bluuebunny/crossref_metadata_2025 huggingface dataset:
Detailed Investigation of Thermal-Hydraulic Aspects During the Reflood Phase in QUENCH Experiments
Authors: Homann Christoph , Hering Wolfgang , Miassoedov Alexei , Sepold Leo
Published: November 2008

The QUENCH program, performed at Forschungszentrum Karlsruhe, Germany, is dedicated to out-of-pile studies of the initiation and progression of damage during core reflood of a degraded commercial nuclear reactor. Main work in this program is spent on the investigation of the material behavior of the solid structures. However, for the deeper understanding of the integral tests, especially of the quench phase, as well as for computational support of the tests and for the validation of severe accident codes, a sufficient knowledge of thermal-hydraulics in the bundle during the quench phase is also mandatory. Though much instrumentation is available in the test section, information to interpret thermal-hydraulics is scare due to principal and technical reasons. The main objective of the present paper is to get a better idea of the reflood process, based on all available experimental data. For this purpose, the test QUENCH-06 is used because of the amount of available qualified experimental data and because of its special importance for code validation, this test being selected as OECD International Standard Problem (ISP) no. 45. At reflood initiation of QUENCH-06, some irregularity of water injection occurred due to the malfunction of a check valve. A thorough inspection and comparison of experimental data is presented in this paper to clarify details of the start of the quench phase. It is complemented by still more detailed computations with the in-house version of SCDAP/RELAP5 mod 3.2 than at the time of ISP-45. Apart from its relevance for this special test and for ISP-45, this work sheds light on the consistency of the involved experimental data. Besides to this investigation, the transition from two- to single-phase flow is examined in more detail than before, giving indications for the axial extension of the two-phase flow region with large droplets or a sensible fluid fraction and for the duration of two-phase flow near saturation temperature. Again, the consistency of data of various instrumentations is assessed. Despite of this success, a better instrumentation for thermal-hydraulics, mainly of void sensors in the lower part of the bundle, is desirable to facilitate interpretation of thermal-hydraulic aspects of the tests.
Mercury Target and Its Peripheral Devices for 1 MW Spallation Neutron Source
Authors: Haga Katsuhiro , Kaminaga Masanori , Kinoshita Hidetaka , Kogawa Hiroyuki , Satoh Hiroshi , Ishikura Shuichi , Torii Yoshikatsu , Hino Ryutaro
Published: November 2008

The Japan Atomic Energy Research Institute (JAERI) and the High Energy Accelerator Research Organization (KEK) are promoting a plan to construct a 1MW neutron source facility at the Tokai Research Establishment, JAERI, under the Japan Proton Accelerator Research Complex (J-PARC) Project. In the facility, 1 MW pulsed proton beam from a high-intensity proton accelerator will be injected into a mercury target in order to produce high-intensity pulse neutrons for use in the fields of life and material sciences. In order to realize such a high-power neutron source, the design activity of a cross flow type (CFT) mercury target and its peripheral devices has continued and the results is reflected in the ordering specifications of the facility construction. The arrangement of each component and their structure was optimized through experimental and analytical studies. In this paper, the present design of the mercury target components for 1MW spallation neutron source including the target vessel, a mercury circulation system, and a target trolley will be reported.
Interface Stability Criteria for Ex-Vessel Corium Solidification
Authors: Frolov Kyrill N. , Duclot Michel , Journeau Christophe
Published: November 2008

In case of a severe accident at a nuclear power plant (NPP) involving the reactor core melt-down and the subsequent reactor pressure vessel (RPV) melt-through, confident solidification of ex-vessel corium is considered to be the imperative condition of safe retention of corium within the plant containment in the long term. The rate-determining process for solidification of ex-vessel coriums in the long-term is the chemical diffusion in the liquid phase at the solid-liquid interface. The process of chemical diffusion in the diffusive boundary layer can evolve and take on different rates, depending on the boundary conditions and the melt composition. The chemical diffusion coefficient models presented to date in the literature resort to correlations of the former to the self-diffusion coefficients among other intrinsic properties. The general feature of such models is that they predict in the tracer limit that the main diagonal coefficients tend towards the self-diffusion coefficients whereas the cross-over terms cancel out. It is revealed in this study that this particular feature is characteristic of prototypic corium melts, mixtures of several major as well as minor components. Following the corium-concrete interaction, the multicomponent ex-vessel corium melts would contain certain fractions of silica. Accordingly, they are considered in this paper as silicate oxide melts. As a first contribution, this paper comes up with a development of interface stability criteria for its application to solidification of silicate oxide melts. For ex-vessel corium melts, not far removed from equilibrium solidification conditions (long-term retention), the extension of the FICK’s law due to ONSAGER can be applied to description of the diffusive mass transfer. This formalism implies that the diffusive fluxes are linear combinations of the products of the phenomenological diffusion coefficients and the driving forces (gradients). In this regard, the near equilibrium solidification of corium containing N components is determined by a (N−1)(N−1) chemical diffusion matrix comprising the proper and cross-over coefficients. On the other hand, by comparison to the constitutional super cooling criterion of the interface stability in the course of solidification, a relationship between the macroscopic solidification conditions and the phenomenological coefficients can be established. This analysis, earlier developed for liquid metal solidification, has received attention in this study in view of its extension onto the solidification of multicomponent oxide melts. The important conclusion whatsoever is that the crossover terms can’t be neglected as easily as in the case of liquid metal alloys, particularly for silicate melts. As in prototypic corium compositions certain tracer diffusion coefficients can be relatively easily obtained from an experiment, this paper suggests an empirical method for determination of corium constituents’ self-diffusivities from controlled solidification tests.
An Electrical Condition Monitoring Approach for Wire and Cable
Authors: Watkins Kenneth S. , Morris Shelby J. , Wong C. P. , Fan Lianhua , Sun Yang Yang , Masakowski Daniel D. , Alvis Wendy
Published: November 2008

An electrical cable condition monitoring (CCM) method utilizing conductive polymer age sensors provides a distributed, in-situ approach that reduces access considerations and eliminates destructive testing, increasing safety by monitoring areas otherwise impractical or impossible. It reduces the cost of Generation IV cable condition monitoring by eliminating sample-retrieval and significantly reducing testing costs associated with conventional mechanical and chemical condition monitoring. Future applications include simple, lowcost condition monitoring of virtually any polymer used in industry, transportation, construction and recreation. The proposed CCM method utilizes inert conductive particles compounded with candidate insulation materials to provide an age “sensor” distributed in the wire or cable insulation or jacket. A simple electrical measurement, the resistivity of the sensor, correlates age-related degradation of mechanical properties such as elongation at break (EAB) and provides a means to determine remaining life of the insulation material. This paper summarizes the results of research being conducted under a DOE Small Business Innovative Research grant in concert with the School of Materials Science and Engineering at Georgia Tech and Rockbestos-Surprenant Cable Corp.
Steady MHD Flow for Molten Metal Coolants in Advanced Nuclear Systems
Authors: Koreshi Zafar Ullah
Published: November 2008

The flow of a molten metal coolant, incorporating viscosity and a magnetic force in a channel typical of a nuclear fusion reactor is formulated. This is based on the flow conservation equations (continuity and momentum), along with Maxwell’s equations and Ohm’s law. These equations are solved with assumptions of steady fully-developed flow for Newtonian fluids. Exact solutions are compared with a Direct Numerical Simulation (DNS) to compute important engineering design parameters such as velocity distribution and pressure drop in a coolant channel. The analysis can be used for several candidate coolants including, molten lithium, sodium, lead, and compounds. The difference in velocity profile, and hence pressure drop, is strongly dependent on the magnetic field. In fact, it is shown that a flat (almost-turbulent) profile is obtained for the flow.
Frictional Pressure Drop in Micro-Channel
Authors: Koizumi Yasuo , Ohtake Hiroyasu , Takahashi Hiroki , Ohno Yoshiaki
Published: November 2008

The friction characteristics of water in a sub-millimeter scale channel were investigated experimentally. The friction factors and the critical Reynolds number were measured using water flow through circular tubes with diameters of 0.5, 0.25 and 0.17 mm. The experimental results show that the measured friction factor for water agreed well with the conventional Poiseuille (λ = 64/Re) and Blasius (λ = 0.316 Re−0.25) equations in laminar and turbulent flow regime; the laminar-turbulent transition Reynolds number was approximately 2300 for diameter 0.5 mm. For diameter 0.25 mm, the friction factor evaluated by the form pressure drop also agreed well with the Poiseuille equation. For diameter 0.17 mm, the measured total friction factor was close to the Poiseuille prediction.
Analysis on Difference of Risk Perception Between People Engaged in Nuclear Business and General Public: From Social Survey for Nuclear Power Plant
Authors: Terado Mika , Yoshikawa Hidekazu , Sugiman Toshio , Hibino Aiko , Akimoto Mariko
Published: November 2008

A new research project has started to develop two kinds of Internet communication systems which are aimed at effective social risk information on nuclear energy. One is mutual communication system for fostering safety culture among the workers in nuclear industry while the other is to enlighten general public about the risk issues on final disposal of high-level radioactive waste. Prior to the Internet systems development, social investigations have been conducted on risk perception for nuclear power for both the nuclear experts and women in the metropolitan area, in order to know how and what should be considered for the effective risk communication methods. It was found from the statistical analysis to the results of social investigation that the majority of nuclear people take business risk seriously but there is a fraction of nuclear people who are afraid of present practice of nuclear power operation while women in metropolitan area are evenly afraid of radioactive risk. The obtained results of social investigation gave useful insight for developing two kinds of risk communication systems and the related field study for enhancing safety culture in nuclear industries.
An Overview of Cylindrical Water Tank Buckling Analysis Under Seismic Loading
Authors: Turbat Andre´
Published: November 2008

A thin walled cylindrical liquid storage tank submitted to a large seismic excitation may exhibit buckling. Depending on the geometrical and dynamical characteristics of the tank, two buckling patterns are possible: • a bending buckling characterized by an “elephant foot bulge” at the bottom part, • a shear buckling characterized by oblique waves at the middle part of the tank. In a recent paper (Ref. [1]), Tomohiro I. et al. have presented the Japanese experience about bending buckling of cylindrical water tanks. Dynamic buckling experimental tests were performed using large scale water tank models simulating thin walled cylindrical water tanks in Nuclear Power Plants (NPP). Test results were compared with finite element simulations and the applicability of a simple analytical method included in the AIJ (Architectural Institute of Japan) design guide lines on the buckling of liquid storage tanks was also investigated. In Europe, in the frame of the preparation of Eurocodes, a simple analytical method has also been developed to assess the buckling resistance of liquid storage tanks against seismic solicitations. On the other hand, FRAMATOME-ANP has gained her own experience about buckling analysis of large thin tanks where boric water is stored in French NPP. In order to justify the buckling behaviour of these tanks under extreme seismic loadings (Safe Shutdown Earthquake), finite element elastic-plastic calculations on shell models were undertaken where the influence of manufacturing geometrical defects was taken into account and the results were compared with those given by the simple analytical method included in Eurocode 8. In this paper, French and Japanese methodologies will be recalled and applied to a representative example of nuclear industry. Finally, some advanced aspects of the problem like the post-buckling behavior of the tanks and the influence of a possible bottom uplifting will be developed.
Multiwalled Carbon Nanotube/Nanofiber Arrays as Conductive and Dry Adhesive Interface Materials
Authors: Tong Tao , Zhao Yang , Delzeit Lance , Kashani Ali , Majumdar Arun
Published: November 2008

We demonstrate the possibility of making conductive and dry adhesive interfaces between multiwalled carbon nano-tube (MWNT) and nanofiber (MWNF) arrays grown by chemical vapor deposition with transition-metal as catalyst on silicon substrates. The maximum observed adhesion force between MWNT and MWNF surfaces is 3.5 mN for an apparent contact area of 2 mm by 4 mm. The minimum contact resistance measured at the same time is ∼20 Ω. Contact resistances of MWNT-MWNT and MWNT-gold interfaces were also measured as pressure forces around several milli-Newton were applied at the interface. The resulting minimum contact resistances are on the same order but with considerable variation from sample to sample. For MWNT-MWNT contacts, a minimum contact resistance of ∼ 1 Ω is observed for a contact area of 2 mm by 1 mm. The relatively high contact resistances, considering the area density of the nanotubes, might be explained by the high cross-tube resistances at the contact interfaces and limited inter-penetration of the nanotube arrays.
Transport Phenomena in Nanofluidic Channels
Authors: Daiguji Hirofumi , Yang Peidong , Szeri Andrew , Majumdar Arun
Published: November 2008

Ion transport in nanoscale channels has recently received increasing attention. Much of that has resulted from experiments that report modulation of ion transport through the protein ion channel, α-hemolysin, due to passage of single biomolecules of DNA or proteins [1]. This has prompted research towards fabricating synthetic nanopores out of inorganic materials and studying biomolecular transport through them [2]. Recently, the synthesis of arrays of silica nanotubes with internal diameters in the range of 5–100 nm and with lengths 1–20 μm was reported [3]. These tubes could potentially allow new ways of detecting and manipulating single biomolecules and new types of devices to control ion transport. Theoretical modeling of ionic distribution and transport in silica nanotubes, 30 nm in diameter and 5 μm long, suggest that when the diameter is smaller than the Debye length, a unipolar solution of counterions is created within the nanotube and the coions are electrostatically repelled [4]. We proposed two different types of devices to use this unipolar nature of solution, i.e. ‘transistor’ and ‘battery’. When the electric potential bias is applied at two ends of a nanotube, ionic current is generated. By locally modifying the surface charge density through a gate electrode, the concentration of counterions can be depleted under the gate and the ionic current can be significantly suppressed. This could form the basis of a unipolar ionic field-effect transistor. By applying the pressure bias instead of electric potential bias, the fluid flow is generated. Because only the counterions are located inside the channel, the streaming current and streaming potential are generated. This could form the basis of an electro-chemo-mechanical battery. In the present study, transport phenomena in nanofluidic channels were investigated and the performance characteristics were evaluated using continuum dynamics.
Laser Nano-Machining Using Near-Field Optics
Authors: Chung Haseung , Kurabayashi Katsuo , Das Suman
Published: November 2008

A near-field optical technique, using a new type of solid immersion lens (SIL), has been developed and applied to various areas, for example, high-density optical storage, near-field-scanning-optical-microscope probes, photolithography. Solid immersion microscopy offers a method for achieving resolution below the diffraction limit in air with significantly higher optical throughput by focusing light through a high refractive-index SIL held close to a sample [1]. The minimum resolution of a focusing system is inversely proportional to numerical aperture (NA), where NA = n sinθ, θ is the maximum angle of incidence, and n is the index of refraction at the focal point. Light with vacuum wavelength λ can be focused by an aberration-free lens to a spot whose full width at half maximum (FWHM) is λ/(2 NA) in the scalar diffraction limit, equivalent to Sparrow’s criterion for spatial resolution. In a medium of refractive index n, the effective wavelength is λeff = λ/n and corresponding effective numerical aperture is NAeff = n2sinθ. When a SIL is used, improvements in NAeff and spatial resolution are proportional to the refractive index of the SIL material. Fletcher et al. demonstrated imaging in the infrared with a microfabricated SIL [1, 2]. Baba et al. analyzed the aberrations and allowances for an aspheric error, a thickness error, and an air gap when using a hemispherical SIL for photoluminescence microscopy with submicron resolution beyond the diffraction limit [3]. Terris et al. developed and applied a SIL-based near-field optical technique for the writing and reading domains in a magneto-optic material [4]. Song et al. proposed the new concept of a SIL for high density optical recording using the near-field recording technology [5]. In this paper, we propose a sub-micron scale laser processing technique with spatial resolution beyond the diffraction limit in air using near-field optics. Our goal is to eventually develop a massively parallel nano-optical direct-write nano-manufacturing technique.
Transport in Thermal Dip Pen Nanolithography
Authors: Nelson Brent A. , Wright Tanya L. , King William P. , Sheehan Paul E. , Whitman Lloyd J.
Published: November 2008

The manufacture of nanoscale devices is at present constrained by the resolution limits of optical lithography and the high cost of electron beam lithography. Furthermore, traditional silicon fabrication techniques are quite limited in materials compatibility and are not well-suited for the manufacture of organic and biological devices. One nanomanufacturing technique that could overcome these drawbacks is dip pen nanolithography (DPN), in which a chemical-coated atomic force microscope (AFM) tip deposits molecular ‘inks’ onto a substrate [1]. DPN has shown resolution as good as 5 nm [2] and has been performed with a large number of molecules, but has limitations. For molecules to ink the surface they must be mobile at room temperature, limiting the inks that can be used, and since the inks must be mobile in ambient conditions, there is no way to stop the deposition while the tip is in contact with the substrate. In-situ imaging of deposited molecules therefore causes contamination of the deposited features.
Self-Assembled Silicon Microdevices Driven by Muscle
Authors: Xi Jianzhong , Schmidt Jacob , Montemagno Carlo
Published: November 2008

Over the last two decades, a variety of micro-robotic systems have been developed including electrothermal, electrostatic, electrochemical, piezoelectric, and electromagnetic actuators based on MEMS technology. The development of these micro-actuators promises a revolution in biological and medical research and applications analogous to that brought about by the miniaturization of electrical devices in information technology. For example, controllable manipulation of these tiny actuators may enable precise temporal and spatial delivery of chemicals, micro-optics or microelectronics to specific targeted sites.
Nonlinear Compensator Design of Active Proximity Sliders for Head-Disk Spacing Variation Suppression in 3-nm Air Bearings
Authors: Juang Jia-Yang , Bogy David B.
Published: November 2008

Based on the concept that the FH of a portion of the slider that carries the read/write element can be adjusted by a piezoelectric actuator and the FH can be measured according to the magnetic signal, a new 3-DOF analytic model and an observer-based nonlinear compensator are proposed to achieve ultra-low FH with minimum modulation under short range attractive forces. Numerical simulations show that the FHM due to disk waviness is effectively reduced with a control voltage of less than ±2V.
Electrostatic Effect on Jump-to-Contact and Atom Transfer Between AFM Tip and Substrate
Authors: Cheng M. C. , Lai J. L. , Sung C. K. , Tai H. M.
Published: November 2008

Dynamics of atoms around the interface of tip and substrate has close relationship to adhesive forces. This paper investigates the interactive behaviors by utilizing molecular dynamic (MD) simulation with the consideration of external applied electrostatic (ES) field between the atomic force microscopy (AFM) tip and substrate, which are both coated with gold. Morse potential was employed herein for modeling the energy between the atoms on the tip and substrate. The simulation model is composed of the gold-coated parts of the AFM tip and substrate, which are connected to the rest parts of the AFM tip and substrate, respectively, by the use of boundary conditions. The gold atoms were arranged in order according to face centric cubic (FCC) structure. The tip with the pyramidal shape was formed from 664 gold atoms while the substrate with cuboid shape was constructed from 2400 gold atoms. Simulation results show that both jump-to-contact interactions and the atom transfer increase as a result of enhancing the bias voltage between the tip and the substrate. The results agree well with experimental observation and also have the same trend as the experiment.
Mo2C Nanowires and Ribbons on Si via Two-Step Vapor Phase Growth
Authors: Tsakalakos Loucas , Denault Lauraine , Larsen Michael , Rahmane Mohamed , Gao Yan , Balch Joleyn , Wilson Paul
Published: November 2008

Transition metal carbides are an interesting class of electronic materials owing to their high electrical conductivity at room temperature, which is only slightly lower than that of their constituent transition metal elements. For example, the room temperature electrical resistivity of bulk Mo2C is ∼70 μΩ-cm compared to that of Mo (4.85 μΩ-cm), whereas that of NbC is ∼50 μΩ-cm as compared to 15.2 μΩ-cm for Nb. Indeed, the temperature dependent resistivity of many transition metal carbides suggests metallic-like conduction. Furthermore, certain transition metal carbides are known to become superconducting, with transition temperatures ranging from 1.15 °K for TiC1−x to 14 °K for NbC. [1] They are also able to withstand high temperatures and are chemically stable. Initial synthesis of metal carbide nanorods was demonstrated using the carbon nanotube (CNT) confined reaction mechanism by Lieber and co-workers [2] and subsequent superconducting behavior was shown by Fukunaga et al. [3]. Vapor-liquid-solid growth was employed by Johnson et al. [4] to synthesize micron-sized carbide whiskers. Here, we have successfully synthesized Mo2C nanorods and ribbons on Si substrates using a novel two-step catalytic approach, which allows for synthesis of such high temperature nanostructures at manufacturable temperatures (≤ 1000 °C) and time scales (≤ 60 min). In the first step we utilize a catalytic vapor phase process to grow Mo and/or molybdenum oxide nanostructures, which are subsequently carburized in situ to form the desired Mo2C nanostructures. Unlike true VLS growth of carbides, in which high temperature (≤ 1100–1200 °C) is required to adequately dissolve carbon into the catalyst particles, our strategy is to react the nanostructures along their entire length with a carbon vapor source after creating the oxide/metal nanostructures, which for Mo2C can be achieved at relatively low temperatures. (≤ 1000 °C). The nanorods and ribbons are polycrystalline, with a mean grain size of 20–50 nm and 50–150 nm, respectively. We hypothesize that the growth mechanism is a complex mixture of VLS, VSS, and auto-catalytic growth, in which molten catalyst nanoparticles enter a three phase region once the metal precursor is supplied. The growth then presumably continues via a vapor-solid-solid process and is possible assisted by the presence of various molybdenum oxide species on the surface. Initial single nanowire electrical measurements yield a higher resistivity than in the bulk, which is attributed to the fine grain sizes and/or the presence of an oxide layer. A discussion of the growth mechanism will be presented along with issues relating to single nanowire device fabrication and control of nanowire orientation.
Waterwall Quench Crack Inspection Without Cleaning or Scaffolding
Authors: Rhodes George W. , Hennessy Corey J.
Published: November 2008

The Mutual Inductance Bridge (MIB) system scans waterwalls for multiple defect types. Already used successfully to detect fireside corrosion and erosion, the capability has been expanded to quench cracking. The MIB electromagnetic approach uses in-phase and quadrature information to detect defects well before potential breakouts might cause plant outages. Fireside corrosion, scale and clinker deposits as large as 0.5” do not interfere with measurement accuracy or speed. Although quench crack defects alone do not change the mass of ferromagnetic material, the magnetic field perturbations caused by their presence provide a unique signature. The robotic MIB deployment containing a position measuring laser, video cameras and proprietary electronics scans 400 ft2 per hour; the handheld unit scans 125 ft2/hr. Scan results include color-coded maps that describe the condition of scanned areas, and individual tube profiles. Results of several applications are presented.
A Simplified Method for Predicting Performance of Power Plants With Hybrid Cooling Systems
Authors: Srinivasan Ram , Yasi Dan
Published: November 2008

For the purposes of this study, a hybrid cooling system is a combination of an open cycle heat sink such as a river and a closed cycle heat sink such as a cooling tower. Predicting the performance of power plants with hybrid cooling systems is an elaborate process. A typical hybrid power plant operates in four modes. 1) Once Through Mode 2) Hybrid Mode 3) Helper Mode and 4) Closed Cycle Mode. The variables affecting the operating mode of the plant are the ambient wet bulb, river water temperature, river water flow, and the permit allowed river water temperature rise. There are infinite possible combinations of these variables, and use of weekly or monthly average conditions may not capture sufficient detail for a rigorous economic analysis. The usual method to predict plant output, under varying conditions, would be to run heat balances for each case required. Such a process becomes extremely tedious when predicting hourly performance data, which can be desirable for economic studies of such systems. This paper will present a simplified method to predict the performance of a power plant with a hybrid cooling system for any given river water temperature, river water flow, ambient wet bulb temperature, and river water temperature rise. Such a method can be used in spreadsheets, which are convenient to use in financial calculations. This method was used to predict the performance of an actual power plant with hybrid cooling and yielded satisfactory results.
Management Challenges in Emerging European Union Eco-Standards
Authors: Aanstoos Ted A.
Published: November 2008

The European Union is 450 million citizens in 25 otherwise sovereign countries, but connected in a multinational federal metastate that claims a combined economy in excess of $9 trillion (US), making it one of the world’s largest economies. As a community faced with massive decontamination and re-industrialization from devastating wars, Europe places due emphasis on issues of environmental sustainability and pollution prevention. Under broad policy guidelines of the New Approach and Integrated Product Planning frameworks, the European Commission is drafting legislation that will mandate eco-standards for all energized end-use equipment for sale in the internal market. These proposed standards may raise controversy in many industry sectors and international arenas (including within Europe itself) because they may not be based on sound and accepted scientific analysis, because they may constitute a de-facto violation at least in spirit of the Technical Barriers to Trade Agreement, and because nobody can yet predict their cost impact and other market effect. Compliance with these emerging energy efficiency regulations will impose considerable management requirements on manufacturers as they devise documentation and certification programs for their products that are likely to be of a scope similar to ISO 14000. This paper assesses the new requirements from a product and design management perspective.
Metallurgical Assessment of Degradation of a Gas Turbine Bucket Made of Inconel 738LC Alloy After 24000 H in Service
Authors: Mazur Zdzislaw , Luna-Rami´rez Alberto , Jua´rez-Islas Julio A.
Published: November 2008

The assessment of service induced degradation of nickel-base alloy Inconel 738LC of the gas turbine blade airfoil hot section, after 24000 hours of operation at high temperature is presented. The assessment include the blade coating degradation, changes of the gamma prime (γ′) phase (aging and coarsening), carbides and brittle phases precipitation, grain type and size characterization, and evaluation of interface coating/base alloy and cracks. The results of blade hot section (airfoil) microstructural assessment are compared to the cold reference zone (bucket root) to show the degradation degree of the alloy and its lifetime consumed. Finally, conclusions are presented indicating the alloy main microstructure elements which influence of blade behavior and the factors that can be used to determine the grade of material deterioration and lifetime consumed.
A Model for Thermo-Economic Analysis and Optimization of Steam Power Plants for Power and Cogeneration
Authors: Arsie I. , Marano V. , Rizzo G.
Published: November 2008

The paper presents a model for thermoeconomic analysis and optimal design of steam power plants, for power generation and cogeneration use. The model, including both thermodynamic and economic description of a general steam power plant with regeneration, reheating and cogeneration, can be used for simulations, parametric analysis and optimization, with mathematical programming techniques. The variability of components performance and efficiency versus costs can be also analyzed, and optimal trade-off between costs and performace obtained by optimization analysis. Significant applications to cogeneration are presented in the paper, discussing the effects of electrical and thermal loads, fuel price and changes in technology. The computer code, built in Matlab®, allows to perform complex optimization analyses with very limited computational time.
ESP Performance Improvement: Flue Gas Conditioning Finally Arrives in India
Authors: Roy Chandan , Sanyal Anupam , Pande Sanjay
Published: November 2008

Electro Static Precipitator’s in India — that dedust about 65000 MWe capacity — have come a long way from their Western Pedigree. The imported designs mutated, prompted by the Indian coal/ash, which characterize uniquely- essentially high ash content of atypical composition and very high resistivity. Insufficient initial recognition of this aspect, incremental environmental consciousness and progressively deteriorating coal quality led to a convoluted and not so satisfactory ESP performance scenario in the country. Recognizing the need for organic interventions, NTPC undertook multiple studies and tests-backed up by a strong knowledge network- on almost all ESP performance enhancement options. While certain options are under extended observation, Flue Gas Conditioning (FGC) — based on encouraging test results and worldwide presence — is being inducted in some NTPC stations. Triggered by this broad-based program, FGC has started appearing front stage in India. This study visits aspects that make FGC attractive for Indian ESPs. Looking beyond the present, an attempt has been made to examine the potential of ESP-FGC combination as a dependable alternative for the long term. “Technology maturity”, “flexibility in space requirements” and the “blanket performance control” that FGC offers are the critical success factors. Implementation economics though unclear now, is complimented by the relatively low locked capital component, which FGC offers. It emerges that a sound theoretical base for the conditioning agent choice and its action on ash/ESP performance is missing and needs to be developed for a systematic development and spread. Technology initiatives are invited for this task. The paper, oriented as a comprehensive narration to act as a precursor to such developmental work, therefore picks up from ESP advent in India enumerating the key reasons for the pessimistic performance response through the key FGC application determinants.
Capturing the Energy of Ocean Waves
Authors: Wolfe Douglas E.
Published: November 2008

This paper will propose a concept of efficiently capturing the power of ocean waves. Many concepts have been pursued for over 100 years, but none have proven to be commercially viable for widespread operation. The waves offer 2 to 3 million megawatts of clean, renewable energy globally with up to 65 megawatts available per mile of coastline in favorable locations; furthermore, 60% of the world’s population lives within 100 miles of a coastline. Developing a cost-competitive system offers the potential to contribute to the world’s growing energy needs while preserving the environment. The proposed concept is designed to overcome the difficulties of competing concepts by preventing system destruction due to severe storms and bio fouling — the degradation of precision components in a corrosive environment. The author has developed a working model that has been deployed in the ocean, constructed of “low tech” building materials that demonstrated continuous turning of a large flywheel, moment of inertia of 250 kg m**2. The patented concept offers a means for rapidly constructing the energy capture mechanism and keeping the critical precision components protected from the ocean environment. Building on this success, a large-scale demonstration is proposed to assess performance of a commercially viable configuration.
Spectroscopic Analysis of Diffusion Flame Using High Temperature Combustion Air
Authors: Ghaderi M. , Gupta A. K.
Published: November 2008

Results are presented on the effect of high temperature combustion air on the thermal and chemical behavior of propane-air diffusion flames using spectroscopic diagnostic techniques. The oxygen concentration in air was 21% by volume for both the normal and highly preheated air flames. The temperature distribution within the flames has been obtained for a burning fuel jet using normal temperature and high temperature combustion air. Spatial distribution of C2, CH and OH from within the flames in 2-D has been obtained. An ICCD (image intensified charge coupled device) camera fitted with an appropriate narrow band interference filter provided the spontaneous emission signature of the specific specie produced in the flame. The results show that the intensity level of C2 in the flame with highly preheated air is lower than the corresponding normal temperature air flames. In contrast the intensity level of CH radicals in the flame is higher than corresponding normal air temperature flames. The intensity level of OH radicals with highly preheated air is higher than corresponding normal temperature air flames. They suggest faster chemical reaction and higher heat release rate with high temperature combustion air than the corresponding normal temperature air. These findings are much different than those obtained for low oxygen concentration air flames. The Abel transformation technique was applied to obtain 3-D spatial distribution of selected radicals within the flames. Two emission peaks of C2 radical species have been observed in the visible part of the wavelength. The temperature distribution inside the flame was obtained from the ratio of these two peaks using two-color method. The effect of preheated combustion air on the flame temperature has been determined by analyzing the spectra of spontaneous emission of the C2 radicals at two discrete wavelengths.
Utilization of the MK Combustion Optimization System™ to Maximize Combustion Efficiency in an Environment-First Fashion
Authors: Krzysik David
Published: November 2008

Nitrogen oxide (NOx) emissions discharged into the atmosphere from fossil fuel combustion prove to have adverse effects on the environment and human health. Contributing factors include the formation of acid rain, ozone, degradation of visibility, and inhalable fine particles. In addressing these problems, environmental regulations are becoming more stringent on electric utilities. Low NOx burner (LNB) technology was developed to provide a cost-effective means of complying with the NOx Reduction Program under Title IV of the Clean Air Act Amendments (CAAA) of 1990. Prior to LNB technology, standard burners were designed to rapidly mix the fuel and oxidant, producing high combustion efficiency and large quantities of NOx. Limiting the reaction rate at which the air and fuel mix, particularly during the early stages of combustion, can effectively control NOx formation; however, this rate limitation tends to diminish combustion efficiency and proves to be the compromise of LNB technology. Controlling one aspect or the other can be intuitively easy, but controlling both is challenging and trade-offs are necessary. Identifying a happy medium between the standards of yesterday and today is necessary in the optimization of coal-fired combustion. The ultimate effect will improve commercial availability in an environment-first fashion.
Cyclone Maintenance Improvement via Special Refractory Anchor Pin Studs
Authors: Swartz Stephen R.
Published: November 2008

Since the inception of the cyclone style boiler, industry has become accustomed to performing routine maintenance during every scheduled shutdown occurring 12 months to 18 months between cycles. These maintenance cycles are influenced by service factor, loading and the type design. The same problems exist in both the standard and super critical cyclones; severe deterioration of refractory and the anchoring pin studs. This paper focuses on one type of refractory failure mechanism caused by the anchoring pin studs. Most operators have found that the most effective means of applying refractory in this type situation is to “ram” the refractory in and around the anchoring pin studs thus creating a dense lining with maximum integrity. Coupled with proper application of anchoring pin studs and a special designed coating, typical volumetric expansion of the pin studs from corrosion attack and oxidation is eliminated thus extending the life of the refractory. This mechanism is discussed along with the results of the coating performance as it relates to extreme heat oxidation and thermal cycling in laboratory tests. A protective coating was developed using a nano-cored thermal spray wire technology that produces a uniform, adherent protective layer against high temperature corrosion and oxidation. The coating yields similar thermal conductivity as a bare stud thus experiencing excellent thermal cycle performance. This specially designed thermal spray coating is applied to standard 430 stainless steel pin studs thus providing the necessary barrier against aggressive high temperature environments while maintaining excellent heat conductivity. The coating has a high amount of tungsten (40+%) in a nickel matrix with greatly reduced oxides at the substrate and throughout the coating. With these attributes for the anchoring pin studs in mind, a newly designed stud was evaluated in heat oxidation tests up to 2000°F and thermal cycling test and compared to 430 stainless steel, chromized and Alloy 625. The new stud out-performed all others even in the as-welded condition. Further corrosion testing in ferric chloride (ASTM G48) showed them to be superior to Alloy 72 and Alloy 625 in the thermal spray and welded condition. Proper welding equipment and welding techniques are also discussed since weld continuity impacts overall performance of anchoring pin studs with refractory linings. A major test site will be examined in the spring of 2004 for it’s full effectiveness in service and will be documented in order that all data retrieved would be available to the entire industry.
The Hi-Lo Bi-Track System
Authors: Scales Brian T.
Published: November 2008

The Hi-Lo Bi-Track System is an innovative technology that provides appropriate superelevations on curves to suit both high-speed passenger trains and low-speed freight trains. Adoption of the Hi-Lo Bi-Track System would provide the following benefits: • Permit creation of high-speed lines for passenger trains over existing freight train rights-of-way without compromising performance of either train technology. • Provide improvement in typical train trip times due to reduced need for speed reduction at curves. • Provide savings in energy consumption due to less braking for curves and subsequent acceleration back to line speed. • Provide better performance then “tilting trains” in reducing typical train trip times. • Avoid high vertical and lateral track forces resulting from operation of “tilting trains.” • Applicable to high-speed mail and express freight trains in addition to high-speed passenger trains.
Implementation of New Technologies in Traction Power Systems
Authors: Sagareli Sergo , Gelman Vitaly
Published: November 2008

Due to significant developments in power electronics since the 1980’s, a row of new components are being used for both utility [1] and traction power substations, leading to new concepts in their design and construction. Among others, such innovations as incorporation of microprocessor-based multifunction protective relays and programmable logic controllers are changing traditional substations’ equipment layout and inter-connections; the development and experimental use of thyristor rectifiers and solid-state DC circuit breakers is under way. A significant reduction in the amount of protective and control devices (and associated wiring) has been achieved by introduction of multi-function relays (MFR or MPR – Multi-Purpose Relay), capable of replacing a whole group of relays used for equipment protection and automated control; for example, one MFR may perform functions of overcurrent and ground fault protection, over- and undervoltage protection, fault sensing and reclosing. Plus, it may be used for data logging and data recording purposes [2]. Additionally, high end MPRs have remote access features allowing not only to set any parameters, but even provide firmware upgrade without visiting the substation, thus providing labor savings. Therefore, one MFR may replace about a dozen of traditional relays and devices, along with their wiring and save maintenance expenses as well. Thyristor Controlled Rectifiers (TCR’s) are another significant innovation in traditional DC traction power substation design. Thyristor rectifiers are offering very important benefit of regulated DC voltage: at the substation’s bus output, the voltage may be constant from 0 to a 100% or even 150% load, which means improved train performance in terms of speed and reliability, as well as lower losses of energy in third rails, and possibility of raising third rail system voltage in the future, thus further lowering losses of energy in the system. Alternatively, it allows to increase the distance between the substations and thus reduce total number of substations. LIRR installed one thyristor rectifier for experimental use in 2003. Flywheel-based energy storage system is another important innovation that is being installed by the LIRR for experimental use. LIRR is installing for experimental use trackside fly-wheel energy storage system developed and tested by the British uranium enrichment company URENCO. According to Tarrant [3], in March 2002 the company successfully tested the KESS – Kinetic Energy Storage System and demonstrated 11% to 18% energy savings in different conditions of operation, because of the lower losses due to higher voltage during the acceleration period.
Multi Level Boarding Bi-Level Commuter Car for North American Market
Authors: Sarunac Radovan , Soesbee Terry B. , Ohta Shin-Ichiro
Published: November 2008

A multilevel boarding version (low and high level platform boarding) of the bi-level commuter car for the North American market has been developed. The major challenge of the bi-level carbody design with the high and lower boarding access, i.e., passenger doors, is the side sill interruption at the lower level. The side sill is the main structural member (beside the center sill) that transmits the longitudinal load from the one end of the car to the other end. Since the side sill is interrupted by placing lower level passenger doors the alternative load path had to be designed. Originally, a solution similar to the one used on the California bi-level car was considered. However, due to major differences in the equipment arrangement and seating plan, an alternative design was developed. Consequently, the LIRR carbody type was chosen, with the exception that the lower body section between bolsters, “fish belly” was similar to the MARC III section. The specific goal and the first step were to study and confirm the feasibility of the concept. As a good engineering practice, prior to the initiation of any major carbody design, a preliminary structural analysis was provided. The worst-case structural scenarios regarding door and window locations were considered. Preliminary structural analysis included linear, static, finite element carbody analysis for various loads and loads requirements defined. This study summarizes the results of the analyses for each load case. The study also comprises the investigation and applicability of the relevant laws and requirements for Tier-I passenger equipment with specific emphasis to the Bi-level car. The applicability of the Code of Federal Regulations, 49 CFR, Transportation, Parts 200 to 399 and American Public Transit Association (APTA) Manual of Standards and Recommended Practices for Rail Passenger Equipment was investigated in detail. Relevant laws, standards, and requirements for Tier-I passenger equipment were identified, categorized and prioritized. Based on the relevant standards, feasibility analysis was performed for the most demanding design. Stress contour and deflection plots from the finite element analyses are provided only for the worst-case direction for a given loading scenario. Floor and seating plans accommodating the multilevel boarding options were developed.