can be borrowed, such as those related to vehicle dynamics. This paper investigates and compares wind site characterization tools and methodologies based on aerodynamics. Simulations and experimental activities were performed in geographical sites located in the center of Italy, where the complex orography requires efficient methods for site characterization and selection, with the aim of speeding up the start-up of wind turbine installations.
Field Tests of a Wind-Electric Controller for Parallel Stock Water Pumping and Heating
Authors: Morton Scott A. , Nydahl John E.
Published: March 2009

Many of the improvements in wind-electric stock water pumping systems are attributable to advanced controller strategies and hardware that maximize performance over a range of wind speeds. The cost of the early and more complex controllers was of the order of one quarter of the whole system. Sophisticated yet inexpensive-programmable micro-controllers are now being introduced that enhance both performance and reliability. This study utilized a micro-programmable logic controller (PLC) to place a variable auxiliary load in the form of a stock water heater in parallel with the pump motor. This improves the system’s economic viability on the Northern High Plains by mitigating stock tank freezing to help extend the grazing season. For the variable auxiliary load, the PLC uses long period pulse width modulation to drive a 3-phase solid-state relay. This continuously variable load strategy was designed to both increase the power factor when the pump is operating, and to extract resistive heating power in wind regimes not suitable for operating the pump. This paper reports on the preliminary but encouraging field studies directed toward optimizing the low wind speed water heating performance of this multi-tasking controller when the pump motor is inoperable.
Early development of the primary haustorium of Viscum minimum (Viscaceae)
Authors: Olson A. Randall , Kuijt Job
Published: March 2009

The minute South African mistletoe, Viscum minimum, parasitizes succulent species of Euphorbia. Establishment of the parasite from seed requires the formation of a primary haustorium from which the endophyte enters the host by means of an intrusive organ. The development of the haustorial disk from the clavate, radicular tip parallels that of other Viscaceae. The failure to observe the occurrence of a haustorial gland associated with the initiation of the intrusive organ in V. minimum suggests that the Viscaceae may be unique in this respect within the Santalales.
Formation and regeneration of protoplasts from the ectomycorrhizal basidiomycete Laccaria bicolor
Authors: Kropp Bradley R. , Fortin J. A.
Published: March 2009

Protoplasts were released from dikaryotic mycelium of the ectomycorrhizal basidiomycete Laccaria bicolor using the lytic enzyme preparation NovoZyme 234. Protoplast release depended strongly on mycelium age, osmotic stabilizer, and temperature. The protoplasts could regenerate to form both monokaryotic and dikaryotic cultures capable of forming normal ectomycorrhizae with Pinus banksiana.
Morphogenesis of the compound leaf in three genotypes of the pea, Pisum sativum
Authors: Gould K. S. , Cutter Elizabeth G. , Young J. P. W.
Published: March 2009

Leaf anatomy, ontogeny, and morphology were described and compared in a pea line (Pisum sativum L.) with conventional leaves and in isogenic lines carrying the mutations af (afila) or tl (tendril-less or acacia). The anatomy of stem, petiole, and rachis is not modified by these mutations. The tendrils, which in af replace leaflets, have normal tendril anatomy, and the terminal leaflets of the tl form have normal leaflet anatomy. The shoot apical dome has the same size and shape in the three genotypes, as does the leaf primordium up to the stage of initiation of the first laterals. The mature morphology of leaves varies with node of insertion. Some leaves, especially at nodes 3 and 4, have structures that are not typical of their genotype. An in vitro culture system is described for axillary shoots. Such shoots recapitulate most of the foliar features of seedling plants, but leaf morphology is on average more complex, and aberrant structures are more frequent. All these observations are discussed in relation to Young's algebraic model for compound leaf development.
GEOMETRIC INTEGRATION BY SOLUTION INTERPOLATION
Authors: KIM PILWON
Published: March 2009

Numerical schemes that are implemented by interpolation of exact solutions to a differential equation naturally preserve geometric properties of the differential equation. The solution interpolation method can be used for development of a new class of geometric integrators, which generally show better performances than standard method both quantitatively and qualitatively. Several examples including a linear convection equation and a nonlinear heat equation are included.
BIOACTIVE GLASS PARTICLES FIELD-ASSISTED SEALING TO TITANIUM IMPLANT GLASS-BASED COATINGS
Authors: MROZEK PIOTR
Published: March 2009

This paper reports for the first time the use of field-assisted sealing for bioactive implant coating applications. Field-assisted sealing (anodic bonding) of bioactive glass particles to bioinert glass enamel coating of titanium implant was investigated. Biocompatible titanium oxide interlayer was fabricated by deep thermal oxidation of 80 nm thick Ti thin film previously vacuum evaporated onto polished bioactive glass surface. Bioactive glass particle was anodically bonded via the interlayer to polished surface of bioinert glass enamel coating vacuum deposited onto Ti plate at 860°C. A total of 20 min preheating time with constant temperature increase rate, 5 min bonding time, and 100 V DC voltage were applied during field-assisted bond formation at 530°C in air.
Arthralgia and Osteolytic Lesions Associated with Traumatic Pancreatitis in a 10-Year-Old Girl
Authors: Obatake Masayuki , Yamane Yusuke , Tokunaga Takayuki , Taura Yasuaki , Inamura Yukio , Nagayasu Takeshi
Published: March 2009

A case of traumatic pancreatitis with subsequent joint pain and osteolytic lesions is presented. A 10-year-old girl was admitted to our hospital with abdominal pain caused by blunt epigastric injury. She was diagnosed with traumatic pancreatitis, and multiple pancreatic pseudocysts subsequently developed. Two weeks after admission, she complained of joint pain, and MR revealed osteolytic lesions of both knee joints. On the 58th day, endoscopic transgastric pseudocyst drainage was performed. Joint pain and osteolytic lesions resolved rapidly, in parallel with the decrease in serum amylase level and pseudocyst size.
Novel Designs and End Points for Phase II Clinical Trials
Authors: Adjei Alex A. , Christian Michaele , Ivy Percy
Published: March 2009

The large number of negative phase III trials in oncology over the last several years has renewed interest in refining phase II oncology clinical trials to maximize the chances of success in phase III testing. More efficient phase II study designs will improve our ability to identify promising agents for testing while accurately identifying nonefficacious agents. Recognizing that new paradigms of phase II trial designs need to be developed, the Clinical Trial Design Task Force of the National Cancer Institute (NCI) Investigational Drug Steering Committee has tackled the question of improving efficiency of phase II clinical trials. In this issue of CCR Focus, four of the major topics discussed are presented. First, the task force recommended that alternate phase II end points should be studied. Second, depending on the characteristics of the specific trial and study population, historical controls or a randomized design may be more appropriate. Third, rational incorporation of biomarkers into phase II trials should be encouraged. Last, novel imaging modalities will be critical in evaluating the clinical benefit of new cytostatic agents.
Noonan Syndrome and Related Disorders: A Review of Clinical Features and Mutations in Genes of the RAS/MAPK Pathway
Authors: Jorge Alexander A.L. , Malaquias Alexsandra C. , Arnhold Ivo J.P. , Mendonca Berenice B.
Published: March 2009

Noonan syndrome (NS) is one of the most common syndromes transmitted by a mendelian mode. In recent years, germline mutations that affect components of the RAS-MAPK (mitogen-activated protein kinase) pathway were shown to be involved in the pathogenesis of NS and four rare syndromes with clinical features overlapping with NS: Leopard syndrome, cardio-facio-cutaneous syndrome, Costello syndrome and neurofibromatosis type 1. Several hormones act through receptors that stimulate the RAS-MAPK pathway, and therefore, NS and related disorders represent a remarkable opportunity to study the implication of the RAS-MAPK pathway in different endocrine systems. Additionally, children with NS frequently are referred to the endocrinologist because of short stature, delayed puberty and/or undescended testes in males. In this paper, we review the diagnostic, clinical and molecular aspects of NS and NS-related disorders.
Platelet Serotonin Concentration and Monoamine Oxidase Activity in Hypothyroid Patients
Authors: Stipcevic Tamara , Kusacic-Kuna Sanja , Dezeljin Martina , Dodig Damir , Korsic Mirko , Pivac Nela , Muck-Seler Dorotea
Published: March 2009

Background/Aim: The relationship between the hypothalamic-pituitary-thyroid (HPT) axis and the serotonergic (5-hydroxytryptamine, 5-HT) system is not clear. The aim of the study was to determine platelet biochemical markers (5-HT concentration and monoamine oxidase B, MAO-B, activity) in hypothyroid patients. Methods: The study included 25 medication-free female hypothyroid patients in postoperative follow-up after total thyroidectomy due to papillary thyroid carcinoma, who had not been treated with synthetic thyroxine (T4) for 4 weeks, and 44 age-matched euthyroid healthy women. The platelet 5-HT concentration, platelet MAO-B activity, total T4 and thyroid-stimulating hormone (TSH) levels were determined using spectrofluorimetric methods, radioimmunoassay and fluoroimmunoassay, respectively. Results: Hypothyroid patients had significantly higher TSH, significantly lower T4 levels and platelet 5-HT concentrations, and unchanged platelet MAO-B activity than healthy subjects. A positive correlation was found between the 5-HT concentration and platelet MAO-B activity, and between the platelet MAO-B activity and T4 in control subjects. Conclusions: Reduced platelet 5-HT concentrations in hypothyroid patients suggests a complex interaction between the 5-HT system and HPT axis activity, which could be related to the frequent occurrence of depressive symptoms in hypothyroid patients. The determination of platelet 5-HT concentrations should be considered a diagnostic tool for the evaluation of depressive symptoms in hypothyroid patients during the hormone withdrawal procedure.
Cyclothymic Temperament
Authors: Benazzi Franco
Published: March 2009

Background: Cyclothymic temperament (CT) is a more or less ‘permanent’ instability of mood, thinking and activity (behaviour), which is frequent in bipolar disorders. Testing the impact of age on CT items, as has been done in many mood disorders, could further define its features. The aim of the study was to test the relationship between age and CT items. Methods: During follow-up visits in a private practice, 209consecutive remitted bipolar II (BP-II, n = 138) and major depressive disorder (MDD, n = 71) outpatients were re-diagnosed by a mood disorder specialist psychiatrist, using the Structured Clinical Interview for DSM-IV (blind to patients), and self-assessed CT was evaluated by the TEMPS-A questionnaire (blind to interviewer). Results: Mean (SD) age was 39.1 (10.0) years (median 39, range 16–63 years). BP-II had significantly more CT items. Logistic regression tested the association between each CT item and age. Of the 17 CT items, 8 showed a trend (p < 0.10) or significant association with age. Among these items, there were items suggested to be core features of CT, i.e. instability of mood and energy: ‘moods and energy either high or low’, ‘constantly switching between being lively and sluggish’ and ‘being sad and happy at the same time’. However, other CT items related to mood and energy instability, i.e. ‘sudden shifts in mood and energy’ and ‘mood often changing for no reason’, were not significantly associated with age. Discussion: Study findings suggest that age may have an impact on some CT items related to mood and energy, which might become more common with age (according to the item’s wording), and that many CT items may not be impacted by age, suggesting more stability.
Uncorrelated Randomness of the Heart Rate Is Associated with Sepsis in Sick Premature Infants
Authors: Beuchée Alain , Carrault Guy , Bansard Jean Yves , Boutaric Emmanuelle , Bétrémieux Pierre , Pladys Patrick
Published: March 2009

Background: Late-onset sepsis in the premature infant is frequently revealed by severe, unusual and recurrent bradycardias. In view of the high morbidity and mortality associated with infection, reliable markers are needed. Objectives: It was the aim of this study to determine if heart rate (HR) behavior may help the diagnosis of infection in premature infants with such cardiac decelerations. Methods: Electrocardiogram recordings were collected in 51 premature infants with a postmenstrual age <33 weeks with frequent bradycardias. Newborns in the sepsis group (C-reactive protein increase and positive blood culture) were compared with a no-sepsis group (C-reactive protein <5 mg/l before and 24 h after recording and negative blood cultures) for their HR characteristics, i.e. RR series distribution (mean, median, skewness, kurtosis, sample asymmetry), magnitude of variability in time and frequency domain, fractal exponents (α1, α2) and complexity measurements (approximate and sample entropy). Results are presented as the median (25%, 75%). Results: Gestational, chronological and postmenstrual age and gender were similar in the sepsis (n = 10) and no-sepsis group (n = 38). Three infants had an increase in C-reactive protein but negative cultures. Low entropy measurements [approximate entropy 0.4 (0.3, 0.5) vs. 0.8 (0.6, 1); p < 0.001] and long-range fractal exponent [α2 0.78 (0.71, 0.83) vs. 0.92 (0.8, 1.1); p < 0.05] were significantly associated with sepsis. No other HR characteristic was associated with sepsis. The decrease in 0.1 units of approximate entropy was associated with an over 2-fold increase in the odds of sepsis. Conclusion: Late-onset sepsis is associated with uncorrelated randomness of the HR. This abnormal HR behavior may help to monitor premature infants presenting with frequent and severe bradycardias.
Meta-heuristic Methods Applied to the Design of Wood—Plastic Composites, with Some Attention to Environmental Aspects
Authors: Michaud Franck , Castéra Patrick , Fernandez Christophe , Ndiaye Amadou
Published: March 2009

This article addresses the optimization of the quality of wood—plastic composites (WPC) designed for outdoor uses such as decking, taking into account the environmental impact during the life cycle of the product, from production to end of life (from ground to ground). In a context where several conflicting objectives must be satisfied simultaneously in the design process, meta-heuristic approaches provide efficient methods for optimization. Multi-objective particle swarm optimization (MO-PSO) has been chosen here to solve a complex problem in which physical properties such as creep and duration of load, water absorption and swelling, need to be improved with a limited impact on environment. This requires to get reliable information on material properties as related to its composition, environmental impacts through life cycle analysis (LCA), and to implement relevant information such as exhaustion of fossils resources through analytical or probabilistic models in the PSO algorithm in order to obtain a set of optimal solutions for the composite. This article shows the feasibility of this approach, which can be generalized in the design of any type of composite structures, provided objective functions can be specified.