Sample records for thermal cracking process

  1. Process for the hydroformylation of sulfur-containing thermally cracked petroleum residue and novel products thereof

    SciTech Connect (OSTI)

    Oswald, A.A.; Bhatia, R.N.; Mozeleski, E.J.; Glivicky, A.P.; Brueggeman, B.G.; Hooten, J.R.; Smith, C.M.; Hsu, C.S.

    1991-07-09T23:59:59.000Z

    This patent describes a hydroformylation-hydrogenation process comprising reacting an olefinic cracked petroleum distillate feed, produced from petroleum residue by high temperature thermal cracking, and containing C{sub 5} to C{sub 35}-1-n-alkyl olefins as the major type of olefin components, and organic sulfur compounds in concentrations exceeding 0.1% sulfur. It comprises at first with carbon monoxide and hydrogen at temperatures between about 50 and 250{degrees} C and pressures in the range of 50 to 6000 psi; in the presence of a Group VIII transition metal carbonyl complex catalyst in effective amounts to produce aldehydes of a semilinear character having an average of less than one alkyl branch per molecule and 20% by weight or more linear isomers, then with molecular hydrogen at temperatures between 100 and 250{degrees} C and pressures between 200 psi and 5000 psi (13.6 and 340 atm) in the presence of a hydrogenation catalyst in effective amounts the catalyst being sulfur resistant cobalt, molybdenum, nickel, or tungsten or a sulfide thereof to produce the corresponding alcohols of a semilinear character having an average of less than one alkyl branch per molecule and 20% by weight or more linear isomers, then with molecular hydrogen at temperatures between 100 and 250{degrees} C and pressures between 200 psi and 5000 psi (13.6 and 340 atm) in the presence of a hydrogenation catalyst in effective amounts the catalyst being sulfur resistant cobalt, molybdenum, nickel, or tungsten or a sulfide thereof to produce the corresponding alcohols of a semilinear character having an average of less than one alkyl branch per molecule.

  2. Prediction of thermal crack spacing D.H. Timm a

    E-Print Network [OSTI]

    Guzina, Bojan

    understanding of thin film coatings but an understanding of how so-called thermal cracks, a feature of cold

  3. Thermal Processes

    Broader source: Energy.gov [DOE]

    Some thermal processes use the energy in various resources, such as natural gas, coal, or biomass, to release hydrogen, which is part of their molecular structure. In other processes, heat, in...

  4. Prediction of thermal reflection cracking in west Texas

    E-Print Network [OSTI]

    Chang, Hang-Sun

    1975-01-01T23:59:59.000Z

    for the stress intensity factor, Ck, following Barenblatt (53) is used. z 'e(')4' C = ? / k n o (3-11) where C is the distance away from crack tip and o (g) is the surface e stress inside the crack tip element, i. e. ? o is the thermal stress at the depth... of the studies being conducted on pavement temp- erature cracking have been mainly concerned with the fracture suscepti- bilityy of asphalt concrete under extremely low temperature (3, 4). Find- ings of these studies could not provide satisfactory...

  5. Process for magnetic beneficiating petroleum cracking catalyst

    DOE Patents [OSTI]

    Doctor, R.D.

    1993-10-05T23:59:59.000Z

    A process is described for beneficiating a particulate zeolite petroleum cracking catalyst having metal values in excess of 1000 ppm nickel equivalents. The particulate catalyst is passed through a magnetic field in the range of from about 2 Tesla to about 5 Tesla generated by a superconducting quadrupole open-gradient magnetic system for a time sufficient to effect separation of said catalyst into a plurality of zones having different nickel equivalent concentrations. A first zone has nickel equivalents of about 6,000 ppm and greater, a second zone has nickel equivalents in the range of from about 2000 ppm to about 6000 ppm, and a third zone has nickel equivalents of about 2000 ppm and less. The zones of catalyst are separated and the second zone material is recycled to a fluidized bed of zeolite petroleum cracking catalyst. The low nickel equivalent zone is treated while the high nickel equivalent zone is discarded. 1 figures.

  6. Process for magnetic beneficiating petroleum cracking catalyst

    DOE Patents [OSTI]

    Doctor, Richard D. (Lisle, IL)

    1993-01-01T23:59:59.000Z

    A process for beneficiating a particulate zeolite petroleum cracking catalyst having metal values in excess of 1000 ppm nickel equivalents. The particulate catalyst is passed through a magnetic field in the range of from about 2 Tesla to about 5 Tesla generated by a superconducting quadrupole open-gradient magnetic system for a time sufficient to effect separation of said catalyst into a plurality of zones having different nickel equivalent concentrations. A first zone has nickel equivalents of about 6,000 ppm and greater, a second zone has nickel equivalents in the range of from about 2000 ppm to about 6000 ppm, and a third zone has nickel equivalents of about 2000 ppm and less. The zones of catalyst are separated and the second zone material is recycled to a fluidized bed of zeolite petroleum cracking catalyst. The low nickel equivalent zone is treated while the high nickel equivalent zone is discarded.

  7. High-Resolution Crack Imaging Reveals Degradation Processes in...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Reveals Degradation Processes in Nuclear Reactor Structural Materials. Abstract: Corrosion and cracking represent critical failure mechanisms for structural materials in many...

  8. Thermal resistance of bridged cracks in fiber-reinforced ceramic John Dryden

    E-Print Network [OSTI]

    Zok, Frank

    -reinforced ceramic composites obtain high toughness is through the de- velopment of multiple matrix cracksThermal resistance of bridged cracks in fiber-reinforced ceramic composites John Dryden Department November 2000; accepted for publication 16 January 2001 The thermal resistance of a bridged matrix crack

  9. Effects of Matrix Cracks on the Thermal Diffusivity of a Fiber-Reinforced Ceramic Composite

    E-Print Network [OSTI]

    Zok, Frank

    Effects of Matrix Cracks on the Thermal Diffusivity of a Fiber-Reinforced Ceramic Composite of Engineering Science, University of Western Ontario, London, Ontario N6A 5B9, Canada Effects of matrix cracks conductances coupled with a unit cell model for a fiber composite containing a periodic array of matrix cracks

  10. Sulfur distribution in the oil fractions obtained by thermal cracking of Jordanian El-Lajjun oil Shale

    E-Print Network [OSTI]

    Shawabkeh, Reyad A.

    by the thermal cracking process of the El-Lujjan oil shale showed that the yield of oil was around 12 wt of the boiling point for different distillate fractions. Sulfur in Jordanian oil shale was found to be mainly the dominant phases in these fractions. q 2005 Published by Elsevier Ltd. 1. Introduction Oil shale

  11. A nanomechanical investigation of the crack tip process zone of marble

    E-Print Network [OSTI]

    Brooks, Zenzile (Zenzile Z.)

    2010-01-01T23:59:59.000Z

    This study explores the interaction between crack initiation and nanomechanical properties in the crack tip process zone (zone of microcracking at the tip of a propagating crack) of a brittle geomaterial. Samples of Carrara ...

  12. Enlargement of concrete blocks of arch dams with allowance of the formation of radial thermal cracks

    SciTech Connect (OSTI)

    Verbetskii, G.P.; Chogovadze, G.I.; Daneliya, A.I.

    1988-04-01T23:59:59.000Z

    Considerable acceleration of the construction of arch dams with the use of highly productive continuous concreting mechanisms is possible with enlargement of the blocks and allowance of the formation of thermal radial cracks in them. A theoretical analysis and the results of on-site observations show that under the effect of the hydrostatic head of water, radial joints and cracks in compressed zones of an arch dam close and the dam in these zones works as a solid dam. Thermal cracking in concrete blocks of arch dams enlarged in plan should be controlled by making radial notches to concentrate tensile stresses providing the formation of radial cracks at prescribed places and through the usual methods of thermal regulation. The block size along the face of an arch dam is then no longer limited by the condition of crack resistance but is determined by the rate of concreting. The technical and economic effects from concreting arch dams are cited.

  13. Thermal cracking of rubber modified pavements, May 1995. Final report

    SciTech Connect (OSTI)

    Raad, L.; Yuan, X.; Saboundjian, S.

    1995-05-01T23:59:59.000Z

    In accordance with the original ISTEA mandate (1991) to use crumb tire rubber in pavements, Alaska would be required to use about 250 tons of used tire rubber starting in 1994 and increasing to about 1,000 tons of rubber in 1997 and each year thereafter. A number of pavements using crumb rubber modifiers have been built in the state and have been in service for periods of 8 to 15 years. Knowledge of the behavior of these rubber-modified pavements under extreme climate conditions, particularly in relation to their low temperature cracking resistance, is necessary for future design and construction of rubberized pavements in Alaska. This report presents results of a study to determine the low temperature cracking resistance of rubber modified pavements in Alaska in comparison with conventional asphalt concrete pavements.

  14. Rapid thermal processing by stamping

    DOE Patents [OSTI]

    Stradins, Pauls; Wang, Qi

    2013-03-05T23:59:59.000Z

    A rapid thermal processing device and methods are provided for thermal processing of samples such as semiconductor wafers. The device has components including a stamp (35) having a stamping surface and a heater or cooler (40) to bring it to a selected processing temperature, a sample holder (20) for holding a sample (10) in position for intimate contact with the stamping surface; and positioning components (25) for moving the stamping surface and the stamp (35) in and away from intimate, substantially non-pressured contact. Methods for using and making such devices are also provided. These devices and methods allow inexpensive, efficient, easily controllable thermal processing.

  15. Materials Selection Considerations for Thermal Process Equipment...

    Broader source: Energy.gov (indexed) [DOE]

    Materials Selection Considerations for Thermal Process Equipment: A BestPractices Process Heating Technical Brief Materials Selection Considerations for Thermal Process Equipment:...

  16. Hot-crack test for aluminium alloys welds using TIG process , F. Deschaux1

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Hot-crack test for aluminium alloys welds using TIG process A. Niel1,a , F. Deschaux1 , C cracking in welds : state of art Aluminium alloys are highly sensitive to hot tearing phenomenon. It appears during solidification of the alloy, so it can be observed during welding, as well as during

  17. Roles of grain boundaries in cleavage cracking and thermal crack arrest experiments in iron-silicon alloy

    E-Print Network [OSTI]

    Qiao, Yu, 1972-

    2002-01-01T23:59:59.000Z

    High-angle grain boundaries in steel offer an important resistance to the propagation of cleavage cracks that affects the fracture toughness and can modulate the ductile-to-brittle transition temperature of fracture downward. ...

  18. Gamma prime embrittlement and thermal fatigue cracking of a hydrogen reformer burner end

    SciTech Connect (OSTI)

    Dias, O.C.; Mack, N.C. [Amoco Oil Co., Texas City, TX (United States)

    1994-12-31T23:59:59.000Z

    An investigation into the premature failure of an Alloy 800HT (UNS N08811) oxygen-gas mixer water jacketed end is discussed. Detailed metallurgical analyses showed that gamma prime [Ni{sub 3} (Al, Ti)] embrittlement and thermal fatigue cracking led to eventual leakage. The reduced lif e of the Alloy 800HT (UNS N08811) replacement (problems after only a year) was traced to its higher Al + Ti content (1.1%) compared to Alloy 800H (0.6% Al + Ti) which lasted over two years. While higher aluminum and titanium levels improve high temperature creep and stress rupture properties, both are sigma formers and, at levels > 0.6%, tend to form gamma prime with nickel. The choice of alternative metallurgies requires careful considerations of physical, mechanical and thermal properties as well as an understanding of complex stresses and stress distributions.

  19. Concrete cover cracking with reinforcement corrosion of RC beam during chloride-induced corrosion process

    SciTech Connect (OSTI)

    Zhang Ruijin, E-mail: rjzhang@mail.neu.edu.c [Modern Design and Analysis Research Institute, Northeastern University, Shenyang (China); Castel, Arnaud; Francois, Raoul [LMDC - Laboratoire Materiaux et Durabilite des Constructions, Universite de Toulouse, UPS, INSA, Toulouse (France)

    2010-03-15T23:59:59.000Z

    This paper deals with the evolution of the corrosion pattern based on two beams corroded by 14 years (beam B1CL1) and 23 years (beam B2CL1) of conservation in a chloride environment. The experimental results indicate that, at the cracking initiation stage and the first stage of cracking propagation, localized corrosion due to chloride ingress is the predominant corrosion pattern and pitting corrosion is the main factor that influences the cracking process. As corrosion cracking increases, general corrosion develops rapidly and gradually becomes predominant in the second stage of cracking propagation. A comparison between existing models and experimental results illustrates that, although Vidal et al.'s model can better predict the reinforcement corrosion of beam B1CL1 under localized corrosion, it cannot predict the corrosion of beam B2CL1 under general corrosion. Also, Rodriguez's model, derived from the general corrosion due to electrically accelerated corrosion experiments, cannot match natural chloride corrosion irrespective of whether corrosion is localized or general. Thus, for natural general corrosion in the second stage of cracking propagation, a new model based on the parameter of average steel cross-section loss is put forward to predict steel corrosion from corrosion cracking.

  20. WATTS TOWERS: THE EFFECTS OF THERMAL CYCLES ON THE FORMATION AND BEHAVIOR OF CRACKS

    E-Print Network [OSTI]

    Spencer, Matthew T

    2013-02-06T23:59:59.000Z

    The development of cracks in Portland Cement Concrete (PCC) and Grout has become a problem of rising concern in a country with an aging infrastructure. A detailed understanding of the causes as well as the behavior of these cracks is vital...

  1. Effects of thermal aging on Stress Corrosion Cracking and mechanical properties of stainless steel weld metals

    E-Print Network [OSTI]

    Hixon, Jeff

    2006-01-01T23:59:59.000Z

    Stress Corrosion Cracking (SCC) in and around primary loop piping welds in Boiling Water Reactors has been observed worldwide as plants continue to operate at temperatures and pressures near 2880C (5500F) and 6.9 MPa (1000 ...

  2. LABORATORY VI ENERGY AND THERMAL PROCESSES

    E-Print Network [OSTI]

    Minnesota, University of

    LABORATORY VI ENERGY AND THERMAL PROCESSES Lab VI - 1 The change of the internal energy of a system temperature. In this lab you will concentrate on quantifying the changes in internal energy within the framework of conservation of energy. In the problems of this lab, you will master the relation

  3. Fatigue testing of high-density polyethylene and polycarbonate with crack length measurement using image processing techniques

    SciTech Connect (OSTI)

    Riemslag, A.C. (Delft Univ. of Technology (Netherlands). Lab. of Materials Science)

    1994-09-01T23:59:59.000Z

    A new automated method of measuring fatigue cracks in polymers is discussed. The new method is based on a video signal of the crack which is analyzed with image processing techniques. With this technique the crack length is measured every 20 s during a fatigue test. The accuracy of one single measurement is about 0.05 mm, but this can be increased by averaging a large number of measurements. The applied automated data collection and subsequent data processing is discussed in relation to the recommendations given in ASTM E 647, Test method for Measurement of Fatigue Crack Growth Rates. The use of the new technique is illustrated on the basis of fatigue tests performed on transparent polycarbonate (PC) and nontransparent polyethylene (PE). The fatigue behavior of PE and PC is briefly discussed.

  4. Value of solar thermal industrial process heat

    SciTech Connect (OSTI)

    Brown, D.R.; Fassbender, L.L.; Chockie, A.D.

    1986-03-01T23:59:59.000Z

    This study estimated the value of solar thermal-generated industrial process heat (IPH) as a function of process heat temperature. The value of solar thermal energy is equal to the cost of producing energy from conventional fuels and equipment if the energy produced from either source provides an equal level of service. This requirement put the focus of this study on defining and characterizing conventional process heat equipment and fuels. Costs (values) were estimated for 17 different design points representing different combinations of conventional technologies, temperatures, and fuels. Costs were first estimated for median or representative conditions at each design point. The cost impact of capacity factor, efficiency, fuel escalation rate, and regional fuel price differences were then evaluated by varying each of these factors within credible ranges.

  5. Theoretical studies of pentene cracking on zeolites: C-C beta-scission processes

    SciTech Connect (OSTI)

    Hay, P.J.; Redondo, A.; Guo, Y.

    1997-04-01T23:59:59.000Z

    The nature of the molecular species involved in the cracking of hydrocarbons into smaller fragments over zeolite catalysts has been studied extensively, as the advent of zeolites such as faujasite to carry out these transformations more selectively has revolutionized the petroleum refining technology. While the nature of the acid-catalyzed process involving proposed carbocationic species has been proposed for nearly fifty years, there have been extensive studies involving heterogeneous processes and analogs with solution superacid chemistry to elucidate these mechanisms more clearly and to attempt to detect the intermediates involved in these reactions. Also in recent years there have been an increasing number of theoretical studies on the nature of the acid sites in zeolites, the interactions of these acid sites with adsorbates including hydrocarbons, and on simple reactions of hydrocarbon species using model systems to represent the zeolite. In this study the authors report the results of ab initio and density functional studies on one aspect--the beta-scission C-C bond-breaking step--that arises in the cracking process of alkanes and alkenes. The authors focus on the species arising from pentene adsorption on an acid site and the subsequent cracking of this C{sub 5} species as an illustration of the carbon-carbon bond-breaking step. In these studies they employ a simple three-T-site to represent the immediate vicinity of the acid site in faujasite comprised of the Si-O-Al-OH-O-Si skeleton with the unsatisfied bonds terminated by hydrogens. They study the reaction of the 2-pentyl cation undergoing beta-scission in the gas phase to form propene and the ethyl cation and the corresponding reaction on the zeolite cluster. The structures of the reactants, products and transition states are determined using ab initio electronic structure techniques.

  6. Thermal processes for heavy oil recovery

    SciTech Connect (OSTI)

    Sarkar, A.K.; Sarathi, P.S.

    1993-11-01T23:59:59.000Z

    This status report summarizes the project BE11B (Thermal Processes for Heavy Oil Recovery) research activities conducted in FY93 and completes milestone 7 of this project. A major portion of project research during FY93 was concentrated on modeling and reservoir studies to determine the applicability of steam injection oil recovery techniques in Texas Gulf Coast heavy oil reservoirs. In addition, an in-depth evaluation of a steamflood predictive model developed by Mobil Exploration and Production Co. (Mobil E&P) was performed. Details of these two studies are presented. A topical report (NIPER-675) assessing the NIPER Thermal EOR Research Program over the past 10 years was also written during this fiscal year and delivered to DOE. Results of the Gulf Coast heavy oil reservoir simulation studies indicated that though these reservoirs can be successfully steamflooded and could recover more than 50% of oil-in-place, steamflooding may not be economical at current heavy oil prices. Assessment of Mobil E&P`s steamflood predictive model capabilities indicate that the model in its present form gives reasonably good predictions of California steam projects, but fails to predict adequately the performance of non-California steam projects.

  7. The effect of stress cracked and broken corn kernels on alkaline processing losses

    E-Print Network [OSTI]

    Jackson, David Scott

    1986-01-01T23:59:59.000Z

    (~. 70, P&. 06). There were significant differences in COD and DML (KRATIO= 100) between highly damaged corn and the less damaged counterpart of the same hybrid. Stress cracked corn, however, only slightly increased COD and DML. The ease of pericarp... Sigruficance of Com and Cooking Parameters . . . LIST OF FIGURES Page Stress Crack, Pericarp, and Broken Kernel Damage of Corn . . Flow Chart of Procedutes and Differences Between Cook Methods I and H 21 24 Correlation between Thousand Kernel Weight...

  8. Discrete Element Model for Simulations of Early-Life Thermal Fracturing Behaviors in Ceramic Nuclear Fuel Pellets

    SciTech Connect (OSTI)

    Hai Huang; Ben Spencer; Jason Hales

    2014-10-01T23:59:59.000Z

    A discrete element Model (DEM) representation of coupled solid mechanics/fracturing and heat conduction processes has been developed and applied to explicitly simulate the random initiations and subsequent propagations of interacting thermal cracks in a ceramic nuclear fuel pellet during initial rise to power and during power cycles. The DEM model clearly predicts realistic early-life crack patterns including both radial cracks and circumferential cracks. Simulation results clearly demonstrate the formation of radial cracks during the initial power rise, and formation of circumferential cracks as the power is ramped down. In these simulations, additional early-life power cycles do not lead to the formation of new thermal cracks. They do, however clearly indicate changes in the apertures of thermal cracks during later power cycles due to thermal expansion and shrinkage. The number of radial cracks increases with increasing power, which is consistent with the experimental observations.

  9. Pulse thermal processing of functional materials using directed plasma arc

    DOE Patents [OSTI]

    Ott, Ronald D. (Knoxville, TN); Blue, Craig A. (Knoxville, TN); Dudney, Nancy J. (Knoxville, TN); Harper, David C. (Kingston, TN)

    2007-05-22T23:59:59.000Z

    A method of thermally processing a material includes exposing the material to at least one pulse of infrared light emitted from a directed plasma arc to thermally process the material, the pulse having a duration of no more than 10 s.

  10. Thermal processing system concepts and considerations for RWMC buried waste

    SciTech Connect (OSTI)

    Eddy, T.L.; Kong, P.C.; Raivo, B.D.; Anderson, G.L.

    1992-02-01T23:59:59.000Z

    This report presents a preliminary determination of ex situ thermal processing system concepts and related processing considerations for application to remediation of transuranic (TRU)-contaminated buried wastes (TRUW) at the Radioactive Waste Management Complex (RWMC) of the Idaho National Engineering Laboratory (INEL). Beginning with top-level thermal treatment concepts and requirements identified in a previous Preliminary Systems Design Study (SDS), a more detailed consideration of the waste materials thermal processing problem is provided. Anticipated waste stream elements and problem characteristics are identified and considered. Final waste form performance criteria, requirements, and options are examined within the context of providing a high-integrity, low-leachability glass/ceramic, final waste form material. Thermal processing conditions required and capability of key systems components (equipment) to provide these material process conditions are considered. Information from closely related companion study reports on melter technology development needs assessment and INEL Iron-Enriched Basalt (IEB) research are considered. Five potentially practicable thermal process system design configuration concepts are defined and compared. A scenario for thermal processing of a mixed waste and soils stream with essentially no complex presorting and using a series process of incineration and high temperature melting is recommended. Recommendations for applied research and development necessary to further detail and demonstrate the final waste form, required thermal processes, and melter process equipment are provided.

  11. Assessment of the Mechanical Stress Improvement Process for Mitigating Primary Water Stress Corrosion Cracking in Nickel Alloy Butt Welds in Piping Systems Approved for Leak-Before-Break

    SciTech Connect (OSTI)

    Sullivan, Edmund J.; Anderson, Michael T.

    2013-01-01T23:59:59.000Z

    This report provides an assessment of the use of Mechanical Stress Improvement Process to reduce, or decrease, stress-driven degradation, i.e., primary water stress corrosion cracking.

  12. Stress corrosion crack growth in porous sandstones. 

    E-Print Network [OSTI]

    Ojala, Ira O

    Stress corrosion crack growth occurs when the chemical weakening of strained crack tip bonds facilitates crack propagation. I have examined the effect of chemical processes on the growth of a creack population by carrying out triaxial compression...

  13. Thermal Insulation Performance in the Process Industries: Facts and Fallacies

    E-Print Network [OSTI]

    Tye, R. P.

    Guarded Hot Box Study on Thermal Performance of Fibrous Insulations Used in Lofts," private com munication. 295 ESL-IE-85-05-54 Proceedings from the Seventh National Industrial Energy Technology Conference, Houston, TX, May 12-15, 1985 ...THERMAL INSULATION PERFORMANCE IN 'mE PROCESS INDUSTRIES: FACTS AND FALLACIES R.P. Tye Dynatech RID Company, Cambridge, MA, U.S.A. ABSTRACT The efficient use of thermal insulation materials and systems for design of cryogenic and elevated...

  14. Process and apparatus for thermal enhancement

    DOE Patents [OSTI]

    Burrill, Jr., Charles E. (Billerica, MA); Smirlock, Martin E. (Brimfield, MA); Krepchin, Ira P. (Newton Upper Falls, MA)

    1984-06-26T23:59:59.000Z

    Thermal treatment apparatus for downhole deployment comprising a combustion stage with an elongated hot wall combustion zone for the substantially complete combustion of the fuel-air mixture and an ignition zone immediately upstream from the combustion zone in which a mixture of atomized liquid fuel and air at or below stoichiometric ratio is ignited; together with a water injection stage immediately downstream from the combustion zone through which essentially partuculate free high temperature combustion products flow from the combustion zone and into which water is sprayed. The resulting mixture of steam and combustion products is injected into an oil formation for enhancing the speed and effectiveness of reservoir response due to physical, chemical, and/or thermal stimulation interactions.

  15. Conductive Thermal Interaction in Evaporative Cooling Process

    E-Print Network [OSTI]

    Kim, B. S.; Degelman, L. O.

    1990-01-01T23:59:59.000Z

    from the evaporative cooler would often be more than 6.5'F lower than that of a conventional evaporative cooling system due to thermal conduction between water and entering air. - Figure 1 Pad type evaporative cooler. DIRECT EVAPORATIVE COOLER... There are several types of direct evaporative cooler configurations available. Two popular system types are pad type unit and rotary type unit. A number of window mounted units are pad type evaporative coolers (Figure 1). In a pad type cooler, water...

  16. Identifying and Understanding Environment-Induced Crack propagation Behavior in Ni-based Superalloy INCONEL 617

    SciTech Connect (OSTI)

    Ma, Longzhou

    2012-11-30T23:59:59.000Z

    The nickel-based superalloy INCONEL 617 is a candidate material for heat exchanger applications in the next-generation nuclear plant (NGNP) system. This project will study the crack propagation process of alloy 617 at temperatures of 650°C-950°C in air under static/cyclic loading conditions. The goal is to identify the environmental and mechanical damage components and to understand in-depth the failure mechanism. Researchers will measure the fatigue crack propagation (FCP) rate (da/dn) under cyclic and hold-time fatigue conditions, and sustained crack growth rates (da/dt) at elevated temperatures. The independent FCP process will be identified and the rate-controlled sustained loading crack process will be correlated with the thermal activation equation to estimate the oxygen thermal activation energy. The FCP-dependent model indicates that if the sustained loading crack growth rate, da/dt, can be correlated with the FCP rate, da/dn, at the full time dependent stage, researchers can confirm stress-accelerated grain-boundary oxygen embrittlement (SAGBOE) as a predominate effect. Following the crack propagation tests, the research team will examine the fracture surface of materials in various cracking stages using a scanning electron microscope (SEM) and an optical microscope. In particular, the microstructure of the crack tip region will be analyzed in depth using high resolution transmission electron microscopy (TEM) and electron energy loss spectrum (EELS) mapping techniques to identify oxygen penetration along the grain boundary and to examine the diffused oxygen distribution profile around the crack tip. The cracked sample will be prepared by focused ion beam nanofabrication technology, allowing researchers to accurately fabricate the TEM samples from the crack tip while minimizing artifacts. Researchers will use these microscopic and spectroscopic results to interpret the crack propagation process, as well as distinguish and understand the environment or SAGBOE damage process under hold-time fatigue and sustained loading conditions

  17. Thermal Systems Process and Components Laboratory (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2011-10-01T23:59:59.000Z

    This fact sheet describes the purpose, lab specifications, applications scenarios, and information on how to partner with NREL's Thermal Systems Process and Components Laboratory at the Energy Systems Integration Facility. The focus of the Thermal Systems Process and Components Laboratory at NREL's Energy Systems Integration Facility (ESIF) is to research, develop, test, and evaluate new techniques for thermal energy storage systems that are relevant to utility-scale concentrating solar power plants. The laboratory holds test systems that can provide heat transfer fluids for the evaluation of heat exchangers and thermal energy storage devices. The existing system provides molten salt at temperatures up to 800 C. This unit is charged with nitrate salt rated to 600 C, but is capable of handling other heat transfer fluid compositions. Three additional test bays are available for future deployment of alternative heat transfer fluids such as hot air, carbon dioxide, or steam systems. The Thermal Systems Process and Components Laboratory performs pilot-scale thermal energy storage system testing through multiple charge and discharge cycles to evaluate heat exchanger performance and storage efficiency. The laboratory equipment can also be utilized to test instrument and sensor compatibility with hot heat transfer fluids. Future applications in the laboratory may include the evaluation of thermal energy storage systems designed to operate with supercritical heat transfer fluids such as steam or carbon dioxide. These tests will require the installation of test systems capable of providing supercritical fluids at temperatures up to 700 C.

  18. Thermal Plasma Systems for Industrial Processes

    E-Print Network [OSTI]

    Fey, M. G.; Meyer, T. N.; Reed, W. H.; Philbrook, W. O.

    1982-01-01T23:59:59.000Z

    furnaces, extending from below 2000 F to almost any conceivably useful processing temperature, with efficiencies much higher than can be achieved with combustion heating equipment. Numerous applications for plasma systems exist in the chemical...

  19. Solar thermal aerosol flow reaction process

    DOE Patents [OSTI]

    Weimer, Alan W.; Dahl, Jaimee K.; Pitts, J. Roland; Lewandowski, Allan A.; Bingham, Carl; Tamburini, Joseph R.

    2005-03-29T23:59:59.000Z

    The present invention provides an environmentally beneficial process using concentrated sunlight to heat radiation absorbing particles to carry out highly endothermic gas phase chemical reactions ultimately resulting in the production of hydrogen or hydrogen synthesis gases.

  20. Technical resource document for assured thermal processing of wastes

    SciTech Connect (OSTI)

    Farrow, R.L.; Fisk, G.A.; Hartwig, C.M.; Hurt, R.H.; Ringland, J.T.; Swansiger, W.A.

    1994-06-01T23:59:59.000Z

    This document is a concise compendium of resource material covering assured thermal processing of wastes (ATPW), an area in which Sandia aims to develop a large program. The ATPW program at Sandia is examining a wide variety of waste streams and thermal processes. Waste streams under consideration include municipal, chemical, medical, and mixed wastes. Thermal processes under consideration range from various incineration technologies to non-incineration processes such as supercritical water oxidation or molten metal technologies. Each of the chapters describes the element covered, discusses issues associated with its further development and/or utilization, presents Sandia capabilities that address these issues, and indicates important connections to other ATPW elements. The division of the field into elements was driven by the team`s desire to emphasize areas where Sandia`s capabilities can lead to major advances and is therefore somewhat unconventional. The report will be valuable to Sandians involved in further ATPW program development.

  1. Solar Thermal Process Heat | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov YouKizildere IRaghuraji Agro Industries Pvt LtdShawangunk, NewSingapore Jump to: navigation,PanelsLight EnergyJumpProcess

  2. Thermal Modeling of A Friction Bonding Process

    SciTech Connect (OSTI)

    John Dixon; Douglas Burkes; Pavel Medvedev

    2007-10-01T23:59:59.000Z

    A COMSOL model capable of predicting temperature evolution during nuclear fuel fabrication is being developed at the Idaho National Laboratory (INL). Fuel plates are fabricated by friction bonding (FB) uranium-molybdenum (U-Mo) alloy foils positioned between two aluminum plates. The ability to predict temperature distribution during fabrication is imperative to ensure good quality bonding without inducing an undesirable chemical reaction between U-Mo and aluminum. A three-dimensional heat transfer model of the FB process implementing shallow pin penetration for cladding monolithic nuclear fuel foils is presented. Temperature distribution during the FB process as a function of fabrication parameters such as weld speed, tool load, and tool rotational frequency are predicted. Model assumptions, settings, and equations are described in relation to standard friction stir welding. Current experimental design for validation and calibration of the model is also demonstrated. Resulting experimental data reveal the accuracy in describing asymmetrical temperature distributions about the tool face. Temperature of the bonded plate drops beneath the pin and is higher on the advancing side than the retreating side of the tool.

  3. Process management using component thermal-hydraulic function classes

    DOE Patents [OSTI]

    Morman, James A. (Woodridge, IL); Wei, Thomas Y. C. (Downers Grove, IL); Reifman, Jaques (Western Springs, IL)

    1999-01-01T23:59:59.000Z

    A process management expert system where following malfunctioning of a component, such as a pump, for determining system realignment procedures such as for by-passing the malfunctioning component with on-line speeds to maintain operation of the process at full or partial capacity or to provide safe shut down of the system while isolating the malfunctioning component. The expert system uses thermal-hydraulic function classes at the component level for analyzing unanticipated as well as anticipated component malfunctions to provide recommended sequences of operator actions. Each component is classified according to its thermal-hydraulic function, and the generic and component-specific characteristics for that function. Using the diagnosis of the malfunctioning component and its thermal hydraulic class, the expert system analysis is carried out using generic thermal-hydraulic first principles. One aspect of the invention employs a qualitative physics-based forward search directed primarily downstream from the malfunctioning component in combination with a subsequent backward search directed primarily upstream from the serviced component. Generic classes of components are defined in the knowledge base according to the three thermal-hydraulic functions of mass, momentum and energy transfer and are used to determine possible realignment of component configurations in response to thermal-hydraulic function imbalance caused by the malfunctioning component. Each realignment to a new configuration produces the accompanying sequence of recommended operator actions. All possible new configurations are examined and a prioritized list of acceptable solutions is produced.

  4. Process management using component thermal-hydraulic function classes

    DOE Patents [OSTI]

    Morman, J.A.; Wei, T.Y.C.; Reifman, J.

    1999-07-27T23:59:59.000Z

    A process management expert system where following malfunctioning of a component, such as a pump, for determining system realignment procedures such as for by-passing the malfunctioning component with on-line speeds to maintain operation of the process at full or partial capacity or to provide safe shut down of the system while isolating the malfunctioning component. The expert system uses thermal-hydraulic function classes at the component level for analyzing unanticipated as well as anticipated component malfunctions to provide recommended sequences of operator actions. Each component is classified according to its thermal-hydraulic function, and the generic and component-specific characteristics for that function. Using the diagnosis of the malfunctioning component and its thermal hydraulic class, the expert system analysis is carried out using generic thermal-hydraulic first principles. One aspect of the invention employs a qualitative physics-based forward search directed primarily downstream from the malfunctioning component in combination with a subsequent backward search directed primarily upstream from the serviced component. Generic classes of components are defined in the knowledge base according to the three thermal-hydraulic functions of mass, momentum and energy transfer and are used to determine possible realignment of component configurations in response to thermal-hydraulic function imbalance caused by the malfunctioning component. Each realignment to a new configuration produces the accompanying sequence of recommended operator actions. All possible new configurations are examined and a prioritized list of acceptable solutions is produced. 5 figs.

  5. Thermal acidization and recovery process for recovering viscous petroleum

    DOE Patents [OSTI]

    Poston, Robert S. (Winter Park, FL)

    1984-01-01T23:59:59.000Z

    A thermal acidization and recovery process for increasing production of heavy viscous petroleum crude oil and synthetic fuels from subterranean hydrocarbon formations containing clay particles creating adverse permeability effects is described. The method comprises injecting a thermal vapor stream through a well bore penetrating such formations to clean the formation face of hydrocarbonaceous materials which restrict the flow of fluids into the petroleum-bearing formation. Vaporized hydrogen chloride is then injected simultaneously to react with calcium and magnesium salts in the formation surrounding the bore hole to form water soluble chloride salts. Vaporized hydrogen fluoride is then injected simultaneously with its thermal vapor to dissolve water-sensitive clay particles thus increasing permeability. Thereafter, the thermal vapors are injected until the formation is sufficiently heated to permit increased recovery rates of the petroleum.

  6. Process and apparatus for cooling during regeneration of fluid cracking catalyst

    SciTech Connect (OSTI)

    Walters, P.W.; Raiche, H.A.; Harness, R.L.; Quodala, G.M.

    1987-10-06T23:59:59.000Z

    This patent describes an apparatus for the regeneration of coke contaminated fluid cracking catalyst. The combination comprises: A. an elongated upflow regeneration vessel, containing a dense bed of catalyst and a regeneration gas grid located within the bed; B. a vertical heat exchanger mounted to the lower side of the vessel adapted to receive hot catalyst directly from the regeneration vessel and adapted to cool the hot catalyst as it passes downwardly through the exchanger; C. a Y junction positioned below the lower end of the heat exchanger; D. a first conduit means for passing cool catalyst downwardly to the Y junction; E. second conduit means for passing cool catalyst from the Y junction upwardly into the dense bed of catalyst in the regeneration vessel, and F. regeneration gas supply means, separate from the second conduit means, for supplying regeneration gas to the gas grid; G. lift gas supply means, separate from the regeneration gas supply means, for introducing lift gas into the second conduit means so as to lift the cool catalyst up through the second conduit means to the regenerator.

  7. Method and apparatus for thermal processing of semiconductor substrates

    DOE Patents [OSTI]

    Griffiths, Stewart K. (Danville, CA); Nilson, Robert H. (Cardiss, CA); Mattson, Brad S. (Los Gatos, CA); Savas, Stephen E. (Alameda, CA)

    2000-01-01T23:59:59.000Z

    An improved apparatus and method for thermal processing of semiconductor wafers. The apparatus and method provide the temperature stability and uniformity of a conventional batch furnace as well as the processing speed and reduced time-at-temperature of a lamp-heated rapid thermal processor (RTP). Individual wafers are rapidly inserted into and withdrawn from a furnace cavity held at a nearly constant and isothermal temperature. The speeds of insertion and withdrawal are sufficiently large to limit thermal stresses and thereby reduce or prevent plastic deformation of the wafer as it enters and leaves the furnace. By processing the semiconductor wafer in a substantially isothermal cavity, the wafer temperature and spatial uniformity of the wafer temperature can be ensured by measuring and controlling only temperatures of the cavity walls. Further, peak power requirements are very small compared to lamp-heated RTPs because the cavity temperature is not cycled and the thermal mass of the cavity is relatively large. Increased speeds of insertion and/or removal may also be used with non-isothermal furnaces.

  8. Thermal response of process equipment to hydrocarbon fires

    SciTech Connect (OSTI)

    Solberg, D.M.; Borgnes, O.

    1983-01-01T23:59:59.000Z

    Requirements for active fire-fighting equipment such as fixed and portable powder extinguishers, foam generators, water guns, and deluge systems, are given in various codes and standards. However, very little is to be found about fire design conditions and passive fire protection. For safety verification of process plants and for designing adequate passive fire protection it is necessary to know the total incident heat fluxes which can occur under realistic conditions and the effects that such heat fluxes may have on process equipment and structures. During the last few years, Det Norske Veritas has been invloved in investigations aimed at estimating realistic fire loads from different types of hydrocarbon fires and the thermal response of process equipment and structures exposed to such fires. These investigations are still in progress and are especially focused on the conditions on off-shore oil and gas production platforms. However, many fire problems will be the same in the land-based process industry. The present paper concentrates on the thermal response of pipes and vessels exposed to a severe hydrocarbon fire with a defined thermal load. (JMT)

  9. Process modeling for the Integrated Thermal Treatment System (ITTS) study

    SciTech Connect (OSTI)

    Liebelt, K.H.; Brown, B.W.; Quapp, W.J.

    1995-09-01T23:59:59.000Z

    This report describes the process modeling done in support of the integrated thermal treatment system (ITTS) study, Phases 1 and 2. ITTS consists of an integrated systems engineering approach for uniform comparison of widely varying thermal treatment technologies proposed for treatment of the contact-handled mixed low-level wastes (MLLW) currently stored in the U.S. Department of Energy complex. In the overall study, 19 systems were evaluated. Preconceptual designs were developed that included all of the various subsystems necessary for a complete installation, from waste receiving through to primary and secondary stabilization and disposal of the processed wastes. Each system included the necessary auxiliary treatment subsystems so that all of the waste categories in the complex were fully processed. The objective of the modeling task was to perform mass and energy balances of the major material components in each system. Modeling of trace materials, such as pollutants and radioactive isotopes, were beyond the present scope. The modeling of the main and secondary thermal treatment, air pollution control, and metal melting subsystems was done using the ASPEN PLUS process simulation code, Version 9.1-3. These results were combined with calculations for the remainder of the subsystems to achieve the final results, which included offgas volumes, and mass and volume waste reduction ratios.

  10. Advanced Reactors Thermal Energy Transport for Process Industries

    SciTech Connect (OSTI)

    P. Sabharwall; S.J. Yoon; M.G. McKellar; C. Stoots; George Griffith

    2014-07-01T23:59:59.000Z

    The operation temperature of advanced nuclear reactors is generally higher than commercial light water reactors and thermal energy from advanced nuclear reactor can be used for various purposes such as liquid fuel production, district heating, desalination, hydrogen production, and other process heat applications, etc. Some of the major technology challenges that must be overcome before the advanced reactors could be licensed on the reactor side are qualification of next generation of nuclear fuel, materials that can withstand higher temperature, improvement in power cycle thermal efficiency by going to combined cycles, SCO2 cycles, successful demonstration of advanced compact heat exchangers in the prototypical conditions, and from the process side application the challenge is to transport the thermal energy from the reactor to the process plant with maximum efficiency (i.e., with minimum temperature drop). The main focus of this study is on doing a parametric study of efficient heat transport system, with different coolants (mainly, water, He, and molten salts) to determine maximum possible distance that can be achieved.

  11. Thermal processing of black liquor from alkaline straw pulping

    SciTech Connect (OSTI)

    Sanchez, J.L.; Garcia, L.; Gea, G.; Bilbao, R.; Arauzo, J. [Univ. of Zaragoza (Spain)

    1996-12-31T23:59:59.000Z

    Black liquor is the wastewater from the cooking of wood or straw in the production of pulp and paper. Nowadays new processes are being investigated as alternatives to the traditional recovery boiler used for black liquor treatment. One of the processes which appears to be more promising is gasification, for which further research is needed for its full industrial implementation. There is not much data about the behavior of soda black liquors from straw cooking in the literature. Therefore the thermal decomposition of one of these liquors has been studied in a thermobalance, in inert (N{sub 2}) atmosphere. The kinetic constants from isothermal experiments have been obtained.

  12. Electrophoretically active sol-gel processes to backfill, seal, and/or densify porous, flawed, and/or cracked coatings on electrically conductive material

    DOE Patents [OSTI]

    Panitz, J.K.; Reed, S.T.; Ashley, C.S.; Neiser, R.A.; Moffatt, W.C.

    1999-07-20T23:59:59.000Z

    Electrophoretically active sol-gel processes to fill, seal, and/or density porous, flawed, and/or cracked coatings on electrically conductive substrates. Such coatings may be dielectrics, ceramics, or semiconductors and, by the present invention, may have deposited onto and into them sol-gel ceramic precursor compounds which are subsequently converted to sol-gel ceramics to yield composite materials with various tailored properties. 6 figs.

  13. Electrophoretically active sol-gel processes to backfill, seal, and/or densify porous, flawed, and/or cracked coatings on electrically conductive material

    DOE Patents [OSTI]

    Panitz, Janda K. (Sandia Park, NM); Reed, Scott T. (Albuquerque, NM); Ashley, Carol S. (Albuquerque, NM); Neiser, Richard A. (Albuquerque, NM); Moffatt, William C. (Albuquerque, NM)

    1999-01-01T23:59:59.000Z

    Electrophoretically active sol-gel processes to fill, seal, and/or density porous, flawed, and/or cracked coatings on electrically conductive substrates. Such coatings may be dielectrics, ceramics, or semiconductors and, by the present invention, may have deposited onto and into them sol-gel ceramic precursor compounds which are subsequently converted to sol-gel ceramics to yield composite materials with various tailored properties.

  14. Thermal Process to Strengthen PLGA Nanoparticle Layers Bull. Korean Chem. Soc. 2009, Vol. 30, No. 9 1985 Thermal Process for Enhancing Mechanical Strength

    E-Print Network [OSTI]

    Park, Jong-Sang

    Thermal Process to Strengthen PLGA Nanoparticle Layers Bull. Korean Chem. Soc. 2009, Vol. 30, No. 9 1985 Thermal Process for Enhancing Mechanical Strength of PLGA Nanoparticle Layers on Coronary Stents@plaza.snu.ac.kr Received June 5, 2009, Accepted July 14, 2009 Poly (lactic-co-glycolic acid) (PLGA) nanoparticles loading

  15. Thermal casting process for the preparation of membranes

    DOE Patents [OSTI]

    Caneba, G.T.M.; Soong, D.S.

    1985-07-10T23:59:59.000Z

    Disclosed is a method for providing anisotropic polymer membrane from a binary polymer/solvent solution using a thermal inversion process. A homogeneous binary solution is cast onto a support and cooled in such a way as to provide a differential in cooling rate across the thickness of the resulting membrane sheet. Isotropic or anisotropic structures of selected porosities can be produced, depending on the initial concentration of polymer in the selected solvent and on the extent of the differential in cooling rate. This differential results in a corresponding gradation in pore size. The method may be modified to provide a working skin by applying a rapid, high-temperature pulse to redissolve a predetermined thickness of the membrane at one of its faces and then freezing the entire structure.

  16. Thermal Analysis of Novel Underfill Materials with Optimum Processing Characteristics

    E-Print Network [OSTI]

    Harmon, Julie P.

    - date the morphology of these composites. © 2005 Wiley Peri- odicals, Inc. J Appl Polym Sci 98: 1300 chip. Polymers are thermally insulating mate- rials; the thermal conductivity of a typical polymer the compos- ite thermal conductivity up to 32.5 W/m K at the maximum filler loading of 78 vol %. Polymer

  17. The analysis of cracks in high-pressure piping and their effects on strength and lifetime of construction components at the Ignalina nuclear plant

    SciTech Connect (OSTI)

    Aleev, A.; Petkevicius, K.; Senkus, V. [and others

    1997-04-01T23:59:59.000Z

    A number of cracks and damages of other sorts have been identified in the high-pressure parts at the Ignalina Nuclear Plant. They are caused by inadequate production- and repair technologies, as well as by thermal, chemical and mechanical processes of their performance. Several techniques are available as predictions of cracks and other defects of pressurized vessels. The choice of an experimental technique should be based on the level of its agreement with the actual processes.

  18. Early stages in the development of stress corrosion cracks

    SciTech Connect (OSTI)

    Jones, R.H.; Simonen, E.P.

    1993-12-01T23:59:59.000Z

    Processes in growth of short cracks and stage I of long stress corrosion cracks were identified and evaluated. There is evidence that electrochemical effects can cause short stress corrosion cracks to grow at rates faster or slower than long cracks. Short cracks can grow at faster rates than long cracks for a salt film dissolution growth mechanism or from reduced oxygen inhibition of hydrolytic acidification. An increasing crack growth rate with increasing crack length could result from a process of increasing crack tip concentration of a critical anion, such as Cl{sup {minus}}, with increasing crack length in a system where the crack velocity is dependent on the Cl{sup {minus}} or some other anion concentration. An increasing potential drop between crack tip and mouth would result in an increased anion concentration at the crack tip and hence an increasing crack velocity. Stage I behavior of long cracks is another early development stage in the life of a stress corrosion crack which is poorly understood. This stage can be described by da/dt = AK{sup m} where da/dt is crack velocity, A is a constant, K is stress intensity and m ranges from 2 to 24 for a variety of materials and environments. Only the salt film dissolution model was found to quantitatively describe this stage; however, the model was only tested on one material and its general applicability is unknown.

  19. PROCESS DESIGN AND CONTROL Efficient Conversion of Thermal Energy into Hydrogen: Comparing Two Methods

    E-Print Network [OSTI]

    Kjelstrup, Signe

    PROCESS DESIGN AND CONTROL Efficient Conversion of Thermal Energy into Hydrogen: Comparing Two for the production of hydrogen from water and high temperature thermal energy are presented and compared. Increasing for the production of hydrogen from water has received considerable attention.1 High temperature thermal energy

  20. Crack detection using pulsed eddy current stimulated thermography

    SciTech Connect (OSTI)

    Kostson, E.; Weekes, B.; Almond, D. P. [RCNDE, Department of Mechanical Engineering, University of Bath (United Kingdom); Wilson, J.; Tian, G. Y. [School of Electrical, Electronic and Computer Engineering, Newcastle University (United Kingdom)

    2011-06-23T23:59:59.000Z

    This contribution presents results from studies investigating factors that influence the detection of surface breaking cracks using pulsed eddy current thermography. The influences of the current strength and crack orientation in both ferromagnetic and non-ferromagnetic metals have been investigated. It has been found that crack detection is far more sensitive to crack orientation in non-ferromagnetic metals than in ferromagnetic metals. The effects of crack size on detectability are presented for a large number of steel, nickel alloy and titanium samples. Results of studies comparing crack images obtained prior and after coating a nickel alloy sample with a thermal barrier coating are presented.

  1. Solar-Thermal Fluid-Wall Reaction Processing

    DOE Patents [OSTI]

    Weimer, A. W.; Dahl, J. K.; Lewandowski, A. A.; Bingham, C.; Raska Buechler, K. J.; Grothe, W.

    2006-04-25T23:59:59.000Z

    The present invention provides a method for carrying out high temperature thermal dissociation reactions requiring rapid-heating and short residence times using solar energy. In particular, the present invention provides a method for carrying out high temperature thermal reactions such as dissociation of hydrocarbon containing gases and hydrogen sulfide to produce hydrogen and dry reforming of hydrocarbon containing gases with carbon dioxide. In the methods of the invention where hydrocarbon containing gases are dissociated, fine carbon black particles are also produced. The present invention also provides solar-thermal reactors and solar-thermal reactor systems.

  2. Solar-thermal fluid-wall reaction processing

    DOE Patents [OSTI]

    Weimer, Alan W.; Dahl, Jaimee K.; Lewandowski, Allan A.; Bingham, Carl; Buechler, Karen J.; Grothe, Willy

    2006-04-25T23:59:59.000Z

    The present invention provides a method for carrying out high temperature thermal dissociation reactions requiring rapid-heating and short residence times using solar energy. In particular, the present invention provides a method for carrying out high temperature thermal reactions such as dissociation of hydrocarbon containing gases and hydrogen sulfide to produce hydrogen and dry reforming of hydrocarbon containing gases with carbon dioxide. In the methods of the invention where hydrocarbon containing gases are dissociated, fine carbon black particles are also produced. The present invention also provides solar-thermal reactors and solar-thermal reactor systems.

  3. Supporting technology for enhanced oil recovery for thermal processes

    SciTech Connect (OSTI)

    Reid, T.B.; Bolivar, J.

    1997-12-01T23:59:59.000Z

    This report contains the results of efforts under the six tasks of the Ninth Amendment and Extension of Annex IV, Enhanced Oil Recovery Thermal Processes of the Venezuela/USA Agreement. The report is presented in sections (for each of the 6 tasks) and each section contains one or more reports prepared by various individuals or groups describing the results of efforts under each of the tasks. A statement of each task, taken from the agreement, is presented on the first page of each section. The tasks are numbered 62 through 67. The first, second, third, fourth fifth, sixth, seventh, eighth, and ninth reports on Annex IV, [Venezuela MEM/USA-DOE Fossil Energy Report IV-1, IV-2, IV-3, IV-4, IV-5, IV-6, IV-7, and IV-8 (DOE/BETC/SP-83/15, DOE/BC-84/6/SP, DOE/BC-86/2/SP, DOE/BC-87/2/SP, DOE/BC-90/1/SP, DOE/BC-90/1/SP) (DOE/BC-92/1/SP, DOE/BC-93/3/SP, and DOE/BC-95/3/SP)] contain the results from the first 61 tasks. Those reports are dated April 1983, August 1984, March 1986, July 1987, November 1988, October 1991, February 1993, and March 1995 respectively.

  4. Slow crack growth in polycarbonate films

    E-Print Network [OSTI]

    Cortet, Pierre-Philippe; Vanel, Loic; Ciliberto, Sergio

    2005-01-01T23:59:59.000Z

    We study experimentally the slow growth of a single crack in polycarbonate films submitted to uniaxial and constant imposed stress. The specificity of fracture in polycarbonate films is the appearance of flame shaped macroscopic process zones at the tips of the crack. Supported by an experimental study of the mechanical properties of polycarbonate films, an analysis of the stress dependence of the mean ratio between the process zone and crack lengths, during the crack growth, show a quantitative agreement with the Dugdale-Barenblatt model of the plastic process zone. We find that the fracture growth curves obey strong scaling properties that lead to a well defined growth master curve.

  5. Thermal Energy Storage/Heat Recovery and Energy Conservation in Food Processing

    E-Print Network [OSTI]

    Combes, R. S.; Boykin, W. B.

    1980-01-01T23:59:59.000Z

    from waste heat streams for reuse in the processing operations. This paper addresses the recovery of waste heat and the storage of thermal energy as a means of energy conservation in food processing. An energy conservation project in a poultry...

  6. Bentonite alteration due to thermal-hydro-chemical processes during the early thermal period in a nuclear waste repository

    SciTech Connect (OSTI)

    Xu, T.; Senger, R.; Finsterle, S.

    2011-02-01T23:59:59.000Z

    After closure of an underground nuclear waste repository, the decay of radionuclides will raise temperature in the repository, and the bentonite buffer will resaturate by water inflow from the surrounding host rock. The perturbations from these thermal and hydrological processes are expected to dissipate within hundreds to a few thousand years. Here, we investigate coupled thermal-hydro-chemical processes and their effects on the short-term performance of a potential nuclear waste repository located in a clay formation. Using a simplified geometric configuration and abstracted hydraulic parameters of the clayey formation, we examine geochemical processes, coupled with thermo-hydrologic phenomena, and potential changes in porosity near the waste container during the early thermal period. The developed models were used for evaluating the mineral alterations and potential changes in porosity of the buffer, which can affect the repository performance. The results indicate that mineral alteration and associated changes in porosity induced by early thermal and hydrological processes are relatively small and are expected to not significantly affect flow and transport properties. Chlorite precipitation was obtained in all simulation cases. A maximum of one percent volume fraction of chlorite could be formed, whose process may reduce swelling and sorption capacity of bentonite clay, affecting the performance of the repository. llitisation process was not obtained from the present simulations.

  7. advanced thermal processing: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    19 20 21 22 23 24 25 Next Page Last Page Topic Index 301 Thermal properties of advanced aerogel insulation MIT - DSpace Summary: Buildings consume too much energy. For example,...

  8. Representation of thermal energy in the design process

    E-Print Network [OSTI]

    Roth, Shaun

    1995-01-01T23:59:59.000Z

    The goal of thermal design is to go beyond the comfort zone. In spatial design architects don't just look up square footage requirements and then draw a rectangle that satisfies the givens. There must be an interpretation. ...

  9. Study on grain boundary character and strain distribution of intergranular cracking in the CGHAZ of T23 steel

    SciTech Connect (OSTI)

    Jin, Y.J.; Lu, H., E-mail: shweld@sjtu.edu.cn; Yu, C.; Xu, J.J.

    2013-10-15T23:59:59.000Z

    Intergranular reheat cracking in the coarse-grained heat-affected zone of T23 steel was produced by strain to fracture tests on a Gleeble 3500 thermal–mechanical simulator. Then the grain boundary character, as well as the strain distribution after reheat crack propagation, was studied by electron backscatter diffraction technique. The results showed that incoherent ?3 boundaries were seldom found on the prior austenite grain boundaries. Therefore, only the type of random high-angle boundaries played a crucial role in the intergranular cracking. Microstructurally cavities and small cracks were preferentially initiated from high-angle grain boundaries. Low-angle grain boundaries and high-angle ones with misorientation angles less than 15° were more resistant to the cracking. More importantly, the fraction of high-angle grain boundaries increased with the plastic strain induced by both temperature gradient and stress in the coarse-grained heat-affected zone, which contributed to the crack initiation and propagation. Furthermore, the strain distributions in the vicinity of cavities and cracks revealed the accommodation processes of plastic deformation during stress relaxation. It also reflected the strength differences between grain interior and grain boundary at different heat-treated temperatures, which had a large influence on the cracking mechanism. - Highlights: • The coincidence site lattice boundaries play little role in the reheat cracking. • Cavity and crack occur at high-angle grain boundaries rather than low-angle ones. • The strain leads low-angle grain boundaries to transform to high-angle ones. • Strain distribution differs for cavity and crack zones at different temperatures.

  10. Comparison of closed and open thermochemical processes, for long-term thermal energy storage applications

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 Comparison of closed and open thermochemical processes, for long-term thermal energy storage-term thermal storage, second law analysis * Corresponding author: E-mail: mazet@univ-perp.fr Nomenclature c Energy Tecnosud, Rambla de la thermodynamique, 66100 Perpignan, France b Université de Perpignan Via

  11. THERMAL PROPERTIES AND PROCESSES D Hillel, Columbia University, New York, NY, USA

    E-Print Network [OSTI]

    - lengths, is proportional to the fourth power of the absolute temperature Tof the body's surface. This lawTHERMAL PROPERTIES AND PROCESSES D Hillel, Columbia University, New York, NY, USA Ã? 2005, Elsevier, and microbial activity. Soil temperature varies in response to changes in the radiant, thermal, and latent

  12. Cascading of fluid cracking catalysts

    SciTech Connect (OSTI)

    Kovach, S.M.; Miller, C.B.

    1986-05-27T23:59:59.000Z

    A process is described for conversion of hydrocarbon feedstocks by cascading a cracking catalyst containing zeolite in an acidic matrix from one hydrocarbon processing unit to another, wherein there are at least three different interconnected hydrocarbon processing units comprising a first unit having a regeneration zone and a riser zone, a second unit having having a regeneration zone and a riser zone, and a third unit having a riser zone and a regeneration zone, each unit having different processing conditions.

  13. Engineering atom-atom thermal entanglement via two-photon process

    E-Print Network [OSTI]

    Y. Q. Guo; L. Zhou; H. S. Song

    2005-09-21T23:59:59.000Z

    We study the system that two atoms simultaneously interact with a single-mode thermal field via different couplings and different spontaneous emission rates when two-photon process is involved. It is found that we indeed can employ the different couplings to produce the atom-atom thermal entanglement in two-photon process. The different atomic spontaneous emission rates are also utilizable in generating thermal entanglement. We also investigate the effect of the cavity leakage. To the initial atomic state $|ee> ,$a slight leakage can relieve the restriction of interaction time and we can obtain a large and steady entanglement.

  14. Process of making cryogenically cooled high thermal performance crystal optics

    DOE Patents [OSTI]

    Kuzay, T.M.

    1992-06-23T23:59:59.000Z

    A method is disclosed for constructing a cooled optic wherein one or more cavities are milled, drilled or formed using casting or ultrasound laser machining techniques in a single crystal base and filled with porous material having high thermal conductivity at cryogenic temperatures. A non-machined strain-free single crystal can be bonded to the base to produce superior optics. During operation of the cooled optic, N[sub 2] is pumped through the porous material at a sub-cooled cryogenic inlet temperature and with sufficient system pressure to prevent the fluid bulk temperature from reaching saturation. 7 figs.

  15. Process of making cryogenically cooled high thermal performance crystal optics

    DOE Patents [OSTI]

    Kuzay, Tuncer M. (Naperville, IL)

    1992-01-01T23:59:59.000Z

    A method for constructing a cooled optic wherein one or more cavities are milled, drilled or formed using casting or ultrasound laser machining techniques in a single crystal base and filled with porous material having high thermal conductivity at cryogenic temperatures. A non-machined strain-free single crystal can be bonded to the base to produce superior optics. During operation of the cooled optic, N.sub.2 is pumped through the porous material at a sub-cooled cryogenic inlet temperature and with sufficient system pressure to prevent the fluid bulk temperature from reaching saturation.

  16. Continuous Processing of High Thermal Conductivity Fibers and...

    Energy Savers [EERE]

    proprietary, confidential, or otherwise restricted information. Project Objective Plastics are less expensive, lighter, and require less energy to process than metals; however,...

  17. Automated Process for the Fabrication of Highly Customized Thermally...

    Energy Savers [EERE]

    2 of 2 A project member completes cuts foam insulating via a process known as computer numerically controlled (CNC) foam cutting. Image: Worcester Polytechnic Institute...

  18. Automated Process for the Fabrication of Highly Customized Thermally...

    Broader source: Energy.gov (indexed) [DOE]

    Polytechnic Institute 2 of 2 A project member completes cuts foam insulating via a process known as computer numerically controlled (CNC) foam cutting. Image: Worcester...

  19. Surface process study for oil recovery using a thermal extraction process

    SciTech Connect (OSTI)

    Sethl, V.K.; Satchwell, R.M.; Johnson, L.A. Jr.

    1994-06-01T23:59:59.000Z

    Geological studies have shown that there are many surface or near-surface deposits in the United States that contain large quantities of petroleum. In the State of Wyoming, a high concentration of such deposits exists in the Wind River, Big Horn, and Powder River Basins. These shallow deposits typically occur as unconsolidated or friable formations that contain millions of barrels of oil. Conventional petroleum production techniques have been attempted in many of these deposits with little or no economic success. In an attempt to improve the production economics, the Western Research Institute was solicited to develop a technique for the recovery of oil from these deposits. WRI, with support from the Economic and Community Development Division of the State of Wyoming, and as a part of the WRI/US Department of Energy, Jointly Sponsored Research program, proposed to develop, test, and demonstrate a viable and economical technology for the recovery of oil using mining and surface recovery processes. Reneau Energy, Inc. of La Quinta, California, agreed to participate in the project in providing a test site and mined materials. The goal of the proposed project to be completed in two phases, was to develop existing energy resources which are not presently being utilized. Phase 1 of the project, consisting of six specific tasks, was conducted to evaluate the suitability of various surface processing schemes. Phase 1 also included gravity drainage tests to determine if recovery techniques such as horizontal drilling could be applied. Phase 1 work was completed, and a final report was prepared and submitted to the funding agencies. Based on the results obtained in Phase 1 of the project, fluidized-bed based thermal recovery appeared to be a viable option. A 100 tons per day pilot plant was designed, constructed, and operated in the field. This report describes the results and experiences of the Phase 2 testing.

  20. Processing and thermal properties of molecularly oriented polymers

    E-Print Network [OSTI]

    Skow, Erik (Erik Dean)

    2007-01-01T23:59:59.000Z

    High molecular weight polymers that are linear in molecular construction can be oriented such that some of their physical properties in the oriented direction are enhanced. For over 50 years polymer orientation and processing ...

  1. Crack coalescence in granite

    E-Print Network [OSTI]

    Miller, James Thomas, Ph. D. Massachusetts Institute of Technology

    2008-01-01T23:59:59.000Z

    This thesis experimentally investigates crack coalescence in prismatic Barre Granite specimens with two pre-cut, open flaws under uniaxial compression. Using a high-speed video system, crack initiation, propagation, and ...

  2. Nonlinear structural crack growth monitoring

    DOE Patents [OSTI]

    Welch, Donald E. (Oak Ridge, TN); Hively, Lee M. (Philadelphia, TN); Holdaway, Ray F. (Clinton, TN)

    2002-01-01T23:59:59.000Z

    A method and apparatus are provided for the detection, through nonlinear manipulation of data, of an indicator of imminent failure due to crack growth in structural elements. The method is a process of determining energy consumption due to crack growth and correlating the energy consumption with physical phenomena indicative of a failure event. The apparatus includes sensors for sensing physical data factors, processors or the like for computing a relationship between the physical data factors and phenomena indicative of the failure event, and apparatus for providing notification of the characteristics and extent of such phenomena.

  3. A model of the thermal processing of particles in solar nebula shocks: Application to the cooling rates of chondrules

    E-Print Network [OSTI]

    Connolly Jr, Harold C.

    A model of the thermal processing of particles in solar nebula shocks: Application to the cooling for the thermal processing of particles in shock waves typical of the solar nebula. This shock model improves are accounted for in their ef fects on the mass, momentum and energy fluxes. Also, besides thermal exchange

  4. Rapid thermal processing of steel using high energy electron beams

    SciTech Connect (OSTI)

    Elmer, J.W.; Newton, A.; Smith, C. Jr.

    1993-11-10T23:59:59.000Z

    High energy electron beams (HEEBs) with megavolt energies represent a new generation of charged particle beams that rapidly deposit up to several hundred joules/pulse over areas on the order of a few square millimeters to 100s of square centimeters. These pulsed beams have energies in the 1 to 10 MeV range, which enables the electrons to deposit large amounts of energy deeply into the material being processed, and these beams have short pulse durations (50 ns) that can heat materials at rates as high as 10{sup 10} {degrees}C/s for a 1000 {degree}C temperature rise in the material. Lower heating rates, on the order of 10{sup 4} {degrees}C/s, can be produced by reducing the energy per pulse and distributing the total required energy over a series of sub-ms pulses, at pulse repetition frequencies (PRFs) up to several kHz. This paper presents results from materials processing experiments performed on steel with a 6 MeV electron beam, analyzes these results using a Monte Carlo transport code, and presents a first-order predictive method for estimating the peak energy deposition, temperature, and heating rate for HEEB processed steel.

  5. Application of the cracked pipe element to creep crack growth prediction

    SciTech Connect (OSTI)

    Brochard, J.; Charras, T.

    1997-04-01T23:59:59.000Z

    The modification of a computer code for leak before break analysis is very briefly described. The CASTEM2000 code was developed for ductile fracture assessment of piping systems with postulated circumferential through-wall cracks under static or dynamic loading. The modification extends the capabilities of the cracked pipe element to the determination of fracture parameters under creep conditions (C*, {phi}c and {Delta}c). The model has the advantage of evaluating significant secondary effects, such as those from thermal loading.

  6. Composite material having high thermal conductivity and process for fabricating same

    DOE Patents [OSTI]

    Colella, N.J.; Davidson, H.L.; Kerns, J.A.; Makowiecki, D.M.

    1998-07-21T23:59:59.000Z

    A process is disclosed for fabricating a composite material such as that having high thermal conductivity and having specific application as a heat sink or heat spreader for high density integrated circuits. The composite material produced by this process has a thermal conductivity between that of diamond and copper, and basically consists of coated diamond particles dispersed in a high conductivity metal, such as copper. The composite material can be fabricated in small or relatively large sizes using inexpensive materials. The process basically consists, for example, of sputter coating diamond powder with several elements, including a carbide forming element and a brazeable material, compacting them into a porous body, and infiltrating the porous body with a suitable braze material, such as copper-silver alloy, thereby producing a dense diamond-copper composite material with a thermal conductivity comparable to synthetic diamond films at a fraction of the cost. 7 figs.

  7. Turbulent thermalization process in high-energy heavy-ion collisions

    E-Print Network [OSTI]

    Jürgen Berges; Björn Schenke; Sören Schlichting; Raju Venugopalan

    2014-09-05T23:59:59.000Z

    We discuss the onset of the thermalization process in high-energy heavy-ion collisions from a weak coupling perspective, using classical-statistical real-time lattice simulations as a first principles tool to study the pre-equilibrium dynamics. Most remarkably, we find that the thermalization process is governed by a universal attractor, where the space-time evolution of the plasma becomes independent of the initial conditions and exhibits the self-similar dynamics characteristic of wave turbulence. We discuss the consequences of our weak coupling results for the thermalization process in heavy-ion experiments and briefly comment on the use of weak coupling techniques at larger values of the coupling.

  8. Process to improve boiler operation by supplemental firing with thermally beneficiated low rank coal

    DOE Patents [OSTI]

    Sheldon, Ray W. (Huntley, MT)

    2001-01-01T23:59:59.000Z

    The invention described is a process for improving the performance of a commercial coal or lignite fired boiler system by supplementing its normal coal supply with a controlled quantity of thermally beneficiated low rank coal, (TBLRC). This supplemental TBLRC can be delivered either to the solid fuel mill (pulverizer) or directly to the coal burner feed pipe. Specific benefits are supplied based on knowledge of equipment types that may be employed on a commercial scale to complete the process. The thermally beneficiated low rank coal can be delivered along with regular coal or intermittently with regular coal as the needs require.

  9. THERMODYNAMIC CONSIDERATIONS FOR THERMAL WATER SPLITTING PROCESSES AND HIGH TEMPERATURE ELECTROLYSIS

    SciTech Connect (OSTI)

    J. E. O'Brien

    2008-11-01T23:59:59.000Z

    A general thermodynamic analysis of hydrogen production based on thermal water splitting processes is presented. Results of the analysis show that the overall efficiency of any thermal water splitting process operating between two temperature limits is proportional to the Carnot efficiency. Implications of thermodynamic efficiency limits and the impacts of loss mechanisms and operating conditions are discussed as they pertain specifically to hydrogen production based on high-temperature electrolysis. Overall system performance predictions are also presented for high-temperature electrolysis plants powered by three different advanced nuclear reactor types, over their respective operating temperature ranges.

  10. Gas-chromatographic identification of volatile products from thermal processing of Bitumen

    SciTech Connect (OSTI)

    Zenkevich, I.G.; Ventura, K. [Advanced Chemical Engineering Institute, Pardubice (Czechoslovakia)

    1992-03-10T23:59:59.000Z

    The variety of bitumen industrial brands is evident in the significant variation of composition and ratio of volatile thermal processing products, which makes their detailed characterization difficult. For that reason, in the authors` opinion a simple and easily reproducible method for gas chromatographic analysis and identification of these substances should be of greater interest than gathering more such results. In this report the authors discuss the selection of an optimal combination of group and individual gas chromatographic methods for identification of volatile thermal processing products in the presence of air, using the example of AP bitumen, the main brand used in Czechoslavakia for production of asphalt. 15 refs., 1 tab.

  11. Energy Efficient Process Heating: Insulation and Thermal Mass Kevin Carpenter and Kelly Kissock

    E-Print Network [OSTI]

    Kissock, Kelly

    1 Energy Efficient Process Heating: Insulation and Thermal Mass Kevin Carpenter and Kelly Kissock/or evaporation. A practical way of reducing heat loss is by insulating or covering the surfaces. This paper presents methods to quantify heat loss and energy savings from insulating hot surfaces and open tanks

  12. Evolution of seismic velocities in heavy oil sand reservoirs during thermal recovery process

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 Evolution of seismic velocities in heavy oil sand reservoirs during thermal recovery process localiser la chambre à vapeur. INTRODUCTION [1] Huge quantities of heavy oils (heavy oil, extra heavy oil. Larribau 64018 Pau Cedex, France Oil and Gas Science and Technology 2012, 67 (6), 1029-1039, doi:10

  13. Application of the cracked pipe element to creep crack growth prediction

    SciTech Connect (OSTI)

    Brochard, J.; Charras, T. [C.E.A.-C.E.-Saclay DRN/DMT, Gif Sur Yvette (France); Ghoudi, M. [C.E.A.-C.E.-Saclay, Gif Sur Yvette (France)

    1997-04-01T23:59:59.000Z

    Modifications to a computer code for ductile fracture assessment of piping systems with postulated circumferential through-wall cracks under static or dynamic loading are very briefly described. The modifications extend the capabilities of the CASTEM2000 code to the determination of fracture parameters under creep conditions. The main advantage of the approach is that thermal loads can be evaluated as secondary stresses. The code is applicable to piping systems for which crack propagation predictions differ significantly depending on whether thermal stresses are considered as primary or secondary stresses.

  14. Modeling of thermally driven hydrological processes in partially saturated fractured rock

    SciTech Connect (OSTI)

    Tsang, Yvonne; Birkholzer, Jens; Mukhopadhyay, Sumit

    2009-03-15T23:59:59.000Z

    This paper is a review of the research that led to an in-depth understanding of flow and transport processes under strong heat stimulation in fractured, porous rock. It first describes the anticipated multiple processes that come into play in a partially saturated, fractured porous volcanic tuff geological formation, when it is subject to a heat source such as that originating from the decay of radionuclides. The rationale is then given for numerical modeling being a key element in the study of multiple processes that are coupled. The paper outlines how the conceptualization and the numerical modeling of the problem evolved, progressing from the simplified to the more realistic. Examples of numerical models are presented so as to illustrate the advancement and maturation of the research over the last two decades. The most recent model applied to in situ field thermal tests is characterized by (1) incorporation of a full set of thermal-hydrological processes into a numerical simulator, (2) realistic representation of the field test geometry, in three dimensions, and (3) use of site-specific characterization data for model inputs. Model predictions were carried out prior to initiation of data collection, and the model results were compared to diverse sets of measurements. The approach of close integration between modeling and field measurements has yielded a better understanding of how coupled thermal hydrological processes produce redistribution of moisture within the rock, which affects local permeability values and subsequently the flow of liquid and gases. The fluid flow in turn will change the temperature field. We end with a note on future research opportunities, specifically those incorporating chemical, mechanical, and microbiological factors into the study of thermal and hydrological processes.

  15. Numerical simulation of oxidation and its effect on the crack growth resistance of titanium alloys

    E-Print Network [OSTI]

    Triharjanto, Robertus Heru

    1997-01-01T23:59:59.000Z

    . Such applications expose the MMC to highly variable mechanical and thermal loading and corrosive environments. The mechanical and thermal loading may introduce macrocracks, which may promote oxidation from the crack surfaces. Previous research has noted that even...

  16. Topology of desiccation crack patterns in clay and invariance of crack interface area with thickness

    E-Print Network [OSTI]

    Tajkera Khatun; Tapati Dutta; Sujata Tarafdar

    2014-12-09T23:59:59.000Z

    We study the crack patterns developed on desiccating films of an aqueous colloidal suspension of bentonite on a glass substrate. Varying the thickness of the layer $h$ gives the following new and interesting results: (i)We identify a critical thickness $h_{c}$, above which isolated cracks join each other to form a fully connected network. A topological analysis of the crack network shows that the Euler number falls to a minimum at $h_{c}$. (ii) We find further, that the total vertical surface area of the clay $A_v$, which has opened up due to cracking, is a constant independent of the layer thickness for $h \\geq h_c$. (iii) The total area of the glass substrate $A_s$, exposed by the hierarchical sequence of cracks is also a constant for $h \\geq h_c$. These results are shown to be consistent with a simple energy conservation argument, neglecting dissipative losses. (iv) Finally we show that if the crack pattern is viewed at successively finer resolution, the total cumulative area of cracks visible at a certain resolution, scales with the layer thickness. A suspension of Laponite in methanol is found to exhibit similar salient features (i)-(iv), though in this case the crack initiation process for very thin layers is quite different.

  17. Determination of crack morphology parameters from service failures for leak-rate analyses

    SciTech Connect (OSTI)

    Wilkowski, G.; Ghadiali, N.; Paul, D. [Battelle Memorial Institute, Columbus, OH (United States)] [and others

    1997-04-01T23:59:59.000Z

    In leak-rate analyses described in the literature, the crack morphology parameters are typically not well agreed upon by different investigators. This paper presents results on a review of crack morphology parameters determined from examination of service induced cracks. Service induced cracks were found to have a much more tortuous flow path than laboratory induced cracks due to crack branching associated with the service induced cracks. Several new parameters such as local and global surface roughnesses, as well as local and global number of turns were identified. The effect of each of these parameters are dependent on the crack-opening displacement. Additionally, the crack path is typically assumed to be straight through the pipe thickness, but the service data show that the flow path can be longer due to the crack following a fusion line, and/or the number of turns, where the number of turns in the past were included as a pressure drop term due to the turns, but not the longer flow path length. These parameters were statistically evaluated for fatigue cracks in air, corrosion-fatigue, IGSCC, and thermal fatigue cracks. A refined version of the SQUIRT leak-rate code was developed to account for these variables. Sample calculations are provided in this paper that show how the crack size can vary for a given leak rate and the statistical variation of the crack morphology parameters.

  18. Evolution of seismic velocities in heavy oil sand reservoirs during thermal recovery process

    E-Print Network [OSTI]

    Nauroy, Jean-François; Guy, N; Baroni, Axelle; Delage, Pierre; Mainguy, Marc; 10.2516/ogst/2012027

    2013-01-01T23:59:59.000Z

    In thermally enhanced recovery processes like cyclic steam stimulation (CSS) or steam assisted gravity drainage (SAGD), continuous steam injection entails changes in pore fluid, pore pressure and temperature in the rock reservoir, that are most often unconsolidated or weakly consolidated sandstones. This in turn increases or decreases the effective stresses and changes the elastic properties of the rocks. Thermally enhanced recovery processes give rise to complex couplings. Numerical simulations have been carried out on a case study so as to provide an estimation of the evolution of pressure, temperature, pore fluid saturation, stress and strain in any zone located around the injector and producer wells. The approach of Ciz and Shapiro (2007) - an extension of the poroelastic theory of Biot-Gassmann applied to rock filled elastic material - has been used to model the velocity dispersion in the oil sand mass under different conditions of temperature and stress. A good agreement has been found between these pre...

  19. The effects of controlled thermal cycling on dislocation creation during semiconductor device processing

    E-Print Network [OSTI]

    Spaw, William James

    1971-01-01T23:59:59.000Z

    . The controlled cycling serves to reduce the temperature gradients existing within the wafers during such high temperature (&1000'C) heat-cycling as encountered during semiconductor device processing. These reduced dislocation densities are compared with those... UNDER THERMAL CYCLING CONDITIONS. V. CONCLUSIONS Page 25 REFERENCES APPENDIX 27 30 VITA LIST OF FIGURES Fi gure Page 3. 1 Furnace temperature during cycling from 800'C to Tmax and back. . . 3. 2 Temperature response curves for Thermco...

  20. Waste Heat Recovery and Recycling in Thermal Separation Processes: Distillation, Multi-Effect Evaporation (MEE) and Crystallization Processes

    SciTech Connect (OSTI)

    Emmanuel A. Dada; Chandrakant B. Panchal; Luke K. Achenie; Aaron Reichl; Chris C. Thomas

    2012-12-03T23:59:59.000Z

    Evaporation and crystallization are key thermal separation processes for concentrating and purifying inorganic and organic products with energy consumption over 1,000 trillion Btu/yr. This project focused on a challenging task of recovering low-temperature latent heat that can have a paradigm shift in the way thermal process units will be designed and operated to achieve high-energy efficiency and significantly reduce the carbon footprint as well as water footprint. Moreover, this project has evaluated the technical merits of waste-heat powered thermal heat pumps for recovery of latent heat from distillation, multi-effect evaporation (MEE), and crystallization processes and recycling into the process. The Project Team has estimated the potential energy, economics and environmental benefits with the focus on reduction in CO2 emissions that can be realized by 2020, assuming successful development and commercialization of the technology being developed. Specifically, with aggressive industry-wide applications of heat recovery and recycling with absorption heat pumps, energy savings of about 26.7 trillion Btu/yr have been estimated for distillation process. The direct environmental benefits of this project are the reduced emissions of combustible products. The estimated major reduction in environmental pollutants in the distillation processes is in CO2 emission equivalent to 3.5 billion lbs/year. Energy consumption associated with water supply and treatments can vary between 1,900 kWh and 23,700 kWh per million-gallon water depending on sources of natural waters [US DOE, 2006]. Successful implementation of this technology would significantly reduce the demand for cooling-tower waters, and thereby the use and discharge of water treatment chemicals. The Project Team has also identified and characterized working fluid pairs for the moderate-temperature heat pump. For an MEE process, the two promising fluids are LiNO3+KNO3+NANO3 (53:28:19 ) and LiNO3+KNO3+NANO2(53:35:12). And for an H2O2 distillation process, the two promising fluids are Trifluoroethanol (TFE) + Triethylene Glycol Dimethyl ether (DMETEG) and Ammonia+ Water. Thermo-physical properties calculated by Aspen+ are reasonably accurate. Documentation of the installation of pilot-plants or full commercial units were not found in the literature for validating thermo-physical properties in an operating unit. Therefore, it is essential to install a pilot-scale unit to verify thermo-physical properties of working fluid pairs and validate the overall efficiency of the thermal heat pump at temperatures typical of distillation processes. For an HO2 process, the ammonia-water heat pump system is more compact and preferable than the TFE-DMETEG heat pump. The ammonia-water heat pump is therefore recommended for the H2O2 process. Based on the complex nature of the heat recovery system, we anticipated that capital costs could make investments financially unattractive where steam costs are low, especially where co-generation is involved. We believe that the enhanced heat transfer equipment has the potential to significantly improve the performance of TEE crystallizers, independent of the absorption heat-pump recovery system. Where steam costs are high, more detailed design/cost engineering will be required to verify the economic viability of the technology. Due to the long payback period estimated for the TEE open system, further studies on the TEE system are not warranted unless there are significant future improvements to heat pump technology. For the H2O2 distillation cycle heat pump waste heat recovery system, there were no significant process constraints and the estimated 5 years payback period is encouraging. We therefore recommend further developments of application of the thermal heat pump in the H2O2 distillation process with the focus on the technical and economic viability of heat exchangers equipped with the state-of-the-art enhancements. This will require additional funding for a prototype unit to validate enhanced thermal performances of heat transfer equipment, evaluat

  1. Automated pavement crack detection

    E-Print Network [OSTI]

    Rao, Ashok Madhava

    1991-01-01T23:59:59.000Z

    : Electrical Engineering AUTOMATED PAVEMENT CRACK DETECTION A Thesis by ASHOK MADHAVA RAO Approved as to style and content by . c Norman C. Grisw d (Chair of Committ ) Nasser Kehtarnavaz (Member) g, J~, Karan Watson Robert L. Lytt (Member) Jo W.... Howze (Head of Department) December 1991 111 ABSTRACT Automated Pavement Crack Detection. (December 1991) Ashok Madhava, Rao, B. E. , Mysore University Chair of Advisory Committee: Norman. C. Griswold Due to load, environmental and structural...

  2. Supporting technology for enhanced oil recovery: EOR thermal processes. Seventh Amendment and Extension to Annex 4, Enhanced oil recovery thermal processes

    SciTech Connect (OSTI)

    Reid, T B [USDOE Bartlesville Project Office, OK (United States)] [USDOE Bartlesville Project Office, OK (United States); Colonomos, P [INTEVEP, Filial de Petroleos de Venezuela, SA, Caracas (Venezuela)] [INTEVEP, Filial de Petroleos de Venezuela, SA, Caracas (Venezuela)

    1993-02-01T23:59:59.000Z

    This report contains the results of efforts under the six tasks of the Seventh Amendment and Extension of Annex IV, Enhanced Oil Recovery Thermal Processes of the Venezuela/USA Agreement. The report is presented in sections (for each of the 6 tasks) and each section contains one or more reports prepared by various individuals or groups describing the results of efforts under each of the tasks. A statement of each task, taken from the agreement, is presented on the first page of each section. The tasks are numbered 50 through 55. The first, second, third, fourth, fifth, sixth and seventh reports on Annex IV, Venezuela MEM/USA-DOE Fossil Energy Report IV-1, IV-2, IV-3, IV-4, IV-5 and IV-6 (DOE/BETC/SP-83/15, DOE/BC-84/6/SP, DOE/BC-86/2/SP, DOE/BC-87/2/SP, DOE/BC-89/l/SP, DOE/BC-90/l/SP, and DOE/BC-92/l/SP) contain the results for the first 49 tasks. Those reports are dated April 1983, August 1984, March 1986, July 1987, November 1988, December 1989, and October 1991, respectively. Each task report has been processed separately for inclusion in the Energy Science and Technology Database.

  3. Latex and two-roll mill processing of thermally-exfoliated graphite oxide/natural rubber nanocomposites

    E-Print Network [OSTI]

    Latex and two-roll mill processing of thermally-exfoliated graphite oxide/natural rubber t Thermally-exfoliated graphite oxide (TEGO) is a graphene-based material that has been previously shown to graphene-based materials [4]. GO can be exfoliated in water into single-layer graphene oxide platelets

  4. Heavy-Section Steel Technology Program: Recent developments in crack initiation and arrest research

    SciTech Connect (OSTI)

    Pennell, W.E.

    1991-01-01T23:59:59.000Z

    Technology for the analysis of crack initiation and arrest is central to the reactor pressure vessel fracture-margin-assessment process. Regulatory procedures for nuclear plants utilize this technology to assure the retention of adequate fracture-prevention margins throughout the plant operating license period. As nuclear plants age and regulatory procedures dictate that fracture-margin assessments be performed, interest in the fracture-mechanics technology incorporated into those procedures has heightened. This has led to proposals from a number of sources for development and refinement of the underlying crack-initiation and arrest-analysis technology. This paper presents an overview of ongoing Heavy-Section Steel Technology (HSST) Program research aimed at refining the fracture toughness data used in the analysis of fracture margins under pressurized-thermal-shock loading conditions. 33 refs., 13 figs.

  5. Site-specific investigations of aquifer thermal energy storage for space and process cooling

    SciTech Connect (OSTI)

    Brown, D R; Hattrup, M P; Watts, R L

    1991-08-01T23:59:59.000Z

    The Pacific Northwest Laboratory (PNL) has completed three preliminary site-specific feasibility studies that investigated using aquifer thermal energy storage (ATES) to reduce space and process cooling costs. Chilled water stored in an ATES system could be used to meet all or part of the process and/or space cooling loads at the three facilities investigated. The work was sponsored by the US Department of Energy's (DOE) Office of Energy Management. The ultimate goal of DOE's Thermal Energy Storage Program is to successfully transfer ATES technology to industrial and commercial sectors. The primary objective of this study was to identify prospective sites and determine the technical and economic feasibility of implementing chill ATES technology. A secondary objective was to identify site-specific factors promoting or inhibiting the application of chill ATES technology so that other potentially attractive sites could be more easily identified and evaluated. A preliminary investigation of the feasibility of commercializing chill ATES in automotive assembly facilities was completed. The results suggested that automotive assembly facilities was completed. The results suggested that automotive assembly facilities represent a good entry market for chill ATES, if the system is cost-effective. As a result, this study was undertaken to identify and evaluate prospective chill ATES applications in the automotive industry. The balance of the report contains two main sections. Section 2.0 describes the site identification process. Site feasibility is addressed in Section 3.0. Overall study conclusions and recommendations are than presented in Section 4.0.

  6. Modeling and Optimization of Direct Chill Casting to Reduce Ingot Cracking

    SciTech Connect (OSTI)

    Das, S.K.; Ningileri, S.; Long, Z.; Saito, K.; Khraisheh, M.; Hassan, M.H.; Kuwana, K.; Han, Q.; Viswanathan, S.; Sabau, A.S.; Clark, J.; Hyrn, J. (ANL)

    2006-08-15T23:59:59.000Z

    Approximately 68% of the aluminum produced in the United States is first cast into ingots prior to further processing into sheet, plate, extrusions, or foil. The direct chill (DC) semi-continuous casting process has been the mainstay of the aluminum industry for the production of ingots due largely to its robust nature and relative simplicity. Though the basic process of DC casting is in principle straightforward, the interaction of process parameters with heat extraction, microstructural evolution, and development of solidification stresses is too complex to analyze by intuition or practical experience. One issue in DC casting is the formation of stress cracks [1-15]. In particular, the move toward larger ingot cross-sections, the use of higher casting speeds, and an ever-increasing array of mold technologies have increased industry efficiencies but have made it more difficult to predict the occurrence of stress crack defects. The Aluminum Industry Technology Roadmap [16] has recognized the challenges inherent in the DC casting process and the control of stress cracks and selected the development of 'fundamental information on solidification of alloys to predict microstructure, surface properties, and stresses and strains' as a high-priority research need, and the 'lack of understanding of mechanisms of cracking as a function of alloy' and 'insufficient understanding of the aluminum solidification process', which is 'difficult to model', as technology barriers in aluminum casting processes. The goal of this Aluminum Industry of the Future (IOF) project was to assist the aluminum industry in reducing the incidence of stress cracks from the current level of 5% to 2%. Decreasing stress crack incidence is important for improving product quality and consistency as well as for saving resources and energy, since considerable amounts of cast metal could be saved by eliminating ingot cracking, by reducing the scalping thickness of the ingot before rolling, and by eliminating butt sawing. Full-scale industrial implementation of the results of the proposed research would lead to energy savings in excess of 6 trillion Btu by the year 2020. The research undertaken in this project aimed to achieve this objective by a collaboration of industry, university, and national laboratory personnel through Secat, Inc., a consortium of aluminum companies. During the four-year project, the industrial partners and the research team met in 16 quarterly meetings to discuss research results and research direction. The industrial partners provided guidance, facilities, and experience to the research team. The research team went to two industrial plants to measure temperature distributions in commercial 60,000-lb DC casting ingot production. The project focused on the development of a fundamental understanding of ingot cracking and detailed models of thermal conditions, solidification, microstructural evolution, and stress development during the initial transient in DC castings of the aluminum alloys 3004 and 5182. The microstructure of the DC casting ingots was systematically characterized. Carefully designed experiments were carried out at the national laboratory and university facilities as well as at the industrial locations using the industrial production facilities. The advanced computational capabilities of the national laboratories were used for thermodynamic and kinetic simulations of phase transformation, heat transfer and fluid flow, solidification, and stress-strain evolution during DC casting. The achievements of the project are the following: (1) Identified the nature of crack formation during DC casting; (2) Developed a novel method for determining the mechanical properties of an alloy at the nonequilibrium mushy zone of the alloy; (3) Measured heat transfer coefficients (HTCs) between the solidifying ingot and the cooling water jet; (4) Determined the material constitutive model at high temperatures; and (5) Developed computational capabilities for the simulation of cracking formation in DC casting ingot. The models and the database de

  7. Isolated many-body quantum systems far from equilibrium: Relaxation process and thermalization

    SciTech Connect (OSTI)

    Torres-Herrera, E. J.; Santos, Lea F. [Physics Department, Yeshiva University, New York, New York 10016 (United States)

    2014-10-15T23:59:59.000Z

    We present an overview of our recent numerical and analytical results on the dynamics of isolated interacting quantum systems that are taken far from equilibrium by an abrupt perturbation. The studies are carried out on one-dimensional systems of spins-1/2, which are paradigmatic models of many-body quantum systems. Our results show the role of the interplay between the initial state and the post-perturbation Hamiltonian in the relaxation process, the size of the fluctuations after equilibration, and the viability of thermalization.

  8. Thermal stability of TaSi/sub x/-GaAs Schottky barriers in rapid thermal processing. [Self-aligned gate fabrication of GaAs MESFETs

    SciTech Connect (OSTI)

    Haynes, T.E.; Han, C.C.; Lau, S.S.; Picraux, S.T.; Chu, W.K.

    1987-01-01T23:59:59.000Z

    Co-sputtered TaSi/sub x/ films on GaAs have been examined as potential refractory Schottky barrier contacts suitable for self-aligned gate fabrication of GaAs MESFETs. Thermal stability of electrical and physical characteristics has been studied following furnace annealing and rapid thermal processing of contacts with compositions near Ta/sub 5/Si/sub 3/ (x = 0.6). Assessment of integrity of the annealed contacts has been made based on measurement of electrical characteristics, interface interdiffusion, and evaporation of GaAs through the contact. Superior stability as a function of anneal temperature up to 900/sup 0/C was achieved for TaSi/sub 0.6/ contacts using rapid thermal processing (RTP) techniques rather than furnace annealing. Current-voltage characteristics were found to be insensitive to RTP temperature between 700 and 900/sup 0/C.

  9. Transition from cool flame to thermal flame in compression ignition process

    SciTech Connect (OSTI)

    Yamada, Hiroyuki; Suzaki, Kotaro; Goto, Yuichi [National Traffic Safety and Environment Laboratory, 7-42-27 Jindaiji-Higashimachi, Chofu, Tokyo 182-0012 (Japan); Tezaki, Atsumu [Department of Mechanical and Intellectual Systems Engineering, University of Toyama, Gofuku 3190, Toyama-shi, Toyama 930-8555 (Japan)

    2008-07-15T23:59:59.000Z

    The mechanism that initiates thermal flames in compression ignition has been studied. Experimentally, a homogeneous charge compression ignition (HCCI) engine was used with DME, n-heptane, and n-decane. Arrhenius plots of the heat release rate in the HCCI experiments showed that rates of heat release with DME, n-heptane, and n-decane exhibited a certain activation energy that is identical to that of the H{sub 2}O{sub 2} decomposition reaction. The same feature was observed in diesel engine operation using ordinary diesel fuel with advanced ignition timing to make ignition occur after the end of fuel injection. These experimental results were reproduced in nondimensional simulations using kinetic mechanisms for DME, n-heptane, and n-decane, the last being developed by extending the n-heptane mechanism. Methanol addition, which suppresses low-temperature oxidation (LTO) and delays the ignition timing, had no effect on the activation energy obtained from the Arrhenius plot of heat release rate. Nevertheless, methanol addition lowered the heat release rates during the prethermal flame process. This is because H{sub 2}O{sub 2} formation during cool flame was reduced by adding methanol. The mechanism during the transition process from cool flame to thermal flame can be explained quantitatively using thermal explosion theory, in which the rate-determining reaction is H{sub 2}O{sub 2} decomposition, assuming that heat release in this period is caused by partial oxidation of DME and HCHO initiated with the reaction with OH produced though H{sub 2}O{sub 2} decomposition. (author)

  10. Evaluation of gasification and novel thermal processes for the treatment of municipal solid waste

    SciTech Connect (OSTI)

    Niessen, W.R.; Marks, C.H.; Sommerlad, R.E. [Camp Dresser and McKee, Inc., Cambridge, MA (United States)] [Camp Dresser and McKee, Inc., Cambridge, MA (United States)

    1996-08-01T23:59:59.000Z

    This report identifies seven developers whose gasification technologies can be used to treat the organic constituents of municipal solid waste: Energy Products of Idaho; TPS Termiska Processor AB; Proler International Corporation; Thermoselect Inc.; Battelle; Pedco Incorporated; and ThermoChem, Incorporated. Their processes recover heat directly, produce a fuel product, or produce a feedstock for chemical processes. The technologies are on the brink of commercial availability. This report evaluates, for each technology, several kinds of issues. Technical considerations were material balance, energy balance, plant thermal efficiency, and effect of feedstock contaminants. Environmental considerations were the regulatory context, and such things as composition, mass rate, and treatability of pollutants. Business issues were related to likelihood of commercialization. Finally, cost and economic issues such as capital and operating costs, and the refuse-derived fuel preparation and energy conversion costs, were considered. The final section of the report reviews and summarizes the information gathered during the study.

  11. Fracture process zone : microstructure and nanomechanics in quasi-brittle materials

    E-Print Network [OSTI]

    Brooks, Zenzile (Zenzile Z.)

    2013-01-01T23:59:59.000Z

    Cracks begin (and end) at a crack tip; the "Fracture Process Zone" (FPZ) is a region of damage around the crack tip. The context of this research is the FPZ in quasi-brittle materials, which is characterized by cracking ...

  12. STRESS CORROSION CRACKING IN TEAR DROP SPECIMENS

    SciTech Connect (OSTI)

    Lam, P; Philip Zapp, P; Jonathan Duffey, J; Kerry Dunn, K

    2009-05-01T23:59:59.000Z

    Laboratory tests were conducted to investigate the stress corrosion cracking (SCC) of 304L stainless steel used to construct the containment vessels for the storage of plutonium-bearing materials. The tear drop corrosion specimens each with an autogenous weld in the center were placed in contact with moist plutonium oxide and chloride salt mixtures. Cracking was found in two of the specimens in the heat affected zone (HAZ) at the apex area. Finite element analysis was performed to simulate the specimen fabrication for determining the internal stress which caused SCC to occur. It was found that the tensile stress at the crack initiation site was about 30% lower than the highest stress which had been shifted to the shoulders of the specimen due to the specimen fabrication process. This finding appears to indicate that the SCC initiation took place in favor of the possibly weaker weld/base metal interface at a sufficiently high level of background stress. The base material, even subject to a higher tensile stress, was not cracked. The relieving of tensile stress due to SCC initiation and growth in the HAZ and the weld might have foreclosed the potential for cracking at the specimen shoulders where higher stress was found.

  13. Managing Abnormal Operation through Process Integration and Cogeneration Systems

    E-Print Network [OSTI]

    Kamrava, Serveh

    2014-08-05T23:59:59.000Z

    & Webster Company, Linde company method. *“Part of this chapter is reprinted with permission from “Managing abnormal operation through process integration and cogeneration systems” by Serveh... (75% for ethane to 28% for hydrogenated gasoline). In Linde method ethylene and propylene is produced from ethane to naphta hydrocarbons by thermal cracking method. Ethylene efficiency is different for different feedstock. For gasoline, naphta...

  14. Rheological and thermal study of the curing process of a cycloaliphatic epoxy resin: application to the optimization of the

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 Rheological and thermal study of the curing process of a cycloaliphatic epoxy resin: application-4-67-14-37-80; Fax: 33-4-67-14-40-28 ABSTRACT The curing process of a cycloaliphatic epoxy resin was defined using of structure-properties relationships. Keywords: curing kinetics, epoxy resin, dynamic mechanical properties

  15. Hydrocarbon cracking catalyst

    SciTech Connect (OSTI)

    Lochow, C.F.; Kovacs, D.B.

    1988-12-27T23:59:59.000Z

    This patent describes a catalyst composition for cracking hydrocarbons to maximize gasoline comprising: rare earth exchanged ''Y'' crystalline faujasite dispersed in a clay containing matrix material; and which has been subsequently further ion exchanged to contain 0.20 to 3.0 wt% yttrium, calculated as the oxide, whereby the yttrium is chemically combined in the catalyst composition.

  16. The thermal expansion coefficient as a key design parameter for thermoelectric materials and its relationship to processing-dependent bloating

    SciTech Connect (OSTI)

    Ni, Jennifer E. [Michigan State University, East Lansing; Case, Eldon D [Michigan State University, East Lansing; Schmidt, Robert [Michigan State University, East Lansing; Wu, Chun-I [Michigan State University, East Lansing; Hogan, Timothy [Michigan State University, East Lansing; Trejo, Rosa M [ORNL; Kirkham, Melanie J [ORNL; Lara-Curzio, Edgar [ORNL; Kanatzidis, Mercouri G. [Northwestern University, Evanston

    2013-01-01T23:59:59.000Z

    The coefficient of thermal expansion (CTE) is a key design parameter for thermoelectric (TE) materials, especially in energy harvesting applications since stresses generated by CTE mismatch, thermal gradients, and thermal transients scale with the CTE of the TE material. For the PbTe PbS-based TE material (Pb 0.95 Sn 0.05 Te) 0.92(PbS) 0.08 0.055 % PbI 2 over the temperature ranges of 293 543 and 293 773 K, a CTE, alpha avg , of 21.4 0.3 x 10-6 K-1 was measured using (1) dilatometry and (2) high-temperature X-ray diffraction (HT-XRD) for powder and bulk specimens. The CTE values measured via dilatometry and HT-XRD are similar to the literature values for other Pb-based chalcogenides. However, the processing technique was found to impact the thermal expansion such that bloating (which leads to a hysteresis in thermal expansion) occurred for hot pressed billets heated to temperatures [603 K while specimens fabricated by pulsed electric current sintering and as-cast specimens did not show a bloating-modified thermal expansion even for temperatures up to 663 K. The relationship of bloating to the processing techniques is discussed, along with a pos- sible mechanism for inhibiting bloating in powder processed specimens.

  17. Thermal plasma processed ferro-magnetically ordered face-centered cubic iron at room temperature

    SciTech Connect (OSTI)

    Raut, Suyog A.; Kanhe, Nilesh S.; Bhoraskar, S. V.; Mathe, V. L., E-mail: vlmathe@physics.unipune.ac.in [Department of Physics, Savitribai Phule Pune University, Pune 411007 (India); Das, A. K. [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

    2014-10-28T23:59:59.000Z

    Here, we report tailor made phase of iron nanoparticles using homogeneous gas phase condensation process via thermal plasma route. It was observed that crystal lattice of nano-crystalline iron changes as a function of operating parameters of the plasma reactor. In the present investigation iron nanoparticles have been synthesized in presence of argon at operating pressures of 125–1000?Torr and fixed plasma input DC power of 6?kW. It was possible to obtain pure fcc, pure bcc as well as the mixed phases for iron nanoparticles in powder form as a function of operating pressure. The as synthesized product was characterized for understanding the structural and magnetic properties by using X-ray diffraction, vibrating sample magnetometer, and Mössbauer spectroscopy. The data reveal that fcc phase is ferromagnetically ordered with high spin state, which is unusual whereas bcc phase is found to be ferromagnetic as usual. Finally, the structural and magnetic properties are co-related.

  18. Rapid thermal annealing of ion implanted 6H-SiC by microwave processing

    SciTech Connect (OSTI)

    Gardner, J.A.; Rao, M.V.; Tian, Y.L. [George Mason Univ., Fairfax, VA (United States); Holland, O.W.; Roth, E.G. [Oak Ridge National Lab., TN (United States); Chi, P.H. [National Inst. of Standards and Technology, Gaithersburg, MD (United States); Ahmad, I. [FM Technologies, Fairfax, VA (United States)

    1997-03-01T23:59:59.000Z

    Rapid thermal processing utilizing microwave energy has been used to anneal N, P, and Al ion-implanted 6H-SiC. The microwaves raise the temperature of the sample at a rate of 200{degree}C/min vs 10{degree}C/min for conventional ceramic furnace annealing. Samples were annealed in the temperature range of 1400-1700{degree}C for 2-10 min. The implanted/annealed samples were characterized using van der Pauw Hall, Rutherford backscattering, and secondary ion mass spectrometry. For a given annealing temperature, the characteristics of the microwave-annealed material are similar to those of conventional furnace anneals despite the difference in cycle time. 19 refs., 7 figs., 3 tabs.

  19. Deployment of an innovative thermally enhanced soil mixing process augmented with zero-valent iron.

    SciTech Connect (OSTI)

    Lynch, P. L.

    1999-01-15T23:59:59.000Z

    An innovative in-situ soil treatment process, referred to as soil mixing/thermally enhanced soil vapor extraction (SM/TESVE), was used to remediate the 317 Area of Argonne National Laboratory-East (i.e., Argonne), which is contaminated with volatile organic compounds (VOCs). Following the initial soil treatment, polishing was required to reduce residual concentrations of contaminants. A study of polishing methods was conducted. It determined that injecting metallic iron particles into the soil, in conjunction with soil mixing, would reduce residual VOC concentrations more effectively than the original conventional soil ventilation approach. After the effectiveness of iron injection was verified, it replaced the soil ventilation step. The modified process involved mixing the soil while hot air and steam were injected into it. Off-gases were captured in a hood over the treatment area. During this process, an iron slurry, consisting of up to 50% iron particles in water with guar gum added as a thickening agent, was injected and mixed into the soil by the mixing equipment. Approximately 6,246 m{sup 3} (8, 170 yd{sup 3}) of soil was treated during this project. Confirmatory samples were then collected. In these samples, VOC concentrations were usually reduced by more than 80%.

  20. Solar thermal hydrogen production process: Final report, January 1978-December 1982

    SciTech Connect (OSTI)

    Not Available

    1982-12-01T23:59:59.000Z

    Under sponsorship by the United States Department of Energy, Westinghouse Advanced Energy-Systems Division has investigated the potential for using solar thermal energy to split water into hydrogen and oxygen. A hybrid thermochemical/electrochemical process, known as the Sulfur Cycle, has been the focus of these investigations. Process studies have indicated that, with adequate and ongoing research and development, the Sulfur Cycle can be effectively driven with solar heat. Also, economic analyses have indicated that the cycle has the potential to produce hydrogen in economic competitiveness with conventional methods (e.g. methane/steam reforming) by the turn of the century. A first generation developmental system has been defined along with its critical components, i.e. those components that need substantial engineering development. Designs for those high temperature components that concentrate, vaporize and decompose the process circulating fluid, sulfuric acid, have been prepared. Extensive experimental investigations have been conducted with regard to the selection of construction materials for these components. From these experiments, which included materials endurance tests for corrosion resistance for periods up to 6000 hours, promising materials and catalysts have been identified.

  1. Development of the fluidized bed thermal treatment process for treating mixed waste

    SciTech Connect (OSTI)

    Semones, G.B.; Williams, P.M.; Stiefvater, S.P.; Mitchell, D.L.; Roecker, B.D.

    1993-05-01T23:59:59.000Z

    A fluidized bed system is being developed at Rocky Flats for the treatment of mixed waste (a mixture of radioactive and chemically hazardous waste). The current program builds on experience gained in the 1970`s and 1980`s in tests with bench-scale, pilot-scale, and demonstration-scale fluidized bed systems. The system operates at low temperatures ({approx} 525--600{degree}C) which eliminates many of the disadvantages associated with high temperature thermal treatment processes. The process has shown the ability to destroy polychlorinated biphenyls (PCB`s) with 99.9999% (``six-nines``) destruction efficiency in tests monitored by the Environmental Protection Agency (EPA). The bed makes use of in situ neutralization of acidic off-gases by incorporating sodium carbonate (Na{sub 2}CO{sub 3}) in the bed media. This eliminates using wet scrubbers to treat the off-gas; these produce a high volume of secondary waste. Once in operation, it is expected that the fluidized bed process will yield up to a 40:1 reduction in the volume of the waste.

  2. Modeling of crack initiation, propagation and coalescence in rocks

    E-Print Network [OSTI]

    Gonçalves da Silva, Bruno Miguel

    2009-01-01T23:59:59.000Z

    Natural or artificial fracturing of rock plays a very important role in geologic processes and for engineered structures in and on rock. Fracturing is associated with crack initiation, propagation and coalescence, which ...

  3. High-Resolution Characterizations of Stress-Corrosion Cracks in Austenitic Stainless Steel from Crack Growth Tests in BWR-Simulated Environments

    SciTech Connect (OSTI)

    Bruemmer, Stephen M.; Thomas, Larry E.

    2005-07-20T23:59:59.000Z

    Mechanisms controlling environmental degradation and cracking in light-water-reactor (LWR) systems have been investigated by analytical transmission electron microscopy (ATEM) of cracks and crack tips. The current work focuses on intergranular stress corrosion cracking (IGSCC) of 300-series, austenitic stainless steels in high-temperature LWR environments. Comparisons are made between cold-worked 304SS containing stress-corrosion cracks produced in a simulated boiling-water-reactor (BWR) environment during crack-growth tests, and a 304SS core component with cracks produced during 26-year BWR service. Similar corrosion products consisting of duplex-layered spinel oxides were found along the walls of open cracks in the service and laboratory test samples. These oxide films consisted of oriented Cr-rich spinel up to ~30 nm thick along the metal crack walls and large-grained Fe-rich spinel at the crack centers. Cracks in the service sample were generally more filled with oxide, perhaps reflecting the much longer times available for corrosion to occur after the crack passage. Crack tips in the BWR top-guide sample exhibited unique and unexpected structures with oxide-filled cracks <10 nm wide ending in finger-like attack and locally “dealloyed” zones of Fe/Cr-depleted, Ni-rich metal. Alloy compositions measured at numerous crack tips were 40 wt% Fe, 4 wt% Cr and 55 wt% Ni immediately ahead of the degradation front versus approximately 70 wt% Fe, 19 wt% Cr and 9 wt% Ni in the bulk 304SS. Laboratory samples with cracks grown over much shorted times (~1.5 months) did not show the distinctive crack tip structures or strong Ni enrichment in the metal ahead of the crack tips as for the service sample. This suggests that although selective oxidation processes occur during degradation, significant composition differences may only develop after crack propagation has slowed or stopped. Additional nanometer-scale measurements elucidating corrosion processes occurring during crack advance are presented to provide insights into mechanisms controlling IGSCC.

  4. Causes and solutions for cracking of coextruded and weld overlay floor tubes in black liquor recovery boilers

    SciTech Connect (OSTI)

    Keiser, J.R.; Taljat, B.; Wang, X.L. [and others

    1998-09-01T23:59:59.000Z

    Cracking of coextruded, black liquor recovery boiler floor tubes is both a safety and an economic issue to mill operators. In an effort to determine the cause of the cracking and to identify a solution, extensive studies, described in this and three accompanying papers, are being conducted. In this paper, results of studies to characterize both the cracking and the chemical and thermal environment are reported. Based on the results described in this series of papers, a possible mechanism is presented and means to lessen the likelihood of cracking or to totally avoid cracking of floor tubes are offered.

  5. Crack-resistant siloxane molding compounds. [Patent application

    DOE Patents [OSTI]

    McFarland, J.W.; Swearngin, C.B.

    1980-11-03T23:59:59.000Z

    The crack resistance of phenyl silicone molding resins containing siliceous fillers is improved by incorporating therein about 0.5 to 5.5% by weight of ..beta..-eucryptite, a lithium aluminum silicate having a negative thermal expansion coefficient. These molding resins are particularly suitable for encapsulating electronic devices such as diodes, coils, resistors, and the like.

  6. Status Report on Studies of Recovery Boiler Composite Floor Tube Cracking

    SciTech Connect (OSTI)

    Eng, P.; Frederick, L.A.; Hoffmann, C.M.; Keiser, J.R.; Mahmood, J.; Maziasz, P.J.; Prescott, R.; Sarma, G.B.; Singbeil, D.L.; Singh, P.M.; Swindeman, R.W.; Wang, X.-L.

    1999-09-12T23:59:59.000Z

    Cracking of the stainless steel layer of co-extruded 304L stainless steel/SA210 Gd A 1 carbon steel black liquor recovery boiler floor tubes has been identified as one of the most serious material problems in the pulp and paper industry. A DOE-funded study was initiated in 1995 with the goal of determining the cause of and possible solutions to this cracking problem. These studies have characterized tube cracking as well as the chemical and thermal environment and stress state of floor tubes. Investigations of possible cracking mechanisms indicate that stress corrosion cracking rather than thermal fatigue is a more likely cause of crack initiation. The cracking mechanism appears to require the presence of hydrated sodium sulfide and is most likely active during shut-downs and/or start-ups. Based on these results and operating experience, certain alloys appear to be more resistant than others to cracking in the floor environment, and certain operating practices appear to significantly lessen the likelihood of cracking. This report is the latest in a series of progress reports presented on this project.

  7. Characterization of oxygen and nitrogen rapid thermal annealing processes for ultra-low-k SiCOH films

    E-Print Network [OSTI]

    Boo, Jin-Hyo

    Characterization of oxygen and nitrogen rapid thermal annealing processes for ultra-low-k Si is suggested and characterized in this work for improvement of SiCOH ultra-low-k (k 2.4) film properties. Low is decreased, and the ultra-low-k films (k

  8. Study on Commissioning Process for Control Logic of Thermal Storage System

    E-Print Network [OSTI]

    Shioya, M.; Tsubaki, M.; Nakahara, N.

    2004-01-01T23:59:59.000Z

    thermal storage system in an actual building using the CLT. Introduction In thermal storage systems, as large temperature difference between the supply water and the return water as possible should be maintained in order to ensure high system..., at the secondary water circuit of a heat exchanger installed between the thermal storage system and secondary HVAC system of an actual building. One of the authors, Nakahara, acted as Commissioning Authority during construction phase and later as a consultant...

  9. Thermal Processing Effects on Microstructure and Composition of Cu3SbSe3

    SciTech Connect (OSTI)

    Majsztrik, Paul W [ORNL; Kirkham, Melanie J [ORNL; Garcia Negron, Valerie [Polytechnic University of Puerto Rico (PUPR); Lara-Curzio, Edgar [ORNL; Skoug, Eric [Michigan State University, East Lansing; Morelli, Donald [Michigan State University, East Lansing

    2013-01-01T23:59:59.000Z

    We report on the effects of thermal processing on the microstructure and composition of a system with overall stoichiometry of 3Cu:1Sb:3Se with the aim of producing single-phase Cu3SbSe3. It was found that slowly cooling from the melt produced a multiphase material consisting of Cu2Se and CuSbSe2, but devoid of Cu3SbSe3. Cooling rapidly from the melt resulted in three-phase microstructures consisting of Cu2Se, CuSbSe2, and Cu3SbSe3. Subsequent annealing of the three-phase material between 325 C and 400 C shifted composition towards nearly pure Cu3SbSe3, the target compound of this work. The kinetics of the transformation into Cu3SbSe3 is successfully described using a modified Avrami model, which suggests that diffusion is the rate-controlling step. Values of Young s modulus and hardness, obtained by nanoindentation, are reported for Cu2Se, CuSbSe2, and Cu3SbSe3.

  10. Supporting Technology for Enhanced Oil Recovery-EOR Thermal Processes Report IV-12

    SciTech Connect (OSTI)

    Izequeido, Alexandor

    2001-04-01T23:59:59.000Z

    This report contains the results of efforts under the six tasks of the Ninth Amendment and Extension of Annex IV, Enhanced Oil Recovery Thermal Processes of the Venezuela/USA Agreement. The report is presented in sections (for each of the 6 tasks) and each section contains one or more reports prepared by various individuals or groups describing the results of efforts under each of the tasks. A statement of each task, taken from the agreement, is presented on the first page of each section. The tasks are numbered 62 through 67. The first, second, third, fourth, fifth, sixth, seventh, eight, and ninth reports on Annex IV, [Venezuela MEM/USA-DOE Fossil Energy Report IV-1, IV-2, IV-3, IV-4, IV-5, IV-6, IV-7, and IV-8 (DOE/BETC/SP-83/15, DOE/BC-84/6/SP, DOE/BC-86/2/SP, DOE/BC-87/2/SP, DOE/BC-89/1/SP, DOE/BC-90/1/SP) DOE/BC-92/1/SP, DOE/BC-93/3/SP, and DOE/BC-95/3/SP] contain the results from the first 61 tasks. Those reports are dated April 1983, August 1984, March 1986, July 1! 987, November 1988, December 1989, October 1991, February 1993, and March 1995 respectively.

  11. Crack Path Selection Fatigue crack path imaged via SEM

    E-Print Network [OSTI]

    Rollins, Andrew M.

    Crack path selects secondary phases and interface Conclusions ·Nb-Si Alloys tested exhibited toughness phases fail in a brittle manner Fatigue Crack Growth ABSTRACT Advanced aerospace materials continue at high temperatures. An important property of any high temperature aerospace engineering material is its

  12. Structures for dense, crack free thin films

    DOE Patents [OSTI]

    Jacobson, Craig P. (Lafayette, CA); Visco, Steven J. (Berkeley, CA); De Jonghe, Lutgard C. (Lafayette, CA)

    2011-03-08T23:59:59.000Z

    The process described herein provides a simple and cost effective method for making crack free, high density thin ceramic film. The steps involve depositing a layer of a ceramic material on a porous or dense substrate. The deposited layer is compacted and then the resultant laminate is sintered to achieve a higher density than would have been possible without the pre-firing compaction step.

  13. Enhancement of thermal and electrical properties of carbon nanotube polymer composites by magnetic field processing

    E-Print Network [OSTI]

    Garmestani, Hamid

    of thermal conductance in a composite material assuming a linear law of mixing, and nanotube­polymerEnhancement of thermal and electrical properties of carbon nanotube polymer composites by magnetic and electrical properties of single wall carbon nanotube CNT -polymer composites are significantly enhanced

  14. Cracking blends of gas oil and residual oil

    SciTech Connect (OSTI)

    Myers, G.D.

    1988-03-01T23:59:59.000Z

    In a catalytic cracking process unit wherein a gas oil feed is cracked in a cracking zone at an elevated temperature in the presence of a cracking catalyst, the cracking catalyst is regenerated in a regeneration zone by burning coke of the catalyst, and catalyst is circulated between the cracking zone and the regeneration zone. The improvement is described for obtaining a naphtha product of improved octane number comprising introducing sufficient of a nickel and vanadium metals-containing heavy feedstock with the gas oil feed introduced into the cracking zone to deposit nickel and vanadium metals on the catalyst and raise the nickel and metals-content of the catalyst to a level ranging from about 1500 to about 6000 parts per million of the metals expressed as equivalent nickel, based on the weight of the catalyst, and maintaining the nickel and vanadium metals level on the catalyst by withdrawing high nickel and vanadium metals containing catalyst and adding low nickel and vanadium metals-containing catalyst to the regeneration zone.

  15. Standard test method for creep-fatigue crack growth testing

    E-Print Network [OSTI]

    American Society for Testing and Materials. Philadelphia

    2010-01-01T23:59:59.000Z

    1.1 This test method covers the determination of creep-fatigue crack growth properties of nominally homogeneous materials by use of pre-cracked compact type, C(T), test specimens subjected to uniaxial cyclic forces. It concerns fatigue cycling with sufficiently long loading/unloading rates or hold-times, or both, to cause creep deformation at the crack tip and the creep deformation be responsible for enhanced crack growth per loading cycle. It is intended as a guide for creep-fatigue testing performed in support of such activities as materials research and development, mechanical design, process and quality control, product performance, and failure analysis. Therefore, this method requires testing of at least two specimens that yield overlapping crack growth rate data. The cyclic conditions responsible for creep-fatigue deformation and enhanced crack growth vary with material and with temperature for a given material. The effects of environment such as time-dependent oxidation in enhancing the crack growth ra...

  16. Quantum information processing and multiatom entanglement engineering with a thermal cavity

    E-Print Network [OSTI]

    Shi-Biao Zheng

    2012-02-24T23:59:59.000Z

    We propose a scheme for realizing two-qubit quantum phase gates with atoms in a thermal cavity. The photon-number dependent parts in the evolution operator are canceled with the assistant of a strong classical field. Thus the scheme is insensitive to the thermal field. In the scheme the detuning between the atoms and the cavity is equal to the atom-cavity coupling strength and thus the gates operate at a high speed, which is also important in view of decoherence. The scheme can be generalized to generate multiatom entangled states with a thermal cavity.

  17. Technique to eliminate helium induced weld cracking in stainless steels

    SciTech Connect (OSTI)

    Chin-An Wang; Chin, B.A. [Auburn Univ., AL (United States). Dept. of Materials Engineering; Grossbeck, M.L. [Oak Ridge National Lab., TN (United States)

    1992-12-31T23:59:59.000Z

    Experiments have shown that Type 316 stainless steel is susceptible to heat-affected-zone (HAZ) cracking upon cooling when welded using the gas tungsten arc (GTA) process under lateral constraint. The cracking has been hypothesized to be caused by stress-assisted helium bubble growth and rupture at grain boundaries. This study utilized an experimental welding setup which enabled different compressive stresses to be applied to the plates during welding. Autogenous GTA welds were produced in Type 316 stainless steel doped with 256 appm helium. The application of a compressive stress, 55 Mpa, during welding suppressed the previously observed catastrophic cracking. Detailed examinations conducted after welding showed a dramatic change in helium bubble morphology. Grain boundary bubble growth along directions parallel to the weld was suppressed. Results suggest that stress-modified welding techniques may be used to suppress or eliminate helium-induced cracking during joining of irradiated materials.

  18. automated thermal cycling: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    IGBT failure mode, due to thermal fatigue, is the solder cracks between the copper base plate and the Direct Boyer, Edmond 28 The effects of controlled thermal cycling on...

  19. EFFECT OF THERMAL PROCESSES ON COPPER-TIN ALLOYS FOR ZINC GETTERING

    SciTech Connect (OSTI)

    Korinko, P.; Golyski, M.

    2013-11-01T23:59:59.000Z

    A contamination mitigation plan was initiated to address the discovery of radioactive zinc‐65 in a glovebox. A near term solution was developed, installation of heated filters in the glovebox piping. This solution is effective at retaining the zinc in the currently contaminated area, but the gamma emitting contaminant is still present in a system designed for tritium beta. A project was initiated to develop a solution to contain the {sup 65}Zn in the furnace module. Copper and bronze (a Cu/Sn alloy) were found to be candidate materials to combine with zinc‐65 vapor, using thermodynamic calculations. A series of binary Cu/Sn alloys were developed (after determining that commercial alloys were unacceptable), that were found to be effective traps of zinc vapor. The task described in this report was undertaken to determine if the bronze substrates would retain their zinc gettering capability after being exposed to simulated extraction conditions with oxidizing and reducing gases. Pure copper and three bronze alloys were prepared, exposed to varying oxidation conditions from 250 to 450{degree}C, then exposed to varying reduction conditions in He-H{sub 2} from 250-450{degree}C, and finally exposed to zinc vapor at 350{degree}C for four hours. The samples were characterized using scanning electron microscopy, X-ray diffraction, differential thermal analysis, mass change, and visual observation. It was observed that the as fabricated samples and the reduced samples all retained their zinc gettering capacity while samples in the "as-oxidized" condition exhibited losses in zinc gettering capacity. Over the range of conditions tested, i.e., composition, oxidation temperature, and reduction temperature, no particular sample composition appeared better. Samples reduced at 350{degree}C exhibited the greatest zinc capacity, although there were some testing anomalies associated with these samples. This work clearly demonstrated that the zinc gettering was not adversely affected by exposure to simulated process conditions and a full scale lithium and zinc trap should be fabricated for testing in the Tritium Extraction Facility.

  20. Energy conservation in dissipative processes: Teacher expectations and strategies associated with imperceptible thermal energy

    E-Print Network [OSTI]

    Daane, Abigail R; Vokos, Stamatis; Scherr, Rachel E

    2014-01-01T23:59:59.000Z

    Research has demonstrated that many students and some teachers do not consistently apply the conservation of energy principle when analyzing mechanical scenarios. In observing elementary and secondary teachers engaged in learning activities that require tracking and conserving energy, we find that challenges to energy conservation often arise in dissipative scenarios in which kinetic energy transforms into thermal energy (e.g., a ball rolls to a stop). We find that teachers expect that when they can see the motion associated with kinetic energy, they should be able to perceive the warmth associated with thermal energy. Their expectations are violated when the warmth produced is imperceptible. In these cases, teachers reject the idea that the kinetic energy transforms to thermal energy. Our observations suggest that apparent difficulties with energy conservation may have their roots in a strong and productive association between forms of energy and their perceptible indicators. We see teachers resolve these ch...

  1. Thermal imaging measurement of lateral diffusivity and non-invasive material defect detection

    DOE Patents [OSTI]

    Sun, Jiangang (Westmont, IL); Deemer, Chris (Downers Grove, IL)

    2003-01-01T23:59:59.000Z

    A system and method for determining lateral thermal diffusivity of a material sample using a heat pulse; a sample oriented within an orthogonal coordinate system; an infrared camera; and a computer that has a digital frame grabber, and data acquisition and processing software. The mathematical model used within the data processing software is capable of determining the lateral thermal diffusivity of a sample of finite boundaries. The system and method may also be used as a nondestructive method for detecting and locating cracks within the material sample.

  2. Peridynamic model for fatigue cracking.

    SciTech Connect (OSTI)

    Silling, Stewart A.; Abe Askari (Boeing)

    2014-10-01T23:59:59.000Z

    The peridynamic theory is an extension of traditional solid mechanics in which the field equations can be applied on discontinuities, such as growing cracks. This paper proposes a bond damage model within peridynamics to treat the nucleation and growth of cracks due to cyclic loading. Bond damage occurs according to the evolution of a variable called the %22remaining life%22 of each bond that changes over time according to the cyclic strain in the bond. It is shown that the model reproduces the main features of S-N data for typical materials and also reproduces the Paris law for fatigue crack growth. Extensions of the model account for the effects of loading spectrum, fatigue limit, and variable load ratio. A three-dimensional example illustrates the nucleation and growth of a helical fatigue crack in the torsion of an aluminum alloy rod.

  3. The origin of thermal component in the transverse momentum spectra in high energy hadronic processes

    E-Print Network [OSTI]

    Alexander A. Bylinkin; Dmitri E. Kharzeev; Andrei A. Rostovtsev

    2014-07-15T23:59:59.000Z

    The transverse momentum spectra of hadrons produced in high energy collisions can be decomposed into two components: the exponential ("thermal") and the power ("hard") ones. Recently, the H1 Collaboration has discovered that the relative strength of these two components in Deep Inelastic Scattering depends drastically upon the global structure of the event - namely, the exponential component is absent in the diffractive events characterized by a rapidity gap. We discuss the possible origin of this effect, and speculate that it is linked to confinement. Specifically, we argue that the thermal component is due to the effective event horizon introduced by the confining string, in analogy to the Hawking-Unruh effect. In diffractive events, the $t$-channel exchange is color-singlet and there is no fragmenting string -- so the thermal component is absent. The slope of the soft component of the hadron spectrum in this picture is determined by the saturation momentum that drives the deceleration in the color field, and thus the Hawking-Unruh temperature. We analyze the data on non-diffractive $pp$ collisions and find that the slope of the thermal component of the hadron spectrum is indeed proportional to the saturation momentum.

  4. Degradation of Structural Alloys Under Thermal Insulation

    E-Print Network [OSTI]

    McIntyre, D. R.

    1984-01-01T23:59:59.000Z

    Wet thermal insulation may actively degrade steel and stainless steel structures by general corrosion or stress-corrosion cracking. Two different mechanisms of water ingress into insulation are discussed; flooding from external sources...

  5. Degradation of Structural Alloys Under Thermal Insulation 

    E-Print Network [OSTI]

    McIntyre, D. R.

    1984-01-01T23:59:59.000Z

    Wet thermal insulation may actively degrade steel and stainless steel structures by general corrosion or stress-corrosion cracking. Two different mechanisms of water ingress into insulation are discussed; flooding from external sources...

  6. Oxidation-resistant, solution-processed plasmonic Ni nanochain-SiO{sub x} (x?thermal absorbers

    SciTech Connect (OSTI)

    Yu, Xiaobai; Wang, Xiaoxin; Liu, Jifeng, E-mail: Jifeng.Liu@dartmouth.edu [Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, New Hampshire 03755 (United States); Zhang, Qinglin [Department of Chemical and Materials Engineering, University of Kentucky, 177 F. Paul Anderson Tower, Lexington, Kentucky 40506 (United States); Li, Juchuan [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    2014-08-21T23:59:59.000Z

    Metal oxidation at high temperatures has long been a challenge in cermet solar thermal absorbers, which impedes the development of atmospherically stable, high-temperature, high-performance concentrated solar power (CSP) systems. In this work, we demonstrate solution-processed Ni nanochain-SiO{sub x} (x?thermal absorbers that exhibit a strong anti-oxidation behavior up to 600?°C in air. The thermal stability is far superior to previously reported Ni nanoparticle-Al{sub 2}O{sub 3} selective solar thermal absorbers, which readily oxidize at 450?°C. The SiO{sub x} (x?processed by low-cost solution-chemical methods for future generations of CSP systems.

  7. Weld solidification cracking in 304 to 204L stainless steel

    SciTech Connect (OSTI)

    Hochanadel, Patrick W [Los Alamos National Laboratory; Lienert, Thomas J [Los Alamos National Laboratory; Martinez, Jesse N [Los Alamos National Laboratory; Johnson, Matthew Q [Los Alamos National Laboratory

    2010-09-15T23:59:59.000Z

    A series of annulus welds were made between 304 and 304L stainless steel coaxial tubes using both pulsed laser beam welding (LBW) and pulsed gas tungsten arc welding (GTAW). In this application, a change in process from pulsed LBW to pulsed gas tungsten arc welding was proposed to limit the possibility of weld solidification cracking since weldability diagrams developed for GTAW display a greater range of compositions that are not crack susceptible relative to those developed for pulsed LBW. Contrary to the predictions of the GTAW weldability diagram, cracking was found.This result was rationalized in terms of the more rapid solidification rate of the pulsed gas tungsten arc welds. In addition, for the pulsed LBW conditions, the material compositions were predicted to be, by themselves, 'weldable' according to the pulsed LBW weldability diagram. However, the composition range along the tie line connecting the two compositions passed through the crack susceptible range. Microstructurally, the primary solidification mode (PSM) of the material processed with higher power LBW was determined to be austenite (A), while solidification mode of the materials processed with lower power LBW apparently exhibited a dual PSM of both austenite (A) and ferrite-austenite (FA) within the same weld. The materials processed by pulsed GTAW showed mostly primary austenite solidification, with some regions of either primary austenite-second phase ferrite (AF) solidification or primary ferrite-second phase austenite (FA) solidification. This work demonstrates that variations in crack susceptibility may be realized when welding different heats of 'weldable' materials together, and that slight variations in processing can also contribute to crack susceptibility.

  8. Weld solidification cracking in 304 to 304L stainless steel

    SciTech Connect (OSTI)

    Hochanadel, Patrick W [Los Alamos National Laboratory; Lienert, Thomas J [Los Alamos National Laboratory; Martinez, Jesse N [Los Alamos National Laboratory; Martinez, Raymond J [Los Alamos National Laboratory; Johnson, Matthew Q [Los Alamos National Laboratory

    2010-01-01T23:59:59.000Z

    A series of annulus welds were made between 304 and 304L stainless steel coaxial tubes using both pulsed laser beam welding (LBW) and pulsed gas tungsten arc welding (GTAW). In this application, a change in process from pulsed LBW to pulsed gas tungsten arc welding was proposed to limit the possibility of weld solidification cracking since weldability diagrams developed for GTAW display a greater range of compositions that are not crack susceptible relative to those developed for pulsed LBW. Contrary to the predictions of the GTAW weldability diagram, cracking was found. This result was rationalized in terms of the more rapid solidification rate of the pulsed gas tungsten arc welds. In addition, for the pulsed LBW conditions, the material compositions were predicted to be, by themselves, 'weldable' according to the pulsed LBW weldability diagram. However, the composition range along the tie line connecting the two compositions passed through the crack susceptible range. Microstructurally, the primary solidification mode (PSM) of the material processed with higher power LBW was determined to be austenite (A), while solidification mode of the materials processed with lower power LBW apparently exhibited a dual PSM of both austenite (A) and ferrite-austenite (FA) within the same weld. The materials processed by pulsed GT A W showed mostly primary austenite solidification, with some regions of either primary austenite-second phase ferrite (AF) solidification or primary ferrite-second phase austenite (FA) solidification. This work demonstrates that variations in crack susceptibility may be realized when welding different heats of 'weldable' materials together, and that slight variations in processing can also contribute to crack susceptibility.

  9. Thermal Energy Storage/Heat Recovery and Energy Conservation in Food Processing 

    E-Print Network [OSTI]

    Combes, R. S.; Boykin, W. B.

    1980-01-01T23:59:59.000Z

    Modern food processing operations often require that the temperature of the processed foodstuff be raised or lowered. These operations result in energy consumption by refrigeration or heating systems, and a portion of this energy can be recovered...

  10. 12.11.2014bo Akademi Univ -Thermal and Flow Engineering Piispankatu 8, 20500 Turku 1/32 4. Refrigeration process comparison;

    E-Print Network [OSTI]

    Zevenhoven, Ron

    . Refrigeration process comparison; process equipment Ron Zevenhoven Åbo Akademi University Themal and Flow") Refrigeration course # 424503.0 v. 2014 ÅA 424503 Refrigeration / Kylteknik 12.11.2014Åbo Akademi Univ - Thermal and Flow Engineering Piispankatu 8, 20500 Turku 2/32 4.1 Refrigeration process comparison #12;12.11.2014Åbo

  11. Process sensing and metrology in gate oxide growth by rapid thermal chemical vapor deposition from SiH4 and N2O

    E-Print Network [OSTI]

    Rubloff, Gary W.

    Process sensing and metrology in gate oxide growth by rapid thermal chemical vapor deposition from for Advanced Electronic Materials Processing, North Carolina State University, Raleigh, North Carolina 27695-7920 Received 7 January 1999; accepted 21 May 1999 Active sampling mass spectrometry has been used for process

  12. Hydrocarbon cracking with yttrium exchanged zeolite y catalyst

    SciTech Connect (OSTI)

    Lochow, C.F.; Kovacs, D.B.

    1987-05-12T23:59:59.000Z

    A process is described for cracking a gas oil boiling range hydrocarbon feedstock comprising the step of contacting the feedstock in a catalytic cracking zone under catalytic cracking conditions to produce convulsion products comprising gasoline with a catalyst composition. The process comprises: a Y crystalline aluminosilicate zeolite, having the structure of faujasite and having uniform pore diameters and a silica to alumina mole ratio of at least about 5; an inorganic oxide matrix; and the zeolite having been ion exchanged with a mixture of rare earths prior to compositing with the matrix; and the zeolite having been subsequently further ion exchanged with yttrium following compositing with the matrix, whereby the catalyst composition contains 0.30 to 3.0 wt% yttrium.

  13. Method for fabrication of crack-free ceramic dielectric films

    DOE Patents [OSTI]

    Ma, Beihai; Balachandran, Uthamalingam; Chao, Sheng; Liu, Shanshan; Narayanan, Manoj

    2014-02-11T23:59:59.000Z

    The invention provides a process for forming crack-free dielectric films on a substrate. The process comprise the application of a dielectric precursor layer of a thickness from about 0.3 .mu.m to about 1.0 .mu.m to a substrate. The deposition is followed by low temperature heat pretreatment, prepyrolysis, pyrolysis and crystallization step for each layer. The deposition, heat pretreatment, prepyrolysis, pyrolysis and crystallization are repeated until the dielectric film forms an overall thickness of from about 1.5 .mu.m to about 20.0 .mu.m and providing a final crystallization treatment to form a thick dielectric film. Also provided was a thick crack-free dielectric film on a substrate, the dielectric forming a dense thick crack-free dielectric having an overall dielectric thickness of from about 1.5 .mu.m to about 20.0 .mu.m.

  14. Development of reduced crude cracking catalysts

    SciTech Connect (OSTI)

    Hettinger, W.P. Jr. (Ashland Petroleum Company, KY (USA))

    1987-08-01T23:59:59.000Z

    In 1974 OPEC imposed an embargo on oil to the United States and caused a rapid rise in the price of a barrel of oil. At the time of the embargo, Ashland imported a considerable portion of its oil from the Middle East, thus raising the question of oil availability. As the problem increased in severity, Messrs. George Meyer, Oliver Zandona and Llyod Busch, began to explore alternative ways of squeezing more product from a given barrel of crude. After considering many alternatives, they arrived at the innovative thought that it might be possible to catalytically crack the 1050{degree}F plus fraction of the barrel directly to gasoline which would in effect, give them an additional volume of crude oil. Also, if vacuum fractionation were eliminated and if the entire 650{degree}F plus (reduced crude) portion of the barrel processed, this would further reduce operating costs. With these objectives and some new process innovations in mind, they began reduced crude cracking experimentation in a small 12,000 B/D FCC operating unit at Louisville. It was from these goals, concepts and a small operating unit, that the RCC process was born.

  15. Parallel interacting edge cracks under pure bending

    E-Print Network [OSTI]

    Moran, Ivan

    1991-01-01T23:59:59.000Z

    specimens. . . 66 Table 6. 4 a SIFs for interactive cracks. Position 14. . 73 Table 6. 4 b SIFs for interactive cracks. Position 24 . . 79 Table 6. 4 c SIFs for interactive cracks. Position 13. . 83 Table 6. 5 a K~ff for position 14 Table 6. 5 b K... Table 5. 3 Models Dimensions SPECIMEN MODEL 1 MODEL 2 Length L (inches) Dimension m (in) 6. 50 6. 50 1. 25 1. 25 Spec. Width H (in) 1. 100 1. 276 Thickness t (in) 0. 238 0. 238 Crack Angle p (o) 90 54 Crack Width c (in) Crack Length a (in) 0...

  16. Influence of thermal history on the mechanical properties of carbon fiber-acrylate composites cured by electron beam and thermal processes

    SciTech Connect (OSTI)

    Vautard, Frederic [ORNL] [ORNL; Ozcan, Soydan [ORNL] [ORNL; Poland, Laura E [ORNL] [ORNL; Meyer III, Harry M [ORNL] [ORNL

    2013-01-01T23:59:59.000Z

    The mechanical properties of an acrylate resin and its carbon fiber composite, as well as the adhesion strength between them, were characterized in the case of thermal and electron beam curing. The thermal history during the cure was also recorded. It was shown that the properties of the matrix were similar but that the thermal history during the curing had a direct influence on the type of interactions that were generated at the interface, leading to different level of adhesion strength and level of performance for the associated composites. In the case of a thermal cure, the thermal profile allowed the generation of covalent bonding at the interface, leading to a high level of adhesion strength, which was not the case for electron beam curing. The thermal history during the cure appeared to be a determining parameter for the level of performance of composites cured by electron beam.

  17. Multiple use of waste catalysts with and without regeneration for waste polymer cracking

    SciTech Connect (OSTI)

    Salmiaton, A., E-mail: mie@eng.upm.edu.my [Department of Chemical and Environmental Engineering, Faculty of Engineering, Universiti Putra Malaysia (UPM), 43400 UPM Serdang, Selangor (Malaysia); Garforth, A.A. [School of Chemical Engineering and Analytical Science, University of Manchester, P.O. Box 88, Sackville Street, Manchester M60 1QD (United Kingdom)

    2011-06-15T23:59:59.000Z

    Waste plastics contain a substantial number of valuable chemicals. The wastes from post-consumer as well as from industrial production can be recycled to valuable chemical feedstock, which can be used in refineries and/or petrochemical industries. This chemical recycling process is an ideal approach in recycling the waste for a better environment. Polymer cracking using a laboratory fluidised bed reactor concentrated on the used highly contaminated catalyst, E-Cat 2. Even though E-Cat 2 had low activity due to fewer acid sites, the products yielded were similar with amorphous ASA and were far better than thermal cracking. The high levels of heavy metals, namely nickel and vanadium, deposited during their lifetime as an FCC catalyst, did not greatly affect on the catalyst activity. It was also shown that E-Cat 2 could be used with and without regeneration. Although there was more deactivation when there was no regeneration step, the yield of gases (C{sub 2}-C{sub 7}) remained fairly constant. For the first time, these results indicate that 'waste' FCC catalyst (E-Cat) is a good candidate for future feedstock recycling of polymer waste. The major benefits of using E-Cat are a low market price, the ability to tolerate reuse and regeneration capacity.

  18. EFFECT OF ELECTROLYZER CONFIGURATION AND PERFORMANCE ON HYBRID SULFUR PROCESS NET THERMAL EFFICIENCY

    SciTech Connect (OSTI)

    Gorensek, M

    2007-03-16T23:59:59.000Z

    Hybrid Sulfur cycle is gaining popularity as a possible means for massive production of hydrogen from nuclear energy. Several different ways of carrying out the SO{sub 2}-depolarized electrolysis step are being pursued by a number of researchers. These alternatives are evaluated with complete flowsheet simulations and on a common design basis using Aspen Plus{trademark}. Sensitivity analyses are performed to assess the performance potential of each configuration, and the flowsheets are optimized for energy recovery. Net thermal efficiencies are calculated for the best set of operating conditions for each flowsheet and the results compared. This will help focus attention on the most promising electrolysis alternatives. The sensitivity analyses should also help identify those features that offer the greatest potential for improvement.

  19. Investigations in cool thermal storage: storage process optimization and glycol sensible storage enhancement

    E-Print Network [OSTI]

    Abraham, Michaela Marie

    1993-01-01T23:59:59.000Z

    process. This method minimizes the amount of required compressor work, per unit mass of ice produced, by adjusting evaporating temperatures and/or heat exchanger size. The heat transfer irreversibility is also used to exemplify the usefulness...

  20. Controlled Thermal-Mechanical Processing of Tubes and Pipes for Enhanced Manufacturing and Performance

    SciTech Connect (OSTI)

    Kolarik, Robert V.

    2005-11-11T23:59:59.000Z

    The Alloy Steel Business of The Timken Company won an award for the controlled thermo-mechanical processing (CTMP) project and assembled a strong international public/private partnership to execute the project. The premise of the CTMP work was to combine Timken's product understanding with its process expertise and knowledge of metallurgical and deformation fundamentals developed during the project to build a predictive process design capability. The CTMP effort succeeded in delivering a pc-based capability in the tube optimization model, with a virtual pilot plant (VPP) feature to represent the desired tube making process to predict the resultant microstructure tailored for the desired application. Additional tasks included a system for direct, online measurement of grain size and demonstration of application of CTMP via robotically enhanced manufacturing.

  1. High-temperature microfluidic systems for thermally-efficient fuel processing

    E-Print Network [OSTI]

    Arana, Leonel R

    2003-01-01T23:59:59.000Z

    Miniaturized fuel cell systems have the potential to outperform batteries in powering a variety of portable electronics. The key to this technology is the ability to efficiently process an easily-stored, energy-dense fuel. ...

  2. Progress in Statistical Crack Mechanics : An Approach to Initiation

    SciTech Connect (OSTI)

    Dienes, John K.; Middleditch, J. (John); Kershner, James D.; Zuo, Q. K. (Qiuhai K.); Starobin, A. J. (Andre J.)

    2002-01-01T23:59:59.000Z

    We have developed a general theory for the formation of hot spots from defects in explosives and propellants, and applied the theory to a variety of issues concerning the sensitivity of reactive materials. The defects of greatest concern in PBXs are cracks formed in the explosive grains, which are normally brittle. The theory accounts for the opening, shear, growth, and coalescence of cracks. In addition, the theory accounts for the heating caused by interfacial friction in closed (shear) cracks and the ignition process that results. Heat conduction and chemical reactions are treated on a smaller spatial scale than the overall continuum response; this is accomplished in the numerical (FEA) simulation with a sub-grid model. In previous work we have shown the feasibility of using this approach to model explosions that result from relatively mild insults, where many other hot-spot mechanisms fail. This paper addresses some of the complications that arise as mechanical failure and heating are examined in greater detail, including the effects of crack orientation, friction, melting, viscosity in molten regions, radial crack formation via a new approach to percolation theory, and 3-D effects.

  3. CrackTree: Automatic crack detection from pavement images Qin Zou a,b,c,

    E-Print Network [OSTI]

    Wang, Song

    CrackTree: Automatic crack detection from pavement images Qin Zou a,b,c, , Yu Cao c , Qingquan Li b t Pavement cracks are important information for evaluating the road condition and conducting the neces- sary pavement images. In practice, crack detection is a very challenging problem because of (1) low con- trast

  4. Boundary integral formulation for interfacial cracks in thermodiffusive bimaterials

    E-Print Network [OSTI]

    L. Morini; A. Piccolroaz

    2015-04-29T23:59:59.000Z

    An original boundary integral formulation is proposed for the problem of a semi-infinite crack at the interface between two dissimilar elastic materials in the presence of heat flows and mass diffusion. Symmetric and skew-symmetric weight function matrices are used together with a generalized Betti's reciprocity theorem in order to derive a system of integral equations that relate the applied loading, the temperature and mass concentration fields, the heat and mass fluxes on the fracture surfaces and the resulting crack opening. The obtained integral identities can have many relevant applications, such as for the modelling of crack and damage processes at the interface between different components in electrochemical energy devices characterized by multi-layered structures (solid oxide fuel cells and lithium ions batteries).

  5. Original article Stem cracks in Norway spruce

    E-Print Network [OSTI]

    Boyer, Edmond

    Original article Stem cracks in Norway spruce in southern Scandinavia: causes and consequences Garpenberg, Sweden (Received 1st September 1992; accepted 17 June 1993) Summary — Stem cracks in Norway;INTRODUCTION Background During this century, the widespread crack- ing of Norway spruce (Picea abies L Karst

  6. Cracking Resistance of Asphalt Rubber Mix Versus

    E-Print Network [OSTI]

    Mobasher, Barzin

    . crack length curve for KR #12;Load vs. CMOD 0.0 0.5 1.0 1.5 2.0 Crack mouth opening, mm 0 500 1000 1500 non-linear fracture mechanics ·Compliance approach ·R-Curve approach #12;Conventional Fatigue Testing factor R-Curve approach Resistance to initiation & growth of cracks Evaluates fracture toughness

  7. Interaction between corrosion crack width and steel loss in RC beams corroded under load

    SciTech Connect (OSTI)

    Malumbela, Goitseone, E-mail: malumbela@mopipi.ub.b [Dpt. of Civil Eng., Univ. of Cape Town, Private Bag X3, Rondebosch, 7700 (South Africa); Alexander, Mark; Moyo, Pilate [Dpt. of Civil Eng., Univ. of Cape Town, Private Bag X3, Rondebosch, 7700 (South Africa)

    2010-09-15T23:59:59.000Z

    This paper presents results and discussions on an experimental study conducted to relate the rate of widening of corrosion cracks with the pattern of corrosion cracks as well as the level of steel corrosion for RC beams (153 x 254 x 3000 mm) that were corroded whilst subjected to varying levels of sustained loads. Steel corrosion was limited to the tensile reinforcement and to a length of 700 mm at the centre of the beams. The rate of widening of corrosion cracks as well as strains on uncracked faces of RC beams was constantly monitored during the corrosion process, along the corrosion region and along other potential cracking faces of beams using a demec gauge. The distribution of the gravimetric mass loss of steel along the corrosion region was measured at the end of the corrosion process. The results obtained showed that: the rate of widening of each corrosion crack is dependent on the overall pattern of the cracks whilst the rate of corrosion is independent of the pattern of corrosion cracks. A mass loss of steel of 1% was found to induce a corrosion crack width of about 0.04 mm.

  8. Iron-Based Amorphous Coatings Produced by HVOF Thermal Spray Processing-Coating Structure and Properties

    SciTech Connect (OSTI)

    Beardsley, M B

    2008-03-26T23:59:59.000Z

    The feasibility to coat large SNF/HLW containers with a structurally amorphous material (SAM) was demonstrated on sub-scale models fabricated from Type 316L stainless steel. The sub-scale model were coated with SAM 1651 material using kerosene high velocity oxygen fuel (HVOF) torch to thicknesses ranging from 1 mm to 2 mm. The process parameters such as standoff distance, oxygen flow, and kerosene flow, were optimized in order to improve the corrosion properties of the coatings. Testing in an electrochemical cell and long-term exposure to a salt spray environment were used to guide the selection of process parameters.

  9. doi: 10.3176/oil.2008.2.02 © 2008 Estonian Academy Publishers THERMAL PROCESSING OF POLYVINYLCHLORIDE WASTE WITH OIL SHALE ASH TO CAPTURE

    E-Print Network [OSTI]

    V. Oja; A. Elenurm; I. Rohtla; E. Tearo; E. Tali

    This study is concerned with thermal processing of polyvinylchloride (PVC) in the presence of alkaline oil shale ash. Solid heat carrier (Galoter process)-type oil shale retorting units, where the feedstock is heated by mixing with ash from retorted feed-stock combustion, are potentially an

  10. Investigation of HNCO isomers formation in ice mantles by UV and thermal processing: an experimental approach

    E-Print Network [OSTI]

    Jiménez-Escobar, A; Caro, G M Muñoz; Cernicharo, J; Marcelino, N

    2014-01-01T23:59:59.000Z

    Current gas phase models do not account for the abundances of HNCO isomers detected in various environments, suggesting a formation in icy grain mantles. We attempted to study a formation channel of HNCO and its possible isomers by vacuum-UV photoprocessing of interstellar ice analogues containing H$_2$O, NH$_3$, CO, HCN, CH$_3$OH, CH$_4$, and N$_2$ followed by warm-up, under astrophysically relevant conditions. Only the H$_2$O:NH$_3$:CO and H$_2$O:HCN ice mixtures led to the production of HNCO species. The possible isomerization of HNCO to its higher energy tautomers following irradiation or due to ice warm-up has been scrutinized. The photochemistry and thermal chemistry of H$_2$O:NH$_3$:CO and H$_2$O:HCN ices was simulated using the Interstellar Astrochemistry Chamber (ISAC), a state-of-the-art ultra-high-vacuum setup. The ice was monitored in situ by Fourier transform mid-infrared spectroscopy in transmittance. A quadrupole mass spectrometer (QMS) detected the desorption of the molecules in the gas phase....

  11. Polyx multicrystalline silicon solar cells processed by PF+5 unanalysed ion implantation and rapid thermal annealing

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    695 Polyx multicrystalline silicon solar cells processed by PF+5 unanalysed ion implantation of terrestrial solar cells as compared to classical furnace or pulsed laser annealing. Unfortunately, drawbacks for the fabrication of solar cells. It offers the possibility of achieving strong reduction of cell cost in spite

  12. A low thermal impact annealing process for SiO{sub 2}-embedded Si nanocrystals with optimized interface quality

    SciTech Connect (OSTI)

    Hiller, Daniel, E-mail: daniel.hiller@imtek.uni-freiburg.de; Gutsch, Sebastian; Hartel, Andreas M.; Zacharias, Margit [IMTEK, Faculty of Engineering, Albert-Ludwigs-University Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg (Germany); Löper, Philipp [Fraunhofer ISE, Heidenhofstr. 2, 79110 Freiburg (Germany); Gebel, Thoralf [DTF Technology GmbH, Am Promigberg 16, 01108 Dresden (Germany)

    2014-04-07T23:59:59.000Z

    Silicon nanocrystals (Si NCs) for 3rd generation photovoltaics or optoelectronic applications can be produced by several industrially compatible physical or chemical vapor deposition technologies. A major obstacle for the integration into a fabrication process is the typical annealing to form and crystallize these Si quantum dots (QDs) which involves temperatures ?1100??°C for 1?h. This standard annealing procedure allows for interface qualities that correspond to more than 95% dangling bond defect free Si NCs. We study the possibilities to use rapid thermal annealing (RTA) and flash lamp annealing to crystallize the Si QDs within seconds or milliseconds at high temperatures. The Si NC interface of such samples exhibits huge dangling bond defect densities which makes them inapplicable for photovoltaics or optoelectronics. However, if the RTA high temperature annealing is combined with a medium temperature inert gas post-annealing and a H{sub 2} passivation, luminescent Si NC fractions of up to 90% can be achieved with a significantly reduced thermal load. A new figure or merit, the relative dopant diffusion length, is introduced as a measure for the impact of a Si NC annealing procedure on doping profiles of device structures.

  13. Prediction of crack propagation paths in the unit cell of SOFC stacks

    SciTech Connect (OSTI)

    Joulaee, N.; Makradi, A.; Ahzi, Said; Khaleel, Mohammad A.; Koeppel, Brian J.

    2009-08-01T23:59:59.000Z

    Planar Solid Oxide Fuel Cells (SOFC) stacks are multi-material layered systems with different thermo-mechanical properties. Due to their severe thermal loading, these layers have to meet high demands to preserve their mechanical integrity without initiation and propagation of fracture. Here, we focus on a typical unit cell of the stack which consists of positive electrode-electrolyte-negative electrode (PEN). Based on the mechanical properties of each layer and their interfaces, an energy criterion as a function of crack length is used for the prediction of possible crack extensions in the PEN. This criterion is a pure local criterion, independent of applied loads and geometry of the specimen. An analysis of the competition between crack deflections in the interfaces and crack penetration in layers is presented.

  14. Avoiding Carbon Bed Hot Spots in Thermal Process Off-Gas Systems

    SciTech Connect (OSTI)

    Nick Soelberg; Joe Enneking

    2011-05-01T23:59:59.000Z

    Mercury has had various uses in nuclear fuel reprocessing and other nuclear processes, and so is often present in radioactive and mixed (radioactive and hazardous) wastes. Test programs performed in recent years have shown that mercury in off-gas streams from processes that treat radioactive wastes can be controlled using fixed beds of activated sulfur-impregnated carbon, to levels low enough to comply with air emission regulations such as the Hazardous Waste Combustor (HWC) Maximum Achievable Control Technology (MACT) standards. Carbon bed hot spots or fires have occurred several times during these tests, and also during a remediation of tanks that contained mixed waste. Hot spots occur when localized areas in a carbon bed become heated to temperatures where oxidation occurs. This heating typically occurs due to heat of absoption of gas species onto the carbon, but it can also be caused through external means such as external heaters used to heat the carbon bed vessel. Hot spots, if not promptly mitigated, can grow into bed fires. Carbon bed hot spots and fires must be avoided in processes that treat radioactive and mixed waste. Hot spots are detected by (a) monitoring in-bed and bed outlet gas temperatures, and (b) more important, monitoring of bed outlet gas CO concentrations. Hot spots are mitigated by (a) designing for appropriate in-bed gas velocity, for avoiding gas flow maldistribution, and for sufficient but not excessive bed depth, (b) appropriate monitoring and control of gas and bed temperatures and compositions, and (c) prompt implementation of corrective actions if bed hot spots are detected. Corrective actions must be implemented quickly if bed hot spots are detected, using a graded approach and sequence starting with corrective actions that are simple, quick, cause the least impact to the process, and are easiest to recover from.

  15. Oxidation resistant high temperature thermal cycling resistant coatings on silicon-based substrates and process for the production thereof

    DOE Patents [OSTI]

    Sarin, V.K.

    1990-08-21T23:59:59.000Z

    An oxidation resistant, high temperature thermal cycling resistant coated ceramic article for ceramic heat engine applications is disclosed. The substrate is a silicon-based material, i.e. a silicon nitride- or silicon carbide-based monolithic or composite material. The coating is a graded coating of at least two layers: an intermediate AlN or Al[sub x]N[sub y]O[sub z] layer and an aluminum oxide or zirconium oxide outer layer. The composition of the coating changes gradually from that of the substrate to that of the AlN or Al[sub x]N[sub y]O[sub z] layer and further to the composition of the aluminum oxide or zirconium oxide outer layer. Other layers may be deposited over the aluminum oxide layer. A CVD process for depositing the graded coating on the substrate is also disclosed.

  16. Supporting technology for enhanced oil recovery: Sixth amendment and extension to Annex IV enhanced oil recovery thermal processes

    SciTech Connect (OSTI)

    Reid, T.B. (USDOE Bartlesville Project Office, OK (United States)); Rivas, O. (INTEVEP, Filial de Petroleos de Venezuela, SA, Caracas (Venezuela))

    1991-10-01T23:59:59.000Z

    This report contains the results of efforts under the six tasks of the Sixth Amendment and Extension of Annex 4, Enhanced Oil Recovery Thermal Processes of the Venezuela/USA Agreement. The report is presented in sections (for each of the 6 tasks) and each section contains one or more reports prepared by various individuals or groups describing the results of efforts under each of the tasks. A statement of each task, taken from the agreement, is presented on the first page of each section. The tasks are numbered 44 through 49. Tasks are: DOE-SUPRI-laboratory research on steam foam, CAT-SCAN, and in-situ combustion; INTEVEP-laboratory research and field projects on steam foam; DOE-NIPER-laboratory research and field projects light oil steam flooding; INTEVEP-laboratory research and field studies on wellbore heat losses; DOE-LLNL-laboratory research and field projects on electromagnetic induction tomography; INTEVEP-laoboratory research on mechanistic studies.

  17. Saber's heavy oil cracking refinery project

    SciTech Connect (OSTI)

    Benefield, C.S.; Glasscock, W.L.

    1983-03-01T23:59:59.000Z

    Perhaps more than any other industry, petroleum refining has been subjected to the radical swings in business and political climates of the past several decades. Because of the huge investments and long lead times to construct refining facilities, stable government policies, predictable petroleum prices, secure feedstock supplies and markets, and reliable cost estimates are necessary ingredients to effectively plan new refinery projects. However, over the past ten years the political and economic climates have provided anything but these conditions. Yet, refiners have demonstrated a willingness to undertake risks by continuing to expand and modernize their refineries. The refining business -- just as most businesses -- responds to economic incentives. These incentives, when present, result in new technology and capacity additions. In the 1940's, significant technology advances were commercialized to refine higher-octane motor gasolines. Such processes as continuous catalytic cracking (Houdry Process Corporation), fluid catalytic cracking (Standard Oil Development Company), HF alkylation (UOP and Phillips Petroleum Company), and catalytic reforming (UOP) began to supply a growing gasoline market, generated from the war effort and the ever increasing numbers of automobiles on the road. The post-war economy of the 1950's and 1960's further escalated demand for refined products, products which had to meet higher performance specifications and be produced from a wider range of raw materials. The refining industry met the challenge by introducing hydro-processing technology, such as hydrocracking developed in 1960. But, the era must be characterized by the large crude processing capacity additions, required to meet demand from the rapidly expanding U.S. economy. In 1950, refining capacity was 6.2 million BPD. By 1970, capacity had grown to 11.9 million BPD, an increase of 91%.

  18. The effect of complex inclusion geometries on fracture and crack coalescence behavior in brittle material

    E-Print Network [OSTI]

    Morgan, Stephen Philip

    2011-01-01T23:59:59.000Z

    This research study investigates the cracking processes in a brittle material associated with inclusions of varying shape, orientation and materials. Specifically, this study summarizes a series of uniaxial compression ...

  19. Environmentally assisted cracking of LWR materials

    SciTech Connect (OSTI)

    Chopra, O.K.; Chung, H.M.; Kassner, T.F.; Shack, W.J.

    1995-12-01T23:59:59.000Z

    Research on environmentally assisted cracking (EAC) of light water reactor materials has focused on (a) fatigue initiation in pressure vessel and piping steels, (b) crack growth in cast duplex and austenitic stainless steels (SSs), (c) irradiation-assisted stress corrosion cracking (IASCC) of austenitic SSs, and (d) EAC in high- nickel alloys. The effect of strain rate during different portions of the loading cycle on fatigue life of carbon and low-alloy steels in 289{degree}C water was determined. Crack growth studies on wrought and cast SSs have been completed. The effect of dissolved-oxygen concentration in high-purity water on IASCC of irradiated Type 304 SS was investigated and trace elements in the steel that increase susceptibility to intergranular cracking were identified. Preliminary results were obtained on crack growth rates of high-nickel alloys in water that contains a wide range of dissolved oxygen and hydrogen concentrations at 289 and 320{degree}C. The program on Environmentally Assisted Cracking of Light Water Reactor Materials is currently focused on four tasks: fatigue initiation in pressure vessel and piping steels, fatigue and environmentally assisted crack growth in cast duplex and austenitic SS, irradiation-assisted stress corrosion cracking of austenitic SSs, and environmentally assisted crack growth in high-nickel alloys. Measurements of corrosion-fatigue crack growth rates (CGRs) of wrought and cast stainless steels has been essentially completed. Recent progress in these areas is outlined in the following sections.

  20. Thermal barrier coating resistant to sintering

    DOE Patents [OSTI]

    Subramanian, Ramesh; Seth, Brig B.

    2005-08-23T23:59:59.000Z

    A device (10) is made, having a ceramic thermal barrier coating layer (16) characterized by a microstructure having gaps (18) with a sintering inhibiting material (22) disposed on the columns (20) within the gaps (18). The sintering resistant material (22) is stable over the range of operating temperatures of the device (10), is not soluble with the underlying ceramic layer (16) and is applied by a process that is not an electron beam physical vapor deposition process. The sintering inhibiting material (22) has a morphology adapted to improve the functionality of the sintering inhibiting material (22), characterized as continuous, nodule, rivulet, grain, crack, flake and combinations thereof and being disposed within at least some of the vertical and horizontal gaps.

  1. Prediction of reinforcement corrosion using corrosion induced cracks width in corroded reinforced concrete beams

    SciTech Connect (OSTI)

    Khan, Inamullah; François, Raoul [Université de Toulouse, UPS, INSA, LMDC (Laboratoire Matériaux et Durabilité des Constructions), 135, Avenue de Rangueil, F-31077 Toulouse (France)] [Université de Toulouse, UPS, INSA, LMDC (Laboratoire Matériaux et Durabilité des Constructions), 135, Avenue de Rangueil, F-31077 Toulouse (France); Castel, Arnaud [Centre for Infrastructure Engineering and Safety, School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW (Australia)] [Centre for Infrastructure Engineering and Safety, School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW (Australia)

    2014-02-15T23:59:59.000Z

    This paper studies the evolution of reinforcement corrosion in comparison to corrosion crack width in a highly corroded reinforced concrete beam. Cracking and corrosion maps of the beam were drawn and steel reinforcement was recovered from the beam to observe the corrosion pattern and to measure the loss of mass of steel reinforcement. Maximum steel cross-section loss of the main reinforcement and average steel cross-section loss between stirrups were plotted against the crack width. The experimental results were compared with existing models proposed by Rodriguez et al., Vidal et al. and Zhang et al. Time prediction models for a given opening threshold are also compared to experimental results. Steel cross-section loss for stirrups was also measured and was plotted against the crack width. It was observed that steel cross-section loss in the stirrups had no relationship with the crack width of longitudinal corrosion cracks. -- Highlights: •Relationship between crack and corrosion of reinforcement was investigated. •Corrosion results of natural process and then corresponds to in-situ conditions. •Comparison with time predicting model is provided. •Prediction of load-bearing capacity from crack pattern was studied.

  2. Experimental investigation of an innovative thermochemical process operating with a hydrate salt and moist air for thermal storage of solar

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    and moist air for thermal storage of solar energy: global performance Benoit Michela, *, Nathalie Mazeta-gas reaction, hydration, thermal storage, seasonal storage, solar energy * Corresponding author: E-mail: mazet Der energy density of the reactor, Jm -3 thermal conductivity, Wm -1 .K -1 G reactive gas

  3. Modeling shear failure and permeability enhancement due to coupled Thermal-Hydrological-Mechanical processes in Enhanced Geothermal Reservoirs

    SciTech Connect (OSTI)

    Kelkar, Sharad [Los Alamos National Laboratory

    2011-01-01T23:59:59.000Z

    The connectivity and accessible surface area of flowing fractures, whether natural or man-made, is possibly the single most important factor, after temperature, which determines the feasibility of an Enhanced Geothermal System (EGS). Rock deformation and in-situ stress changes induced by injected fluids can lead to shear failure on preexisting fractures which can generate microseismic events, and also enhance the permeability and accessible surface area of the geothermal formation. Hence, the ability to accurately model the coupled thermal-hydrologic-mechanical (THM) processes in fractured geological formations is critical in effective EGS reservoir development and management strategies. The locations of the microseismic events can serve as indicators of the zones of enhanced permeability, thus providing vital information for verification of the coupled THM models. We will describe a general purpose computational code, FEHM, developed for this purpose, that models coupled THM processes during multiphase fluid flow and transport in fractured porous media. The code incorporates several models of fracture aperture and stress behavior combined with permeability relationships. We provide field scale examples of applications to geothermal systems to demonstrate the utility of the method.

  4. Surrogate formulations for thermal treatment of low-level mixed waste. Part 3: Plasma hearth process testing

    SciTech Connect (OSTI)

    Chiang, J.M.; Bostick, W.D.; Hoffman, D.P.; Hermes, W.H.; Gibson, L.V. Jr.; Richmond, A.A. [Martin Marietta Energy Systems, Inc., Oak Ridge, TN (United States)

    1994-01-01T23:59:59.000Z

    The plasma hearth process (PHP) presented in this report has been tested at a facility at Ukiah, California, in a cooperative effort between the Department of Energy (DOE), Science Applications International Corporation, Inc., and ReTech, Inc. The electrically heated plasma gas is used to destroy organic materials and bind radionuclides and Resource Conservation and Recovery Act (RCRA) metals in the glassy slag. Proof-of-principle tests were conducted successfully using nonhazardous and non-radioactive materials placed in 30-gal steel drums. On-line analyses of the gaseous effluents indicated complete combustion; emissions of CO, NO{sub x}, and particulates were low. The process also produced highly stable solid waste forms. The experiments for the next phase have been planned employing surrogates for the hazardous and radioactive components of the simulated waste streams. Natural cerium oxide is selected to simulate the behavior of radioactive actinide and transuranium elements, while natural cesium chloride is simulated for the study of relatively volatile radioactive fission products. For RCRA organics, naphthalene and 1,2-dichlorobenzene are semivolatile compounds selected to represent significant challenges to thermal destruction, whereas chlorobenzene is selected for the study of relatively volatile organics. Salts of chromium, nickel, lead, and cadmium are chosen to represent the twelve regulated toxic metals for emission and partitioning studies. The simulated waste packages presented in the text do not necessarily represent an individual waste stream within the DOE complex; rather, they were formulated to represent the most probable components in generic waste stream categories.

  5. Methodology for predicting asphalt concrete overlay life against reflection cracking

    E-Print Network [OSTI]

    Jayawickrama, Priyantha Warnasuriya

    1985-01-01T23:59:59.000Z

    of thermal expansion = change in temperature E K - (so gT) vc/h F3(c/h) +(I-u ) By defining, !40) (41) Jc/h F3(c/h) T Kt (42 ) 29 ~Summa r The proper variables to be used in a design equation and the form of the equation to be used is best... obtained are presented in this chapter. The stress intensity factor computations were carr1ed out for different crack-tip positions and for different levels of aggregate interlock act1on. These results were obtained for each of the three mechanisms...

  6. A numerical study of crack initiation in a bcc iron system based on dynamic bifurcation theory

    SciTech Connect (OSTI)

    Li, Xiantao, E-mail: xli@math.psu.edu [Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

    2014-10-28T23:59:59.000Z

    Crack initiation under dynamic loading conditions is studied under the framework of dynamic bifurcation theory. An atomistic model for BCC iron is considered to explicitly take into account the detailed molecular interactions. To understand the strain-rate dependence of the crack initiation process, we first obtain the bifurcation diagram from a computational procedure using continuation methods. The stability transition associated with a crack initiation, as well as the connection to the bifurcation diagram, is studied by comparing direct numerical results to the dynamic bifurcation theory [R. Haberman, SIAM J. Appl. Math. 37, 69–106 (1979)].

  7. Characterization of cracking restraint at sawcut joints using the German Cracking Frame

    E-Print Network [OSTI]

    Vepakomma, Shilpa

    2002-01-01T23:59:59.000Z

    Cracking of concrete slabs at sawcut notches is a major concern in the early stages of construction. Several factors affecting crack initiation are material strength parameters, method and quality of curing, slab/subbase stiffness, and concrete...

  8. Crack stability analysis of low alloy steel primary coolant pipe

    SciTech Connect (OSTI)

    Tanaka, T.; Kameyama, M. [Kansai Electric Power Company, Osaka (Japan); Urabe, Y. [Mitsubishi Heavy Industries, Ltd., Takasago (Japan)] [and others

    1997-04-01T23:59:59.000Z

    At present, cast duplex stainless steel has been used for the primary coolant piping of PWRs in Japan and joints of dissimilar material have been applied for welding to reactor vessels and steam generators. For the primary coolant piping of the next APWR plants, application of low alloy steel that results in designing main loops with the same material is being studied. It means that there is no need to weld low alloy steel with stainless steel and that makes it possible to reduce the welding length. Attenuation of Ultra Sonic Wave Intensity is lower for low alloy steel than for stainless steel and they have advantageous inspection characteristics. In addition to that, the thermal expansion rate is smaller for low alloy steel than for stainless steel. In consideration of the above features of low alloy steel, the overall reliability of primary coolant piping is expected to be improved. Therefore, for the evaluation of crack stability of low alloy steel piping to be applied for primary loops, elastic-plastic future mechanics analysis was performed by means of a three-dimensioned FEM. The evaluation results for the low alloy steel pipings show that cracks will not grow into unstable fractures under maximum design load conditions, even when such a circumferential crack is assumed to be 6 times the size of the wall thickness.

  9. A review of carbide fuel corrosion for nuclear thermal propulsion applications

    SciTech Connect (OSTI)

    Pelaccio, D.G.; El-Genk, M.S. [Univ. of New Mexico, Albuquerque, NM (United States). Inst. for Space Nuclear Power Studies; Butt, D.P. [Los Alamos National Lab., NM (United States)

    1993-12-01T23:59:59.000Z

    At the operation conditions of interest in nuclear thermal propulsion reactors, carbide materials have been known to exhibit a number of life limiting phenomena. These include the formation of liquid, loss by vaporization, creep and corresponding gas flow restrictions, and local corrosion and fuel structure degradation due to excessive mechanical and/or thermal loading. In addition, the radiation environment in the reactor core can produce a substantial change in its local physical properties, which can produce high thermal stresses and corresponding stress fractures (cracking). Time-temperature history and cyclic operation of the nuclear reactor can also accelerate some of these processes. The University of New Mexico`s Institute for Space Nuclear Power Studies, under NASA sponsorship has recently initiated a study to model the complicated hydrogen corrosion process. In support of this effort, an extensive review of the open literature was performed, and a technical expert workshop was conducted. This paper summarizes the results of this review.

  10. Fuel reforming for scramjet thermal management and combustion optimization

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    and the composition of the cracked fuel entering the combustor, an accurate predictive model of the thermalFuel reforming for scramjet thermal management and combustion optimization E. DANIAU* , M. BOUCHEZ of the main issues of hypersonic flight is the thermal management of the overall vehicle and more specifically

  11. Characterization of geothermal reservoir crack patterns using...

    Open Energy Info (EERE)

    reservoir crack patterns using shear-wave splitting Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: Characterization of geothermal reservoir...

  12. White Etching Cracks | Argonne National Laboratory

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Etching Cracks Presented by Walter Holweger of Schaeffler at the Wind Turbine Tribology Seminar 2014. NREL Chicago291014Holweger26nosec...

  13. Venezuela-MEM/USA-DOE Fossil Energy Report IV-11: Supporting technology for enhanced oil recovery - EOR thermal processes

    SciTech Connect (OSTI)

    Venezuela

    2000-04-06T23:59:59.000Z

    This report contains the results of efforts under the six tasks of the Tenth Amendment anti Extension of Annex IV, Enhanced Oil Recovery Thermal Processes of the Venezuela/USA Energy Agreement. This report is presented in sections (for each of the six Tasks) and each section contains one or more reports that were prepared to describe the results of the effort under each of the Tasks. A statement of each Task, taken from the Agreement Between Project Managers, is presented on the first page of each section. The Tasks are numbered 68 through 73. The first through tenth report on research performed under Annex IV Venezuela MEM/USA-DOE Fossil Energy Report Number IV-1, IV-2, IV-3, IV-4, IV-5, IV-6, IV-7, IV-8, IV-9, IV-10 contain the results of the first 67 Tasks. These reports are dated April 1983, August 1984, March 1986, July 1987, November 1988, December 1989, October 1991, February 1993, March 1995, and December 1997, respectively.

  14. 7. Low temperature cracking in HMA Pavement Cracking Al-Qadi, Scarpas & Loizos (eds)

    E-Print Network [OSTI]

    Paulino, Glaucio H.

    7. Low temperature cracking in HMA 367 #12;#12;Pavement Cracking ­ Al-Qadi, Scarpas & Loizos (eds, Storrs, Connecticut, USA ABSTRACT: Low temperature cracking remains one of the major pavement distresses in asphalt concrete pavements in cold regions. An integrated laboratory testing, field performance data

  15. A study of the mechanism of laser welding defects in low thermal expansion superalloy GH909

    SciTech Connect (OSTI)

    Yan, Fei; Wang, Chunming, E-mail: yanxiangfei225@163.com; Wang, Yajun; Hu, Xiyuan; Wang, Tianjiao; Li, Jianmin; Li, Guozhu

    2013-04-15T23:59:59.000Z

    In this paper, we describe experimental laser welding of low-thermal-expansion superalloy GH909. The main welding defects of GH909 by laser in the weld are liquation cracks and porosities, including hydrogen and carbon monoxide porosity. The forming mechanism of laser welding defects was investigated. This investigation was conducted using an optical microscope, scanning electron microscope, energy diffraction spectrum, X-ray diffractometer and other methodologies. The results demonstrated that porosities appearing in the central weld were related to incomplete removal of oxide film on the surface of the welding samples. The porosities produced by these bubbles were formed as a result of residual hydrogen or oxygenium in the weld. These elements failed to escape from the weld since laser welding has both a rapid welding speed and cooling rate. The emerging crack in the heat affected zone is a liquation crack and extends along the grain boundary as a result of composition segregation. Laves–Ni{sub 2}Ti phase with low melting point is a harmful phase, and the stress causes grain boundaries to liquefy, migrate and even crack. Removing the oxides on the surface of the samples before welding and carefully controlling technological parameters can reduce welding defects and improve formation of the GH909 alloy weld. - Highlights: ? It is a new process for the forming of GH909 alloy via laser welding. ? The forming mechanism of laser welding defects in GH909 has been studied. ? It may be a means to improve the efficiency of aircraft engine production.

  16. Method for making dense crack free thin films

    DOE Patents [OSTI]

    Jacobson, Craig P. (Lafayette, CA); Visco, Steven J. (Berkeley, CA); De Jonghe, Lutgard C. (Lafayette, CA)

    2007-01-16T23:59:59.000Z

    The process described herein provides a simple and cost effective method for making crack free, high density thin ceramic film. The steps involve depositing a layer of a ceramic material on a porous or dense substrate. The deposited layer is compacted and then the resultant laminate is sintered to achieve a higher density than would have been possible without the pre-firing compaction step.

  17. Characterizing the cracking behavior of hard alpha defects in rotor grade Ti-6-4 alloy

    SciTech Connect (OSTI)

    McKeighan, P.C.; Perocchi, L.C.; Nicholls, A.E.; McClung, R.C.

    1999-07-01T23:59:59.000Z

    A program sponsored by the FAA is currently underway to develop predictive tools utilizing state-of-the-art damage tolerance and probabilistic methodologies that can be used in the life management of high energy rotors. The program is focusing on fatigue crack nucleation and growth from anomalies in titanium alloys known as hard alpha, an inclusion-like feature that can occur during the melting process. In the work detailed in this paper, two sizes of synthetic hard alpha defects are created in Ti-6Al-4V and subjected to static and fatigue loading. In addition, two different geometry anomalies are considered: one intersecting the surface of the specimen and another embedded internally. A number of crack detection transducers are used and shown to compare well to results from visual inspections on the surface defect specimens. These surface specimens tend to exhibit defect cracking at relatively low stress levels, typically on the order of 5--10 ksi. Although it appeared from the crack detection transducer that little or no cracking occurred in the interior anomaly specimens given an applied static stress of 100 ksi, subsequent metallographic sectioning demonstrated more extensive cracking and damage. The observed cracking behavior indicates that the diffusion zone may play an important role in the structural integrity of the hard alpha anomalies.

  18. A NOVEL LOW THERMAL BUDGET THIN-FILM POLYSILICON FABRICATION PROCESS FOR LARGE-AREA, HIGH-THROUGHPUT SOLAR CELL PRODUCTION

    SciTech Connect (OSTI)

    Yue Kuo

    2010-08-15T23:59:59.000Z

    A novel thin-film poly-Si fabrication process has been demonstrated. This low thermal budget process transforms the single- and multi-layer amorphous silicon thin films into a poly-Si structure in one simple step over a pulsed rapid thermal annealing process with the enhancement of an ultrathin Ni layer. The complete poly-Si solar cell was fabricated in a short period of time without deteriorating the underneath glass substrate. The unique vertical crystallization process including the mechanism is discussed. Influences of the dopant type and process parameters on crystal structure will be revealed. The poly-Si film structure has been proved using TEM, XRD, Raman, and XPS methods. The poly-Si solar cell structure and the performance have been examined. In principle, the new process is potentially applicable to produce large-area thin-film poly-Si solar cells at a high throughput and low cost. A critical issue in this process is to prevent the excessive dopant diffusion during crystallization. Process parameters and the cell structure have to be optimized to achieve the production goal.

  19. Crack shape developments and leak rates for circumferential complex-cracked pipes

    SciTech Connect (OSTI)

    Brickstad, B.; Bergman, M. [SAQ Inspection Ltd., Stockholm (Sweden)

    1997-04-01T23:59:59.000Z

    A computerized procedure has been developed that predicts the growth of an initial circumferential surface crack through a pipe and further on to failure. The crack growth mechanism can either be fatigue or stress corrosion. Consideration is taken to complex crack shapes and for the through-wall cracks, crack opening areas and leak rates are also calculated. The procedure is based on a large number of three-dimensional finite element calculations of cracked pipes. The results from these calculations are stored in a database from which the PC-program, denoted LBBPIPE, reads all necessary information. In this paper, a sensitivity analysis is presented for cracked pipes subjected to both stress corrosion and vibration fatigue.

  20. Development of crack shape: LBB methodology for cracked pipes

    SciTech Connect (OSTI)

    Moulin, D.; Chapuliot, S.; Drubay, B. [Commissariat a l Energie Atomique, Gif sur Yvette (France)

    1997-04-01T23:59:59.000Z

    For structures like vessels or pipes containing a fluid, the Leak-Before-Break (LBB) assessment requires to demonstrate that it is possible, during the lifetime of the component, to detect a rate of leakage due to a possible defect, the growth of which would result in a leak before-break of the component. This LBB assessment could be an important contribution to the overall structural integrity argument for many components. The aim of this paper is to review some practices used for LBB assessment and to describe how some new R & D results have been used to provide a simplified approach of fracture mechanics analysis and especially the evaluation of crack shape and size during the lifetime of the component.

  1. SciTech Connect: CRACK TIP PLASTICITY AND FRACTURE INITIATION...

    Office of Scientific and Technical Information (OSTI)

    N50000* --Metals, Ceramics, & Other Materials; CRACKS; FRACTURE PROPERTIES; METALS BUILDING MATERIALSfracture of metal, crack tip plasticity and initiation criteria for;...

  2. Simulations of Failure via Three-Dimensional Cracking in Fuel Cladding for Advanced Nuclear Fuels

    SciTech Connect (OSTI)

    Lu, Hongbing; Bukkapatnam, Satish; Harimkar, Sandip; Singh, Raman; Bardenhagen, Scott

    2014-01-09T23:59:59.000Z

    Enhancing performance of fuel cladding and duct alloys is a key means of increasing fuel burnup. This project will address the failure of fuel cladding via three-dimensional cracking models. Researchers will develop a simulation code for the failure of the fuel cladding and validate the code through experiments. The objective is to develop an algorithm to determine the failure of fuel cladding in the form of three-dimensional cracking due to prolonged exposure under varying conditions of pressure, temperature, chemical environment, and irradiation. This project encompasses the following tasks: 1. Simulate 3D crack initiation and growth under instantaneous and/or fatigue loads using a new variant of the material point method (MPM); 2. Simulate debonding of the materials in the crack path using cohesive elements, considering normal and shear traction separation laws; 3. Determine the crack propagation path, considering damage of the materials incorporated in the cohesive elements to allow the energy release rate to be minimized; 4. Simulate the three-dimensional fatigue crack growth as a function of loading histories; 5. Verify the simulation code by comparing results to theoretical and numerical studies available in the literature; 6. Conduct experiments to observe the crack path and surface profile in unused fuel cladding and validate against simulation results; and 7. Expand the adaptive mesh refinement infrastructure parallel processing environment to allow adaptive mesh refinement at the 3D crack fronts and adaptive mesh merging in the wake of cracks. Fuel cladding is made of materials such as stainless steels and ferritic steels with added alloying elements, which increase stability and durability under irradiation. As fuel cladding is subjected to water, chemicals, fission gas, pressure, high temperatures, and irradiation while in service, understanding performance is essential. In the fast fuel used in advanced burner reactors, simulations of the nuclear fuels are critical to understand the burnup, and thus the fuel efficiency.

  3. Life prediction for bridged fatigue cracks

    SciTech Connect (OSTI)

    Cox, B.N.

    1994-08-01T23:59:59.000Z

    One of the more promising classes of composites touted for high temperature applications, and certainly the most available, is that of relatively brittle matrices, either ceramic or intermetallic, reinforced by strong, aligned, continuous fibers. Under cyclic loading in the fiber direction, these materials develop matrix cracks that often run perpendicular to the fibers, while the fibers remain intact in the crack wake, supplying bridging tractions across the fracture surfaces. The bridging tractions shield the crack tip from the applied load, dramatically reducing the crack velocity from that expected in an unreinforced material subjected to the same value, {Delta}K{sub a}, of the cyclic applied stress intensity factor. An important issue in reliability is the prediction of the growth rates of the bridged cracks. The growth rates of matrix fatigue cracks bridged by sliding fibers are now commonly predicted by models based on the micromechanics of frictional interfaces. However, there exist many reasons, both theoretical and experimental, for suspecting that the most popular micromechanical models are probably wrong in detail in the context of fatigue cracks. Furthermore, a review of crack growth data reveals that the validity of the micromechanics-based predictive model has never been tested and may never be tested. In this paper, two alternative approaches are suggested to the engineering problem of predicting the growth rates of bridged cracks without explicit recourse to micromechanics. Instead, it is shown that the material properties required to analyze bridging effects can be deduced directly from crack growth data. Some experiments are proposed to test the validity of the proposals.

  4. Thermal stress analysis of fused-cast AZS refractories during production; Part 2: Development of thermo-elastic stress model

    SciTech Connect (OSTI)

    Cockcroft, S.L.; Brimacombe, J.K. (Univ. of British Columbia, Vancouver, British Columbia (Canada). Centre for Metallurgical Process Engineering); Walrod, D.G.; Myles, T.A. (Carborundum Co., Falconer, NY (United States). Monofrax-S Plant)

    1994-06-01T23:59:59.000Z

    Mathematical models of heat flow and thermo-elastic stress, based on the finite-element method, have been developed and utilized to analyze the voidless,'' fused-cast, AZS, solidification process. The results of the mathematical analysis, in conjunction with information obtained in a comprehensive industrial study, presented in Part 1 of this paper, describe the mechanisms for the formation of the various crack types found in the fused-cast product. Thermal stresses are generated early in the solidification process by rapid cooling of the refractory surface as it contacts the initially cool mold and later in conjunction with the tetragonal-to-monoclinic phase transformation which occurs in the zirconia component of the AZS refractory. Applying this model, castings were made using a revised mold design. Preliminary results indicate these castings to be free of objectionable transverse cracks.

  5. Contact fatigue behavior and gas cell thermal wave NDE of sintered reaction bonded silicon nitride

    SciTech Connect (OSTI)

    Barla, J.R.; Edler, J.P.; Lin, H. [Eaton Corp. R & D, Southfield, MI (United States)] [and others

    1996-12-31T23:59:59.000Z

    Silicon nitride is being evaluated for potential applications as structural components subjected to contact fatigue loading. A new testing and evaluation methodology for evaluation of Hertzian contact fatigue damage in ceramic materials has been developed and is described. Contact fatigue damage is induced in three test specimens simultaneously. The material investigated is Eaton Corporation`s low cost E - Process Silicon Nitride. Tests were conducted at several Hertzian stress levels to evaluate contact fatigue damage behavior. Gas cell thermal wave NDE was employed to study the induced subsurface damage. Damage behavior was also investigated using optical microscopy. Two specimens were evaluated in detail; one that was tested for 17,400 cycles, P{sub max} = 2700 N and one that was tested for 1 x 10{sup 6} cycles, P{sub max} = 1800 N. The 2700 N specimen has a partial cone crack and contains a small concentration of vertical and shallow horizontal cracks. No evidence of a cone crack was detected on the 1800 N specimen. However, a larger concentration of horizontal microcracks at and just below the surface is present in this specimen, with particle debris in and around the surface contact area. Correlation of the optical microscopy observations with gas cell thermal wave NDE of the subsurface damage in these two specimens is discussed.

  6. Preparation of silica aerogels with improved mechanical properties and extremely low thermal conductivities through modified sol-gel process

    E-Print Network [OSTI]

    Zuo, Yanjia

    2010-01-01T23:59:59.000Z

    Reported silica aerogels have a thermal conductivity as low as 15 mW/mK. The fragility of silica aerogels, however, makes them impractical for structural applications. The purpose of the study is to improve the ductility ...

  7. Results from an International Simulation Study on Coupled Thermal, Hydrological, and Mechanical (THM) Processes near Geological Nuclear Waste Repositories

    E-Print Network [OSTI]

    Rutqvist, J.

    2008-01-01T23:59:59.000Z

    in hydrological rock properties caused by the thermallyEuropean countries. The initial rock properties for the twoTABLE II. Some basic rock properties defined for Phase 1 (

  8. Vortex flow in the technology of radiation wave cracking (RWC)

    E-Print Network [OSTI]

    L. A. Tsoy; V. N. Kolushov; A. G. Komarov; A. N. Tsoy

    2012-09-16T23:59:59.000Z

    This article examines the theory of vortex flows in relation to the processes occurring in the radiation-wave cracking of crude oil, when the crude oil is sprayed into the gas stream in the form of a mist and then is fed into the reactor, where it is treated by the accelerated electrons and the UHF radiation. The output of this process are the products with the specified parameters (high-octane petroleum products). This process operates at the ambient pressure and temperature, which makes the process safer for industrial purposes. Besides the process itself, the authors described the equipment used in this process, as well as the parameters of the optimal process.

  9. Prediction of early-age cracking of UHPC materials and structures : a thremo-chemo-mechanics approach

    E-Print Network [OSTI]

    Shim, JongMin, 1975-

    2005-01-01T23:59:59.000Z

    Ultra-High Performance Concrete [UHPC] has remarkable performance in mechanical properties, ductility, economical benefit, etc., but early-age cracking of UHPC can become an issue during the manufacturing process due to ...

  10. Investigation of thermal processes in one-and two-layer materials under irradiation with high-energy heavy ions within the thermal peak model

    SciTech Connect (OSTI)

    Amirkhanov, I. V., E-mail: ibrohim@jinr.ru; Didyk, A. Yu.; Muzafarov, D. Z.; Puzynin, I. V.; Puzynina, T. P.; Sarker, N. R.; Sarhadov, I.; Sharipov, Z. A. [Joint Institute for Nuclear Research, Laboratory of Information Technologies (Russian Federation)

    2006-12-15T23:59:59.000Z

    A system of equations for the electron and lattice temperatures around and along the path of a 700-MeV heavy (uranium) ion in nickel (one-layer material) is solved numerically in the axially symmetric cylindrical coordinate system under the assumption of temperature-dependent specific heat and thermal conductivity. The obtained dependences of the lattice temperature on the radius (distance from the ion path) and depth suggest that the ionization energy loss of a 700-MeV uranium ion in nickel is sufficient to melt the material. A comparative analysis with the linear model is performed and the maximum radius and depth of the region where the target material can melt is estimated. Then, the initial system of equations is solved for the region around and along the path of a 710-MeV heavy (bismuth {sup 209}Bi) ion in the two-layer material Ni(2 {mu}m)-W with constant thermophysical parameters. The obtained dependences of the lattice temperature on the radius and depth show that the ionization energy loss of a 710-MeV bismuth ion in this two-layer material is sufficient for melting. The maximum radius and depth of the regions in the target material where phase transitions may occur are estimated.

  11. The Effects of Test Temperature, Temper, and Alloyed Copper on the Hydrogen-Controlled Crack Growth Rate of an Al-Zn-Mg-(Cu) Alloy

    SciTech Connect (OSTI)

    G.A. Young, Jr.; J.R. Scully

    2000-09-17T23:59:59.000Z

    The hydrogen embrittlement controlled stage II crack growth rate of AA 7050 (6.09 wt.% Zn, 2.14 wt% Mg, 2.19 wt.% Cu) was investigated as a function of temper and alloyed copper level in a humid air environment at various temperatures. Three tempers representing the underaged, peak aged, and overaged conditions were tested in 90% relative humidity (RH) air at temperatures between 25 and 90 C. At all test temperatures, an increased degree of aging (from underaged to overaged) produced slower stage II crack growth rates. The stage II crack growth rate of each alloy and temper displayed Arrhenius-type temperature dependence with activation energies between 58 and 99 kJ/mol. For both the normal copper and low copper alloys, the fracture path was predominantly intergranular at all test temperatures (25-90 C) in each temper investigated. Comparison of the stage II crack growth rates for normal (2.19 wt.%) and low (0.06 wt.%) copper alloys in the peak aged and overaged tempers showed the beneficial effect of copper additions on stage II crack growth rate in humid air. In the 2.19 wt.% copper alloy, the significant decrease ({approx} 10 times at 25 C) in stage II crack growth rate upon overaging is attributed to an increase in the apparent activation energy for crack growth. IN the 0.06 wt.% copper alloy, overaging did not increase the activation energy for crack growth but did lower the pre-exponential factor, {nu}{sub 0}, resulting in a modest ({approx} 2.5 times at 25 C) decrease in crack growth rate. These results indicate that alloyed copper and thermal aging affect the kinetic factors that govern stage II crack growth rate. Overaged, copper bearing alloys are not intrinsically immune to hydrogen environment assisted cracking but are more resistant due to an increased apparent activation energy for stage II crack growth.

  12. Studies on fruit cracking of tomatoes

    E-Print Network [OSTI]

    Cotner, Sam Don

    1966-01-01T23:59:59.000Z

    calcium , 33 Means for naturally occurring cracks as influenced by foliar calcium applications 33 Analysis of variance for tomato fruit cracking as influended by foliar applications of CaC12 36 LIST QF TABLES CONTINUED 17. Analysis of variance...on of the cell contents oi' tomato fruits late in the season have been reported (10). Whatley (37) states that there is a 20 percent increase in osmot1c pressure from mature green to the red ripe stags. Radial cracking may be due to an increase...

  13. CRACK SPACING IN STRAINED FILMS B.B. Guzina1

    E-Print Network [OSTI]

    Guzina, Bojan

    , similar transverse cracking patterns are a feature of asphalt concrete pavements systems in cold climates

  14. An investigation of penetrant techniques for detection of machining-induced surface-breaking cracks on monolithic ceramics

    SciTech Connect (OSTI)

    Forster, G.A.; Ellingson, W.A.

    1996-02-01T23:59:59.000Z

    The purpose of this effort was to evaluate penetrant methods for their ability to detect surface-breaking cracks in monolithic ceramic materials with an emphasis on detection of cracks generated by machining. There are two basic penetrant types, visible and fluorescent. The visible penetrant method is usually augmented by powder developers and cracks detected can be seen in visible light. Cracks detected by fluorescent penetrant are visible only under ultraviolet light used with or without a developer. The developer is basically a powder that wicks up penetrant from a crack to make it more observable. Although fluorescent penetrants were recommended in the literature survey conducted early in this effort, visible penetrants and two non-standard techniques, a capillary gaseous diffusion method under development at the institute of Chemical Physics in Moscow, and the {open_quotes}statiflux{close_quotes} method which involves use of electrically charged particles, were also investigated. SiAlON ring specimens (1 in. diameter, 3/4 in. wide) which had been subjected to different thermal-shock cycles were used for these tests. The capillary gaseous diffusion method is based on ammonia; the detector is a specially impregnated paper much like litmus paper. As expected, visible dye penetrants offered no detection sensitivity for tight, surface-breaking cracks in ceramics. Although the non-standard statiflux method showed promise on high-crack-density specimens, it was ineffective on limited-crack-density specimens. The fluorescent penetrant method was superior for surface-breaking crack detection, but successful application of this procedure depends greatly on the skill of the user. Two presently available high-sensitivity fluorescent penetrants were then evaluated for detection of microcracks on Si{sub 3}N{sub 4} and SiC from different suppliers. Although 50X optical magnification may be sufficient for many applications, 200X magnification provides excellent delectability.

  15. Stainless steel pitting and early-stage stress corrosion cracking under ultra-low elastic load

    E-Print Network [OSTI]

    Volinsky, Alex A.

    in the nuclear power plants, petrochemical and aerospace industries, bridges and ships. Much effort has been of the reasons is that the mechanisms of SCC crack initiation and propagation are possibly altered in the process, when pitting precedes SCC, the fundamental steps in the overall process include: pit initiation, pit

  16. Coding the cracks | Argonne Leadership Computing Facility

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    . October 3, 2014 Printer-friendly version Researchers use Mira to study stress-corrosion cracking in silicates Encased in the rocks that comprise much of Earth's crust and...

  17. Catalytic cracking of residual petroleum fractions

    SciTech Connect (OSTI)

    Moore, H.F.; Mayo, S.L.; Goolsby, T.L. (Research and Development Dept., Ashland Petroleum Co., Ashland, KY (US))

    1991-01-01T23:59:59.000Z

    This paper reports on Arabian Light crude oil vacuum bottoms fractionated into five high-boiling fractions by wiped film evaporation, and the fractions subjected to catalytic cracking in a fixed-fluidized bed using a commercial equilibrium cracking catalyst. Density, aromaticity, and heteroatom content generally increased with boiling point, as did metals content except for vanadium and iron which demonstrated possible bimodal distributions. The cracking response of these fractions showed increasing yields of dry gas and coke, with decreasing gasoline yields, as a function of increasing apparent boiling point as would normally be expected. Surprisingly, however, local maxima were observed for wet gas yield and total conversion, with local minima for cycle oil and slurry yields, in the region of the 1200-1263{degrees}F (650-680{degrees}C) middle fraction. All fractions showed significant response to cracking, with coke yields generally being the only negative factor observed.

  18. Cracking in reinforced concrete bent caps 

    E-Print Network [OSTI]

    Young, Bradley S.

    2000-01-01T23:59:59.000Z

    by studying the relationship between stresses in the longitudinal tension reinforcement, reinforcement detailing, shear resistance, and cracking of the bent cap during service loading through to failure. As a part of this investigation, sixteen full...

  19. Shrinkage - cracking characteristics of structural lightweight concrete

    E-Print Network [OSTI]

    McKeen, Robert Gordon

    1969-01-01T23:59:59.000Z

    1969 ABSTRACT Shrinkage-Cracking Characteristics of Structural Lightweight Concrete (August 1969) B. S. C. E. , Texas AERY University Directed by: if. B. Ledbetter Tests were conducted to det. trains the effect of coarse. s -gre- gate type...'csults indicated that both unrestrained shrinkage and concret. c water loss relate to restrained shrinkage stress. Unrestrained shrinks e did not indicate. cracking ter. dency while we+ er loss provided an indi cati on of cr cking tendency. ACRRO!Jr. ROOD. i...

  20. Crack-arrest behavior in SEN wide plates of low-upper-shelf base metal tested under nonisothermal conditions: WP-2 series

    SciTech Connect (OSTI)

    Naus, D.J.; Keeney-Walker, J.; Bass, B.R.; Robinson, G.C. Jr.; Iskander, S.K.; Alexander, D.J. [Oak Ridge National Lab., TN (United States); Fields, R.J.; deWit, R.; Low, S.R. [National Inst. of Standards and Technology, Gaithersburg, MD (United States); Schwartz, C.W. [Maryland Univ., College Park, MD (United States). Dept. of Mechanical Engineering; Johansson, I.B. [Royal Inst. of Tech., Stockholm (Sweden)

    1990-08-01T23:59:59.000Z

    The Heavy-Section Steel Technology (HSST) Program at the Oak Ridge National Laboratory under the sponsorship of the Nuclear Regulatory Commission is conducting analytical and experimental studies aimed at understanding the circumstances that would initiate the growth of an existing crack in a reactor pressure vessel (RPV) and the conditions leading to arrest of a propagating crack. Objectives of these studies are to determine (1) if the material will exhibit crack-arrest behavior when the driving force on a crack exceeds the ASME limit, (2) the relationship between K{sub Ia} and temperature, and (3) the interaction of fracture modes (arrest, stable crack growth, unstable crack growth, and tensile instability) when arrest occurs at high temperatures. In meeting these objectives, crack-arrest data are being developed over an expanded temperature range through tests involving large thermally shocked cylinders, pressurized thermally shocked vessels, and wide-plate specimens. The wide-plate specimens provide the opportunity for a significant number of data points to be obtained at relatively affordable costs. These tests are designed to provide fracture-toughness measurements approaching or above the onset of the Charpy upper-shelf regime in a rising toughness region and with an increasing driving force. This document discusses test methodology and results. 23 refs., 92 figs., 25 tabs.

  1. New field programmable gate array-based image-oriented acquisition and real-time processing applied to plasma facing component thermal monitoring

    SciTech Connect (OSTI)

    Martin, V. [Pulsar Team-Project, INRIA Sophia Antipolis, Sophia Antipolis F-06902 (France); Dunand, G.; Moncada, V. [Sophia Conseil Company, Sophia Antipolis F-06560 (France); Jouve, M.; Travere, J.-M. [CEA, IRFM, Saint-Paul-Lez-Durance F-13108 (France)

    2010-10-15T23:59:59.000Z

    During operation of present fusion devices, the plasma facing components (PFCs) are exposed to high heat fluxes. Understanding and preventing overheating of these components during long pulse discharges is a crucial safety issue for future devices like ITER. Infrared digital cameras interfaced with complex optical systems have become a routine diagnostic to measure surface temperatures in many magnetic fusion devices. Due to the complexity of the observed scenes and the large amount of data produced, the use of high computational performance hardware for real-time image processing is then mandatory to avoid PFC damages. At Tore Supra, we have recently made a major upgrade of our real-time infrared image acquisition and processing board by the use of a new field programmable gate array (FPGA) optimized for image processing. This paper describes the new possibilities offered by this board in terms of image calibration and image interpretation (abnormal thermal events detection) compared to the previous system.

  2. Contstraint effects of shallow cracks in structures containing fillet weld toe cracks

    E-Print Network [OSTI]

    Neligon, Melinda T

    1995-01-01T23:59:59.000Z

    for structures containing a/W--O.l and a/W--O.5 fillet weld toe cracks. The Anderson-Dodds scaling model is applied to quantify the effects of finite size on J contour integral values for structures containing a/W=O.l and a/W=0.5 fillet weld toe cracks loaded...

  3. Contstraint effects of shallow cracks in structures containing fillet weld toe cracks 

    E-Print Network [OSTI]

    Neligon, Melinda T

    1995-01-01T23:59:59.000Z

    for structures containing a/W--O.l and a/W--O.5 fillet weld toe cracks. The Anderson-Dodds scaling model is applied to quantify the effects of finite size on J contour integral values for structures containing a/W=O.l and a/W=0.5 fillet weld toe cracks loaded...

  4. Recent evaluations of crack-opening-area in circumferentially cracked pipes

    SciTech Connect (OSTI)

    Rahman, S.; Brust, F.; Ghadiali, N.; Wilkowski, G.; Miura, N.

    1997-04-01T23:59:59.000Z

    Leak-before-break (LBB) analyses for circumferentially cracked pipes are currently being conducted in the nuclear industry to justify elimination of pipe whip restraints and jet shields which are present because of the expected dynamic effects from pipe rupture. The application of the LBB methodology frequently requires calculation of leak rates. The leak rates depend on the crack-opening area of the through-wall crack in the pipe. In addition to LBB analyses which assume a hypothetical flaw size, there is also interest in the integrity of actual leaking cracks corresponding to current leakage detection requirements in NRC Regulatory Guide 1.45, or for assessing temporary repair of Class 2 and 3 pipes that have leaks as are being evaluated in ASME Section XI. The objectives of this study were to review, evaluate, and refine current predictive models for performing crack-opening-area analyses of circumferentially cracked pipes. The results from twenty-five full-scale pipe fracture experiments, conducted in the Degraded Piping Program, the International Piping Integrity Research Group Program, and the Short Cracks in Piping and Piping Welds Program, were used to verify the analytical models. Standard statistical analyses were performed to assess used to verify the analytical models. Standard statistical analyses were performed to assess quantitatively the accuracy of the predictive models. The evaluation also involved finite element analyses for determining the crack-opening profile often needed to perform leak-rate calculations.

  5. TRANSPORT THROUGH CRACKED CONCRETE: LITERATURE REVIEW

    SciTech Connect (OSTI)

    Langton, C.

    2012-05-11T23:59:59.000Z

    Concrete containment structures and cement-based fills and waste forms are used at the Savannah River Site to enhance the performance of shallow land disposal systems designed for containment of low-level radioactive waste. Understanding and measuring transport through cracked concrete is important for describing the initial condition of radioactive waste containment structures at the Savannah River Site (SRS) and for predicting performance of these structures over time. This report transmits the results of a literature review on transport through cracked concrete which was performed by Professor Jason Weiss, Purdue University per SRR0000678 (RFP-RQ00001029-WY). This review complements the NRC-sponsored literature review and assessment of factors relevant to performance of grouted systems for radioactive waste disposal. This review was performed by The Center for Nuclear Waste Regulatory Analyses, San Antonio, TX, and The University of Aberdeen, Aberdeen Scotland and was focused on tank closure. The objective of the literature review on transport through cracked concrete was to identify information in the open literature which can be applied to SRS transport models for cementitious containment structures, fills, and waste forms. In addition, the literature review was intended to: (1) Provide a framework for describing and classifying cracks in containment structures and cementitious materials used in radioactive waste disposal, (2) Document the state of knowledge and research related to transport through cracks in concrete for various exposure conditions, (3) Provide information or methodology for answering several specific questions related to cracking and transport in concrete, and (4) Provide information that can be used to design experiments on transport through cracked samples and actual structures.

  6. Thermal Integration of CO{sub 2} Compression Processes with Coal-Fired Power Plants Equipped with Carbon Capture

    SciTech Connect (OSTI)

    Edward Levy

    2012-06-29T23:59:59.000Z

    Coal-fired power plants, equipped either with oxycombustion or post-combustion CO{sub 2} capture, will require a CO{sub 2} compression system to increase the pressure of the CO{sub 2} to the level needed for sequestration. Most analyses show that CO{sub 2} compression will have a significant effect on parasitic load, will be a major capital cost, and will contribute significantly to reduced unit efficiency. This project used first principle engineering analyses and computer simulations to determine the effects of utilizing compressor waste heat to improve power plant efficiency and increase net power output of coal-fired power plants with carbon capture. This was done for units with post combustion solvent-based CO{sub 2} capture systems and for oxyfired power plants, firing bituminous, PRB and lignite coals. The thermal integration opportunities analyzed for oxycombustion capture are use of compressor waste heat to reheat recirculated flue gas, preheat boiler feedwater and predry high-moisture coals prior to pulverizing the coal. Among the thermal integration opportunities analyzed for post combustion capture systems are use of compressor waste heat and heat recovered from the stripper condenser to regenerate post-combustion CO{sub 2} capture solvent, preheat boiler feedwater and predry high-moisture coals. The overall conclusion from the oxyfuel simulations is that thermal integration of compressor heat has the potential to improve net unit heat rate by up to 8.4 percent, but the actual magnitude of the improvement will depend on the type of heat sink used and to a lesser extent, compressor design and coal rank. The simulations of a unit with a MEA post combustion capture system showed that thermal integration of either compressor heat or stripper condenser heat to preheat boiler feedwater would result in heat rate improvements from 1.20 percent to 4.19 percent. The MEA capture simulations further showed that partial drying of low rank coals, done in combination with feedwater heating, would result in heat rate reductions of 7.43 percent for PRB coal and 10.45 percent for lignite.

  7. Liquid Salts as Media for Process Heat Transfer from VHTR's: Forced Convective Channel Flow Thermal Hydraulics, Materials, and Coating

    SciTech Connect (OSTI)

    Sridharan, Kumar; Anderson, Mark; Allen, Todd; Corradini, Michael

    2012-01-30T23:59:59.000Z

    The goal of this NERI project was to perform research on high temperature fluoride and chloride molten salts towards the long-term goal of using these salts for transferring process heat from high temperature nuclear reactor to operation of hydrogen production and chemical plants. Specifically, the research focuses on corrosion of materials in molten salts, which continues to be one of the most significant challenges in molten salts systems. Based on the earlier work performed at ORNL on salt properties for heat transfer applications, a eutectic fluoride salt FLiNaK (46.5% LiF-11.5%NaF-42.0%KF, mol.%) and a eutectic chloride salt (32%MgCl2-68%KCl, mole %) were selected for this study. Several high temperature candidate Fe-Ni-Cr and Ni-Cr alloys: Hastelloy-N, Hastelloy-X, Haynes-230, Inconel-617, and Incoloy-800H, were exposed to molten FLiNaK with the goal of understanding corrosion mechanisms and ranking these alloys for their suitability for molten fluoride salt heat exchanger and thermal storage applications. The tests were performed at 850��������C for 500 h in sealed graphite crucibles under an argon cover gas. Corrosion was noted to occur predominantly from dealloying of Cr from the alloys, an effect that was particularly pronounced at the grain boundaries Alloy weight-loss due to molten fluoride salt exposure correlated with the initial Cr-content of the alloys, and was consistent with the Cr-content measured in the salts after corrosion tests. The alloys���¢�������� weight-loss was also found to correlate to the concentration of carbon present for the nominally 20% Cr containing alloys, due to the formation of chromium carbide phases at the grain boundaries. Experiments involving molten salt exposures of Incoloy-800H in Incoloy-800H crucibles under an argon cover gas showed a significantly lower corrosion for this alloy than when tested in a graphite crucible. Graphite significantly accelerated alloy corrosion due to the reduction of Cr from solution by graphite and formation on Cr-carbide on the graphite surface. Ni-electroplating dramatically reduced corrosion of alloys, although some diffusion of Fe and Cr were observed occur through the Ni plating. A pyrolytic carbon and SiC (PyC/SiC) CVD coating was also investigated and found to be effective in mitigating corrosion. The KCl-MgCl2 molten salt was less corrosive than FLiNaK fluoride salts for corrosion tests performed at 850oC. Cr dissolution in the molten chloride salt was still observed and consequently Ni-201 and Hastelloy N exhibited the least depth of attack. Grain-boundary engineering (GBE) of Incoloy 800H improved the corrosion resistance (as measured by weight loss and maximum depth of attack) by nearly 50% as compared to the as-received Incoloy 800H sample. Because Cr dissolution is an important mechanism of corrosion, molten salt electrochemistry experiments were initiated. These experiments were performed using anodic stripping voltammetry (ASV). Using this technique, the reduction potential of Cr was determined against a Pt quasi-reference electrode as well as against a Ni(II)-Ni reference electrode in molten FLiNaK at 650 oC. The integrated current increased linearly with Cr-content in the salt, providing for a direct assessment of the Cr concentration in a given salt of unknown Cr concentration. To study heat transfer mechanisms in these molten salts over the forced and mixed convection regimes, a forced convective loop was constructed to measure heat transfer coefficients, friction factors and corrosion rates in different diameter tubes in a vertical up flow configuration in the laminar flow regime. Equipment and instrumentation for the forced convective loop was designed, constructed, and tested. These include a high temperature centrifugal pump, mass flow meter, and differential pressure sensing capabilities to an uncertainty of < 2 Pa. The heat transfer coefficient for the KCl-MgCl2 salt was measured in t

  8. Mechanistic studies of the thermal decomposition of metal carbonyls on Ni(100) surfaces in connection with chemical vapor deposition processes

    SciTech Connect (OSTI)

    Xu, M.; Zaera, F. [Department of Chemistry, University of California, Riverside, California 92521 (United States)] [Department of Chemistry, University of California, Riverside, California 92521 (United States)

    1996-03-01T23:59:59.000Z

    The thermal decomposition of Fe(CO){sub 5}, Cr(CO){sub 6}, Mo(CO){sub 6}, and W(CO){sub 6} on Ni(100) surfaces and under ultrahigh vacuum conditions was studied by using temperature programmed desorption and x-ray photoelectron spectroscopies. The initial adsorption of those metal carbonyls is mostly molecular at low temperatures, but complete decarbonylation to the naked metal takes place in all cases upon thermal activation. Experiments with coadsorbed isotopically labeled {sup 13}CO provided indirect evidence for a stepwise mechanism for Fe(CO){sub 5} which may include the formation of tetra- and tricarbonyl intermediates on the surface. For Cr(CO){sub 6}, Mo(CO){sub 6}, and W(CO){sub 6}, on the other hand, complete decomposition occurs in a narrow range of temperature, and no intermediate could be isolated on the surface. The deposition of metal films via metal carbonyl activation was studied under steady state conditions as well. Continuous deposition was seen at substrate temperatures as low as 300 K, but the grown films were found to incorporate both carbon and oxygen under most conditions tested and to change their morphology depending on the substrate temperature during deposition. {copyright} {ital 1996 American Vacuum Society}

  9. Environmentally assisted cracking of LWR materials.

    SciTech Connect (OSTI)

    Chopra, O. K.; Chung, H. M.; Kassner, T. F.; Park, J. H.; Shack, W. J.; Zhang, J.; Brust, F. W.; Dong, P.

    1997-12-05T23:59:59.000Z

    The effect of dissolved oxygen level on fatigue life of austenitic stainless steels is discussed and the results of a detailed study of the effect of the environment on the growth of cracks during fatigue initiation are presented. Initial test results are given for specimens irradiated in the Halden reactor. Impurities introduced by shielded metal arc welding that may affect susceptibility to stress corrosion cracking are described. Results of calculations of residual stresses in core shroud weldments are summarized. Crack growth rates of high-nickel alloys under cyclic loading with R ratios from 0.2-0.95 in water that contains a wide range of dissolved oxygen and hydrogen concentrations at 289 and 320 C are summarized.

  10. Crack detection using resonant ultrasound spectroscopy

    DOE Patents [OSTI]

    Migliori, Albert (Santa Fe, NM); Bell, Thomas M. (Santa Fe, NM); Rhodes, George W. (Albuquerque, NM)

    1994-01-01T23:59:59.000Z

    Method and apparatus are provided for detecting crack-like flaws in components. A plurality of exciting frequencies are generated and applied to a component in a dry condition to obtain a first ultrasonic spectrum of the component. The component is then wet with a selected liquid to penetrate any crack-like flaws in the component. The plurality of exciting frequencies are again applied to the component and a second ultrasonic spectrum of the component is obtained. The wet and dry ultrasonic spectra are then analyzed to determine the second harmonic components in each of the ultrasonic resonance spectra and the second harmonic components are compared to ascertain the presence of crack-like flaws in the component.

  11. Crack detection using resonant ultrasound spectroscopy

    DOE Patents [OSTI]

    Migliori, A.; Bell, T.M.; Rhodes, G.W.

    1994-10-04T23:59:59.000Z

    Method and apparatus are provided for detecting crack-like flaws in components. A plurality of exciting frequencies are generated and applied to a component in a dry condition to obtain a first ultrasonic spectrum of the component. The component is then wet with a selected liquid to penetrate any crack-like flaws in the component. The plurality of exciting frequencies are again applied to the component and a second ultrasonic spectrum of the component is obtained. The wet and dry ultrasonic spectra are then analyzed to determine the second harmonic components in each of the ultrasonic resonance spectra and the second harmonic components are compared to ascertain the presence of crack-like flaws in the component. 5 figs.

  12. IDENTIFICATION OF AN {sup 84}Sr-DEPLETED CARRIER IN PRIMITIVE METEORITES AND IMPLICATIONS FOR THERMAL PROCESSING IN THE SOLAR PROTOPLANETARY DISK

    SciTech Connect (OSTI)

    Paton, Chad; Schiller, Martin; Bizzarro, Martin, E-mail: chadpaton@gmail.com, E-mail: schiller@snm.ku.dk, E-mail: bizzarro@snm.ku.dk [Centre for Star and Planet Formation, Natural History Museum of Denmark, University of Copenhagen, Copenhagen DK-1350 (Denmark)

    2013-02-01T23:59:59.000Z

    The existence of correlated nucleosynthetic heterogeneities in solar system reservoirs is now well demonstrated for numerous nuclides. However, it has proven difficult to discriminate between the two disparate processes that can explain such correlated variability: incomplete mixing of presolar material or secondary processing of a well-mixed disk. Using stepwise acid-leaching of the Ivuna CI-chondrite, we show that unlike other nuclides such as {sup 54}Cr and {sup 50}Ti, Sr-isotope variability is the result of a carrier depleted in {sup 84}Sr. The carrier is most likely presolar SiC, which is known to have both high Sr-concentrations relative to solar abundances and extremely depleted {sup 84}Sr compositions. Thus, variability in {sup 84}Sr in meteorites and their components can be attributed to varying contributions from presolar SiC. The observed {sup 84}Sr excesses in calcium-aluminum refractory inclusions (CAIs) suggest their formation from an SiC-free gaseous reservoir, whereas the {sup 84}Sr depletions present in differentiated meteorites require their formation from material with an increased concentration of SiC relative to CI chondrites. The presence of a positive correlation between {sup 84}Sr and {sup 54}Cr, despite being hosted in carriers of negative and positive anomalies, respectively, is not compatible with incomplete mixing of presolar material but instead suggests that the solar system's nucleosynthetic heterogeneity reflects selective thermal processing of dust. Based on vaporization experiments of SiC under nebular conditions, the lack of SiC material in the CAI-forming gas inferred from our data requires that the duration of thermal processing of dust resulting in the vaporization of CAI precursors was extremely short-lived, possibly lasting only hours to days.

  13. A literature review of coupled thermal-hydrologic-mechanical-chemical processes pertinent to the proposed high-level nuclear waste repository at Yucca Mountain

    SciTech Connect (OSTI)

    Manteufel, R.D.; Ahola, M.P.; Turner, D.R.; Chowdhury, A.H. [Southwest Research Inst., San Antonio, TX (United States). Center for Nuclear Waste Regulatory Analyses

    1993-07-01T23:59:59.000Z

    A literature review has been conducted to determine the state of knowledge available in the modeling of coupled thermal (T), hydrologic (H), mechanical (M), and chemical (C) processes relevant to the design and/or performance of the proposed high-level waste (HLW) repository at Yucca Mountain, Nevada. The review focuses on identifying coupling mechanisms between individual processes and assessing their importance (i.e., if the coupling is either important, potentially important, or negligible). The significance of considering THMC-coupled processes lies in whether or not the processes impact the design and/or performance objectives of the repository. A review, such as reported here, is useful in identifying which coupled effects will be important, hence which coupled effects will need to be investigated by the US Nuclear Regulatory Commission in order to assess the assumptions, data, analyses, and conclusions in the design and performance assessment of a geologic reposit``. Although this work stems from regulatory interest in the design of the geologic repository, it should be emphasized that the repository design implicitly considers all of the repository performance objectives, including those associated with the time after permanent closure. The scope of this review is considered beyond previous assessments in that it attempts with the current state-of-knowledge) to determine which couplings are important, and identify which computer codes are currently available to model coupled processes.

  14. Process for upgrading tar sand bitumen

    SciTech Connect (OSTI)

    Bartholic, D.B.; Reagan, W.J.

    1989-02-14T23:59:59.000Z

    A process is described for upgrading a charge of a tar sand bitumen concentrate containing metal impurities, colloidal calcium-containing clay and water. It consists of contacting the charge in a riser contacting zone in the presence of a low boiling organic solvent with hot fluidizable attrition-resistant substantially catalytically-inert microspheres, which are 20 to 150 microns in diameter and are composed of previously calcined kaolin clay. The contact takes place at high temperature and short contact time, which permits vaporization of the high hydrogen containing components of the bitumen. The period of time is less than that which induces substantial thermal cracking of the charge. At the end of the time the vaporized produce is separated from the microspheres of calcined kaolin clay, the microspheres of calcined kaolin clay now bearing a deposit of combustible solid, metal impurities and adherent particles of colloidal calcium-containing clay originally contained in the bitumen concentrate, immediately reducing the temperature of the vaporized product to minimize thermal cracking and recovering the product for further refining to produce one or more premium products.

  15. Fast electromigration crack in nanoscale aluminum film

    SciTech Connect (OSTI)

    Emelyanov, O. A., E-mail: oaemel2@gmail.com; Ivanov, I. O. [St. Petersburg State Polytechnical University, Saint-Petersburg (Russian Federation)

    2014-08-14T23:59:59.000Z

    The current-induced breakage of 20?nm thin aluminum layers deposited onto capacitor grade polypropylene (PP) films is experimentally studied. Biexponential current pulses of different amplitude (10–15?A) and duration (0.1–1??s) were applied to the samples. Breakage occurred after fast development of electromigrating ?200?nm-wide cracks with initial propagation velocity of ?1?m/s under a high current density of ?10{sup 12?}A/m{sup 2}. The cracks stopped when their lengths reached 250–450??m. This behavior is explained by the balance of electromigration and stress-induced atomic fluxes.

  16. Process of welding gamma prime-strengthened nickel-base superalloys

    DOE Patents [OSTI]

    Speigel, Lyle B.; White, Raymond Alan; Murphy, John Thomas; Nowak, Daniel Anthony

    2003-11-25T23:59:59.000Z

    A process for welding superalloys, and particularly articles formed of gamma prime-strengthened nickel-base superalloys whose chemistries and/or microstructures differ. The process entails forming the faying surface of at least one of the articles to have a cladding layer of a filler material. The filler material may have a composition that is different from both of the articles, or the same as one of the articles. The cladding layer is machined to promote mating of the faying surfaces, after which the faying surfaces are mated and the articles welded together. After cooling, the welded assembly is free of thermally-induced cracks.

  17. Time-resolved measurement of photon emission during fast crack propagation in three-point bending fracture of silica glass and soda lime glass

    SciTech Connect (OSTI)

    Shiota, Tadashi, E-mail: tshiota@ceram.titech.ac.jp; Sato, Yoshitaka; Yasuda, Kouichi [Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology, 2-12-1-S7-13 Ookayama, Meguro-ku, Tokyo 152-8550 (Japan)] [Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology, 2-12-1-S7-13 Ookayama, Meguro-ku, Tokyo 152-8550 (Japan)

    2014-03-10T23:59:59.000Z

    Simultaneous time-resolved measurements of photon emission (PE) and fast crack propagation upon bending fracture were conducted in silica glass and soda lime glass. Observation of fracture surfaces revealed that macroscopic crack propagation behavior was similar between the silica glass and soda lime glass when fracture loads for these specimens were comparable and cracks propagated without branching. However, a large difference in the PE characteristics was found between the two glasses. In silica glass, PE (645–655?nm) was observed during the entire crack propagation process, whereas intense PE (430–490?nm and 500–600?nm) was observed during the initial stages of propagation. In contrast, only weak PE was detected in soda lime glass. These results show that there is a large difference in the atomic processes involved in fast crack propagation between these glasses, and that PE can be used to study brittle fracture on the atomic scale.

  18. Environmentally assisted cracking in Light Water Reactors: Semiannual report, April 1993--September 1993. Volume 17

    SciTech Connect (OSTI)

    Chopra, O.K.; Chung, H.M.; Karlsen, T.; Kassner, T.F.; Michaud, W.F.; Ruther, W.E.; Sanecki, J.E.; Shack, W.J.; Soppet, W.K. [Argonne National Lab., IL (United States)

    1994-06-01T23:59:59.000Z

    This report summarizes work performed by Argonne National Laboratory on fatigue and environmentally assisted cracking (EAC) in light water reactors (LWRS) during the six months from April 1993 to September 1993. EAC and fatigue of piping, pressure vessels, and core components in LWRs are important concerns as extended reactor lifetimes are envisaged. Topics that have been investigated include (a) fatigue of low-alloy steel used in piping, steam generators, and reactor pressure vessels; (b) EAC of cast stainless steels (SSs); and (c) radiation-induced segregation and irradiation-assisted stress corrosion cracking of Type 304 SS after accumulation of relatively high fluence. Fatigue tests were conducted on medium-sulfur-content A106-Gr B piping and A533-Gr B pressure vessel steels in simulated PWR water and in air. Additional crack growth data were obtained on fracture-mechanics specimens of cast austenitic SSs in the as-received and thermally aged conditions in simulated boiling-water reactor (BWR) water at 289{degree}C. The data were compared with predictions based on crack growth correlations for wrought austenitic SS in oxygenated water developed at ANL and rates in air from Section 11 of the ASME Code. Microchemical and microstructural changes in high- and commercial-purity Type 304 SS specimens from control-blade absorber tubes and a control-blade sheath from operating BWRs were studied by Auger electron spectroscopy and scanning electron microscopy.

  19. REIMR - A Process for Utilizing Liquid Rocket Propulsion-Oriented 'Lessons Learned' to Mitigate Development Risk in Nuclear Thermal Propulsion

    SciTech Connect (OSTI)

    Ballard, Richard O. [Nuclear and Advanced Propulsion Systems Engineering Branch, NASA Marshall Space Flight Center, AL 35812 (United States)

    2006-01-20T23:59:59.000Z

    This paper is a summary overview of a study conducted at the NASA Marshall Space Flight Center (NASA-MSFC) during the initial phases of the Space Launch Initiative (SLI) program to evaluate a large number of technical problems associated with the design, development, test, evaluation and operation of several major liquid propellant rocket engine systems (i.e., SSME, Fastrac, J-2, F-1). One of the primary results of this study was the identification of the 'Fundamental Root Causes' that enabled the technical problems to manifest, and practices that can be implemented to prevent them from recurring in future propulsion system development efforts, such as that which is currently envisioned in the field of nuclear thermal propulsion (NTP). This paper will discus the Fundamental Root Causes, cite some examples of how the technical problems arose from them, and provide a discussion of how they can be mitigated or avoided in the development of an NTP system.

  20. Crack closure effects on fatigue crack growth thresholds and remaining life in an HSLA steel

    SciTech Connect (OSTI)

    Todd, J.A.; Mostovoy, S. [Illinois Inst. of Tech., Chicago, IL (United States). Dept. of Mechanical, Materials and Aerospace Engineering; Chen, L. [Texas Instruments, Attleboro, MA (United States); Yankov, E.Y. [A. Finkl and Sons, Chicago, IL (United States)

    1997-02-01T23:59:59.000Z

    The effects of crack closure on the near-threshold corrosion fatigue crack growth behavior of Mil S-24645 HSLA steel and its weld metal have been investigated in air, ASTM seawater at the free corrosion potential, and ASTM seawater at {minus}0.8V and {minus}1.0V (SCE) using frequencies of 10, 2, and 0.2 Hz, and a stress ratio, R = 0.1. Remaining life, in the presence and absence of crack closure, has been estimated as a function of applied stress range for a structure containing a 3-mm-deep surface semi-elliptical flaw.

  1. Eddy-current interaction with an ideal crack. II. The inverse problem John FL Bowler

    E-Print Network [OSTI]

    Bowler, John R.

    Eddy-current interaction with an ideal crack. II. The inverse problem John FL Bowler The University 1994) Eddy-current inversion is the process whereby the geometry of a flaw in a metal is derived from eddy-current probe impedance measurements. The approach is based on an optimization scheme that seeks

  2. Analysis of cracked piezoelectric solids by a mixed three-dimensional BE approach

    E-Print Network [OSTI]

    Ariza Moreno, Pilar

    regularization and evaluation of boundary integrals. Quadratic boundary elements and quarter-point boundary isotropy. Piezoelectric ceramics are used for construction of sensors, transducers, actuators as well, these brittle materials are likely to develop cracks. The under- standing and evaluation of the fracture process

  3. Permeability and elastic properties of cracked glass under pressure A. OugierSimonin,1

    E-Print Network [OSTI]

    Fortin, Jérôme

    corrosion, which should be considered in further study. Citation: OugierSimonin, A., Y. Guéguen, J. Fortin issues (stability of boreholes, stimulation of oil and geother- mal reservoirs, the design of tunnels on slow crack growth and stress corrosion processes [Wiederhorn, 1966; Anderson and Grew, 1977; Atkinson

  4. Reflective Cracking Study: HVS Test Section Forensic Investigation

    E-Print Network [OSTI]

    Jones, David; Steven, B.; Harvey, John T

    2008-01-01T23:59:59.000Z

    the asphalt concrete. Summary of Testing on the Underlyingtesting performed to validate Caltrans overlay strategies for the rehabilitation of cracked asphalt concrete.concrete. It describes the forensic investigation of the HVS rutting and reflective cracking testing

  5. Characterization of Fatigue Cracking and Healing of Asphalt Mixtures

    E-Print Network [OSTI]

    Luo, Xue

    2012-07-16T23:59:59.000Z

    mixtures using an energy-based mechanistic approach. A controlled-strain repeated direct tension (RDT) test is selected to generate both fatigue cracking and permanent deformation in an asphalt mixture specimen. Fatigue cracking is separated from...

  6. Grain Boundary Structure Effects on Intergranular Stress Corrosion Cracking of

    E-Print Network [OSTI]

    Olson, Tamara

    Grain Boundary Structure Effects on Intergranular Stress Corrosion Cracking of Alloy X­750 Y. Pan B­of­freedom) and correlations with intergranular stress corrosion cracking observed in Alloy X­750. Orientation imaging

  7. EDDY CURRENT SYSTEM FOR DETECTION OF CRACKING BENEATH BRAIDING IN CORRUGATED METAL HOSE

    SciTech Connect (OSTI)

    Wincheski, Buzz [NASA Langley Research Center, Hampton, VA 23681 (United States); Simpson, John [Lockheed Martin Space Operations, Hampton, VA 23681 (United States); Hall, George [George Washington University, Washington, D.C. 20052 (United States)

    2009-03-03T23:59:59.000Z

    In this paper an eddy current system for the detection of partially-through-the-thickness cracks in corrugated metal hose is presented. Design criteria based upon the geometry and conductivity of the part are developed and applied to the fabrication of a prototype inspection system. Experimental data are used to highlight the capabilities of the system and an image processing technique is presented to improve flaw detection capabilities. A case study for detection of cracking damage in a space shuttle radiator retract flex hoses is also presented.

  8. A dynamical law for slow crack growth in polycarbonate films

    E-Print Network [OSTI]

    Cortet, Pierre-Philippe; Ciliberto, Sergio

    2007-01-01T23:59:59.000Z

    We study experimentally the slow growth of a single crack in polycarbonate films submitted to uniaxial and constant imposed stress. For this visco-plastic material, we uncover a dynamical law that describes the dependence of the instantaneous crack velocity with experimental parameters. The law involves a Dugdale-Barenblatt static description of crack tip plastic zones associated to an Eyring's law and an empirical dependence with the crack length that may come from a residual elastic field.

  9. autogenous shrinkage cracking: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of Restrained Shrinkage Cracking of Concrete Materials," 15th International Glass Fibre Reinforced Concrete Association Engineering Websites Summary: . The experiments...

  10. Progressive flow cracking of coal/oil mixtures with high metals content catalyst

    SciTech Connect (OSTI)

    Zandona, O.J.

    1989-10-10T23:59:59.000Z

    This patent describes a process for economically producing liquid fuel products at least partly from coal. It comprises: introducing a progressive flow catalytic cracking zone a charge stock comprising a pumpable mixture of solid, particulate coal and carbo-metallic oil and forming within the zone a stream having a linear velocity of at least about 25 feet per second. The stream comprising the charge stock and a hydrocarbon zeolite cracking catalyst promoting dehydrogenation of the charge stock; forming mobile hydrogen within the zone by the dehydrogenation; introducing the mobile hydrogen into the stream by dehydrogenation of the charge stock in the absence of added molecular hydrogen, thereby producing liquid products from the charge stock while laying down coke on the hydrocarbon cracking catalyst in the range of about 0.3% to about 3% and thereby producing spent catalyst; separating from the spent catalyst the liquid products.

  11. Nanoparticulate-catalyzed oxygen transfer processes

    DOE Patents [OSTI]

    Hunt, Andrew T. (Atlanta, GA); Breitkopf, Richard C. (Dunwoody, GA)

    2009-12-01T23:59:59.000Z

    Nanoparticulates of oxygen transfer materials that are oxides of rare earth metals, combinations of rare earth metals, and combinations of transition metals and rare earth metals are used as catalysts in a variety of processes. Unexpectedly large thermal efficiencies are achieved relative to micron sized particulates. Processes that use these catalysts are exemplified in a multistage reactor. The exemplified reactor cracks C6 to C20 hydrocarbons, desulfurizes the hydrocarbon stream and reforms the hydrocarbons in the stream to produce hydrogen. In a first reactor stage the steam and hydrocarbon are passed through particulate mixed rare earth metal oxide to crack larger hydrocarbon molecules. In a second stage, the steam and hydrocarbon are passed through particulate material that desulfurizes the hydrocarbon. In a third stage, the hydrocarbon and steam are passed through a heated, mixed transition metal/rare earth metal oxide to reform the lower hydrocarbons and thereby produce hydrogen. Stages can be alone or combined. Parallel reactors can provide continuous reactant flow. Each of the processes can be carried out individually.

  12. CRACK STATISTIC OF CRYSTALLINE SILICON PHOTOVOLTAIC MODULES M. Kntges1

    E-Print Network [OSTI]

    the risk of cracks, as well as for statistical power loss assessment. Keywords: PV module, micro cracks separation, thus resulting in inactive cell parts. For this special case a clear assessment of the power loss this gap and provide a first statistic of cracks in PV modules for future power loss assessment

  13. RESEARCH Open Access Pavement crack characteristic detection based

    E-Print Network [OSTI]

    Joensuu, University of

    RESEARCH Open Access Pavement crack characteristic detection based on sparse representation Xiaoming Sun1 , Jianping Huang1 , Wanyu Liu1* and Mantao Xu2 Abstract Pavement crack detection plays an important role in pavement maintaining and management. The three- dimensional (3D) pavement crack detection

  14. Enhanced ultrasonic detection of fatigue cracks by laser-induced crack closure

    E-Print Network [OSTI]

    Nagy, Peter B.

    , corrosion, etc. . Sec- ond, it is important to distinguish small fatigue cracks as early as possible after threshold in aluminum, aluminum­ lithium, and titanium alloys.1 For example, extensive multiple-site fatigue

  15. Stress corrosion cracking and crack tip characterization of Alloy X-750 in light water reactor environments

    E-Print Network [OSTI]

    Gibbs, Jonathan Paul

    2011-01-01T23:59:59.000Z

    Stress corrosion cracking (SCC) susceptibility of Inconel Alloy X-750 in the HTH condition has been evaluated in high purity water at 93 and 288°C under Boiling Water Reactor Normal Water Chemistry (NWC) and Hydrogen Water ...

  16. Stress Corrosion Cracking and Crack Tip Characterization of Alloy X-750 in Light Water Reactor Environments

    E-Print Network [OSTI]

    Gibbs, Jonathan Paul

    Stress corrosion cracking (SCC) susceptibility of Inconel Alloy X-750 in the HTH condition has been evaluated in high purity water at 93 and 288°C under Boiling Water Reactor Normal Water Chemistry (NWC) and Hydrogen Water ...

  17. Holographic thermalization in noncommutative geometry

    E-Print Network [OSTI]

    Xiao-Xiong Zeng; Xian-Ming Liu; Wen-Biao Liu

    2015-05-02T23:59:59.000Z

    Gravitational collapse of a shell of dust in noncommutative geometry is probed by the renormalized geodesic length, which is dual to probe the thermalization by the two-point correlation function in the dual conformal field theory. We find that larger the noncommutative parameter is, longer the thermalization time is, which implies that the large noncommutative parameter delays the thermalization process. We also investigate how the noncommutative parameter affects the thermalization velocity and thermalization acceleration.

  18. The true toughness of human cortical bone measured with realistically short cracks

    E-Print Network [OSTI]

    Ritchie, Robert

    crack-resistance curves. We find that after only 500 µm of cracking, the driving force for crack. However, the toughness in the longitudinal orientation, where cracks tend to follow the cement lines mechanisms, which act primarily in the crack wake to `shield' the crack from the applied driving force

  19. Digital radiographic systems detect boiler tube cracks

    SciTech Connect (OSTI)

    Walker, S. [EPRI, Charlotte, NC (United States)

    2008-06-15T23:59:59.000Z

    Boiler water wall leaks have been a major cause of steam plant forced outages. But conventional nondestructive evaluation techniques have a poor track record of detecting corrosion fatigue cracking on the inside surface of the cold side of waterwall tubing. EPRI is performing field trials of a prototype direct-digital radiographic system that promises to be a game changer. 8 figs.

  20. Environmentally assisted cracking in light water reactors

    SciTech Connect (OSTI)

    Chopra, O.K.; Chung, H.M.; Gruber, E.E. [and others

    1996-07-01T23:59:59.000Z

    This report summarizes work performed by Argonne National Laboratory on fatigue and environmentally assisted cracking (EAC) in light water reactors (LWRs) from April 1995 to December 1995. Topics that have been investigated include fatigue of carbon and low-alloy steel used in reactor piping and pressure vessels, EAC of Alloy 600 and 690, and irradiation-assisted stress corrosion cracking (IASCC) of Type 304 SS. Fatigue tests were conducted on ferritic steels in water that contained various concentrations of dissolved oxygen (DO) to determine whether a slow strain rate applied during different portions of a tensile-loading cycle are equally effective in decreasing fatigue life. Crack-growth-rate tests were conducted on compact-tension specimens from several heats of Alloys 600 and 690 in simulated LWR environments. Effects of fluoride-ion contamination on susceptibility to intergranular cracking of high- and commercial- purity Type 304 SS specimens from control-tensile tests at 288 degrees Centigrade. Microchemical changes in the specimens were studied by Auger electron spectroscopy and scanning electron microscopy to determine whether trace impurity elements may contribute to IASCC of these materials.

  1. Process development and techno-economic analysis of a novel process for MeOH production from CO2 using solar-thermal energy.

    SciTech Connect (OSTI)

    Henao, Carlos (University of Wisconsin); Kim, Jiyong (University of Wisconsin); Johnson, Terry Alan; Stechel, Ellen Beth; Dedrick, Daniel E.; Maravelias, Christos T. (University of Wisconsin); Miller, James Edward

    2010-11-01T23:59:59.000Z

    Mitigating and overcoming environmental problems brought about by the current worldwide fossil fuel-based energy infrastructure requires the creation of innovative alternatives. In particular, such alternatives must actively contribute to the reduction of carbon emissions via carbon recycling and a shift to the use of renewable sources of energy. Carbon neutral transformation of biomass to liquid fuels is one of such alternatives, but it is limited by the inherently low energy efficiency of photosynthesis with regard to the net production of biomass. Researchers have thus been looking for alternative, energy-efficient chemical routes inspired in the biological transformation of solar power, CO2 and H2O into useful chemicals; specifically, liquid fuels. Methanol has been the focus of a fair number of publications for its versatility as a fuel, and its use as an intermediate chemical in the synthesis of many compounds. In some of these studies, (e.g. Joo et al., (2004), Mignard and Pritchard (2006), Galindo and Badr (2007)) CO2 and renewable H2 (e.g. electrolytic H2) are considered as the raw materials for the production of methanol and other liquid fuels. Several basic PFD diagrams have been proposed. One of the most promising is the so called CAMERE process (Joo et al., 1999 ). In this process, carbon dioxide and renewable hydrogen are fed to a first reactor and transformed according to: H2 + CO2 <=> H2O + CO Reverse Water Gas Shift (RWGS) After eliminating the produced water the resulting H2/CO2/CO mixture is then feed to a second reactor where it is converted to methanol according to: CO2 + 3.H2 <=> CH3OH + H2O Methanol Synthesis (MS) CO + H2O <=> CO2 + H2 Water Gas Shift (WGS) The approach here is to produce enough CO to eliminate, via WGS, the water produced by MS. This is beneficial since water has been proven to block active sites in the MS catalyst. In this work a different process alternative is presented: One that combines the CO2 recycling of the CAMERE process and the use of solar energy implicit in some of the biomass-based process, but in this case with the potential high energy efficiency of thermo-chemical transformations.

  2. Ashland Oil Inc. has new heavy oil cracking technology

    SciTech Connect (OSTI)

    Not Available

    1980-04-21T23:59:59.000Z

    Ashland's new ''Reduced Crude Conversion'' is a fluid catalytic cracking process that permits more efficient use of the bottoms of the crude barrel, including the production of a given amount of gasoline from 20% less crude. Gasoline yields go from 49.8% for Arabian light crudes to 56.9% for Murban crudes. The new process, details of which have not been revealed, operates at ''high'' temperatures and about 1 atm; requires no feed hydrogen (and therefore, according to Ashland, compares favorably with hydrocracking); is not inhibited by catalyst poisons such as nickel and vanadium, even though these metals might adhere to the proprietary catalyst; and probably uses a zeolite catalyst. Ashland is planning a $70 million, 40,000 bbl/day unit which is scheduled to go on stream in 1982 at its Catlettsburg, Ky., refinery.

  3. Model of crack propagation in a clay soil

    E-Print Network [OSTI]

    Carriere, Patrick Edwidge

    1985-01-01T23:59:59.000Z

    in elevation of the soil surface were recorded over time of drying for each of the treatments. A logarithmic model to predict the crack depth, the crack width, and the drop in elevation of the soil surface expressed by the equation y = A + C*logt, was found... 2 MEANS procedure results for crack depth. 3 ANOVA results for crack depth. 19 29 30 4 Values of A and C obtained from linear regression analysis for crack depth. 35 5 Selection of combinations of independent variables for maximum R...

  4. Why Do Kraft Recovery Boiler Composite Floor Tubes Crack?

    SciTech Connect (OSTI)

    Keiser, J.R.

    2001-10-22T23:59:59.000Z

    Cracks were first reported in 1992 in co-extruded 304L stainless steel/SA210 Gd Al carbon steel floor tubes of North American black liquor recovery boilers. Since then, a considerable amount of information has been collected on the tube environment, crack characteristics, the stress state of the tubes, and the crack initiation and propagation mechanisms. These studies have identified both operating procedures that apparently can greatly lessen the likelihood of crack formation in the stainless steel layer and alternate materials that appear to be much more resistant to cracking than is 304L stainless.

  5. Thermally Processed High-Mobility MOS Thin-Film Transistors on Transferable Single-Crystal Elastically Strain-Sharing Si/SiGe/Si Nanomembranes

    SciTech Connect (OSTI)

    Yuan, H.-C.; Kelly, M. M.; Savage, D. E.; Lagally, M. G.; Celler, G. K.; Zhenqiang, M.

    2008-03-01T23:59:59.000Z

    Demonstration of high-performance MOS thin-film transistors (TFTs) on elastically strain-sharing single-crystal Si/SiGe/Si nanomembranes (SiNMs) that are transferred to foreign substrates is reported. The transferable SiNMs are realized by first growing pseudomorphic SiGe and Si layers on silicon-on-insulator (SOI) substrates, and then, selectively removing the buried oxide (BOX) layer from the SOI. Before the release, only the SiGe layer is compressively strained. Upon release, part of the compressive strain in the SiGe layer is transferred to the thin Si layers, and the Si layers, thus, become tensile strained. Both the initial compressive strain state in the SiGe layer and the final strain sharing state between the SiGe and the Si layers are verified with X-ray diffraction measurements. The TFTs are fabricated employing the conventional high-temperature MOS process on the strain-shared SiNMs that are transferred to an oxidized Si substrate. The transferred strained-sharing SiNMs show outstanding thermal stability and can withstand the high-temperature TFT process on the new host substrate. The strained-channel TFTs fabricated on the new host substrate show high current drive capability and an average electron effective mobility of 270 cm{sup 2}/V ldr s. The results suggest that transferable and thermally stable single-crystal elastically strain- sharing SiNMs can serve as excellent active material for high-speed device application with a simple and scalable transfer method. The demonstration of MOS TFTs on the transferable nanomembranes may create the opportunity for future high-speed Si CMOS heterogeneous integration on any substrate.

  6. Modeling and Optimization of Direct Chill Casting to Reduce Ingot Cracking

    SciTech Connect (OSTI)

    Das, Subodh K.

    2006-01-09T23:59:59.000Z

    A successful four-year project on the modeling and optimization of direct chill (DC) casting to reduce ingot cracking has been completed. The project involved close collaboration among private industries, national laboratories, and universities. During the four-year project, 16 quarterly meetings brought the industrial partners and the research team together for discussion of research results and research direction. The industrial partners provided guidance, facilities, and experience to the research team. The research team went to two industrial plants to measure temperature distributions in commercial 60,000-lb DC casting ingot. The collaborative research resulted in several major accomplishments or findings: (1) Surface cracks were shown to be a result of hot tearing rather than cold cracks, as was thought before this project. These cracks form on the surface of a DC cast ingot just above the impingement point of the secondary cooling water jets. The cracks form along dendrite and grain boundaries, where solute and impurity elements are highly segregated. This understanding led to the development of a new technique for determining the mechanical properties in the nonequilibrium mushy zone of alloys and to thermodynamic predictions of the hot tearing propensity of DC cast ingots. (2) The apparent heat transfer coefficient (HTC) at the ingot surface in the water cooling region during DC casting was determined on the basis of temperature measurements in commercial DC casting ingots and an inverse heat transfer analysis. HTCs were calculated as a function of temperature and time, and covered the different regimes of heat transfer expected during DC casting. The calculated values were extrapolated to include the effect of water flow rate. The calculated HTCs had a peak at around 200 C, corresponding to the high heat transfer rates during nucleate boiling, and the profile was consistent with similar data published in the literature. (3) A new method, termed the reheating-cooling method (RCM), was developed and validated for measuring mechanical properties in the nonequilibrium mushy zones of alloys. The new method captures the brittle nature of aluminum alloys at temperatures close to the nonequilibrium solidus temperature, while specimens tested using the reheating method exhibit significant ductility. The RCM has been used for determining the mechanical properties of alloys at nonequilibrium mushy zone temperatures. Accurate data obtained during this project show that the metal becomes more brittle at high temperatures and high strain rates. (4) The elevated-temperature mechanical properties of the alloy were determined. Constitutive models relating the stress and strain relationship at elevated temperatures were also developed. The experimental data fit the model well. (5) An integrated 3D DC casting model has been used to simulate heat transfer, fluid flow, solidification, and thermally induced stress-strain during casting. A temperature-dependent HTC between the cooling water and the ingot surface, cooling water flow rate, and air gap were coupled in this model. An elasto-viscoplastic model based on high-temperature mechanical testing was used to calculate the stress during casting. The 3D integrated model can be used for the prediction of temperature, fluid flow, stress, and strain distribution in DC cast ingots. (6) The cracking propensity of DC cast ingots can be predicted using the 3D integrated model as well as thermodynamic models. Thus, an ingot cracking index based on the ratio of local stress to local alloy strength was established. Simulation results indicate that cracking propensity increases with increasing casting speed. The composition of the ingots also has a major effect on cracking formation. It was found that copper and zinc increase the cracking propensity of DC cast ingots. The goal of this Aluminum Industry of the Future (IOF) project was to assist the aluminum industry in reducing the incidence of stress cracks in DC castings from a current level of 5% down to 2%. This could lead to energy savings

  7. Residual stresses and stress corrosion cracking in pipe fittings

    SciTech Connect (OSTI)

    Parrington, R.J.; Scott, J.J.; Torres, F.

    1994-06-01T23:59:59.000Z

    Residual stresses can play a key role in the SCC performance of susceptible materials in PWR primary water applications. Residual stresses are stresses stored within the metal that develop during deformation and persist in the absence of external forces or temperature gradients. Sources of residual stresses in pipe fittings include fabrication processes, installation and welding. There are a number of methods to characterize the magnitude and orientation of residual stresses. These include numerical analysis, chemical cracking tests, and measurement (e.g., X-ray diffraction, neutron diffraction, strain gage/hole drilling, strain gage/trepanning, strain gage/section and layer removal, and acoustics). This paper presents 400 C steam SCC test results demonstrating that residual stresses in as-fabricated Alloy 600 pipe fittings are sufficient to induce SCC. Residual stresses present in as-fabricated pipe fittings are characterized by chemical cracking tests (stainless steel fittings tested in boiling magnesium chloride solution) and by the sectioning and layer removal (SLR) technique.

  8. Soil cracking modelling using the mesh-free SPH method

    E-Print Network [OSTI]

    Bui, H H; Kodikara, J; Sanchez, M

    2015-01-01T23:59:59.000Z

    The presence of desiccation cracks in soils can significantly alter their mechanical and hydrological properties. In many circumstances, desiccation cracking in soils can cause significant damage to earthen or soil supported structures. For example, desiccation cracks can act as the preference path way for water flow, which can facilitate seepage flow causing internal erosion inside earth structures. Desiccation cracks can also trigger slope failures and landslides. Therefore, developing a computational procedure to predict desiccation cracking behaviour in soils is vital for dealing with key issues relevant to a range of applications in geotechnical and geo-environment engineering. In this paper, the smoothed particle hydrodynamics (SPH) method will be extended for the first time to simulate shrinkage-induced soil cracking. The main objective of this work is to examine the performance of the proposed numerical approach in simulating the strong discontinuity in material behaviour and to learn about the crack ...

  9. SCREENING TESTS FOR IMPROVED METHANE CRACKING MATERIALS

    SciTech Connect (OSTI)

    Klein, J; Jeffrey Holder, J

    2007-07-16T23:59:59.000Z

    Bench scale (1 to 6 gram) methane cracking tests have been performed on a variety of pure elements, some alloys, and SAES{reg_sign} commercial getters St 101, St 198, St 707, St 737, and St 909 to determine methane cracking performance (MCP) of 5% methane in a helium carrier at 700 C, 101.3 kPa (760 torr) with a 10 sccm feed. The MCP was almost absent from some materials tested while others showed varying degrees of MCP. Re, Cr, V, Gd, and Mo powders had good MCP, but limited capacities. Nickel supported on kieselguhr (Ni/k), a Zr-Ni alloy, and the SAES{reg_sign} getters had good MCP in a helium carrier. The MCP of these same materials was suppressed in a hydrogen carrier stream and the MCP of the Zr-based materials was reduced by nitride formation when tested with a nitrogen carrier gas.

  10. Screening tests for improved methane cracking materials

    SciTech Connect (OSTI)

    Klein, J. E.; Hoelder, J. S. [Savannah River National Laboratory, Aiken, SC 29808 (United States)

    2008-07-15T23:59:59.000Z

    Bench scale (1 to 6 gram) methane cracking tests have been performed on a variety of pure elements, some alloys, and SAES{sup R} commercial getters St 101, St 198, St 707, St 737, and St 909 to determine methane cracking performance (MCP) of 5% methane in a helium carrier at 700 deg.C, 101.3 kPa (760 torr) with a 10 seem feed. The MCP was almost absent from some materials tested while others showed varying degrees of MCP. Re, Cr, V, Gd, and Mo powders had good MCP, but limited capacities. Nickel supported on kieselguhr (Ni/k), a Zr-Ni alloy, and the SAESr getters had good MCP in a helium carrier. The MCP of these same materials was suppressed in a hydrogen carrier stream and the MCP of the Zr-based materials was reduced by nitride formation when tested with a nitrogen carrier gas. (authors)

  11. Circumferential cracking of steam generator tubes

    SciTech Connect (OSTI)

    Karwoski, K.J.

    1997-04-01T23:59:59.000Z

    On April 28, 1995, the U.S. Nuclear Regulatory Commission (NRC) issued Generic Letter (GL) 95-03, {open_quote}Circumferential Cracking of Steam Generator Tubes.{close_quote} GL 95-03 was issued to obtain information needed to verify licensee compliance with existing regulatory requirements regarding the integrity of steam generator tubes in domestic pressurized-water reactors (PWRs). This report briefly describes the design and function of domestic steam generators and summarizes the staff`s assessment of the responses to GL 95-03. The report concludes with several observations related to steam generator operating experience. This report is intended to be representative of significant operating experience pertaining to circumferential cracking of steam generator tubes from April 1995 through December 1996. Operating experience prior to April 1995 is discussed throughout the report, as necessary, for completeness.

  12. The effect of fluence and irradiation temperature on delayed hydride cracking in Zr-2.5Nb

    SciTech Connect (OSTI)

    Sagat, S.; Coleman, C.E.; Griffiths, M. [AECL Research, Chalk River, Ontario (Canada); Wilkins, B.J.S. [AECL Research, Pinawa, Manitoba (Canada)

    1994-12-31T23:59:59.000Z

    Zirconium alloys are susceptible to a stable cracking process called delayed hydride cracking (DHC). DHC has two stages: (a) crack initiation that requires a minimum crack driving force (the threshold stress intensity factor, K{sub IH}) and (b) stable crack growth that is weakly dependent on K{sub l}. The value of K{sub lH} is an important element in determining the tolerance of components to sharp flaws. The rate of cracking is used in estimating the action time for detecting propagating cracks before they become unstable. Hence, it is important for reactor operators to know how these properties change during service in reactors where the components are exposed to neutron irradiation at elevated temperatures. DHC properties were measured on a number of components, made from the two-phase alloy Zr-2.5 Nb, irradiated at temperatures in the range of 250 to 290 C in fast neutron fluxes (E {>=} 1 MeV) between 1.6 {times} 10{sup 17} and 1.8 {times} 10{sup 18} n/m{sup 2} {center_dot} s to fluences between 0.01 {times} 10{sup 25} and 9.8 {times} 10{sup 25} n/m{sup 2}. The neutron irradiation reduced K{sub IH} by about 20% and increased the velocity of cracking by a factor of about five. The increase in crack velocity was greatest with the lowest irradiation temperature. These changes in the rack velocity by neutron irradiation are explained in terms of the combined effects of irradiation hardening associated with increased -type dislocation density, and {beta}-phase decomposition. While the former process increases crack velocity, the latter process decrease it. The combined contribution is controlled by the irradiation temperature. X-ray diffraction analyses showed that the degree of {beta}-phase decomposition was highest with an irradiation temperature of 290 C while -type dislocation densities were highest with an irradiation temperature of 250 C.

  13. Syngas Production from Propane Using Atmospheric Non-thermal Plasma

    E-Print Network [OSTI]

    Ouni, Fakhreddine; Cormier, Jean Marie; 10.1007/s11090-009-9166-2

    2009-01-01T23:59:59.000Z

    Propane steam reforming using a sliding discharge reactor was investigated under atmospheric pressure and low temperature (420 K). Non-thermal plasma steam reforming proceeded efficiently and hydrogen was formed as a main product (H2 concentration up to 50%). By-products (C2-hydrocarbons, methane, carbon dioxide) were measured with concentrations lower than 6%. The mean electrical power injected in the discharge is less than 2 kW. The process efficiency is described in terms of propane conversion rate, steam reforming and cracking selectivity, as well as by-products production. Chemical processes modelling based on classical thermodynamic equilibrium reactor is also proposed. Calculated data fit quiet well experimental results and indicate that the improvement of C3H8 conversion and then H2 production can be achieved by increasing the gas fraction through the discharge. By improving the reactor design, the non-thermal plasma has a potential for being an effective way for supplying hydrogen or synthesis gas.

  14. Solar Thermal Conversion

    SciTech Connect (OSTI)

    Kreith, F.; Meyer, R. T.

    1982-11-01T23:59:59.000Z

    The thermal conversion process of solar energy is based on well-known phenomena of heat transfer (Kreith 1976). In all thermal conversion processes, solar radiation is absorbed at the surface of a receiver, which contains or is in contact with flow passages through which a working fluid passes. As the receiver heats up, heat is transferred to the working fluid which may be air, water, oil, or a molten salt. The upper temperature that can be achieved in solar thermal conversion depends on the insolation, the degree to which the sunlight is concentrated, and the measures taken to reduce heat losses from the working fluid.

  15. Radiation-induced instability of MnS precipitates and its possible consequences on irradiation-induced stress corrosion cracking of austenitic stainless steels

    SciTech Connect (OSTI)

    Chung, H.M.; Sanecki, J.E. [Argonne National Lab., IL (United States); Garner, F.A. [Pacific Northwest National Lab., Richland, WA (United States)

    1996-12-01T23:59:59.000Z

    Irradiation-assisted stress corrosion cracking (IASCC) is a significant materials issue for the light water reactor (LWR) industry and may also pose a problem for fusion power reactors that will use water as coolant. A new metallurgical process is proposed that involves the radiation-induced release into solution of minor impurity elements not usually thought to participate in IASCC. MnS-type precipitates, which contain most of the sulfur in stainless steels, are thought to be unstable under irradiation. First, Mn transmutes strongly to Fe in thermalized neutron spectra. Second, cascade-induced disordering and the inverse Kirkendall effect operating at the incoherent interfaces of MnS precipitates are thought to act as a pump to export Mn from the precipitate into the alloy matrix. Both of these processes will most likely allow sulfur, which is known to exert a deleterious influence on intergranular cracking, to re-enter the matrix. To test this hypothesis, compositions of MnS-type precipitates contained in several unirradiated and irradiated heats of Type 304, 316, and 348 stainless steels (SSs) were analyzed by Auger electron spectroscopy. Evidence is presented that shows a progressive compositional modification of MnS precipitates as exposure to neutrons increases in boiling water reactors. As the fluence increases, the Mn level in MnS decreases, whereas the Fe level increases. The S level also decreases relative to the combined level of Mn and Fe. MnS precipitates were also found to be a reservoir of other deleterious impurities such as F and O which could be also released due to radiation-induced instability of the precipitates.

  16. Systems analysis of thermal storage

    SciTech Connect (OSTI)

    Copeland, R.J.

    1981-08-01T23:59:59.000Z

    During FY 1981, analyses were conducted on thermal storage concepts for solar thermal applications. These studies include estimates of both the obtainable costs of thermal storage concepts and their worth to a user (i.e., value). Based on obtainable costs and performance, an in-depth study evaluated thermal storage concepts for water/steam, organic fluid, and gas/Brayton solar thermal receivers. Promising and nonpromising concepts were identified. A study to evaluate thermal storage concepts for a liquid metal receiver was initiated. The value of thermal storage in a solar thermal industrial process heat application was analyzed. Several advanced concepts are being studied, including ground-mounted thermal storage for parabolic dishes with Stirling engines.

  17. CYCLIC PLASTICITY OF A CRACKED STRUCTURE SUBJECTED TO MIXED MODE LOADING

    E-Print Network [OSTI]

    CYCLIC PLASTICITY OF A CRACKED STRUCTURE SUBJECTED TO MIXED MODE LOADING Sylvie Pommier1, a 1 LMT, mixed mode crack propagation, plasticity, crack deflection. Abstract. Cyclic plasticity in the crack tip stresses in the overload's plastic zone. Moreover, if the overload's ratio is large enough, the crack may

  18. amplitude fatigue crack: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    rate testing to evaluate the susceptibility of metallic materials to environmentally assisted cracking CERN Preprints Summary: 1.1 This practice covers procedures for the design,...

  19. assisted cracking resistance: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    video system, crack initiation, propagation, and ... Miller, James Thomas, Ph. D. Massachusetts Institute of Technology 2008-01-01 36 Dynamic fracture of compositionally...

  20. alligator cracking: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    video system, crack initiation, propagation, and ... Miller, James Thomas, Ph. D. Massachusetts Institute of Technology 2008-01-01 40 A new alligator-clip compound for...

  1. P wave anisotropy, stress, and crack distribution at Coso geothermal...

    Open Energy Info (EERE)

    Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: P wave anisotropy, stress, and crack distribution at Coso geothermal field, California...

  2. Tribological Analysis of White Etching Crack (WEC) Failures in...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Crack (WEC) Failures in Rolling Element Bearings Presented by Arnaud Ruellan, INSA de Lyon at the Wind Turbine Tribology Seminar 2014. 20141030NREL2014ArgonneRuellancomV...

  3. NORTHWESTERN UNIVERSITY Qualification of Autonomous Crack Monitoring Systems

    E-Print Network [OSTI]

    NORTHWESTERN UNIVERSITY Qualification of Autonomous Crack Monitoring Systems A Thesis Submitted Term or Static Testing Equipment Setup.............................................29 Long Term Response.....................................................................33 Dynamic Testing Equipment

  4. Crack opening area estimates in pressurized through-wall cracked elbows under bending

    SciTech Connect (OSTI)

    Franco, C.; Gilles, P.; Pignol, M.

    1997-04-01T23:59:59.000Z

    One of the most important aspects in the leak-before-break approach is the estimation of the crack opening area corresponding to potential through-wall cracks at critical locations during plant operation. In order to provide a reasonable lower bound to the leak area under such loading conditions, numerous experimental and numerical programs have been developed in USA, U.K. and FRG and widely discussed in literature. This paper aims to extend these investigations on a class of pipe elbows characteristic of PWR main coolant piping. The paper is divided in three main parts. First, a new simplified estimation scheme for leakage area is described, based on the reference stress method. This approach mainly developed in U.K. and more recently in France provides a convenient way to account for the non-linear behavior of the material. Second, the method is carried out for circumferential through-wall cracks located in PWR elbows subjected to internal pressure. Finite element crack area results are presented and comparisons are made with our predictions. Finally, in the third part, the discussion is extended to elbows under combined pressure and in plane bending moment.

  5. Cracking in reinforced concrete bent caps

    E-Print Network [OSTI]

    Young, Bradley S.

    2000-01-01T23:59:59.000Z

    ) . . . . . . . . . . . . . . . . 4. 2 Group It2 Response (Specimens 3C, 3D, 4C, 4E, 5D, 5E) . . . 4. 3 Group tt3 Response (Specimens 6F, 6G, 7F, 7H, 8G, 8H) . . . 4. 4 General Response 4. 5 Sununary. . . . . 49 . . . . 58 . . . . 64 70 . . . 75 5. STRUT-AND-TIE MODELING... be expressed as the product of the steel strain (s, ) at that level multiplied by the crack spacing (s, ); 20 w =z*s C S C (2. 6) a linear strain gradient can be used to project the maximum strain occurring at the level of the flexural reinforcement...

  6. 3:2:1 Crack Spread

    Gasoline and Diesel Fuel Update (EIA)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for On-Highway4,1,50022,3,,,,6,1,9,1,50022,3,,,,6,1,Decade Year-0E (2001)gasoline prices4 Oil demand8)Commercial5 1:2:1 Crack

  7. Composite tube cracking in kraft recovery boilers: A state-of-the-art review

    SciTech Connect (OSTI)

    Singbeil, D.L.; Prescott, R. [Pulp and Paper Research Inst. of Canada, Vancouver, British Columbia (Canada); Keiser, J.R.; Swindeman, R.W. [Oak Ridge National Lab., TN (United States)

    1997-07-01T23:59:59.000Z

    Beginning in the mid-1960s, increasing energy costs in Finland and Sweden made energy recovery more critical to the cost-effective operation of a kraft pulp mill. Boiler designers responded to this need by raising the steam operating pressure, but almost immediately the wall tubes in these new boilers began to corrode rapidly. Test panels installed in the walls of the most severely corroding boiler identified austenitic stainless steel as sufficiently resistant to the new corrosive conditions, and discussions with Sandvik AB, a Swedish tube manufacturer, led to the suggestion that coextruded tubes be used for water wall service in kraft recovery boilers. Replacement of carbon steel by coextruded tubes has solved most of the corrosion problems experienced by carbon steel wall tubes, however, these tubes have not been problem-free. Beginning in early 1995, a multidisciplinary research program funded by the US Department of Energy was established to investigate the cause of cracking in coextruded tubes and to develop improved materials for use in water walls and floors of kraft recovery boilers. One portion of that program, a state-of-the-art review of public- and private-domain documents related to coextruded tube cracking in kraft recovery boilers is reported here. Sources of information that were consulted for this review include the following: tube manufacturers, boiler manufacturers, public-domain literature, companies operating kraft recovery boilers, consultants and failure analysis laboratories, and failure analyses conducted specifically for this project. Much of the information contained in this report involves cracking problems experienced in recovery boiler floors and those aspects of spout and air-port-opening cracking not readily attributable to thermal fatigue. 61 refs.

  8. Solar-thermal reaction processing

    DOE Patents [OSTI]

    Weimer, Alan W; Dahl, Jaimee K; Lewandowski, Allan A; Bingham, Carl; Raska Buechler, Karen J; Grothe, Willy

    2014-03-18T23:59:59.000Z

    In an embodiment, a method of conducting a high temperature chemical reaction that produces hydrogen or synthesis gas is described. The high temperature chemical reaction is conducted in a reactor having at least two reactor shells, including an inner shell and an outer shell. Heat absorbing particles are included in a gas stream flowing in the inner shell. The reactor is heated at least in part by a source of concentrated sunlight. The inner shell is heated by the concentrated sunlight. The inner shell re-radiates from the inner wall and heats the heat absorbing particles in the gas stream flowing through the inner shell, and heat transfers from the heat absorbing particles to the first gas stream, thereby heating the reactants in the gas stream to a sufficiently high temperature so that the first gas stream undergoes the desired reaction(s), thereby producing hydrogen or synthesis gas in the gas stream.

  9. An experimental and numerical investigation on the influence of external gas recirculation on the HCCI autoignition process in an engine: Thermal, diluting, and chemical effects

    SciTech Connect (OSTI)

    Machrafi, Hatim; Cavadias, Simeon [UPMC Universite Paris 06, LGPPTS, Ecole Nationale Superieure de Chimie de Paris, 11, rue de Pierre et Marie Curie, 75005 Paris (France); UPMC Universite Paris 06, FRT, Institut Jean Le Rond D'Alembert, 2, place de la Gare de Ceinture, 78210 St Cyr l'Ecole (France); Guibert, Philippe [UPMC Universite Paris 06, FRT, Institut Jean Le Rond D'Alembert, 2, place de la Gare de Ceinture, 78210 St Cyr l'Ecole (France)

    2008-11-15T23:59:59.000Z

    In order to contribute to the solution of controlling the autoignition in a homogeneous charge compression ignition (HCCI) engine, parameters linked to external gas recirculation (EGR) seem to be of particular interest. Experiments performed with EGR present some difficulties in interpreting results using only the diluting and thermal aspect of EGR. Lately, the chemical aspect of EGR is taken more into consideration, because this aspect causes a complex interaction with the dilution and thermal aspects of EGR. This paper studies the influence of EGR on the autoignition process and particularly the chemical aspect of EGR. The diluents present in EGR are simulated by N{sub 2} and CO{sub 2}, with dilution factors going from 0 to 46 vol%. For the chemically active species that could be present in EGR, the species CO, NO, and CH{sub 2}O are used. The initial concentration in the inlet mixture of CO and NO is varied between 0 and 170 ppm, while that of CH{sub 2}O alters between 0 and 1400 ppm. For the investigation of the effect of the chemical species on the autoignition, a fixed dilution factor of 23 vol% and a fixed EGR temperature of 70 C are maintained. The inlet temperature is held at 70 C, the equivalence ratios between 0.29 and 0.41, and the compression ratio at 10.2. The fuels used for the autoignition are n-heptane and PRF40. It appeared that CO, in the investigated domain, did not influence the ignition delays, while NO had two different effects. At concentrations up until 45 ppm, NO advanced the ignition delays for the PRF40 and at higher concentrations, the ignition delayed. The influence of NO on the autoignition of n-heptane seemed to be insignificant, probably due to the higher burn rate of n-heptane. CH{sub 2}O seemed to delay the ignition. The results suggested that especially the formation of OH radicals or their consumption by the chemical additives determines how the reactivity of the autoignition changed. (author)

  10. The displacement field characterization of two interacting parallel edge cracks in a finite body

    E-Print Network [OSTI]

    Keener, Todd Whitney

    1996-01-01T23:59:59.000Z

    The goals of this research were to: (1) develop a model to represent the displacement field surrounding two interacting, parallel edge cracks; and (2) use this model to investigate the influence of crack separation and relative crack length...

  11. Field Manual for Crack Sealing in Asphalt Pavements

    E-Print Network [OSTI]

    Texas at Austin, University of

    Field Manual for Crack Sealing in Asphalt Pavements Yetkin Yildirim, Ahmed Qatan, and Jorge Prozzi January 2006 3208RedRiver Austin,TX78705 #12;Dr. Yetkin Yildirim, P.E. Director Texas Pavement for Crack Sealing in Asphalt Pavements #12;Performing Organization: Center for Transportation Research

  12. NORTHWESTERN UNIVERSITY Crack Response to Weather Effects, Blasting, and Construction

    E-Print Network [OSTI]

    NORTHWESTERN UNIVERSITY Crack Response to Weather Effects, Blasting, and Construction Vibrations Acknowledgements iii Abstract iv List of Figures v List of Tables xi Chapter 1- Introduction 1 Chapter 2- Blast Vibration Response, Southbury, Connecticut 5 Structural Description Instrumentation Blast Response Crack

  13. Crack-based analysis of concrete with brittle reinforcement

    E-Print Network [OSTI]

    Burgoyne, Chris

    { FaberMaunsell Ltd; University of Cambridge Brittle reinforcement (such as fibre-reinforced plastic to the surround- ing concrete, at a crack surface sL=sR s on the left/right side of a crack u increase in unbonded

  14. Demetallization of asphaltenes: Thermal and catalytic effects with small-pore catalysts

    SciTech Connect (OSTI)

    Adarme, R. (Oklahoma State Univ., Stillwater, OK (United States)); Sughrue, E.L.; Johnson, M.M.; Kidd, D.R.; Phillips, M.D.; Shaw, J.E. (Phillips Petroleum Co., Bartlesville, OK (United States))

    1990-08-01T23:59:59.000Z

    Residual oil hydrotreating has become an important front end process in commercial oil upgrading schemes because of tighter environmental regulations and a continuing trend toward processing heavier crudes. At Phillips Petroleum, residual oil hydrotreating pretreates feed for heavy oil cracking (HOC) by removing sulfur, a pollutant in the HOC stack gas, and metals such as nickel and vanadium, which adversely affect the cracking catalyst and gasoline yield in the HOC. Metals in residual oil are found almost exclusively in the resin and asphaltene fractions. Research has showed that metals in the resin fraction react more rapidly than metals in the asphaltene fraction. The hydrodemetallization (HDM) reaction is known to be diffusion limited and the larger molecular size of the asphaltene molecules may explain the slower reaction rates. Richardson and Alley and Asaoka, et al. have shown a reduction in asphaltene molecular weights with thermal and catalytic processing. Reynolds and Biggs demonstrated shifts in vanadium size distributions from thermally and catalytically treated residual. Recently Savage and Javanmaridian showed theoretically that reduction in molecular sizes external to catalyst pellets increases the reaction rate by as much as the inverse of the effectiveness factor. This work attempts to extend information on how metals are removed from asphaltenes and the interaction with small-pore catalysts generally found at the back end of residual oil hydrotreaters, where they are protected from deactivation by metal deposition. The small-pore catalysts are generally high in hydrodesulfurization (HDS) activity and generally restrict the large asphaltene molecules from entering their pores and depositing metals.

  15. Experimental Verification of a Cracked Fuel Mechanical Model

    SciTech Connect (OSTI)

    Williford, R. E.

    1982-12-01T23:59:59.000Z

    This report describes the results of a series of laboratory experiments conducted to independently verify a model that describes the nonlinear mechanical behavior of cracked fuel in pelletized UO{sub 2}/Zircaloy nuclear fuel rods under normal operating conditions. After a brief description of the analytical model, each experiment is discussed in detail. Experiments were conducted to verify the general behavior and numerical values for the three primary independent modelling parameters (effective crack roughness, effective gap roughness, and total crack length), and to verify the model predictions that the effective Young's moduli for cracked fuel systems were substantially less than those for solid UO{sub 2} pellets. In general, the model parameters and predictions were confirmed, and new insight was gained concerning the complexities of cracked fuel mechanics.

  16. SciTech Connect: Stress corrosion cracking of alloy 600 using...

    Office of Scientific and Technical Information (OSTI)

    Stress corrosion cracking of alloy 600 using the constant strain rate test Citation Details In-Document Search Title: Stress corrosion cracking of alloy 600 using the constant...

  17. A Crack in the Pipeline: Why Female Underrepresented Racial Minority Students Leave Engineering

    E-Print Network [OSTI]

    Vazquez-Akim, Jenn

    2014-01-01T23:59:59.000Z

    Espinosa, Lorelle L. (2011). Pipelines and pathways: womenAngeles A Crack in the Pipeline: Why Female UnderrepresentedA Crack in the Pipeline: Why Female Underrepresented Racial

  18. In-Line Crack and Stress Detection in Silicon Solar Cells Using Resonance Ultrasonic Vibrations

    SciTech Connect (OSTI)

    Ostapenko, Sergei

    2013-04-03T23:59:59.000Z

    Statement of Problem and Objectives. Wafer breakage in automated solar cell production lines is identified as a major technical problem and a barrier for further cost reduction of silicon solar module manufacturing. To the best of our knowledge, there are no commercial systems addressing critical needs for in-line inspection of the mechanical quality of solar wafers and cells. The principal objective of the SBIR program is to validate through experiments and computer modeling the applicability of the Resonance Ultrasonic Vibrations system, which ultimately can be used as a real-time in-line manufacturing quality control tool for fast detection of mechanically unstable silicon solar cells caused by cracks. The specific objective of Phase II is to move the technology of in-line crack detection from the laboratory level to commercial demonstration through development of a system prototype. The fragility of silicon wafers possessing low mechanical strength is attributed to peripheral and bulk millimeter-length cracks. The research program is based on feasibility results obtained during Phase I, which established that: (i) the Resonance Ultrasonic Vibrations method is applicable to as-cut, processed wafers and finished cells; (ii) the method sensitivity depends on the specific processing step; it is highest in as-cut wafers and lowest in wafers with metallization pattern and grid contacts; (iii) the system is capable of matching the 2.0 seconds per wafer throughput rate of state-of-art solar cell production lines; (iv) finite element modeling provides vibration mode analysis along with peak shift versus crack length and crack location dependence; (v) a high 91% crack rejection rate was confirmed through experimentation and statistical analysis. The Phase II project has the following specific tasks: (i) specify optimal configurations of the in-line system�¢����s component hardware and software; (ii) develop and justify a system prototype that meets major specifications for an in-line crack detection unit, such as high throughput rate, high level of stability, reproducibility of data acquisition and analysis, and high sensitivity with respect to crack length and crack location; (iii) design a system platform that allows easy integration within and adaptation to various solar cell belt-type production lines; (iv) develop a testing protocol providing quality certification of the production-grade system. Commercial Application of the proposed activity consists of bringing to the solar market a new high-tech product based on an innovative solution and patented methodology to contribute to cost reduction of silicon solar module production. The solar industry, with crystalline silicon as a dominant segment, shows outstanding performance, with approximately 25% yearly growth during the last years. Despite a slowdown with only 5.6 GW installations in 2009, solar module production for the 2010 and 2011 years was recovered. According to European Photonics Industry Consortium new solar PV installations grow by 56% compared to 2010 reached 64.7 GW in 2011. Revenues in the PV industry reached a record high of $93 billion in 2011, a 13.4 percent gain over 2010 â�� and 150 percent over 2009. This growth was forecasted to continue in 2013 with double digits growth. The solar industry is economically driven to make solar panels of the highest conversion efficiency and reliability at the lowest production cost. The Resonance Ultrasonic Vibration system addresses critical needs of the silicon-based solar industry by providing a quality control method and tool, which will improve productivity, increase reliability of products and reduce manufacturing cost of solar panels.

  19. MacroscoMacroscopic Cracking Determination in LaBS Glasspic Cracking Determination in LaBS Glass

    SciTech Connect (OSTI)

    Marra, James

    2005-08-01T23:59:59.000Z

    The DOE/EM plans to conduct the Plutonium Vitrification Project at the Savannah River Site (SRS). An important part of this project is to reduce the attractiveness of the plutonium by fabricating a plutonium glass form and immobilizing the Pu form within the high level waste (HLW) glass prepared in the Defense Waste Processing Facility (DWPF). This requires that a project schedule that is consistent with EM plans for DWPF and cleanup of the SRS be developed. Critical inputs to key decisions in the vitrification project schedule are near-term data that will increase confidence that the lanthanide borosilicate (LaBS) glass product is suitable for disposal in the Yucca Mountain Repository. A workshop was held on April 28, 2005 at Bechtel SAIC Company (BSC) facility in Las Vegas, NV to define the near term data needs. Dissolution rate data and the fate of plutonium oxide and the neutron absorbers during the dissolution process were defined as key data needs. A suite of short-term tests were defined at the workshop to obtain the needed data. The objectives of these short-term tests are to obtain data that can be used to show that the dissolution rate of a LaBS glass is acceptable and to show that the extent of Pu separation from neutron absorbers, as the glass degrades and dissolves, is not likely to lead to criticality concerns. An additional data need was identified regarding the degree of macroscopic cracking and/or voiding that occurs during processing of the Pu glass waste form and subsequent pouring of HLW glass in the DWPF. A final need to evaluate new frit formulations that may increase the durability of the plutonium glass and/or decrease the degree to which neutron absorbers separate from the plutonium during dissolution was identified. This task plan covers the need to evaluate the degree of macroscopic cracking and/or voiding that occurs during processing of the Vitrified Plutonium Waste Form (i.e. the can-in-canister configuration containing the vitrified Pu product). Separate task plans were developed for Pu glass performance testing of the current baseline LaBS glass composition and development of alternative frit formulations. Recent results from Pressurized Unsaturated Flow (PUF) testing showed the potential separation of Pu from Gd during the glass dissolution process [3]. Post-test analysis of the LaBS glass from a 6-year PUF test showed a region where Pu had apparently accumulated in a Pu-bearing disk-like phase that had become separated from neutron absorber (Gd). It should be noted that this testing was conducted on the early LaBS Frit A glass composition that was devoid of HfO{sub 2} as a neutron absorber. PUF testing is currently being initiated using the LaBS Frit B composition that contains HfO{sub 2}. The potential for fissile material and neutron absorber separation is a criticality risk for the repository. The surface area that is available for leaching (i.e. due to the degree of cracking or voiding within the Pu glass cylinder) is a factor in modeling the amount of fissile material and neutron absorber released during the dissolution process. A mathematical expression for surface area is used in the Total Systems Performance Assessment (TSPA) performed by BSC personnel. Specifically, the surface area available for leaching is being used in current external criticality assessments. The planned processing steps for producing a VPWF assembly involves processing Pu feed and LaBS frit to produce a can of Pu LaBS glass, packaging this can into a second can (i.e. bagless transfer) for removal from the glovebox processing environment, placing a series of bagless transfer cans into a DWPF canister, and pouring HLW glass into the DWPF canister to encapsulate bagless transfer cans. The objective of this task is to quantify the degree of cracking and/or voiding that will occur during the processing of the VPWF.

  20. Implications of early stages in the growth of stress corrosion cracking on component reliability

    SciTech Connect (OSTI)

    Jones, R.H.; Simonen, E.P.

    1995-04-01T23:59:59.000Z

    Environment-induced crack growth generally progresses through several stages prior to component failure. Crack initiation, short crack growth, and stage 1 growth are early stages in crack development that are summarized in this paper. The implications of these stages on component reliability, derive from the extended time that the crack exists in the early stages because crack velocity is slow. The duration of the early stages provides a greater opportunity for corrective action if cracks can be detected. Several important factors about the value of understanding short crack behavior include: (1) life prediction requires a knowledge of the total life cycle of the crack including the early stages, (2) greater reliability is possible if the transition between short and long crack behavior is known component life after this transition is short and (3) remedial actions are more effective for short than long cracks.

  1. Reliability of steam generator tubes with axial cracks

    SciTech Connect (OSTI)

    Cizelj, L.; Mavko, B. [Jozef Stefan Inst., Ljubljana (Slovenia). Reactor Engineering Div.; Vencelj, P. [Univ. of Ljubljana (Slovenia). Faculty of Mathematics and Physics

    1996-11-01T23:59:59.000Z

    An approach for estimating the failure probability of tubes containing through-wall axial cracks has already been proposed by the authors. It is based on probabilistic fracture mechanics and accounts for scatter in tube geometry and material properties, scatter in residual and operational stresses responsible for crack propagation, and characteristics of nondestructive examination and plugging procedures (e.g., detection probability, sizing accuracy, human errors). Results of preliminary tests demonstrated wide applicability of this approach and triggered some improvements. The additions to the model are extensively discussed in this paper. Capabilities are demonstrated by results of analysis of steam generator no. 1 in Slovenian nuclear power plant located in Krsko after the 1992 inspection and plugging campaign. First, the number of cracked tubes and the crack length distribution were estimated using data obtained by the 100% motorized pancake coil inspection. The inspection and plugging activities were simulated in the second step to estimate the efficiency of maintenance in terms of single and multiple-tube rupture probabilities. They were calculated as a function of maximum allowable crack length. The importance of human errors and some limitations of present nondestructive examination techniques were identified. The traditional wall thickness and crack-length-based plugging criteria are compared. The crack-length-based criterion is shown to be more efficient and more safe, especially because of strong suppression effect on probability of multiple-tube rupture. The results are considered to be important for safety and maintenance of existing plants and for further research.

  2. The Role of Thermal Energy Storage in Industrial Energy Conservation

    E-Print Network [OSTI]

    Duscha, R. A.; Masica, W. J.

    1979-01-01T23:59:59.000Z

    Thermal Energy Storage for Industrial Applications is a major thrust of the Department of Energy's Thermal Energy Storage Program. Utilizing Thermal Energy Storage (TES) with process or reject heat recovery systems has been shown to be extremely...

  3. Development of an Innovative High-Thermal Conductivity UO2 Ceramic Composites Fuel Pellets with Carbon Nano-Tubes Using Spark Plasma Sintering

    SciTech Connect (OSTI)

    Subhash, Ghatu; Wu, Kuang-Hsi; Tulenko, James

    2014-03-10T23:59:59.000Z

    Uranium dioxide (UO2) is the most common fuel material in commercial nuclear power reactors. Despite its numerous advantages such as high melting point, good high-temperature stability, good chemical compatibility with cladding and coolant, and resistance to radiation, it suffers from low thermal conductivity that can result in large temperature gradients within the UO2 fuel pellet, causing it to crack and release fission gases. Thermal swelling of the pellets also limits the lifetime of UO2 fuel in the reactor. To mitigate these problems, we propose to develop novel UO2 fuel with uniformly distributed carbon nanotubes (CNTs) that can provide high-conductivity thermal pathways and can eliminate fuel cracking and fission gas release due to high temperatures. CNTs have been investigated extensively for the past decade to explore their unique physical properties and many potential applications. CNTs have high thermal conductivity (6600 W/mK for an individual single- walled CNT and >3000 W/mK for an individual multi-walled CNT) and high temperature stability up to 2800°C in vacuum and about 750°C in air. These properties make them attractive candidates in preparing nano-composites with new functional properties. The objective of the proposed research is to develop high thermal conductivity of UO2–CNT composites without affecting the neutronic property of UO2 significantly. The concept of this goal is to utilize a rapid sintering method (5–15 min) called spark plasma sintering (SPS) in which a mixture of CNTs and UO2 powder are used to make composites with different volume fractions of CNTs. Incorporation of these nanoscale materials plays a fundamentally critical role in controlling the performance and stability of UO2 fuel. We will use a novel in situ growth process to grow CNTs on UO2 particles for rapid sintering and develop UO2-CNT composites. This method is expected to provide a uniform distribution of CNTs at various volume fractions so that a high thermally conductive UO2-CNT composite is obtained with a minimal volume fraction of CNTs. The mixtures are sintered in the SPS facility at a range of temperatures, pressures, and time durations so as to identify the optimal processing conditions to obtain the desired microstructure of sintered UO2-CNT pellets. The second objective of the proposed work is to identify the optimal volume fraction of CNTs in the microstructure of the composites that provides the desired high thermal conductivity yet retaining the mechanical strength required for efficient function as a reactor fuel. We will systematically study the resulting microstructure (grain size, porosity, distribution of CNTs, etc.) obtained at various SPS processing conditions using optical microscopy, scanning electron microscopy (SEM), and transmission electron microscope (TEM). We will conduct indentation hardness measurements and uniaxial strength measurements as a function of volume fraction of CNTs to determine the mechanical strength and compare them to the properties of UO2. The fracture surfaces will be studied to determine the fracture characteristics that may relate to the observed cracking during service. Finally, we will perform thermal conductivity measurements on all the composites up to 1000° C. This study will relate the microstructure, mechanical properties, and thermal properties at various volume fractions of CNTs. The overall intent is to identify optimal processing conditions that will provide a well-consolidated compact with optimal microstructure and thermo-mechanical properties. The deliverables include: (1) fully characterized UO2-CNT composite with optimal CNT volume fraction and high thermal conductivity and (2) processing conditions for production of UO2-CNT composite pellets using SPS method.

  4. PLASMA Approximate Dynamic Programming finally cracks the locomotive optimization problem

    E-Print Network [OSTI]

    Powell, Warren B.

    PLASMA ­ Approximate Dynamic Programming finally cracks the locomotive optimization problem schedules and new operating policies. PLASMA is currently running at Norfolk Southern for strategic of PLASMA: Each locomotive is modeled individually, making it possible to capture both horsepower

  5. Automated crack control analysis for concrete pavement construction

    E-Print Network [OSTI]

    Jang, Se Hoon

    2005-11-01T23:59:59.000Z

    The focus of this research is on the control of random cracking in concrete paving by using sawcut notch locations in the early stages of construction. This is a major concern in concrete pavement construction. This research also addresses a...

  6. Shear-wave splitting and reservoir crack characterization: the...

    Open Energy Info (EERE)

    Shear-wave splitting and reservoir crack characterization: the Coso geothermal field Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: Shear-wave...

  7. Climate change: A crack in the natural-gas bridge

    E-Print Network [OSTI]

    Davis, SJ; Shearer, C

    2014-01-01T23:59:59.000Z

    J. D. & Wirth, T. E. Natural Gas: A Bridge Fuel for the 21stexpanding supplies of natural gas will not help us to avoidLIM ATE CHANGE A crack in the natural-gas bridge Integrated

  8. A crack in the natural-gas bridge

    E-Print Network [OSTI]

    Davis, SJ; Shearer, C

    2014-01-01T23:59:59.000Z

    J. D. & Wirth, T. E. Natural Gas: A Bridge Fuel for the 21stexpanding supplies of natural gas will not help us to avoidLIM ATE CHANGE A crack in the natural-gas bridge Integrated

  9. Crack coalescence in rock-like material under cycling loading

    E-Print Network [OSTI]

    Ko, Tae Young, 1973-

    2005-01-01T23:59:59.000Z

    A total of 170 tests (68 tests for monotonic loading, 102 tests for cyclic loading) have been performed to investigate crack initiation, propagation and coalescence. The specimens have two pre-existing flaws which are ...

  10. Field Examples of Axial Cracked Bearings in Wind Turbine Gearboxes...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Field Examples of Axial Cracked Bearings in Wind Turbine Gearboxes Presented by Paul John Baker of FrontierPro Services at the Wind Turbine Tribology Seminar 2014. 141030 Axial...

  11. VEBA-Combi-cracking - A technology for upgrading of heavy oils and bitumen

    SciTech Connect (OSTI)

    Doehler, W.; Kretschmar, D.I.K.; Merz, L.; Niemann, K. (VEBA OEL Entwicklungs-Gesellschaft mbH, Gelsenkirchen (West Germany))

    1987-04-01T23:59:59.000Z

    Based on experiences with liquid phase hydrogenation for coal liquefaction according to the Berguis-Pier-Process as well as crude oil residue hydrogenation in the Fifties and Sixties, VEBA OEL in recent years developed the VEBA-LQ-Cracking (VLC) and the VEBA-Combi-Cracking (VCC) Processes. Since 1978, more than 20 different feedstocks have been converted in small scale plants with a capacity of 3-20 kg/h. Together with LURGI GmbH, Frankfurt, the next steps were taken: the design and construction of a 1 t/h Pilot Plant located at the RUHR OEL refinery in Gelsenkirchen. After 18 months of construction, the heavy oil pilot plant was put on stream in May 1983. Since the beginning of 1983, the plant has been funded and owned by LURGI GmbH, VEBA OEL AG and INTEVEP S.A., the research institute of Petroleos de Venezuela, all of whom have participated in the development of the VLC/VCC process. Reported here are the results of the intensive experimental work for the development of the VLC/VCC-processes in a scale covering all aspects relevant for a scale-up, demonstrate the technical maturity of the processes developed by VEBA OEL to convert refinery residues and natural heavy crude oils.

  12. Assessment of crack opening area for leak rates

    SciTech Connect (OSTI)

    Sharples, J.K.; Bouchard, P.J.

    1997-04-01T23:59:59.000Z

    This paper outlines the background to recommended crack opening area solutions given in a proposed revision to leak before break guidance for the R6 procedure. Comparisons with experimental and analytical results are given for some selected cases of circumferential cracks in cylinders. It is shown that elastic models can provide satisfactory estimations of crack opening displacement (and area) but they become increasingly conservative for values of L{sub r} greater than approximately 0.4. The Dugdale small scale yielding model gives conservative estimates of crack opening displacement with increasing enhancement for L{sub r} values greater than 0.4. Further validation of the elastic-plastic reference stress method for up to L{sub r} values of about 1.0 is presented by experimental and analytical comparisons. Although a more detailed method, its application gives a best estimate of crack opening displacement which may be substantially greater than small scale plasticity models. It is also shown that the local boundary conditions in pipework need to be carefully considered when evaluating crack opening area for through-wall bending stresses resulting from welding residual stresses or geometry discontinuities.

  13. Catastrophic Cracking Courtesy of Quiescent Cavitation

    E-Print Network [OSTI]

    Daily, D Jesse; Thomson, Scott L; Truscott, Tadd T

    2012-01-01T23:59:59.000Z

    A popular party trick is to fill a glass bottle with water and hit the top of the bottle with an open hand, causing the bottom of the bottle to break open. We investigate the source of the catastrophic cracking through the use of high-speed video and an accelerometer attached to the bottom of a glass bottle. Upon closer inspection, it is obvious that the acceleration caused by hitting the top of the bottle is followed by the formation of bubbles near the bottom. The nearly instantaneous acceleration creates an area of low pressure on the bottom of the bottle where cavitation bubbles form. Moments later, the cavitation bubbles collapse at roughly 10 times the speed of formation, causing the bottle to break. The accelerometer data shows that the bottle is broken after the bubbles collapse and that the magnitude of the bubble collapse is greater than the initial impact. The fluid dynamics video highlights that this trick will not work if the bottle is empty nor if it is filled with a carbonated fluid because the...

  14. Materials processing issues for non-destructive laser gas sampling (NDLGS)

    SciTech Connect (OSTI)

    Lienert, Thomas J [Los Alamos National Laboratory

    2010-12-09T23:59:59.000Z

    The Non-Destructive Laser Gas Sampling (NDLGS) process essentially involves three steps: (1) laser drilling through the top of a crimped tube made of 304L stainles steel (Hammar and Svennson Cr{sub eq}/Ni{sub eq} = 1.55, produced in 1985); (2) gas sampling; and (3) laser re-welding of the crimp. All three steps are performed in a sealed chamber with a fused silica window under controlled vacuum conditions. Quality requirements for successful processing call for a hermetic re-weld with no cracks or other defects in the fusion zone or HAZ. It has been well established that austenitic stainless steels ({gamma}-SS), such as 304L, can suffer from solidification cracking if their Cr{sub eq}/Ni{sub eq} is below a critical value that causes solidification to occur as austenite (fcc structure) and their combined impurity level (%P+%S) is above {approx}0.02%. Conversely, for Cr{sub eq}/Ni{sub eq} values above the critical level, solidification occurs as ferrite (bcc structure), and cracking propensity is greatly reduced at all combined impurity levels. The consensus of results from studies of several researchers starting in the late 1970's indicates that the critical Cr{sub eq}/Ni{sub eq} value is {approx}1.5 for arc welds. However, more recent studies by the author and others show that the critical Cr{sub eq}/Ni{sub eq} value increases to {approx}1 .6 for weld processes with very rapid thermal cycles, such as the pulsed Nd:YAG laser beam welding (LBW) process used here. Initial attempts at NDLGS using pulsed LBW resulted in considerable solidification cracking, consistent with the results of work discussed above. After a brief introduction to the welding metallurgy of {gamma}-SS, this presentation will review the results of a study aimed at developing a production-ready process that eliminates cracking. The solution to the cracking issue, developed at LANL, involved locally augmenting the Cr content by applying either Cr or a Cr-rich stainless steel (ER 312) to the top of the crimp using the electro-spark deposition (ESD) process followed by laser mixing, drilling and rewelding. Results of a study of the ESD parameters on deposition rate and efficiency will be discussed along with mass balance calculations for determining the desired Cr content to eliminate cracking. The study also required purchase of new pulsed Nd:YAG laser welders. Evaluation of the performance of the new lasers, including beam profiling results, will also be presented. Development of a mixing, drilling and re-welding process at atmospheric pressure with inert gas shielding demonstrated the efficacy of the Cr-augmentation approach. However, extending the process to vacuum conditions proved more challenging owing to loss of laser transmission through the window from spatter and condensation of metal vapors. Solutions developed to circumvent hese issues will be reviewed. Weld microstructures found with various Cr levels will be presented and discussed.

  15. ffe1098 FFE March 7, 2007 21:55 Crack tip displacements of microstructurally small cracks in 316L steel

    E-Print Network [OSTI]

    Cizelj, Leon

    steel and their dependence on crystallographic orientations of grains I. SIMONOVSKI1 , KARL orientations on a short Stage I surface crack in a 316L stainless steel. The analysis is based on a plane

  16. Alterations of bitumen produced by the in-situ combustion process at the oxygen Wolf Lake Project, Alberta

    SciTech Connect (OSTI)

    Riechert, C.; Fuhr, B. (Alberta Research Council, Edmonton (Canada)); Williams, G. (British Petroleum Canada Ltd., Calgary, Alberta (Canada)); Sawatzky, H.; Jha, K.; Lafleur, R. (Canmet, Energy Mines and Resources Canada, Ottawa, Ontario (Canada))

    1989-04-01T23:59:59.000Z

    The Oxygen Wolf Lake Project, operated by BP Resources Canada Limited, recovers bitumen by an in-situ combustion process. Bitumen samples produced from this process were analyzed and compared with analyses of unaltered bitumen from the same formation. The naphtha and middle distillate fractions were greater in the samples produced by the in-situ combustion process, which indicates thermal cracking has occurred. Gas chromatograph and Mass Spectral analyses of these samples have been used to further describe the changes to the oil. The compositional changes found in the study have been related to reductions in viscosity and density. Implications of bitumen alterations to the performance of the combustion process and production problems are discussed.

  17. Crack growth rates and fracture toughness of irradiated austenitic stainless steels in BWR environments.

    SciTech Connect (OSTI)

    Chopra, O. K.; Shack, W. J.

    2008-01-21T23:59:59.000Z

    In light water reactors, austenitic stainless steels (SSs) are used extensively as structural alloys in reactor core internal components because of their high strength, ductility, and fracture toughness. However, exposure to high levels of neutron irradiation for extended periods degrades the fracture properties of these steels by changing the material microstructure (e.g., radiation hardening) and microchemistry (e.g., radiation-induced segregation). Experimental data are presented on the fracture toughness and crack growth rates (CGRs) of wrought and cast austenitic SSs, including weld heat-affected-zone materials, that were irradiated to fluence levels as high as {approx} 2x 10{sup 21} n/cm{sup 2} (E > 1 MeV) ({approx} 3 dpa) in a light water reactor at 288-300 C. The results are compared with the data available in the literature. The effects of material composition, irradiation dose, and water chemistry on CGRs under cyclic and stress corrosion cracking conditions were determined. A superposition model was used to represent the cyclic CGRs of austenitic SSs. The effects of neutron irradiation on the fracture toughness of these steels, as well as the effects of material and irradiation conditions and test temperature, have been evaluated. A fracture toughness trend curve that bounds the existing data has been defined. The synergistic effects of thermal and radiation embrittlement of cast austenitic SS internal components have also been evaluated.

  18. Strengthening, Crack Arrest And Multiple Cracking In Brittle Materials Using Residual Stresses.

    DOE Patents [OSTI]

    Green, David J. (State College, PA); Sglavo, Vincenzo M. (Roncegno, IT); Tandon, Rajan (Fremont, CA)

    2003-02-11T23:59:59.000Z

    Embodiments include a method for forming a glass which displays visible cracking prior to failure when subjected to predetermined stress level that is greater than a predetermined minimum stress level and less than a failure stress level. The method includes determining a critical flaw size in the glass and introducing a residual stress profile to the glass so that a plurality of visible cracks are formed prior to failure when the glass is subjected to a stress that is greater than the minimum stress level and lower than the critical stress. One method for forming the residual stress profile includes performing a first ion exchange so that a first plurality of ions of a first element in the glass are exchanged with a second plurality of ions of a second element that have a larger volume than the first ions. A second ion exchange is also performed so that a plurality of the second ions in the glass are exchanged back to ions of the first element.

  19. Investigation of Interfaces Under Mechanical and Thermal Loading Using a Cohesive Zone Model

    E-Print Network [OSTI]

    Ozsoy, Ovul Ozgu

    2014-04-28T23:59:59.000Z

    ) and failures often initiate at material interfaces. Interactions between different material phases, as well as crack initiation and propagation, make fracture and damage processes very difficult to analyze. The interfaces between dissimilar layers...

  20. Environmentally assisted cracking in light water reactors annual report January - December 2005.

    SciTech Connect (OSTI)

    Alexandreanu, B.; Chen, Y.; Chopra, O. K.; Chung, H. M.; Gruber, E. E.; Shack, W. J.; Soppet, W. K.

    2007-08-31T23:59:59.000Z

    This report summarizes work performed from January to December 2005 by Argonne National Laboratory on fatigue and environmentally assisted cracking in light water reactors (LWRs). Existing statistical models for estimating the fatigue life of carbon and low-alloy steels and austenitic stainless steels (SSs) as a function of material, loading, and environmental conditions were updated. Also, the ASME Code fatigue adjustment factors of 2 on stress and 20 on life were critically reviewed to assess the possible conservatism in the current choice of the margins. An approach, based on an environmental fatigue correction factor, for incorporating the effects of LWR environments into ASME Section III fatigue evaluations is discussed. The susceptibility of austenitic stainless steels and their welds to irradiation-assisted stress corrosion cracking (IASCC) is being evaluated as a function of the fluence level, water chemistry, material chemistry, and fabrication history. For this task, crack growth rate (CGR) tests and slow strain rate tensile (SSRT) tests are being conducted on various austenitic SSs irradiated in the Halden boiling water reactor. The SSRT tests are currently focused on investigating the effects of the grain boundary engineering process on the IASCC of the austenitic SSs. The CGR tests were conducted on Type 316 SSs irradiated to 0.45-3.0 dpa, and on sensitized Type 304 SS and SS weld heat-affected-zone material irradiated to 2.16 dpa. The CGR tests on materials irradiated to 2.16 dpa were followed by a fracture toughness test in a water environment. The effects of material composition, irradiation, and water chemistry on growth rates are discussed. The susceptibility of austenitic SS core internals to IASCC and void swelling is also being evaluated for pressurized water reactors. Both SSRT tests and microstructural examinations are being conducted on specimens irradiated in the BOR-60 reactor in Russia to doses up to 20 dpa. Crack growth rate data, obtained in the pressurized water reactor environment, are presented on Ni-alloy welds prepared in the laboratory or obtained from the nozzle-to-pipe weld of the V. C. Summer reactor. The experimental CGRs under cyclic and constant load are compared with the existing CGR data for Ni-alloy welds to determine the relative susceptibility of these materials to environmentally enhanced cracking under a variety of loading conditions.

  1. Develop statewide recommendations for application of PCC joint reflective cracking rehabilitation strategies

    E-Print Network [OSTI]

    Jain, Rahul Padamkumar

    2004-11-15T23:59:59.000Z

    Spalling of cracks and joints is the cracking, breaking or chipping of the slab edges within 2 ft (0.6m) if the joint or crack (Huang et. al 2004). Joint spalling is a construction related distress in the rigid pavement that mainly affects the structural... in the asphalt concrete overlays laid on the concrete pavements. Reflection cracks are caused by discontinuities in the underlying layers which propagate through the HMA surface due to movement at crack (Roberts et al 1996). Reflection cracks in AC overlays...

  2. Combination process for upgrading residual oils

    SciTech Connect (OSTI)

    Busch, L.E.; Walters, P.W.; Zandona, O.

    1990-01-16T23:59:59.000Z

    This patent describes a method for upgrading high boiling residual portions of crude oils comprising metal contaminants, porphyrins, asphaltenes and high molecular weight multi-ring hydrocarbon material. It comprises: charging a high boiling residual portion of crude oil admixed with diluent in contact with suspended upflowing substantially inert fluidizable solids particulate material at an elevated thermal visbreaking temperature in a riser contact zone for a time sufficient to recover therefrom a vaporous hydrocarbon product higher boiling than gasoline partially decarbonized and demetallized to a lower contaminating metals level, quenching the vaporous product of thermal visbreaking below its dew point after separation from solids, charging quenched thermally modified high boiling hydrocarbon product with a crystalline zeolite cracking catalyst under cracking conditions for a hydrocarbon residence time in a riser cracking zone; recovering a hydrocarbon conversion product; separating a combined C{sub 4} minus wet gas product stream of the visbreaking and zeolite catalyst cracking operating to recover a C{sub 3}-C{sub 4} rich fraction separately from a C{sub 2} minus dry gas product fraction, and regenerating the crystalline zeolite contcontaining catalyst.

  3. Effect of aging of the pillaring reagent on the microstructure and cracking activity of pillared clay

    SciTech Connect (OSTI)

    Harris, J.R. (Phillips Petroleum Company, Bartlesville, OK (USA))

    1987-08-01T23:59:59.000Z

    Pillared interlayer clay (PILC) is formed by exchanging large hydroxyaluminum polycations into the interlayer of a smectite clay such as montmorillonite, which is made up of sheet-like silica/alumina layers. Calcination of the exchanged clay gives a well dispersed array of metal oxide clumps (i.e., pillars) bonded top and bottom to the silica/alumina layers of the clay. The permanent separation of the clay layers gives an 8 to 10-fold increase in surface area, from 30 to 250-300 m{sup 2}/g, and a microporous structure similar to but less constrained than that of zeolites. Recently, there has been an increased interest in the use of these clays as cracking catalysts. For example, pillared clays have been shown to be an active cracking catalyst for both single component and gas oil feeds. PILC's also lead to both higher light cycle oil (LCO) and coke yields than conventional cracking catalysts. Commercially available, metal-hydrolyzed hydroxyaluminum solutions containing chlorhydrol, A1{sub 2}(OH){sub 5}C1.2H{sub 2}O, have been used as one source of the polycation solution. The approach of these hydrolyzed polycation solutions to equilibrium is known as aging. During the aging process certain polycationic species disappear from the solution and new species are formed. For this reason, the aging process can have a significant influence on the properties of the pillared clays. The objective of this work was to determine how the physical and catalytic properties of the pillared clay depend on the aging of dilute cholorhydrol solutions.

  4. Thermal stress analysis of fused-cast AZS refractories during production; Part 1: Industrial study

    SciTech Connect (OSTI)

    Cockcroft, S.L.; Brimacombe, J.K. (Univ. of British Columbia, Vancouver, British Columbia (Canada). Centre for Metallurgical Process Engineering); Walrod, D.G.; Myles, T.A. (Carborundum Co., Falconer, NY (United States). Monofrax-S Plant)

    1994-06-01T23:59:59.000Z

    A study has been conducted to understand and prevent the formation of cracks in alumina-zirconia-silica (AZS) refractory blocks during solidification processing. A fundamental approach has been taken, centered on the development of a three-dimensional mathematical model to predict heat flow and stress generation in fused-cast AZS refractory blocks. In the first part of a two-part study, the voidless'' casting process has been carefully examined in an industrial setting. From a survey of the distribution, frequency of occurrence, and fracture surface morphology of cracks, an attempt was made to link the crack types found in the study to process variables. In-mold temperature data collected for a single casting throughout the normal cooling period have been used to validate the heat-flow model which is described in Part 2. The stress analysis, cause of the different cracks, and remedial action are also presented in Part 2.

  5. A two-dimensional thermomechanical simulation of a gas metal arc welding process

    SciTech Connect (OSTI)

    Ortega, A.R.

    1990-08-01T23:59:59.000Z

    A low heat input gas metal arc (GMA) weld overlay process is being investigated as a possible means to repair Savannah River nuclear reactor tanks in the event cracks are detected in the reactor walls. Two-dimensional thermomechanical simulations of a GMA welding process were performed using the finite element code ABAQUS to assist in the design of the upcoming weld experiments on helium-charged specimens. The thermal model correlated well with existing test data, i.e., fusion zone depth and thermocouple data. In addition, numerical results revealed that after cool-down the final deformation of the workpiece was qualitatively similar to the shape observed experimentally. Based on these analyses, conservative recommendations were made for the workpiece dimensions, weld pass spacing, and thermomechanical boundary conditions to ensure the experiments would be as representative as possible of welding on the reactor walls. 12 refs., 13 figs.

  6. EELE408 Photovoltaics Lecture 02: Silicon Processing

    E-Print Network [OSTI]

    Kaiser, Todd J.

    -1200°C in H2O ­ Thick Chart 16 Flow of Wafer of metal Thermally Activated Processes · Thermal energy required to initiate process. · Diffusion Activated Process Energy below the activation energy 4 Energy above the activation energy Diffusion

  7. Protocol development for evaluation of commercial catalytic cracking catalysts

    SciTech Connect (OSTI)

    Mitchell, M.M. Jr.; Moore, H.F. (Ashland Petroleum Co., KY (USA))

    1988-09-01T23:59:59.000Z

    A complete, new set of testing protocols has been developed for qualification of catalysts for Ashland's commercial catalytic cracking units. The objective of this test development is to identify new generations of improved cracking catalysts. Prior test protocols have classically utilized microactivity (MAT) testing of steamed virgin catalysts, while more advanced methods have utilized fixed fluid bed and/or circulating pilot units. Each of these techniques, however, have been limited by their correlation to commercial operations, weaknesses in metallation and preparation of pseudo-equilibrium catalysts, and mechanical constraints on the use of heavy, vacuum bottoms-containing feedstocks. These new protocols have been baselined, compared to commercial Ashland results on known catalytic cracking catalysts, and utilized to evaluate a range of potentially new catalyst samples.

  8. Reflective Cracking Study: First-level Report on HVS Testing on Section 588RF - 90 mm AR4000-DOverlay

    E-Print Network [OSTI]

    Jones, David; Wu, R; Harvey, John T

    2008-01-01T23:59:59.000Z

    testing being performed to validate Caltrans overlay strategies for the rehabilitation of cracked asphalt concrete.concrete. It describes the results of the fourth HVS reflective cracking testingconcrete. It describes the results of the fourth HVS reflective cracking testing

  9. Reflective Cracking Study: First-Level Report on HVS Testing on Section 590RF - 90 mm MB4-G Overlay

    E-Print Network [OSTI]

    Jones, David; Tsai, Bor-Wen; Harvey, John T

    2008-01-01T23:59:59.000Z

    testing being performed to validate Caltrans overlay strategies for the rehabilitation of cracked asphalt concrete.concrete. It describes the results of the first HVS reflective cracking testingconcrete. It describes the results of the first HVS reflective cracking testing

  10. Dynamic crack initiation toughness : experiments and peridynamic modeling.

    SciTech Connect (OSTI)

    Foster, John T.

    2009-10-01T23:59:59.000Z

    This is a dissertation on research conducted studying the dynamic crack initiation toughness of a 4340 steel. Researchers have been conducting experimental testing of dynamic crack initiation toughness, K{sub Ic}, for many years, using many experimental techniques with vastly different trends in the results when reporting K{sub Ic} as a function of loading rate. The dissertation describes a novel experimental technique for measuring K{sub Ic} in metals using the Kolsky bar. The method borrows from improvements made in recent years in traditional Kolsky bar testing by using pulse shaping techniques to ensure a constant loading rate applied to the sample before crack initiation. Dynamic crack initiation measurements were reported on a 4340 steel at two different loading rates. The steel was shown to exhibit a rate dependence, with the recorded values of K{sub Ic} being much higher at the higher loading rate. Using the knowledge of this rate dependence as a motivation in attempting to model the fracture events, a viscoplastic constitutive model was implemented into a peridynamic computational mechanics code. Peridynamics is a newly developed theory in solid mechanics that replaces the classical partial differential equations of motion with integral-differential equations which do not require the existence of spatial derivatives in the displacement field. This allows for the straightforward modeling of unguided crack initiation and growth. To date, peridynamic implementations have used severely restricted constitutive models. This research represents the first implementation of a complex material model and its validation. After showing results comparing deformations to experimental Taylor anvil impact for the viscoplastic material model, a novel failure criterion is introduced to model the dynamic crack initiation toughness experiments. The failure model is based on an energy criterion and uses the K{sub Ic} values recorded experimentally as an input. The failure model is then validated against one class of problems showing good agreement with experimental results.

  11. Analysis of weld solidification cracking in cast nickel aluminide alloys

    SciTech Connect (OSTI)

    Santella, M.L.; Feng, Z. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

    1995-09-01T23:59:59.000Z

    A study of the response of several nickel aluminide alloys to SigmaJig testing was done to examine their weld solidification cracking behavior and the effect of Zr concentration. The alloys were based on the Ni-8Al-7.7Cr-1.5Mo-0.003B wt% composition and contained Zr concentrations of 3, 4.5, and 6 wt%. Vacuum induction melted ingots with a diameter of 2.7 in and weight about 18 lb were made of each alloy, and were used to make 2 x 2 x 0.030 in specimens for the Sigmajig test. The gas tungsten arc welds were made at travel speeds of 10, 20, and 30 ipm with heat inputs of 2--2.5 kJ/in. When an arc was established before traveling onto the test specimen centerline cracking was always observed. This problem was overcome by initiating the arc directly on the specimens. Using this approach, the 3 wt% Zr alloy withstood an applied stress of 24 ksi without cracking at a welding speed of 10 ipm. This alloy cracked at 4 ksi applied at 20 ipm, and with no applied load at 30 ipm. Only limited testing was done on the remaining alloys, but the results indicate that resistance to solidification cracking increases with Zr concentration. Zirconium has limited solid solubility and segregates strongly to interdendritic regions during solidification where it forms a Ni solid solution-Ni{sub 5}Zr eutectic. The volume fraction of the eutectic increases with Zr concentration. The solidification cracking behavior of these alloys is consistent with phenomenological theory, and is discussed in this context. The results from SigmaJig testing are analyzed using finite element modeling of the development of mechanical strains during solidification of welds. Experimental data from the test substantially agree with recent analysis results.

  12. Stress Corrosion Crack Detection on HU-25 Guardian Aircraft

    SciTech Connect (OSTI)

    Blackmon, R.; Huffman, J.; Mello, C.W.; Moore, D.G.; Walkington, P.D.

    1999-02-17T23:59:59.000Z

    Several ultrasonic inspection methods were developed at the Federal Aviation Administration's Airworthiness Assurance NDI Validation Center (AANC) to easily and rapidly detect hidden stress corrosion cracks in all vertical windshield posts on the US Coast Guard (USCG) HU-25 Guardian aircraft. The inspection procedure locates cracks as small as 2.0 millimeters emanating from internal fastener holes and determines their length. A test procedure was developed and a baseline assessment of the USCG fleet was conducted. Inspection results on twenty-five aircraft revealed a good correlation with results made during subsequent structural disassembly and visual inspection.

  13. Experimental and analytical investigations of mass transport processes of 12Cr-1MoVW steel in thermally-convected lithium systems

    SciTech Connect (OSTI)

    Bell, G.E.; Abdou, M.A.; Tortorelli, P.F.

    1988-01-01T23:59:59.000Z

    Experimental data on corrosion and mass transport in lithium12Cr-1MoVW steel were obtained from two thermal convection loops; one operated from 360 to 505/sup 0/C for 3040 hours and the other from 525 to 655/sup 0/C for 2510 hours. The experimental effort was supported by analytical investigations of mechanisms of corrosion and mass transport. It was found that mass transfer is not a simple function of temperature and alloy component solubility, but that temperature gradient also plays an important role. Above 580/sup 0/C mass transfer appears dominated by temperature gradient. Between 450 and 580/sup 0/C, mass transfer appears related to surface reactions involving nitrogen in lithium with chromium, and carbides on the steel surface. The corrosion rates from this work are significantly lower than those adopted in recent blanket design studies. 16 refs., 5 figs

  14. AQUIFER THERMAL ENERGY STORAGE

    E-Print Network [OSTI]

    Tsang, C.-F.

    2011-01-01T23:59:59.000Z

    aquifers for thermal energy storage. Problems outlined aboveModeling of Thermal Energy Storage in Aquifers," Proceed-ings of Aquifer Thermal Energy Storage Workshop, Lawrence

  15. AQUIFER THERMAL ENERGY STORAGE

    E-Print Network [OSTI]

    Tsang, C.-F.

    2011-01-01T23:59:59.000Z

    using aquifers for thermal energy storage. Problems outlinedmatical Modeling of Thermal Energy Storage in Aquifers,"ings of Aquifer Thermal Energy Storage Workshop, Lawrence

  16. AQUIFER THERMAL ENERGY STORAGE

    E-Print Network [OSTI]

    Tsang, C.-F.

    2011-01-01T23:59:59.000Z

    using aquifers for thermal energy storage. Problems outlinedmatical Modeling of Thermal Energy Storage in Aquifers,"Proceed- ings of Aquifer Thermal Energy Storage Workshop,

  17. Failure probability of axially cracked steam generator tubes; A probabilistic fracture mechanics model

    SciTech Connect (OSTI)

    Mavko, B.; Cizelj, L. (Jozef Stefan Inst., Reactor Engineering Div., P.O. Box 100, 61111 Ljubljana, Slovenia (YU))

    1992-05-01T23:59:59.000Z

    In this paper a model for estimating the failure probability of axially cracked steam generator tubes is proposed. The model compares observed crack length distribution with critical crack length distribution by means of probabilistic fracture mechanics. The observed crack length is influenced by measured data, measurement reliability, sizing accuracy, and predicted crack growth rate. The critical crack length is defined by a deterministic mechanical model. All cracks are conservatively assumed to extend through the tube wall. The effect of the plugging limit is studied along with the number of cracked tubes to perform risk-based lifetime optimization of steam generators. A numerical example presented considers hypothetical accidental operating conditions during a feedwater line break.

  18. Monitoring Cracking of a Smectitic Vertisol using Three-dimensional Electrical Resistivity Tomography

    E-Print Network [OSTI]

    Ackerson, Jason Paul

    2013-11-20T23:59:59.000Z

    Upon desiccation, the matrix of Vertisols and other expansive soils shrinks. Matrix shrinkage results in the formation of cracks that can alter the hydrology of the soil. Despite the importance of cracks, many hydrologic models do not account...

  19. Modeling the steady-state ISV (in situ vitrification) process: A 3-D finite element analysis of coupled thermal-electric fields

    SciTech Connect (OSTI)

    Langerman, M.A.

    1990-09-01T23:59:59.000Z

    Steady-state modeling considerations for simulating the in situ vitrification (ISV) process are documented based upon the finite element numerical approach. Recommendations regarding boundary condition specifications and mesh discretization are presented. The effects of several parameters on the ISV process response are calculated and the results discussed. The parameters investigated include: (1) electrode depth, (2) ambient temperature, (3) supplied current, (4) electrical conductivity, (5) electrode separation, and (6) soil/waste characterization. 13 refs., 29 figs., 1 tab.

  20. Microwave Enhanced Direct Cracking of Hydrocarbon Feedstock for Energy Efficient Production of Ethylene and Propylene.

    SciTech Connect (OSTI)

    Shulman, Holly; Fall, Morgana; Wagner, Eric; Bowlin, Ricardo

    2012-02-13T23:59:59.000Z

    This project demonstrated microwave cracking of ethane with good product conversion and ethylene selectivity, with a short residence time ({approx}0.001 sec). The laboratory scale equipment was designed and built, along with concept designs for larger scale implementation. The system was operated below atmospheric pressures, in the range of 15-55 torr, with argon as a carrier gas. The measured products included hydrogen, methane, acetylene, and ethylene. The results followed similar trends to those predicted by the modeling software SPYRO{reg_sign}, with the exception that the microwave appeared to produce slightly lower amounts of ethylene and methane, although enhanced analytical analysis should reduce the difference. Continued testing will be required to verify these results and quantify the energy consumption of microwave vs. conventional. The microwave cracking process is an attractive option due to the possibility of selectively heating the reaction volume rather than the reactor walls, which may allow novel reactor designs that result in more efficient production of ethylene. Supplemental studies are needed to continue the laboratory testing and refine processing parameters.

  1. Fluid Catalytic Cracking Power Recovery Computer Simulation

    E-Print Network [OSTI]

    Samurin, N. A.

    1979-01-01T23:59:59.000Z

    operating conditions. The digital computer model simulates the performance of the axial compressor, power recovery expander, regenerator section, and system pressure drops. The program can simulate the process system design conditions for compatibility...

  2. Fluid Catalytic Cracking Power Recovery Computer Simulation 

    E-Print Network [OSTI]

    Samurin, N. A.

    1979-01-01T23:59:59.000Z

    operating conditions. The digital computer model simulates the performance of the axial compressor, power recovery expander, regenerator section, and system pressure drops. The program can simulate the process system design conditions for compatibility...

  3. alloy processing plant: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    pricing. This, in turn, negatively...-product of the olefins cracking process. This off-gas is routinely used as fuel for the olefins furnaces. Supplemental fuel for the...

  4. acid processing plant: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    pricing. This, in turn, negatively...-product of the olefins cracking process. This off-gas is routinely used as fuel for the olefins furnaces. Supplemental fuel for the...

  5. THERMAL HYDRAULICS KEYWORDS: thermal hydraulics,

    E-Print Network [OSTI]

    Smith, Barton L.

    -fluid modeling of nuclear reactor systems. Thermal-hydraulic analysis codes such as RELAP5-3D ~Ref. 1! and FLICA regions of the system. In fact, the CFD code FLUENT has previously been coupled to RELAP5-3D ~Refs. 3

  6. Compliant alkali silicate sealing glass for solid oxide fuel cell applications: thermal cycle stability and chemical compatibility

    SciTech Connect (OSTI)

    Chou, Y. S.; Thomsen, Edwin C.; Williams, Riley T.; Choi, Jung-Pyung; Canfield, Nathan L.; Bonnett, Jeff F.; Stevenson, Jeffry W.; Shyam, Amit; Lara-Curzio, E.

    2011-03-01T23:59:59.000Z

    An alkali silicate glass (SCN-1) is currently being evaluated as a candidate sealing glass for solid oxide fuel (SOFC) applications. The glass containing ~17 mole% alkalis (K2O and Na2O) remains vitreous and compliant during SOFC operation, unlike conventional SOFC sealing glasses, which experience substantial devitrification after the sealing process. The non-crystallizing compliant sealing glass has lower glass transition and softening temperatures since the microstructure remains glassy without significant crystallite formation, and hence can relieve or reduce residual stresses and also has the potential for crack healing. Sealing approaches based on compliant glass will also need to satisfy all the mechanical, thermal, chemical, physical, and electrical requirements for SOFC applications, not only in bulk properties but also at sealing interfaces. In this first of a series of papers we will report the thermal cycle stability of the glass when sealed between two SOFC components, i.e., a NiO/YSZ anode supported YSZ bilayer and a coated ferritic stainless steel interconnect material. High temperature leak rates were monitored versus thermal cycles between 700-850oC using back pressures ranging from 0.2 psi to 1.0 psi. Isothermal stability was also evaluated in a dual environment consisting of flowing dilute H2 fuel versus ambient air. In addition, chemical compatibility at the alumina and YSZ interfaces was examined with scanning electron microscopy and energy dispersive spectroscopy. The results shed new light on the topic of SOFC glass seal development.

  7. SEPTARIAN CONCRETIONS Septarian structures are former cracks, often lled with cement

    E-Print Network [OSTI]

    S SEPTARIAN CONCRETIONS Septarian structures are former cracks, often ®lled with cement may show a component of shear displacement. Crack filling cements Cracks may range from largely un®lled to fully cement ®lled, often with a variety of distinctively colored spar cements. The ®lls may also

  8. A fast multipole boundary element method for modeling 2-D multiple crack problems with constant elements

    E-Print Network [OSTI]

    Liu, Yijun

    A fast multipole boundary element method for modeling 2-D multiple crack problems with constant 3 April 2014 Accepted 20 May 2014 Keywords: Fast multipole BEM 2-D multi-crack problems Constant elements Crack opening displacements Stress intensity factors a b s t r a c t A fast multipole boundary

  9. Hot cracking in tungsten inert gas welding of magnesium alloy AZ91D

    E-Print Network [OSTI]

    Zhou, Wei

    Hot cracking in tungsten inert gas welding of magnesium alloy AZ91D W. Zhou*, T. Z. Long and C. K of the plates were produced using tungsten inert gas (TIG) welding method. The TIG arc was also used to deposit welding beads on some of the thin plates. No cracking was found in the butt joints. However, hot cracking

  10. Stress corrosion cracking under low stress: Continuous or discontinuous Longkui K. Zhu a

    E-Print Network [OSTI]

    Volinsky, Alex A.

    Stress corrosion cracking under low stress: Continuous or discontinuous cracks? Longkui K. Zhu a , Yu Yan a , Jinxu X. Li a , Lijie J. Qiao a, , Alex A. Volinsky b,a a Corrosion and Protection Center. Stress corrosion C. Anodic dissolution a b s t r a c t Two-dimensional and three-dimensional crack

  11. Analytical Investigation of Repair Methods for Fatigue Cracks in Steel Bridges

    E-Print Network [OSTI]

    Richardson, Temple

    2012-08-31T23:59:59.000Z

    ..................................................................................................................... 22 Retrofit measure 5: Bolted Stiffener-to-Flange Angles .......................................................................................... 23 Retrofit measure 6: Bolted Web-to-Stiffener Angles and Backing Plate... crack and a 204-mm (8-in.) web-to-flange weld crack. ............................................. 55 Table 2. Comparison of stress intensity factors for three crack surface displacements with the web-to-stiffener angles and a backing plate retrofit...

  12. A cracked beam finite element for rotating shaft dynamics and stability analysis

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    A cracked beam finite element for rotating shaft dynamics and stability analysis Saber El Arem Palaiseau, France Abstract In this paper, a method for the construction of a cracked beam finite element is presented. The additional flexibility due to the cracks is identified from three- dimensional finite element

  13. A creep model for austenitic stainless steels incorporating cavitation and wedge cracking

    E-Print Network [OSTI]

    Mahesh, Sivasambu

    A creep model for austenitic stainless steels incorporating cavitation and wedge cracking S Mahesh evolution in the form of cavitation and wedge- cracking on grain boundary facets is considered. Both: Austenitic stainless steel, creep, grain boundary sliding, cavitation, wedge- cracking. Submitted to

  14. Solvent control of crack dynamics in a reversible hydrogel

    E-Print Network [OSTI]

    Tristan Baumberger; Christiane Caroli; David Martina

    2006-05-16T23:59:59.000Z

    The resistance to fracture of reversible biopolymer hydrogels is an important control factor of the cutting/slicing and eating characteristics of food gels. It is also critical for their utilization in tissue engineering, for which mechanical protection of encapsulated components is needed. Its dependence on loading rate and, recently, on the density and strength of cross-links has been investigated. But no attention was paid so far to solvent nor to environment effects. Here we report a systematic study of crack dynamics in gels of gelatin in water/glycerol mixtures. We show on this model system that: (i) increasing solvent viscosity slows down cracks; (ii) soaking with solvent increases markedly gel fragility; (iii) tuning the viscosity of the (miscible) environmental liquid affects crack propagation via diffusive invasion of the crack tip vicinity. The results point toward the fact that fracture occurs by viscoplastic chain pull-out. This mechanism, as well as the related phenomenology, should be common to all reversibly cross-linked (physical) gels.

  15. Thin film with oriented cracks on a flexible substrate

    DOE Patents [OSTI]

    Feng, Bao; McGilvray, Andrew; Shi, Bo

    2010-07-27T23:59:59.000Z

    A thermoelectric film is disclosed. The thermoelectric film includes a substrate that is substantially electrically non-conductive and flexible and a thermoelectric material that is deposited on at least one surface of the substrate. The thermoelectric film also includes multiple cracks oriented in a predetermined direction.

  16. CONTAINED PLASTIC DEFORMATION NEAR CRACKS AND NOTCHES UNDER LONGITUDINAL SHEAR

    E-Print Network [OSTI]

    CONTAINED PLASTIC DEFORMATION NEAR CRACKS AND NOTCHES UNDER LONGITUDINAL SHEAR James R. Rice* ABSTRACT An exact linear elastic-perfectly plastic solution is presented for the problem of a sharp notch coordinates corresponding to given stresses, position of the elastic-plastic boundary, and accompanying

  17. Variable amplitude fatigue crack growth, experimental results and modeling

    E-Print Network [OSTI]

    a,*, F. Bumbieler b a Laboratory of Mechanics and Technology Cachan, 61, Avenue du Pre´s. Wilson method. This identification was performed for a 0.48%C carbon steel. Then various fatigue crack growth) is required so as to capture the very details of the elastic­plastic cyclic deformation of the mate- rial

  18. Fracture mechanics analysis of slow crack growth in polyethylene

    E-Print Network [OSTI]

    Self, Robert Alan

    1997-01-01T23:59:59.000Z

    polyethylenes were used to evaluate the new test and analysis methods. Static loading of deeply notched three-point bend specimens was conducted at 26.7 'C, 40 'C, and 70 'C on 1.27 cm , 0.953 cm, and 0.635 cm material. The crack length as a function of time...

  19. EARLY-AGE CRACKING REVIEW: MECHANISMS, MATERIAL PROPERTIES,

    E-Print Network [OSTI]

    Bentz, Dale P.

    ://cementbarriers.org/ and Savannah River National Laboratory website: http://srnl.doe.gov #12;Early-Age Cracking Review: Mechanisms Commission (NRC), the National Institute of Standards and Technology (NIST), the Savannah River National of work performed in part under that contract. This report was prepared in support of the Savannah River

  20. AUTONOMOUS CRACK MEASUREMENT FOR COMPARISON OF VIBRATORY COMPACTION EXCITATION AND

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Establishment of the fragility of historic structures near rights of way often produces costly delays the potential for adjacent construction activities to cause cosmetic cracking in both historic and non-historic of Civil & Environmental Engineering, Northwestern University c-dowding@northwestern.edu ABSTRACT

  1. Method of making crack-free zirconium hydride

    DOE Patents [OSTI]

    Sullivan, Richard W. (Denver, CO)

    1980-01-01T23:59:59.000Z

    Crack-free hydrides of zirconium and zirconium-uranium alloys are produced by alloying the zirconium or zirconium-uranium alloy with beryllium, or nickel, or beryllium and scandium, or nickel and scandium, or beryllium and nickel, or beryllium, nickel and scandium and thereafter hydriding.

  2. Steady crack growth in elasticplastic uid-saturated porous media

    E-Print Network [OSTI]

    Bigoni, Davide

    at the crack-tip were analyzed by van den Hoek et al. (1993) and Mohr-Coulomb elastoplasticity was considered a combined ®nite dierence/®nite element technique. In this article, an asymptotic solution is obtained criterion with volumetric non-associative ¯ow law and isotropic hardening. The technique used to solved

  3. Thin film cracking and ratcheting caused by temperature cycling

    E-Print Network [OSTI]

    Suo, Zhigang

    Thin film cracking and ratcheting caused by temperature cycling M. Huang and Z. Suo Mechanical caused by ratcheting in an adjacent ductile layer. For example, on a silicon die directly attached corners. Aided by cycling temperature, the shear stresses cause ratcheting in the aluminum pads

  4. Incipient Crack Detection in Composite Wind Turbine Blades

    SciTech Connect (OSTI)

    Taylor, Stuart G. [Los Alamos National Laboratory; Choi, Mijin [Chonbuk National University, Korea; Jeong, Hyomi [Chonbuk National University, Korea; Jang, Jae Kyeong [Chonbuk National University, Korea; Park, Gyuhae [Chonnam National University, Korea; Farinholt, Kevin [Commonwealth Center for Advanced Manufacturing, VA; Farrar, Charles R. [Los Alamos National Laboratory; Ammerman, Curtt N. [Los Alamos National Laboratory; Todd, Michael D. [Los Alamos National Laboratory; Lee, Jung-Ryul [Chonbuk National University, Korea

    2012-08-28T23:59:59.000Z

    This paper presents some analysis results for incipient crack detection in a 9-meter CX-100 wind turbine blade that underwent fatigue loading to failure. The blade was manufactured to standard specifications, and it underwent harmonic excitation at its first resonance using a hydraulically-actuated excitation system until reaching catastrophic failure. This work investigates the ability of an ultrasonic guided wave approach to detect incipient damage prior to the surfacing of a visible, catastrophic crack. The blade was instrumented with piezoelectric transducers, which were used in an active, pitchcatch mode with guided waves over a range of excitation frequencies. The performance results in detecting incipient crack formation in the fiberglass skin of the blade is assessed over the range of frequencies in order to determine the point at which the incipient crack became detectable. Higher excitation frequencies provide consistent results for paths along the rotor blade's carbon fiber spar cap, but performance falls off with increasing excitation frequencies for paths off of the spar cap. Lower excitation frequencies provide more consistent performance across all sensor paths.

  5. Mechanical Engineering & Thermal Group

    E-Print Network [OSTI]

    Mojzsis, Stephen J.

    Mechanical Engineering & Thermal Group The Mechanical Engineering (ME) & Thermal Group at LASP has · STOP (Structural, Thermal, and Optical Performance) analyses of optical systems Thermal engineers lead evolved with the complexity of instrument design demands, LASP mechanical engineers develop advanced

  6. ME 343 Thermal-Fluid Systems ABET EC2000 syllabus

    E-Print Network [OSTI]

    Ben-Yakar, Adela

    ) 8. Unsteady thermal system modeling, energy storage 9. Software design and development ClassME 343 ­ Thermal-Fluid Systems Page 1 ABET EC2000 syllabus ME 343 ­ Thermal-Fluid Systems Spring thermal and fluid processes are central to function and performance: thermodynamics of nonreacting

  7. Effect of Processing and Microalloying Elements on the Thermal Stability of Cr-Cr3Si and NiAl-Mo Eutectic Alloys

    SciTech Connect (OSTI)

    Gali, Aravind [ORNL; Bei, Hongbin [ORNL; George, Easo P [ORNL

    2007-01-01T23:59:59.000Z

    The thermal stability of multiphase intermetallics at temperatures to 1400 C was investigated by studying two model eutectic systems: Cr-Cr{sub 3}Si having a lamellar microstructure and NiAl-Mo having a fibrous microstructure. In drop cast Cr-Cr{sub 3}Si, coarsening was found to be interface controlled. The coarsening rate could be reduced by microalloying with Ce and Re, two elements which were chosen because they were expected to segregate to the Cr-Cr{sub 3}Si interfaces and decrease their energies. Similarly, directional solidification, which is also expected to lower the Cr-Cr{sub 3}Si interfacial energy, was found to dramatically decrease the coarsening rate. In the case of NiAl-Mo, coarsening was found to occur by fault migration and annihilation. Microalloying with B was found to significantly decrease the coarsening rate. The fiber density in the B-doped alloy was smaller than in the undoped alloy, suggesting that B affects the coarsening rate by lowering the fault density.

  8. Economics for iso-olefin production using the fluid catalytic cracking unit

    SciTech Connect (OSTI)

    McClung, R.G.; Witoshkin, A.; Bogert, D.C.; Winkler, W.S. [Englehard Corp., Iselin, NJ (United States)

    1993-12-31T23:59:59.000Z

    The Clean Air Act of 1990 requires use of oxygenates in some gasolines to improve both CO and hydrocarbon auto tailpipe emissions. Various oxygenates are currently being used by the refining industry. For the fully integrated refinery having a fluid catalytic cracking unit, the most commonly used oxygenates are methyl tertiary butyl ether (MTBE) and tertiary amyl ether (TAME). The FCC unit produces the isobutylene and iso-amylases need for manufacture of both MTBE and TAME. The economics for an assumed refinery processing scheme for several FCC cases are examined giving estimates of income and investments for each case. Up to one-third of the total gasoline pool can be made in reformulated gasoline using TAME and MTBE with the FCC unit as the sole source of feedstock. This processing route is much more economical than the alternative scheme using butane isomerization/iosbutane dehydrogenation.

  9. Thermal Shock-resistant Cement

    SciTech Connect (OSTI)

    Sugama T.; Pyatina, T.; Gill, S.

    2012-02-01T23:59:59.000Z

    We studied the effectiveness of sodium silicate-activated Class F fly ash in improving the thermal shock resistance and in extending the onset of hydration of Secar #80 refractory cement. When the dry mix cement, consisting of Secar #80, Class F fly ash, and sodium silicate, came in contact with water, NaOH derived from the dissolution of sodium silicate preferentially reacted with Class F fly ash, rather than the #80, to dissociate silicate anions from Class F fly ash. Then, these dissociated silicate ions delayed significantly the hydration of #80 possessing a rapid setting behavior. We undertook a multiple heating -water cooling quenching-cycle test to evaluate the cement’s resistance to thermal shock. In one cycle, we heated the 200 and #61616;C-autoclaved cement at 500 and #61616;C for 24 hours, and then the heated cement was rapidly immersed in water at 25 and #61616;C. This cycle was repeated five times. The phase composition of the autoclaved #80/Class F fly ash blend cements comprised four crystalline hydration products, boehmite, katoite, hydrogrossular, and hydroxysodalite, responsible for strengthening cement. After a test of 5-cycle heat-water quenching, we observed three crystalline phase-transformations in this autoclaved cement: boehmite and #61614; and #61543;-Al2O3, katoite and #61614; calcite, and hydroxysodalite and #61614; carbonated sodalite. Among those, the hydroxysodalite and #61614; carbonated sodalite transformation not only played a pivotal role in densifying the cementitious structure and in sustaining the original compressive strength developed after autoclaving, but also offered an improved resistance of the #80 cement to thermal shock. In contrast, autoclaved Class G well cement with and without Class F fly ash and quartz flour failed this cycle test, generating multiple cracks in the cement. The major reason for such impairment was the hydration of lime derived from the dehydroxylation of portlandite formed in the autoclaved cement, causing its volume to expand.

  10. FURTHER EXAMINATION OF CRACK TIP MICROSTRUCTURES IN F82H ON THE LOWER SHELF

    SciTech Connect (OSTI)

    Gelles, David S.; Odette, George R.; Spatig, P.

    2003-09-03T23:59:59.000Z

    Dislocation microstructures have been further examined near the crack tip of a compact tension specimen of unirradiated F82H loaded to 25.6 MPa m square root at –196 degrees C after fatigue precracking. A specimen was prepared by sectioning, dimple grinding and ion milling to produce electron transparency just ahead of the crack tip. Further ion milling has allowed improved examination of the microstructure immediately ahead of the crack tip. It is found that subgrain structure is relatively unaffected near the crack tip whereas 3 micron from the crack tip, dislocation loop structure was identified.

  11. Thermal Stress Cracking of Sliding Gate Plates Hyoung-Jun Lee1

    E-Print Network [OSTI]

    Thomas, Brian G.

    , Warrendale, PA. #12;may b aspira b). Th indica show Previ their differ tempe mech [1]. A pressu be very

  12. Thermal Stabilization Blend Plan

    SciTech Connect (OSTI)

    RISENMAY, H.R.

    2000-05-02T23:59:59.000Z

    This Blend Plan documents the feed material items that are stored in 2736-2 vaults, the 2736-ZB 638 cage, the 192C vault, and the 225 vault that will be processed through the thermal stabilization furnaces. The purpose of thermal stabilization is to heat the material to 1000 degrees Celsius to drive off all water and leave the plutonium and/or uranium as oxides. The stabilized material will be sampled to determine the Loss On Ignition (LOI) or percent water. The stabilized material must meet water content or LOI of less than 0.5% to be acceptable for storage under DOE-STD-3013-99 specifications. Out of specification material will be recycled through the furnaces until the water or LOI limits are met.

  13. Selective thermal and photooxidation of hydrocarbons in zeolites by oxygen

    DOE Patents [OSTI]

    Frei, Heinz (Berkeley, CA); Blatter, Fritz (Basel, CH); Sun, Hai (Saint Charles, MO)

    1999-01-01T23:59:59.000Z

    A process for selective thermal oxidation or photooxidation of hydrocarbons adsorbed onto zeolite matrices. A highly selective thermal oxidation and photooxidation of unsubstituted or alkyl substituted alkanes, alkenes, aromatics and cycloalkyls in solvent free zeolites under dark thermal conditions or under irradiation with visible light. The process oxidizes hydrocarbons almost completely selectively without substantial production of byproducts.

  14. Selective thermal oxidation of hydrocarbons in zeolites by oxygen

    DOE Patents [OSTI]

    Frei, Heinz (Berkeley, CA); Blatter, Fritz (Basel, CH); Sun, Hai (Saint Charles, MO)

    2000-01-01T23:59:59.000Z

    A process for selective thermal oxidation of hydrocarbons adsorbed onto zeolite matrices. A highly selective thermal oxidation of unsubstituted or alkyl substituted alkanes, alkenes, aromatics and cycloalkyls is carried out in solvent free zeolites under dark thermal conditions. The process oxidizes hydrocarbons almost completely selectively without substantial production of byproducts.

  15. Selective thermal and photooxidation of hydrocarbons in zeolites by oxygen

    DOE Patents [OSTI]

    Frei, Heinz (Berkeley, CA); Blatter, Fritz (Basel, CH); Sun, Hai (Saint Charles, MO)

    2001-01-01T23:59:59.000Z

    A process for a combined selective thermal oxidation and photooxidation of hydrocarbons adsorbed onto zeolite matrices. A highly combined selective thermal oxidation and photooxidation of unsubstituted or alkyl substituted alkanes, alkenes, aromatics and cycloalkyls in solvent free zeolites under dark thermal conditions or under irradiation with visible light. The process oxidizes hydrocarbons almost completely selectively without substantial production of byproducts.

  16. Selective thermal and photooxidation of hydrocarbons in zeolites by oxygen

    DOE Patents [OSTI]

    Frei, H.; Blatter, F.; Sun, H.

    1999-06-22T23:59:59.000Z

    A process is described for selective thermal oxidation or photooxidation of hydrocarbons adsorbed onto zeolite matrices. A highly selective thermal oxidation and photooxidation of unsubstituted or alkyl substituted alkanes, alkenes, aromatics and cycloalkyls in solvent free zeolites under dark thermal conditions or under irradiation with visible light. The process oxidizes hydrocarbons almost completely selectively without substantial production of byproducts. 19 figs.

  17. Fatigue and Creep Crack Propagation behaviour of Alloy 617 in the Annealed and Aged Conditions

    SciTech Connect (OSTI)

    Julian K. Benz; Richard N. Wright

    2013-10-01T23:59:59.000Z

    The crack propagation behaviour of Alloy 617 was studied under various conditions. Elevated temperature fatigue and creep-fatigue crack growth experiments were conducted at 650 and 800 degrees C under constant stress intensity (triangle K) conditions and triangular or trapezoidal waveforms at various frequencies on as-received, aged, and carburized material. Environmental conditions included both laboratory air and characteristic VHTR impure helium. As-received Alloy 617 displayed an increase in the crack growth rate (da/dN) as the frequency was decreased in air which indicated a time-dependent contribution component in fatigue crack propagation. Material aged at 650°C did not display any influence on the fatigue crack growth rates nor the increasing trend of crack growth rate with decreasing frequency even though significant microstructural evolution, including y’ (Ni3Al) after short times, occurred during aging. In contrast, carburized Alloy 617 showed an increase in crack growth rates at all frequencies tested compared to the material in the standard annealed condition. Crack growth studies under quasi-constant K (i.e. creep) conditions were also completed at 650 degrees C and a stress intensity of K = 40 MPa9 (square root)m. The results indicate that crack growth is primarily intergranular and increased creep crack growth rates exist in the impure helium environment when compared to the results in laboratory air. Furthermore, the propagation rates (da/dt) continually increased for the duration of the creep crack growth either due to material aging or evolution of a crack tip creep zone. Finally, fatigue crack propagation tests at 800 degrees C on annealed Alloy 617 indicated that crack propagation rates were higher in air than impure helium at the largest frequencies and lowest stress intensities. The rates in helium, however, eventually surpass the rates in air as the frequency is reduced and the stress intensity is decreased which was not observed at 650 degrees C.

  18. Initiation of environmentally-assisted cracking in low-alloy steels

    SciTech Connect (OSTI)

    Wire, G.L.; Li, Y.Y.

    1996-06-01T23:59:59.000Z

    Environmentally-Assisted Cracking (EAC) in low alloy steels is activated by a critical level of sulfide ions at the crack tip, which is produced from dissolution of sulfide inclusions (MnS, FeS, etc.) in the steel following exposure by a growing crack. EAC of concern herein is the increase of fatigue crack growth rate of up to 40 to 100 times the rate in air that occurs at 240--300 C in high temperature LWR or boiler water environments. The initiation of EAC is the onset of the higher fatigue crack growth rates in fully developed cracks already presumed to be present due to fatigue, stress corrosion cracking, or induced by fabrication. Initiation of EAC is induced by a change in loading parameters causing the fatigue crack growth rate to increase from a small multiple (2--4) to 40--100 times the air rate. A steady state theory developed by Combrade, suggests that EAC will initiate only above a critical crack velocity and cease below this same velocity. However, more recent tests show that EAC can persist down to much lower velocities (100 times lower) in low oxygen water at slightly lower temperatures. A special set of experiments on high sulfur plate material demonstrate that EAC will not initiate from surface cracks with low sulfide inventories at low crack tip velocities. Transient diffusion calculations show that a finite crack extension at a high crack tip velocity is necessary to initiate EAC, providing a possible explanation for the lack of high crack growth observations reported in low alloy steels in structural applications involving low oxygen environments.

  19. Thermal conductivity of thermal-battery insulations

    SciTech Connect (OSTI)

    Guidotti, R.A.; Moss, M.

    1995-08-01T23:59:59.000Z

    The thermal conductivities of a variety of insulating materials used in thermal batteries were measured in atmospheres of argon and helium using several techniques. (Helium was used to simulate the hydrogen atmosphere that results when a Li(Si)/FeS{sub 2} thermal battery ages.) The guarded-hot-plate method was used with the Min-K insulation because of its extremely low thermal conductivity. For comparison purposes, the thermal conductivity of the Min-K insulating board was also measured using the hot-probe method. The thermal-comparator method was used for the rigid Fiberfrax board and Fiberfrax paper. The thermal conductivity of the paper was measured under several levels of compression to simulate the conditions of the insulating wrap used on the stack in a thermal battery. The results of preliminary thermal-characterization tests with several silica aerogel materials are also presented.

  20. Synthesis and design of optimal thermal membrane distillation networks

    E-Print Network [OSTI]

    Nyapathi Seshu, Madhav

    2006-10-30T23:59:59.000Z

    Thermal membrane distillation is one of the novel separation methods in the process industry. It involves the simultaneous heat and mass transfer through a hydrophobic semipermeable membrane through the use of thermal energy to bring about...

  1. Thermal and Non-thermal Physiochemical Processes in Nanoscale...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    nanoscale films of ASW at low temperatures. To study the transport properties (viscosity, diffusivity), the amorphous films can be heated above their glass transition...

  2. ANALYZING THE THERMAL ANNEALING BEHAVIOR OF LASER THERMAL PROCESSED SILICON

    E-Print Network [OSTI]

    Florida, University of

    Talwar for allowing access to the laser annealing tools at Verdant Technologies. I would also like;useless discussions. I would especially like to thank Lance Robertson who encouraged me to "just give grad

  3. The Thermal Expansion, Elastic and Fracture Properties of Porous Cordierite at Elevated Temperatures

    SciTech Connect (OSTI)

    Shyam, Amit [ORNL; Lara-Curzio, Edgar [ORNL; Pandey, Amit [ORNL; Watkins, Thomas R [ORNL; More, Karren [Oak Ridge National Laboratory (ORNL)

    2012-01-01T23:59:59.000Z

    The properties that determine the thermal shock resistance in materials are reported for porous cordierite, a leading candidate material for the fabrication of diesel particulate filters. Fracture toughness and slow crack growth tests were performed on test specimens obtained from the walls of diesel particulate filter monolithic substrates using the double-torsion test method at temperatures between 20 C and 900 C. The thermal expansion and elastic properties were characterized between 20 C and 1000 C. The role of the microstructure of porous cordierite in determining its unusual thermal expansion and elevated temperature Young's modulus and fracture toughness are discussed.

  4. High Temperature Thermal Array for Next Generation Solar Thermal...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    High Temperature Thermal Array for Next Generation Solar Thermal Power Production High Temperature Thermal Array for Next Generation Solar Thermal Power Production This...

  5. Microstructural and solidification cracking evaluation of electron beam welds in 304L

    SciTech Connect (OSTI)

    Sturgill, P.L.; Campbell, R.D.; Henningsen, J.L.

    1991-01-01T23:59:59.000Z

    Weld hot cracking of stainless steels is a major materials-related problem in the welding industry. This present investigation evaluates the crack susceptibility of highly-constrained EB welds made in materials whose DeLong ferrite potentials range from zero to nine FN. In addition, the effect of piece part strength level on cracking is examined. This study has revealed that these deep penetration EB welds have regions that solidify as primary austenite, even when the DeLong ferrite potential is as high as 9 FN. This points out the critical role that solidification rate plays in the crack susceptibility of these highly restrained welds. In addition, 0 FN to 0 FN welds had primarily transverse cracks while 6 FN to 0 FN welds had primarily centerline cracks. Of particular interest is the observation that cracks still occur if a high ferrite (greater than 6 FN) component is welded to a zero FN component. Cracking is always associated with regions which solidify as primary austenite and these cracks occur because there are areas in the weld which do not mix. Thus it is not a recommended production practice to compensate for low ferrite in one piece part with high ferrite in its mate. Finally, it is shown that a DeLong FN threshold of 4 to prevent cracking in EB welds in not valid. 21 refs., 16 figs.

  6. Process for upgrading tar sand bitumen

    SciTech Connect (OSTI)

    Bartholic, D.B.; Reagan, W.J.

    1989-04-04T23:59:59.000Z

    A process is described for upgrading a charge of a tar sand bitumen concentrate containing mineral matter including fine particles which comprises contacting the charge in a riser in the presence of a low boiling organic solvent diluent with finely divided attrition-resistant particles of a hot fluidizable substantially catalytically inert solid which is substantially chemically inert to a solution of mineral acid. The contact of the charge with the particles is at high temperature and short contact time to vaporize the high hydrogen containing components of the bitumen, the period of time being less than that which induces substantial thermal cracking of the charge, at the end of the time separating the vaporizing product from the fluidizable particles. The fluidizable particles now bear a deposit of both combustible solid, adherent particles of fine particles of mineral matter and metals. The particles of inert solid are passed with deposit of combustibles and fine particles of mineral matter to a regenerator to oxidize the combustible portion of the deposits, removing at least a portion of deposit of mineral matter and metals by removing the inert solid from the regenerator and contacting removed inert solid with a hot mineral acid, and recirculating fluidizable solid depleted at least in part of deposited mineral matter to contact with incoming charge of tar sand bitumen concentrate and diluent.

  7. Fatigue Crack Propagation from Notched Specimens of 304 SS in elevated Temperature Aqueous Environment

    SciTech Connect (OSTI)

    Wire, G. L.; Mills, W. J.

    2002-08-01T23:59:59.000Z

    Fatigue crack propagation (FCP) rates for 304 stainless steel (304SS) were determined in 24 degree C and 288 degree C air and 288 degree C water using double-edged notch (DEN) specimens of 304 stainless steel (304 SS). Test performed at matched loading conditions in air and water at 288 degree C with 20-6- cc h[sub]2/kg h[sub]2O provided a direct comparison of the relative crack growth rates in air and water over a wide range of crack growth rates. The DEN crack extension ranged from short cracks (0.03-0.25 mm) to long cracks up to 4.06 mm, which are consistent with conventional deep crack tests. Crack growth rates of 304 SS in water were about 12 times the air rate. This 12X environmental enhancement persisted to crack extensions up to 4.06 mm, far outside the range associated with short crack effects. The large environmental degradation for 304 SS crack growth is consistent with the strong reduction of fatigue life in high hydrogen water. Further, very similar environmental effects w ere reported in fatigue crack growth tests in hydrogen water chemistry (HWC). Most literature data in high hydrogen water show only a mild environmental effect for 304 SS, of order 2.5 times air or less, but the tests were predominantly performed at high cyclic stress intensity or equivalently, high air rates. The environmental effect in low oxygen environments at low stress intensity depends strongly on both the stress ratio, R, and the load rise time, T[sub]r, as recently reported for austenitic stainless steel in BWR water. Fractography was performed for both tests in air and water. At 288 degree C in water, the fracture surfaces were crisply faceted with a crystallographic appearance, and showed striations under high magnification. The cleavage-like facets on the fracture surfaces suggest that hydrogen embrittlement is the primary cause of accelerated cracking.

  8. To Crack or Not to Crack: Strain in High TemperatureSuperconductors

    SciTech Connect (OSTI)

    Godeke, Arno

    2007-08-22T23:59:59.000Z

    Round wire Bi 2212 is emerging as a viable successor ofNb3Sn in High Energy Physics and Nuclear Magnetic Resonance, to generatemagnetic fields that surpass the intrinsic limitations of Nb3Sn. Ratherbold claims are made on achievable magnetic fields in applications usingBi 2212, due to the materials' estimated critical magnetic field of 100 Tor higher. High transport currents in high magnetic fields, however, leadto large stress on, and resulting large strain in the superconductor. Theeffect of strain on the critical properties of Bi-2212 is far fromunderstood, and strain is, as with Nb3Sn, often treated as a secondaryparameter in the design of superconducting magnets. Reversibility of thestrain induced change of the critical surface of Nb3Sn, points to anelectronic origin of the observed strain dependence. Record breaking highfield magnets are enabled by virtue of such reversible behavior. Straineffects on the critical surface of Bi-2212, in contrast, are mainlyirreversible and suggest a non-electronic origin of the observed straindependence, which appears to be dominated by the formation of cracks inthe superconductor volumes. A review is presented of available results onthe effects of strain on the critical surface of Bi-2212, Bi-2223 andYBCO. It is shown how a generic behavior emerges for the (axial) straindependence of the critical current density, and how the irreversiblereduction of the critical current density is dominated by strain inducedcrack formation in the superconductor. From this generic model it becomesclear that magnets using high temperature superconductors will be strainlimited far before the intrinsic magnetic field limitations will beapproached, or possibly even before the magnetic field limitation ofNb3Sn can be surpassed. On a positive note, in a very promising recentresult from NIST on the axial strain dependence of the critical currentdensity in extremely well aligned YBCO, reversible behavior was observed.This result emphasizes the need for further conductor development,specifically for round wire Bi-2212, to generate a wire with a similarreversible dependence on strain. Availability of such a wire will enablethe construction of magnets that can indeed generate fields that farsurpass the limitations of Nb3Sn superconductors.

  9. Energy-Saving Melting and Revert Reduction Technology (E-SMARRT): Use of Laser Engineered Net Shaping for Rapid Manufacturing of Dies with Protective Coatings and Improved Thermal Management

    SciTech Connect (OSTI)

    Brevick, Jerald R. [Ohio State University

    2014-06-13T23:59:59.000Z

    In the high pressure die casting process, molten metal is introduced into a die cavity at high pressure and velocity, enabling castings of thin wall section and complex geometry to be obtained. Traditional die materials have been hot work die steels, commonly H13. Manufacture of the dies involves machining the desired geometry from monolithic blocks of annealed tool steel, heat treating to desired hardness and toughness, and final machining, grinding and polishing. The die is fabricated with internal water cooling passages created by drilling. These materials and fabrication methods have been used for many years, however, there are limitations. Tool steels have relatively low thermal conductivity, and as a result, it takes time to remove the heat from the tool steel via the drilled internal water cooling passages. Furthermore, the low thermal conductivity generates large thermal gradients at the die cavity surfaces, which ultimately leads to thermal fatigue cracking on the surfaces of the die steel. The high die surface temperatures also promote the metallurgical bonding of the aluminum casting alloy to the surface of the die steel (soldering). In terms of process efficiency, these tooling limitations reduce the number of die castings that can be made per unit time by increasing cycle time required for cooling, and increasing downtime and cost to replace tooling which has failed either by soldering or by thermal fatigue cracking (heat checking). The objective of this research was to evaluate the feasibility of designing, fabricating, and testing high pressure die casting tooling having properties equivalent to H13 on the surface in contact with molten casting alloy - for high temperature and high velocity molten metal erosion resistance – but with the ability to conduct heat rapidly to interior water cooling passages. A layered bimetallic tool design was selected, and the design evaluated for thermal and mechanical performance via finite element analysis. H13 was retained as the exterior layer of the tooling, while commercially pure copper was chosen for the interior structure of the tooling. The tooling was fabricated by traditional machining of the copper substrate, and H13 powder was deposited on the copper via the Laser Engineered Net Shape (LENSTM) process. The H13 deposition layer was then final machined by traditional methods. Two tooling components were designed and fabricated; a thermal fatigue test specimen, and a core for a commercial aluminum high pressure die casting tool. The bimetallic thermal fatigue specimen demonstrated promising performance during testing, and the test results were used to improve the design and LENS TM deposition methods for subsequent manufacture of the commercial core. Results of the thermal finite element analysis for the thermal fatigue test specimen indicate that it has the ability to lose heat to the internal water cooling passages, and to external spray cooling, significantly faster than a monolithic H13 thermal fatigue sample. The commercial core is currently in the final stages of fabrication, and will be evaluated in an actual production environment at Shiloh Die casting. In this research, the feasibility of designing and fabricating copper/H13 bimetallic die casting tooling via LENS TM processing, for the purpose of improving die casting process efficiency, is demonstrated.

  10. Methods of cracking a crude product to produce additional crude products

    DOE Patents [OSTI]

    Mo, Weijian (Sugar Land, TX); Roes, Augustinus Wilhelmus Maria (Houston, TX); Nair, Vijay (Katy, TX)

    2009-09-08T23:59:59.000Z

    A method for producing a crude product is disclosed. Formation fluid is produced from a subsurface in situ heat treatment process. The formation fluid is separated to produce a liquid stream and a first gas stream. The first gas stream includes olefins. The liquid stream is fractionated to produce one or more crude products. At least one of the crude products has a boiling range distribution from 38.degree. C. and 343.degree. C. as determined by ASTM Method D5307. The crude product having the boiling range distribution from 38.degree. C. and 343.degree. C. is catalytically cracked to produce one or more additional crude products. At least one of the additional crude products is a second gas stream. The second gas stream has a boiling point of at most 38.degree. C. at 0.101 MPa.

  11. Characterization of microstructure and crack propagation in alumina using orientation imaging microscopy (OIM). December 1996

    SciTech Connect (OSTI)

    Glass, S.J.; Michael, J.R. [Sandia National Labs., Albuquerque, NM (United States); Readey, M.J. [Caterpillar, Inc., Peoria, IL (United States); Wright, S.I.; Field, D.P. [TSL, Inc., Provo, UT (United States)

    1996-12-01T23:59:59.000Z

    A more complete description requires the lattice orientations of a statistically significant number of grains, coupled with morphology such as grain size and shape; this can be obtained using orientation imaging microscopy (OIM), which uses crystallographic orientation data from Backscattered Electron Kikuchi patterns (BEKP) collected using a SEM. This report describes the OIM results for alumina; these include image quality maps, grain boundary maps, pole figures, and lattice misorientations depicted on MacKenzie plot and in Rodrigues space. High quality BEKP were obtained and the images and data readily reveal the grain morphology, texture, and grain boundary misorientations, including those for cracked boundaries. A larger number of grains should be measured to make statistical comparisons between materials with different processing histories.

  12. Fatigue-crack growth correlations for design and analysis of stainless steel components

    SciTech Connect (OSTI)

    James, L.A.

    1981-10-01T23:59:59.000Z

    A relatively large collection of fatigue-crack growth results for annealed Types 304 and 316 stainless steels over a wide range of temperature was processed and analyzed in a consistent way. Only data that satisfied the criteria of ASTM E647-82 was retained and used in the statistical treatments that followed. Linear least-squares regression equations and 95% confidence intervals were fitted through the results for each material/temperature set. The regression results (and their associated limits of validity) provide useful equations for the analysis of structural components. Overlap (or the lack of overlap) of the confidence intervals was employed as a criterion as to whether the results for Types 304 and 316 should be separated into discrete sets, and on this basis it was concluded that the two alloys should be treated separately. 38 references, 16 figures, 1 table.

  13. Seasonal thermal energy storage

    SciTech Connect (OSTI)

    Allen, R.D.; Kannberg, L.D.; Raymond, J.R.

    1984-05-01T23:59:59.000Z

    This report describes the following: (1) the US Department of Energy Seasonal Thermal Energy Storage Program, (2) aquifer thermal energy storage technology, (3) alternative STES technology, (4) foreign studies in seasonal thermal energy storage, and (5) economic assessment.

  14. Carbo-metallic oil-conversion process and catalysts

    SciTech Connect (OSTI)

    Hettinger, W.P.; Beck, W.

    1989-10-31T23:59:59.000Z

    This patent describes a continuous process for cracking of a residual hydrocarbon feedstock into lower molecular weight hydrocarbon transportation fuels. The cracking being carried out in the presence of a catalyst having catalyst parameters comprising porosity, metals content, rare earth content, and zeolite content. The residual hydrocarbon feedstock comprising metal contaminants, fractions boiling above 1025{degrees}F. comprising asphaltenes, polynuclear aromatics, naphthenes and prophyrins.

  15. Thermo Tracer Infrared Thermal Imager

    E-Print Network [OSTI]

    Walker, D. Greg

    such as production lines, electric power facilities, petrochemical plants and public institutions, etc. by thermal-range area G Environment monitoring Volcano, ecology, vegetation, global warming, pollution G R&D Evaluation Production line monitoring Quality anomalies in production processes G Facility monitoring Anomalies

  16. Subcritical Crack Growth in Ceramic Composites at High Temperature Measured Using Digital Image Correlation

    SciTech Connect (OSTI)

    Mumm, D.R.; Morris, W.L.; Dadkhah, M.S.; Cox, B.N.

    1996-01-11T23:59:59.000Z

    An in situ experimental technique is described that allows high resolution, high sensitivity determination of displacements and full-field strains during high temperature mechanical testing. The technique is used to investigate elevated temperature crack growth in SiC/Nicalon sub f composites. At 1150 degrees C, the reinforcing fibers have a higher creep susceptibility than the matrix. Fiber creep leads to relaxation of crack bridging tractions, resulting in subcritical crack growth. Differential image analysis is used to measure the crack opening displacement profile u(x) of an advancing, bridged crack. With appropriate modeling, such data can be used to determine the traction law, from which the mechanics of cracking and failure may be determined.

  17. Thermal Control & System Integration

    Broader source: Energy.gov [DOE]

    The thermal control and system integration activity focuses on issues such as the integration of motor and power control technologies and the development of advanced thermal control technologies....

  18. Solar Thermal Powered Evaporators

    E-Print Network [OSTI]

    Moe, Christian Robert

    2015-01-01T23:59:59.000Z

    and C. Y. Zhao, "A review of solar collectors and thermalenergy storage in solar thermal applications," Appliedon photovoltaic/thermal hybrid solar technology," Applied

  19. Thermal conductivity and heat transfer in superlattices

    SciTech Connect (OSTI)

    Chen, G.; Neagu, M.; Borca-Tasciuc, T.

    1997-07-01T23:59:59.000Z

    Understanding the thermal conductivity and heat transfer processes in superlattice structures is critical for the development of thermoelectric materials and devices based on quantum structures. This work reports progress on the modeling of thermal conductivity of superlattice structures. Results from the models established based on the Boltzmann transport equation could explain existing experimental results on the thermal conductivity of semiconductor superlattices in both in plane and cross-plane directions. These results suggest the possibility of engineering the interfaces to further reduce thermal conductivity of superlattice structures.

  20. California Solar Initiative- Solar Thermal Program

    Broader source: Energy.gov [DOE]

    Originally restricted to just solar water heaters, the prorgam was expanded by CPUC Decision 13-02-018 in February 2013 to include other solar thermal technologies, including solar process heatin...

  1. Simulation of the ultrasonic array response from real branched cracks using an efficient finite element method

    SciTech Connect (OSTI)

    Felice, Maria V. [Department of Mechanical Engineering, University of Bristol, Bristol BS8 1TR, United Kingdom and Rolls-Royce plc., Bristol BS34 7QE (United Kingdom); Velichko, Alexander; Wilcox, Paul D. [Department of Mechanical Engineering, University of Bristol, Bristol BS8 1TR (United Kingdom); Barden, Tim J.; Dunhill, Tony K. [Rolls-Royce plc., Bristol BS34 7QE (United Kingdom)

    2014-02-18T23:59:59.000Z

    A hybrid model to simulate the ultrasonic array response from stress corrosion cracks is presented. These cracks are branched and difficult to detect so the model is required to enable optimization of an array design. An efficient frequency-domain finite element method is described and selected to simulate the ultrasonic scattering. Experimental validation results are presented, followed by an example of the simulated ultrasonic array response from a real stress corrosion crack whose geometry is obtained from an X-ray Computed Tomography image. A simulation-assisted array design methodology, which includes the model and use of real crack geometries, is proposed.

  2. Assessment and prediction of drying shrinkage cracking in bonded mortar overlays

    SciTech Connect (OSTI)

    Beushausen, Hans, E-mail: hans.beushausen@uct.ac.za; Chilwesa, Masuzyo

    2013-11-15T23:59:59.000Z

    Restrained drying shrinkage cracking was investigated on composite beams consisting of substrate concrete and bonded mortar overlays, and compared to the performance of the same mortars when subjected to the ring test. Stress development and cracking in the composite specimens were analytically modeled and predicted based on the measurement of relevant time-dependent material properties such as drying shrinkage, elastic modulus, tensile relaxation and tensile strength. Overlay cracking in the composite beams could be very well predicted with the analytical model. The ring test provided a useful qualitative comparison of the cracking performance of the mortars. The duration of curing was found to only have a minor influence on crack development. This was ascribed to the fact that prolonged curing has a beneficial effect on tensile strength at the onset of stress development, but is in the same time not beneficial to the values of tensile relaxation and elastic modulus. -- Highlights: •Parameter study on material characteristics influencing overlay cracking. •Analytical model gives good quantitative indication of overlay cracking. •Ring test presents good qualitative indication of overlay cracking. •Curing duration has little effect on overlay cracking.

  3. Effects of weld residual stresses on crack-opening area analysis of pipes for LBB applications

    SciTech Connect (OSTI)

    Dong, P.; Rahman, S.; Wilkowski, G. [and others

    1997-04-01T23:59:59.000Z

    This paper summarizes four different studies undertaken to evaluate the effects of weld residual stresses on the crack-opening behavior of a circumferential through-wall crack in the center of a girth weld. The effect of weld residual stress on the crack-opening-area and leak-rate analyses of a pipe is not well understood. There are no simple analyses to account for these effects, and, therefore, they are frequently neglected. The four studies involved the following efforts: (1) Full-field thermoplastic finite element residual stress analyses of a crack in the center of a girth weld, (2) A comparison of the crack-opening displacements from a full-field thermoplastic residual stress analysis with a crack-face pressure elastic stress analysis to determine the residual stress effects on the crack-opening displacement, (3) The effects of hydrostatic testing on the residual stresses and the resulting crack-opening displacement, and (4) The effect of residual stresses on crack-opening displacement with different normal operating stresses.

  4. Mixed Mode Static and Fatigue Crack Growth in Wind Blade Paste Adhesives

    E-Print Network [OSTI]

    , static GIc and mixed mode fracture, and fatigue crack growth resistance. I. Introduction Wind turbine blades are large composite structures which are typically resin infusion molded in sections

  5. Standard test method for measurement of creep crack growth times in metals

    E-Print Network [OSTI]

    American Society for Testing and Materials. Philadelphia

    2007-01-01T23:59:59.000Z

    1.1 This test method covers the determination of creep crack growth (CCG) in metals at elevated temperatures using pre-cracked specimens subjected to static or quasi-static loading conditions. The time (CCI), t0.2 to an initial crack extension ?ai = 0.2 mm from the onset of first applied force and creep crack growth rate, ?a or da/dt is expressed in terms of the magnitude of creep crack growth relating parameters, C* or K. With C* defined as the steady state determination of the crack tip stresses derived in principal from C*(t) and Ct (1-14). The crack growth derived in this manner is identified as a material property which can be used in modeling and life assessment methods (15-25). 1.1.1 The choice of the crack growth correlating parameter C*, C*(t), Ct, or K depends on the material creep properties, geometry and size of the specimen. Two types of material behavior are generally observed during creep crack growth tests; creep-ductile (1-14) and creep-brittle (26-37). In creep ductile materials, where cr...

  6. On the approximation of crack shapes found during inservice inspection

    SciTech Connect (OSTI)

    Bhate, S.R.; Chawla, D.S.; Kushwaha, H.S. [Bhabha Atomic Research Centre, Bombay (India)] [and others

    1997-04-01T23:59:59.000Z

    This paper addresses the characterization of axial internal flaw found during inservice inspection of a pipe. J-integral distribution for various flaw shapes is obtained using line spring finite, element method. The peak J-value and its distribution across the crack is found to be characteristic feature of each shape. The triangular shape yields peak J-value away from the center, the point of depth. The elliptic approximation results in large overestimate of J-value for unsymmetric flaws. Triangular approximation is recommended for such flaws so that further service can be obtained from the component.

  7. Nonlinear FE analysis of cracks in tension and shear

    E-Print Network [OSTI]

    Kesse, G.; Lees, Janet M.

    2007-05-01T23:59:59.000Z

    Carbon FRP Shear Reinforcement. PhD thesis, University of Cambridge, UK, 2003. 3. Bazant Z. P. and Planas J. Fracture and Size Effect in Con- crete and Other Quasibrittle Materials. CRC Press, Boca Raton, Florida, 1998. Nonlinear FE analysis of cracks... of plain concrete to cyclic tension. ACI Materials Journal, 1987, 84, No. 5, 365–373. 9. Paulay T. and Loeber P. J. Shear transfer by aggregate inter- lock. ACI Special Publication, SP-42, 1974, 1, 1–14. 10. Houde J. and Mirza M. S. A finite element...

  8. Calculate thermal-expansion coefficients

    SciTech Connect (OSTI)

    Yaws, C.L. [Lamar Univ., Beaumont, TX (United States)

    1995-08-01T23:59:59.000Z

    To properly design and use process equipment, an engineer needs a sound knowledge of physical and thermodynamic property data. A lack of such knowledge can lead to design or operating mistakes that can be dangerous, costly or even fatal. One useful type of property data is the thermal-expansion coefficient. This article presents equations and tables to find the thermal-expansion coefficients of many liquids that contain carbon. These data are useful in process-engineering applications, including the design of relief systems which are crucial to safeguarding process equipment. Data are provided for approximately 350 compounds. A computer software program, which contains the thermophysical property data for all of the compounds discussed in this article, is available for $43 prepaid from the author (Carl L. Yaws, Box 10053, Lamar University, beaumont, TX 77710; Tel. 409-880-8787; fax 409-880-8404). The program is in ASCII format, which can be accessed by most other types of computer software.

  9. Gravity stabilized thermal miscible displacement process

    SciTech Connect (OSTI)

    Vogel, J.V.

    1987-10-06T23:59:59.000Z

    A method is described of recovering viscous hydrocarbons from a subterranean reservoir. The reservoir is penetrated by at least one injection well and one production well. The injection well is in fluid communication with the upper portion of the reservoir and the production well is in fluid communication with the lower portion of the reservoir. The injection well and the production well defines a fluid flow path therebetween. The method comprises the steps of: (a) injecting a steam-solvent vapor mixture into the upper portion of the reservoir through the injection well. The steam-solvent vapor mixture is undersaturated in solvent and saturated with steam; (b) reducing the viscosity of the hydrocarbons by heat released upon condensation of the steam-solvent vapor mixture and reducing the viscosity of the hydrocarbons further upon condensation of solvent vapors. The condensed solvent vapors goes into solution with the hydrocarbons; and (c) collecting a mixture of hydrocarbons and solvent accumulated at the bottom of the production well substantially entirely under the force of gravity.

  10. Continuous Processing of High Thermal Conductivity Polyethylene...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    & Publications CX-008993: Categorical Exclusion Determination Evaluation of Natural Gas Pipeline Materials for Hydrogen Science PolymerElastomer and Composite Material Science...

  11. Thermal Plasma Systems for Industrial Processes 

    E-Print Network [OSTI]

    Fey, M. G.; Meyer, T. N.; Reed, W. H.; Philbrook, W. O.

    1982-01-01T23:59:59.000Z

    required to produce hot metal. To plasma superheat wind. energy is transferred to the air stream via a plasma torch. To maximize the coke reduction due to wind superheating. other fuels such as oil. natural gas. coke oven gas. and coal can be considered... tuyere injections of steam. oxygen, methane. natural gas. coke-oven gas. coal gas. fuel oils. or coals of various ranks is a two-stage blast furnace mass and heat balance developed by Rist and Meysson [12.13J and others at IRSID. A constraint...

  12. Method For Brazing And Thermal Processing

    DOE Patents [OSTI]

    Milewski, John O. (Santa Fe, NM); Dave, Vivek R. (Los Alamos, NM); Christensen, Dane (Livermore, CA); Carpenter, II, Robert W. (Los Alamos, NM)

    2005-07-12T23:59:59.000Z

    The present invention includes a method for brazing of two objects or heat treatment of one object. First, object or objects to be treated are selected and initial conditions establishing a relative geometry and material characteristics are determined. Then, a first design of an optical system for directing heat energy onto the object or objects is determined. The initial conditions and first design of the optical system are then input into a optical ray-tracing computer program. The program is then run to produce a representative output of the heat energy input distribution to the object or objects. The geometry of the object or objects, material characteristics, and optical system design are then adjusted until an desired heat input is determined.

  13. Fourth optical inspection of integrated circuits using image processing and mathematical morphology: a report

    E-Print Network [OSTI]

    Chemaly, Ephrem A.

    2013-03-13T23:59:59.000Z

    , cracks, and voids. The latter inspection will be of interest to us in this dissertation. The purpose of this work is to perform the visual inspection automatically. The method used is image processing. In particular mathematical...

  14. Physical process Mechanical mechanisms

    E-Print Network [OSTI]

    Berlin,Technische Universität

    1 Physical process Generation · Mechanical mechanisms F = m·a · Electric/Magnetic mechanisms F = B·i·l · Fluid dynamic/Hydraulic mechanisms q, p, ij · Thermal/Optical #12;2 Source unit

  15. Pattern of Thermal Fluctuations in a Recovery Boiler Floor

    SciTech Connect (OSTI)

    Abdullah, Z.; Gorog, J.P.; Keiser, J.R.; Meyers, L.E.; Swindeman, R.W.

    1999-04-25T23:59:59.000Z

    The floor of a black liquor recovey boiler at a mill in central Canada has experienced cracking and delamination of the composite tubing near the spout wall and deformation of the floor panels that is most severe in the vicinity of the spout wall. One possible explanation for the observed damage is impacts of salt cake falling from the convective section onto the floor. In order to determine if such impacts do occur, strain gauges and thermocouples were installed on the boiler floor in areas where cracking and deformation were most frequent. The data obtained from these instruments indicate that brief, sudden temperature fluctuations do occur, and changes in the strain experienced by the affected tube occur simultaneously. These fluctuations appear to occur less often along the spout wall and more frequently with increasing distance from the wall. The frequency of these temperature fluctuations is insufficient for thermal fatigue to be the sole cause of the cracking observed on the tubes, but the data are consistent with what might be expected from pieces of falling salt cake.

  16. Pattern of thermal fluctuations in a recovery boiler floor

    SciTech Connect (OSTI)

    Keiser, J.R.; Meyers, L.E.; Swindeman, R.W.; Gorog, J.P.; Abdullah, Z.

    1999-07-01T23:59:59.000Z

    The floor of a black liquor recovery boiler at a mill in central Canada has experienced cracking and delamination of the composite tubing near the spout wall and deformation of the floor panels that is most severe in the vicinity of the spout wail. One possible explanation for the observed damage is impacts of salt cake falling from the convective section onto the floor. In order to determine if such impacts do occur, strain gauges and thermocouples were installed on the boiler floor in areas where cracking and deformation were most frequent. The data obtained from these instruments indicate that brief, sudden temperature fluctuations do occur, and changes in the strain experienced by-the affected tube occur simultaneously. These fluctuations appear to occur less often along the spout wall and more frequently with increasing distance from the wall. The frequency of these temperature fluctuations is insufficient for thermal fatigue to be the sole cause of the cracking observed on the tubes, but the data are consistent with what might be expected from pieces of falling salt cake.

  17. Fracture behavior of short circumferentially surface-cracked pipe

    SciTech Connect (OSTI)

    Krishnaswamy, P.; Scott, P.; Mohan, R. [Battelle, Columbus, OH (United States)] [and others

    1995-11-01T23:59:59.000Z

    This topical report summarizes the work performed for the Nuclear Regulatory Comniission`s (NRC) research program entitled ``Short Cracks in Piping and Piping Welds`` that specifically focuses on pipes with short, circumferential surface cracks. The following details are provided in this report: (i) material property deteminations, (ii) pipe fracture experiments, (iii) development, modification and validation of fracture analysis methods, and (iv) impact of this work on the ASME Section XI Flaw Evaluation Procedures. The material properties developed and used in the analysis of the experiments are included in this report and have been implemented into the NRC`s PIFRAC database. Six full-scale pipe experiments were conducted during this program. The analyses methods reported here fall into three categories (i) limit-load approaches, (ii) design criteria, and (iii) elastic-plastic fracture methods. These methods were evaluated by comparing the analytical predictions with experimental data. The results, using 44 pipe experiments from this and other programs, showed that the SC.TNP1 and DPZP analyses were the most accurate in predicting maximum load. New Z-factors were developed using these methods. These are being considered for updating the ASME Section XI criteria.

  18. Pinning and Depinning of Crack Fronts in Heterogeneous Materials

    SciTech Connect (OSTI)

    Daguier, P.; Bouchaud, E. [O.N.E.R.A. (Oman), 29 Avenue de la Division Leclerc, B.P. 72, 92322 Chatillon Cedex (France)] [O.N.E.R.A. (Oman), 29 Avenue de la Division Leclerc, B.P. 72, 92322 Chatillon Cedex (France); Nghiem, B.; Creuzet, F. [Laboratoire CNRS/Saint-Gobain Surface du Verre et Interfaces, 39, Quai Lucien Lefranc, B.P. 135, 93303 Aubervilliers Cedex (France)] [Laboratoire CNRS/Saint-Gobain Surface du Verre et Interfaces, 39, Quai Lucien Lefranc, B.P. 135, 93303 Aubervilliers Cedex (France)

    1997-02-01T23:59:59.000Z

    The fatigue fracture surfaces of a metallic alloy and the stress corrosion fracture surfaces of a silicate glass are investigated as a function of crack velocity. It is shown that in both cases there are two self-affine fracture regimes. At large enough length scales, the universal roughness index {zeta}{approx_equal}0.78 is recovered. At smaller length scales, the roughness exponent is close to {zeta}{sub c}{approx_equal}0.50. The crossover length {xi}{sub c} separating these two regimes strongly depends on the material, and exhibits a power-law decrease with the measured crack velocity {xi}{sub c}{proportional_to}v{sup -{phi}}, with {phi}{approx_equal}1. The exponents {nu} and {beta} characterizing the dependence of {xi}{sub c} and v upon the pulling force are shown to be close to {nu}{approx_equal}2 and {beta}{approx_equal}2. {copyright} {ital 1997} {ital The American Physical Society}

  19. Low-Cracking High-Performance Concrete (LC-HPC) Bridge Decks: Shrinkage-Reducing Admixtures, Internal Curing, and Cracking Performance

    E-Print Network [OSTI]

    Pendergrass, Ben Andrew

    2014-05-31T23:59:59.000Z

    ABSTRACT The development, construction, and evaluation of low-cracking high-performance concrete (LC-HPC) bridge decks is described based on laboratory tests of mixtures containing shrinkage-reducing admixtures and mineral admixtures in conjunction...

  20. Theory of thin-skin eddy-current interaction with surface cracks N. Harfielda)

    E-Print Network [OSTI]

    Bowler, John R.

    Theory of thin-skin eddy-current interaction with surface cracks N. Harfielda) and J. R. Bowler; accepted for publication 14 July 1997 Eddy-current non-destructive evaluation is commonly performed of a typical crack. A thin-skin analysis of eddy currents is presented in which the electromagnetic fields

  1. A NON-ISOTHERMAL FATIGUE CRACK GROWTH LAW FOR THE A356-T7 ALUMINUM ALLOY

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 A NON-ISOTHERMAL FATIGUE CRACK GROWTH LAW FOR THE A356-T7 ALUMINUM ALLOY E. Merhy 1,2,3* , L rate, Damage tolerant design, Life time prediction, A356 cast alloy ABSTRACT Fatigue crack growth period in cylinder heads of A356-T7 casting alloy has been found to constitute an important part

  2. Crack Detection in Dielectric Structures by a Linear Sampling , M. Brignone2

    E-Print Network [OSTI]

    Piana, Michele

    Crack Detection in Dielectric Structures by a Linear Sampling Approach G. Bozza1 , M. Brignone2 , M for the detection of cracks and defects inside dielectric structures is presented. The proposed algorithm is based of the approach is assessed by means of numerical simulations. 1. Introduction The imaging community

  3. Random sequential adsorption model of damage and crack accumulation: Exact one-dimensional results

    E-Print Network [OSTI]

    O. Gromenko; V. Privman; M. L. Glasser

    2008-04-29T23:59:59.000Z

    The random sequential adsorption (RSA) model is modified to describe damage and crack accumulation. The exclusion for object deposition (for damaged region formation) is not for the whole object, as in the standard RSA, but only for the initial point (or higher-dimensional defect) from which the damaged region or crack initiates. The one-dimensional variant of the model is solved exactly.

  4. THE ELASTIC-PLASTIC MECHANICS OF CRACK EXTENSION James R. Rice*

    E-Print Network [OSTI]

    THE ELASTIC-PLASTIC MECHANICS OF CRACK EXTENSION James R. Rice* ABSTRACT This paper briefly reviews progres~in the elastic plastic analysisof crack extension. Analytical results for plane strain and plane stress deformation fields are noted, and elastic-plastic fracture instability as well as transitional

  5. Analysis of the tube-sheet cracking in slurry oil steam , L.J. Qiao a,

    E-Print Network [OSTI]

    Volinsky, Alex A.

    -sheet cracking is a severe problem in the oil refinery industry with the consequences of shortened service life steam generator is a kind of shell and tube heat exchanger extensively used in the oil refinement in the oil refinery industry. Previous study has shown that corrosion, such as stress corrosion cracking (SCC

  6. Thermo-optical modulation for improved ultrasonic fatigue crack detection in Ti6Al4V

    E-Print Network [OSTI]

    Nagy, Peter B.

    scatterers, such as surface grooves, corrosion pits, coarse grains, etc. that might hide the fatigue crack to grow at unexpectedly high growth rates well below the large-crack threshold in aluminum, aluminum­lithium) and secondary irregulari- ties (e.g. uneven machining, mechanical wear, corrosion, etc.). Second

  7. Ultrasonic ply-by-ply detection of matrix cracks in laminated composites

    E-Print Network [OSTI]

    Ganpatye, Atul Shridatta

    2005-02-17T23:59:59.000Z

    on the internal damage state of the composite tank wall. Damage in the form of matrix cracks in the composite material of the tank is responsible for the through-the-thickness permeation of LH2. In this context, the detection of matrix cracks takes...

  8. A model for the ultrasonic detection of surface-breaking cracks by the Scanning

    E-Print Network [OSTI]

    Huerta, Antonio

    A model for the ultrasonic detection of surface-breaking cracks by the Scanning Laser Source, Northwestern University, Evanston, IL 60208, USA Abstract A model for the Scanning Laser Source (SLS) technique- breaking cracks. The generated ultrasonic signal is monitored as a line-focused laser is scanned over

  9. FREE-FORM ANISOTROPY: A NEW METHOD FOR CRACK DETECTION ON PAVEMENT SURFACE IMAGES

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    FREE-FORM ANISOTROPY: A NEW METHOD FOR CRACK DETECTION ON PAVEMENT SURFACE IMAGES Tien Sy NGUYEN(1, in the segmentation step, for crack detection on road pavement images. Features which are calculated along every free on some samples of different kinds of pavements. Results of the method are also given on other kinds

  10. Robust damage assessment of multiple cracks based on the Frequency Response Function and the Constitutive Relation

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Robust damage assessment of multiple cracks based on the Frequency Response Function a damage assessment technique for the non destructive detection and sizing of multiple open cracks in beams, many researchers have performed extensive investigations and damage assess- ment techniques based

  11. Effect of Blast Design on Crack Response C.H. Dowding

    E-Print Network [OSTI]

    Effect of Blast Design on Crack Response C.H. Dowding Professor of Civil & Environmental to assess the effect of changes in blast design on the house response. Velocity response was measured some 11 velocity transducers and 3 crack sensors measured excitation and response for each blast

  12. Assessing Hydrogen-Assisted Cracking Fracture Modes in High-Strength

    E-Print Network [OSTI]

    Eagar, Thomas W.

    I I Ii . I f. Assessing Hydrogen-Assisted Cracking Fracture Modes in High-Strength Steel Weldments Test results substantiate and extend the Beachem theory on hydrogen embrittlement ABSTRACT of the hydrogen content at the crack loca- tion. This relationship was used to assess previously proposed

  13. ccsd-00095604,version1-18Sep2006 Understanding crack versus cavitation in pressure-sensitive

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ccsd-00095604,version1-18Sep2006 Understanding crack versus cavitation in pressure show that in addition to cavitation, interfacial cracks are encountered in a probe-tack traction test mechanisms in usual adhesives. The most common one is cavitation, as evidenced by the first tests

  14. Reflective Cracking Study: First-level Report on HVS Testing on Section 586RF - 45 mm MB15-GOverlay

    E-Print Network [OSTI]

    Jones, David; Wu, R; Harvey, John T

    2008-01-01T23:59:59.000Z

    of the asphalt concrete layer. Testing was stopped when thetesting being performed to validate Caltrans overlay strategies for the rehabilitation of cracked asphalt concrete.concrete. It describes the results of the fifth HVS reflective cracking testing

  15. Reflective Cracking Study: First-Level Report on HVS Testing on Section 589RF - 45 mm MB4-G Overlay

    E-Print Network [OSTI]

    Jones, David; Harvey, John T; Wu, R; Lea, J.

    2008-01-01T23:59:59.000Z

    of the asphalt concrete layer. Testing was stopped when thetesting being performed to validate Caltrans overlay strategies for the rehabilitation of cracked asphalt concrete.concrete. It describes the results of the second HVS reflective cracking testing

  16. Efficient solution of multiple cracks in great number using eigen COD boundary integral equations with iteration procedure

    E-Print Network [OSTI]

    Liu, Yijun

    as the fibre-reinforced brittle materials after certain extent of tensile damage. The prediction of crack in an infinite domain under fictitious traction acting on the crack surface. With the concept of eigen COD

  17. Review of industry efforts to manage pressurized water reactor feedwater nozzle, piping, and feedring cracking and wall thinning

    SciTech Connect (OSTI)

    Shah, V.N.; Ware, A.G.; Porter, A.M.

    1997-03-01T23:59:59.000Z

    This report presents a review of nuclear industry efforts to manage thermal fatigue, flow-accelerated corrosion, and water hammer damage to pressurized water reactor (PWR) feedwater nozzles, piping, and feedrings. The review includes an evaluation of design modifications, operating procedure changes, augmented inspection and monitoring programs, and mitigation, repair and replacement activities. Four actions were taken: (a) review of field experience to identify trends of operating events, (b) review of technical literature, (c) visits to PWR plants and a PWR vendor, and (d) solicitation of information from 8 other countries. Assessment of field experience is that licensees have apparently taken sufficient action to minimize feedwater nozzle cracking caused by thermal fatigue and wall thinning of J-tubes and feedwater piping. Specific industry actions to minimize the wall-thinning in feedrings and thermal sleeves were not found, but visual inspection and necessary repairs are being performed. Assessment of field experience indicates that licensees have taken sufficient action to minimize steam generator water hammer in both top-feed and preheat steam generators. Industry efforts to minimize multiple check valve failures that have allowed backflow of steam from a steam generator and have played a major role in several steam generator water hammer events were not evaluated. A major finding of this review is that analysis, inspection, monitoring, mitigation, and replacement techniques have been developed for managing thermal fatigue and flow-accelerated corrosion damage to feedwater nozzles, piping, and feedrings. Adequate training and appropriate applications of these techniques would ensure effective management of this damage.

  18. Vickers microindentation toughness of a sintered SiC in the median-crack regime

    SciTech Connect (OSTI)

    Ghosh, Asish; Kobayashi, A.S. (Washington Univ., Seattle, WA (United States). Coll. of Engineering); Li, Zhuang (Argonne National Lab., IL (United States)); Henager, C.H. Jr. (Pacific Northwest Lab., Richland, WA (United States)); Bradt, R.C. (Nevada Univ., Reno, NV (United States). Mackay School of Mines)

    1991-01-01T23:59:59.000Z

    The Vickers microindentation method for the determination of the fracture toughness of ceramics was investigated in the median crack regime for a sintered alpha SiC. The results are compared with fracture toughness measurements by conventional fracture mechanics technique and also with the reported indentation toughness for the low-load Palmqvist crack regime. Indentation toughnesses in the median crack regime vary widely depending on the choice of the specific equation which is applied. The indentation toughnesses are also load (crack length) dependent. A decreasing R-curve trend results, in contradiction to the flat R-curve that has been observed with conventional fracture mechanics techniques. It is concluded that the Vickers microindentation method is not a reliable technique for the determination of the fracture toughness of ceramics in the median crack regime.

  19. Fatigue crack propagation in a quasi one-dimensional elasto-plastic model

    E-Print Network [OSTI]

    Tomás M. Guozden; Eduardo A. Jagla

    2012-06-27T23:59:59.000Z

    Fatigue crack advance induced by the application of cyclic quasistatic loads is investigated both numerically and analytically using a lattice spring model. The system has a quasi-one-dimensional geometry, and consists in two symmetrical chains that are pulled apart, thus breaking springs which connect them, and producing the advance of a crack. Quasistatic crack advance occurs as a consequence of the plasticity included in the springs which form the chains, and that implies a history dependent stress-strain curve for each spring. The continuous limit of the model allows a detailed analytical treatment that gives physical insight of the propagation mechanism. This simple model captures key features that cause well known phenomenology in fatigue crack propagation, in particular a Paris-like law of crack advance under cyclic loading, and the overload retardation effect.

  20. Monitoring Thermal Fatigue Damage In Nuclear Power Plant Materials Using Acoustic Emission

    SciTech Connect (OSTI)

    Meyer, Ryan M.; Ramuhalli, Pradeep; Watson, Bruce E.; Pitman, Stan G.; Roosendaal, Timothy J.; Bond, Leonard J.

    2012-04-26T23:59:59.000Z

    Proactive aging management of nuclear power plant passive components requires technologies to enable monitoring and accurate quantification of material condition at early stages of degradation (i.e., pre-macrocrack). Acoustic emission (AE) is well-suited to continuous monitoring of component degradation and is proposed as a method to monitor degradation during accelerated thermal fatigue tests. A key consideration is the ability to separate degradation responses from external sources such as water spray induced during thermal fatigue testing. Water spray provides a significant background of acoustic signals, which can overwhelm AE signals caused by degradation. Analysis of AE signal frequency and energy is proposed in this work as a means for separating degradation signals from background sources. Encouraging results were obtained by applying both frequency and energy filters to preliminary data. The analysis of signals filtered using frequency and energy provides signatures exhibiting several characteristics that are consistent with degradation accumulation in materials. Future work is planned to enable verification of the efficacy of AE for thermal fatigue crack initiation detection. While the emphasis has been placed on the use of AE for crack initiation detection during accelerated aging tests, this work also has implications with respect to the use of AE as a primary tool for early degradation monitoring in nuclear power plant materials. The development of NDE tools for characterization of aging in materials can also benefit from the use of a technology such as AE which can continuously monitor and detect crack initiation during accelerated aging tests.

  1. HEATS: Thermal Energy Storage

    SciTech Connect (OSTI)

    None

    2012-01-01T23:59:59.000Z

    HEATS Project: The 15 projects that make up ARPA-E’s HEATS program, short for “High Energy Advanced Thermal Storage,” seek to develop revolutionary, cost-effective ways to store thermal energy. HEATS focuses on 3 specific areas: 1) developing high-temperature solar thermal energy storage capable of cost-effectively delivering electricity around the clock and thermal energy storage for nuclear power plants capable of cost-effectively meeting peak demand, 2) creating synthetic fuel efficiently from sunlight by converting sunlight into heat, and 3) using thermal energy storage to improve the driving range of electric vehicles (EVs) and also enable thermal management of internal combustion engine vehicles.

  2. Thermal unobtainiums? The perfect thermal conductor and

    E-Print Network [OSTI]

    Braun, Paul

    conduction · Heat conduction in Bose condensates ­ electronic superconductors ­ superfluid helium ­ Bose condensate of magnons #12;Outline--toward perfect thermal insulators · Einstein and minimum thermal directions #12;Gas kinetic equation is a good place to start · Anharmonicity (high T limit) · Point defect

  3. Design of a novel conduction heating based stress-thermal cycling apparatus for composite materials and its utilization to characterize composite microcrack damage thresholds

    E-Print Network [OSTI]

    Ju, Jaehyung

    2006-10-30T23:59:59.000Z

    ???????????..?????????47 viii CHAPTER Page 4.4 Thermal Loading Combined with Bending Conditions?????? 49 4.5 Thermo-Viscoelastic Constitutive....1 Characterization of Crack Formation and Propagation Mechanism?. 93 6.2 Analytical Study of Time Dependent Non-Isothermal Linear Thermo-Viscoelasticity??????????????????...94 6.3 Initial Damage Characterization??????????????.. 101 6.3.1 Cryogenic Temperature...

  4. EFFECT OF STRESS GRADIENT AT THE VICINITY OF A CRACK TIP ON IONIC DIFFUSION IN SILICATE GLASSES: AN AFM STUDY.

    E-Print Network [OSTI]

    Demouchy, Sylvie

    1 EFFECT OF STRESS GRADIENT AT THE VICINITY OF A CRACK TIP ON IONIC DIFFUSION IN SILICATE GLASSES.marliere@univ-montp2.fr ABSTRACT The slow advance of a crack in sodo-silicate glasses was studied at nanometer scale-micrometric vicinity of the tip of a crack running in silicate glass with mobile ions (as sodium cations) and check

  5. ensl-00156750,version1-22Jun2007 A dynamical law for slow crack growth in polycarbonate films

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ensl-00156750,version1-22Jun2007 A dynamical law for slow crack growth in polycarbonate films: 24 juin 2007) We study experimentally the slow growth of a single crack in polycarbonate films experimental insight in our plastic zone pz Fig. 1 ­ Image of a crack in a polycarbonate film with its

  6. Welding aluminum alloys 6061 with the opposing dual-torch GTAW process

    SciTech Connect (OSTI)

    Zhang, Y.M.; Zhang, S.B. [Univ. of Kentucky, Lexington, KY (United States)

    1999-06-01T23:59:59.000Z

    Cracking is a major concern in welding aluminum alloys. Although weld solidification cracks can be eliminated through the addition of filler metal, the additives modify the alloy or base metal constituents and may not always be desirable. High-energy beam processes, such as electron beam welding, that result in minimal heat input reduce crack sensitivity, but their high cost limits their applications. In this study, the conventional gas tungsten arc welding process is modified by disconnecting the workpiece form the power supply and placing a second torch on the opposite side of the workpiece. Such a modification changes the direction of the current flow, improves the weld penetration and reduces the heat input. Using this modified process, 6061-T651 alloy was welded without filler metals. Analysis suggested the reduced heat input, the changed direction of the current flow and the symmetric heating were responsible for the observed reduction of the cracking sensitivity.

  7. Non-thermal Plasma Chemistry Non-thermal Thermal

    E-Print Network [OSTI]

    Greifswald, Ernst-Moritz-Arndt-Universität

    -thermal Plasma Chemical Flow Reactor #12;Werner von Siemens ,, ... construction of an apparatus generation (1857) pollution control volatile organic components, NOx reforming, ... radiation sources excimer;Leuchtstoffröhre Plasma-Bildschirm Energiesparlampe #12;electrical engineering light sources textile industry

  8. Underground Coal Thermal Treatment

    SciTech Connect (OSTI)

    P. Smith; M. Deo; E. Eddings; A. Sarofim; K. Gueishen; M. Hradisky; K. Kelly; P. Mandalaparty; H. Zhang

    2011-10-30T23:59:59.000Z

    The long-term objective of this work is to develop a transformational energy production technology by insitu thermal treatment of a coal seam for the production of substitute natural gas (SNG) while leaving much of the coalâ??s carbon in the ground. This process converts coal to a high-efficiency, low-GHG emitting gas fuel. It holds the potential of providing environmentally acceptable access to previously unusable coal resources. This topical report discusses the development of experimental capabilities, the collection of available data, and the development of simulation tools to obtain process thermo-chemical and geo-thermal parameters in preparation for the eventual demonstration in a coal seam. It also includes experimental and modeling studies of CO{sub 2} sequestration. Efforts focused on: â?¢ Constructing a suite of three different coal pyrolysis reactors. These reactors offer the ability to gather heat transfer, mass transfer and kinetic data during coal pyrolysis under conditions that mimic in situ conditions (Subtask 6.1). â?¢ Studying the operational parameters for various underground thermal treatment processes for oil shale and coal and completing a design matrix analysis for the underground coal thermal treatment (UCTT). This analysis yielded recommendations for terms of targeted coal rank, well orientation, rubblization, presence of oxygen, temperature, pressure, and heating sources (Subtask 6.2). â?¢ Developing capabilities for simulating UCTT, including modifying the geometry as well as the solution algorithm to achieve long simulation times in a rubblized coal bed by resolving the convective channels occurring in the representative domain (Subtask 6.3). â?¢ Studying the reactive behavior of carbon dioxide (CO{sub 2}) with limestone, sandstone, arkose (a more complex sandstone) and peridotite, including mineralogical changes and brine chemistry for the different initial rock compositions (Subtask 6.4). Arkose exhibited the highest tendency of participating in mineral reactions, which can be attributed to the geochemical complexity of its initial mineral assemblage. In experiments with limestone, continuous dissolution was observed with the release of CO{sub 2} gas, indicated by the increasing pressure in the reactor (formation of a gas chamber). This occurred due to the lack of any source of alkali to buffer the solution. Arkose has the geochemical complexity for permanent sequestration of CO{sub 2} as carbonates and is also relatively abundant. The effect of including NH{sub 3} in the injected gas stream was also investigated in this study. Precipitation of calcite and trace amounts of ammonium zeolites was observed. A batch geochemical model was developed using Geochemists Workbench (GWB). Degassing effect in the experiments was corrected using the sliding fugacity model in GWB. Experimental and simulation results were compared and a reasonable agreement between the two was observed.

  9. Thermal Energy Storage

    SciTech Connect (OSTI)

    Rutberg, Michael; Hastbacka, Mildred; Cooperman, Alissa; Bouza, Antonio

    2013-06-05T23:59:59.000Z

    The article discusses thermal energy storage technologies. This article addresses benefits of TES at both the building site and the electricity generation source. The energy savings and market potential of thermal energy store are reviewed as well.

  10. Specified pipe fittings susceptible to sulfide stress cracking

    SciTech Connect (OSTI)

    McIntyre, D.R.; Moore, E.M. Jr. [Saudi Aramco, Dhahran (Saudi Arabia)

    1996-01-01T23:59:59.000Z

    The NACE Standard MR0175 limit of HRC 22 is too high for cold-forged and stress-relieved ASTM A234 WPB pipe fittings. Hardness surveys and sulfide stress cracking test results per ASTM G 39 and NACE TM0177 Method B are presented to support this contention. More stringent inspection and a hardness limit of HB 197 (for cold-forged and stress-relieved fittings only) are recommended. The paper describes a case in which fittings were welded in place in wet sour service flow lines and gas-oil separating plants which were ready to start. The failure of a welded fitting shortly after start-up led to extensive field hardness testing on all fittings from this manufacturer.

  11. SRNL SHELF LIFE STUDIES - SCC STUDIES AT ROOM TEMPERTURE [stress corrosion cracking

    SciTech Connect (OSTI)

    Mickalonis, J.; Duffey, J.

    2014-11-12T23:59:59.000Z

    Phase II, Series 2 corrosion testing performed by the Savannah River National Laboratory (SRNL) for the Department of Energy 3013 container has been completed. The corrosion tests are part of an integrated plan conducted jointly by Los Alamos National Laboratory and the Savannah River Site. SRNL was responsible for conducting corrosion studies in small-scale vessels to address the influence of salt composition, water loading, and type of oxide/salt contact on the relative humidity inside a 3013 container and on the resulting corrosion of Type 304L and 316L stainless steel (304L and 316L). This testing was conducted in two phases: Phase I evaluated a broad spectrum of salt compositions and initial water loadings on the salt mixtures exposed to 304L and 316L and the resulting corrosion; Phase II evaluated the corrosion of 304L at specific water loadings and a single salt composition. During Phase I testing at high initial moisture levels (0.35 to 1.24 wt%)a, the roomtemperature corrosion of 304L exposed to a series of plutonium oxide/chloride salt mixtures ranged from superficial staining to pitting and stress corrosion cracking (SCC). 304L teardrop coupons that exhibited SCC were directly exposed to a mixture composed of 98 wt % PuO2, 0.9 wt % NaCl, 0.9 wt % KCl, and 0.2 wt % CaCl2. Cracking was not observed in a 316L teardrop coupon. Pitting was also observed in this environment for both 304L and 316L with depths ranging from 20 to 100 ?m. Neither pitting nor SCC was observed in mixtures with a greater chloride salt concentration (5 and 28 wt%). These results demonstrated that for a corrosive solution to form a balance existed between the water loading and the salt chloride concentration. This chloride solution results from the interaction of loaded water with the hydrating CaCl2 salt. In Phase II, Series 1 tests, the SCC results were shown to be reproducible with cracking occurring in as little as 85 days. The approximate 0.5 wt% moisture level was found to result in an initial relative humidity of ~55% within the small-scale vessels. Pits were found to be associated with cracks and appeared to act as initiators for the cracking. In a vapor-space only exposure, the weld oxide, which results from the TIG closure weld used to fabricate the teardrop coupon, was also shown to be more susceptible to pitting corrosion than a surface free from weld oxide. This result has important implications for the closure weld of the 3013 inner can since the weld oxide on the can internal surface cannot be removed. The results from the Phase II, Series 2 tests further demonstrated the significance of forming a solution with a critical chloride concentration for corrosion to proceed. 304L teardrop coupons were found to corrode only by pitting with a similar oxide/salt mixture as used in Series 1 testing but with a lower water loading of 0.2 wt%, which resulted in an initial relative humidity of 35-38%. These tests ran twice as long as those for Series 1 testing. The exposure condition was also found to impact the corrosion with salt-exposed surfaces showing lower corrosion resistance. Additional analyses of the Series 2 coupons are recommended especially for determining if cracks emanate from the bottom of pits. Data generated under the 2009 3013 corrosion test plan, as was presented here, increased the understanding of the corrosion process within a sealed 3013 container. Along with the corrosion data from destructive evaluations of 3013 containers, the inner can closure weld region (ICCWR) has been identified as the most vulnerable area of the inner can where corrosion may lead to corrosive species leaking to the interior surface of the outer container, thereby jeopardizing the integrity of the 3013 container. A new corrosion plan has been designed that will characterize the corrosion at the ICCWR of 3013 DEs as well as parameters affecting this corrosion.

  12. Full-field characterization of thermal diffusivity in continuous- fiber ceramic composite materials and components

    SciTech Connect (OSTI)

    Steckenrider, J.S.; Ellingson, W.A. [Argonne National Lab., IL (United States); Rothermel, S.A. [South Dakota State Univ., Brookings, SD (United States)

    1995-05-01T23:59:59.000Z

    Continuous-fiber ceramic matrix composites (CFCCs) are currently being developed for various high-temperature applications, including use in advanced heat engines. Among the material classes of interest for such applications are silicon carbide (SiC)-fiber-reinforced SiC (SiC{sub (f)}/SiC), SiC-fiber-reinforced silicon nitride (SiC {sub (f)}/Si{sub 3}N{sub 4}), aluminum oxide (Al{sub 2}O{sub 3})-fiber-reinforced Al{sub 2}O{sub 3} (Al{sub 2}O{sub 3}{sub (f)}/Al{sub 2}O{sub 3}), and others. In such composites, the condition of the interfaces (between the fibers and matrix) are critical to the mechanical and thermal behavior of the component (as are conventional mechanical defects such as cracks, porosity, etc.). For example, oxidation of this interface (especially on carbon coated fibers) can seriously degrade both mechanical and thermal properties. Furthermore, thermal shock damage can degrade the matrix through extensive crack generation. A nondestructive evaluation method that could be used to assess interface condition, thermal shock damage, and to detect other ``defects`` would thus be very beneficial, especially if applicable to full-scale components. One method under development uses infrared thermal imaging to provide ``single-shot`` full-field assessment of the distribution of thermal properties in large components by measuring thermal diffusivity. By applying digital image filtering, interpolation, and least-squares-estimation techniques for noise reduction, we can achieve acquisition and analysis times of minutes or less with submillimeter spatial resolution. The system developed at Argonne has been used to examine the effects of thermal shock, oxidation treatment, density variations, and variations in oxidation resistant coatings in a full array of test specimens. Subscale CFCC components with nonplanar geometries have also been studied for manufacturing-induced variations in thermal properties.

  13. Hydrocarbons Heterogeneous Pyrolysis: Experiments and Modeling for Scramjet Thermal Management

    E-Print Network [OSTI]

    Bouchez, Marc; Visez, Nicolas; Herbinet, Olivier; Fournet, René; Marquaire, Paul-Marie

    2009-01-01T23:59:59.000Z

    The last years saw a renewal of interest for hypersonic research in general and regenerative cooling specifically, with a large increase of the number of dedicated facilities and technical studies. In order to quantify the heat transfer in the cooled structures and the composition of the cracked fuel entering the combustor, an accurate model of the thermal decomposition of the fuel is required. This model should be able to predict the fuel chemical composition and physical properties for a broad range of pressures, temperatures and cooling geometries. For this purpose, an experimental and modeling study of the thermal decomposition of generic molecules (long-chain or polycyclic alkanes) that could be good surrogates of real fuels, has been started at the DCPR laboratory located in Nancy (France). This successful effort leads to several versions of a complete kinetic model. These models do not assume any effect from the material that constitutes the cooling channel. A specific experimental study was performed ...

  14. Multiwavelength Thermal Emission

    E-Print Network [OSTI]

    California at Santa Cruz, University of

    Multiwavelength Astronomy NASA #12;Thermal Emission #12;Thermal Emission Non-thermal p-p collisions Optical IR Radio/ Microwave sources of emission massive stars, WHIM, Ly many dust, cool objects-ray ~GeV Gamma-ray ~TeV sources of emission AGN, clusters, SNR, binaries, stars AGN (obscured), shocks

  15. Thermal Performance Benchmarking (Presentation)

    SciTech Connect (OSTI)

    Moreno, G.

    2014-11-01T23:59:59.000Z

    This project will benchmark the thermal characteristics of automotive power electronics and electric motor thermal management systems. Recent vehicle systems will be benchmarked to establish baseline metrics, evaluate advantages and disadvantages of different thermal management systems, and identify areas of improvement to advance the state-of-the-art.

  16. Thermal neutron detection system

    DOE Patents [OSTI]

    Peurrung, Anthony J. (Richland, WA); Stromswold, David C. (West Richland, WA)

    2000-01-01T23:59:59.000Z

    According to the present invention, a system for measuring a thermal neutron emission from a neutron source, has a reflector/moderator proximate the neutron source that reflects and moderates neutrons from the neutron source. The reflector/moderator further directs thermal neutrons toward an unmoderated thermal neutron detector.

  17. Fracture analysis of axially cracked pressure tube of pressurized heavy water reactor

    SciTech Connect (OSTI)

    Krishnan, S.; Bhasin, V.; Mahajan, S.C. [Bhabha Atomic Research Centre, Bombay (India)] [and others

    1997-04-01T23:59:59.000Z

    Three Dimensional (313) finite element elastic plastic fracture analysis was done for through wall axially cracked thin pressure tubes of 220 MWe Indian Pressurized Heavy Water Reactor. The analysis was done for Zr-2 and Zr-2.5Nb pressure tubes operating at 300{degrees}C and subjected to 9.5 Mpa internal pressure. Critical crack length was determined based on tearing instability concept. The analysis included the effect of crack face pressure due to the leaking fluid from tube. This effect was found to be significant for pressure tubes. The available formulae for calculating J (for axially cracked tubes) do not take into account the effect of crack face pressure. 3D finite element analysis also gives insight into variation of J across the thickness of pressure tube. It was observed that J is highest at the mid-surface of tube. The results have been presented in the form of across the thickness average J value and a peak factor on J. Peak factor on J is ratio of J at mid surface to average J value. Crack opening area for different cracked lengths was calculated from finite element results. The fracture assessment of pressure tubes was also done using Central Electricity Generating Board R-6 method. Ductile tearing was considered.

  18. Threshold velocity for environmentally-assisted cracking in low alloy steels

    SciTech Connect (OSTI)

    Wire, G.L.; Kandra, J.T.

    1997-04-01T23:59:59.000Z

    Environmentally Assisted Cracking (EAC) in low alloy steels is generally believed to be activated by dissolution of MnS inclusions at the crack tip in high temperature LWR environments. EAC is the increase of fatigue crack growth rate of up to 40 to 100 times the rate in air that occurs in high temperature LWR environments. A steady state theory developed by Combrade, suggested that EAC will initiate only above a critical crack velocity and cease below this same velocity. A range of about twenty in critical crack tip velocities was invoked by Combrade, et al., to describe data available at that time. This range was attributed to exposure of additional sulfides above and below the crack plane. However, direct measurements of exposed sulfide densities on cracked specimens were performed herein and the results rule out significant additional sulfide exposure as a plausible explanation. Alternatively, it is proposed herein that localized EAC starting at large sulfide clusters reduces the calculated threshold velocity from the value predicted for a uniform distribution of sulfides. Calculations are compared with experimental results where the threshold velocity has been measured, and the predicted wide range of threshold values for steels of similar sulfur content but varying sulfide morphology is observed. The threshold velocity decreases with the increasing maximum sulfide particle size, qualitatively consistent with the theory. The calculation provides a basis for a conservative minimum velocity threshold tied directly to the steel sulfur level, in cases where no details of sulfide distribution are known.

  19. Fatigue cracking of a bare steel first wall in an inertial confinement fusion chamber

    SciTech Connect (OSTI)

    Hunt, R. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Abbott, R. P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Havstad, M. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Dunne, A. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2013-06-01T23:59:59.000Z

    Inertial confinement fusion power plants will deposit high energy X-rays onto the outer surfaces of the first wall many times a second for the lifetime of the plant. These X-rays create brief temperature spikes in the first few microns of the wall, which cause an associated highly compressive stress response on the surface of the material. The periodicity of this stress pulse is a concern due to the possibility of fatigue cracking of the wall. We have used finite element analyses to simulate the conditions present on the first wall in order to evaluate the driving force of crack propagation on fusion-facing surface cracks. Analysis results indicate that the X-ray induced plastic compressive stress creates a region of residual tension on the surface between pulses. This tension film will likely result in surface cracking upon repeated cycling. Additionally, the compressive pulse may induce plasticity ahead of the crack tip, leaving residual tension in its wake. However, the stress amplitude decreases dramatically for depths greater than 80–100 ?m into the fusion-facing surface. Crack propagation models as well as stress-life estimates agree that even though small cracks may form on the surface of the wall, they are unlikely to propagate further than 100 ?m without assistance from creep or grain erosion phenomena.

  20. Conditions under which cracks occur in modified 13% chromium steel in wet hydrogen sulfide environments

    SciTech Connect (OSTI)

    Hara, T.; Asahi, H.

    2000-05-01T23:59:59.000Z

    Occurrence of cracks in an API 13% Cr steel, modified 13% Cr steel, and duplex stainless steel were compared in various wet, mild hydrogen sulfide (H{sub 2}S) environments. The conditions under which cracks occurred in the modified 13% Cr steel in oil and gas production environments were made clear. No cracks occurred if pH > depassivation pH (pH{sub d}) and redox potential of sulfur (E{sub S(red/ax)}) < pitting potential (V{sub c}). Hydrogen embrittlement-type cracks occurred in pH > Ph{sub d} and E{sub S(red/ax)} > V{sub c}. The pH inside the pit decreased drastically and hydrogen embrittlement occurred. Cracks of the hydrogen embrittlement type occurred if pH < pH{sub d} and threshold hydrogen concentration under which cracks occur (H{sub th}) < hydrogen concentration in steel (H{sub 0}). No cracks occurred if pH < pH{sub d} and H{sub th} > H{sub 0}.

  1. On the Use of the Polynomial Annihilation Edge Detection for Locating Cracks in Beam-Like Structures

    SciTech Connect (OSTI)

    Saxena, Rishu [ORNL] [ORNL; Surace, Cecilia [Politecnico di Torino] [Politecnico di Torino; Archibald, Richard K [ORNL] [ORNL

    2013-01-01T23:59:59.000Z

    A crack in a structure causes a discontinuity in the first derivative of the mode shapes: On this basis, a numerical method for detecting discontinuities in smooth piecewise functions and their derivatives, based on a polynomial annihilation technique, has been applied to the problem of crack detection and localisation in beam-like structures for which only post-damage mode shapes are available. Using a finite-element model of a cracked beam, the performance of this methodology has been analysed for different crack depths and increasing amounts of noise. Given the crack position, a procedure to estimate its depth is also proposed and corresponding results shown.

  2. Crack growth rates of nickel alloy welds in a PWR environment.

    SciTech Connect (OSTI)

    Alexandreanu, B.; Chopra, O. K.; Shack, W. J.; Energy Technology

    2006-05-31T23:59:59.000Z

    In light water reactors (LWRs), vessel internal components made of nickel-base alloys are susceptible to environmentally assisted cracking. A better understanding of the causes and mechanisms of this cracking may permit less conservative estimates of damage accumulation and requirements on inspection intervals. A program is being conducted at Argonne National Laboratory to evaluate the resistance of Ni alloys and their welds to environmentally assisted cracking in simulated LWR coolant environments. This report presents crack growth rate (CGR) results for Alloy 182 shielded-metal-arc weld metal in a simulated pressurized water reactor (PWR) environment at 320 C. Crack growth tests were conducted on 1-T compact tension specimens with different weld orientations from both double-J and deep-groove welds. The results indicate little or no environmental enhancement of fatigue CGRs of Alloy 182 weld metal in the PWR environment. The CGRs of Alloy 182 in the PWR environment are a factor of {approx}5 higher than those of Alloy 600 in air under the same loading conditions. The stress corrosion cracking for the Alloy 182 weld is close to the average behavior of Alloy 600 in the PWR environment. The weld orientation was found to have a profound effect on the magnitude of crack growth: cracking was found to propagate faster along the dendrites than across them. The existing CGR data for Ni-alloy weld metals have been compiled and evaluated to establish the effects of key material, loading, and environmental parameters on CGRs in PWR environments. The results from the present study are compared with the existing CGR data for Ni-alloy welds to determine the relative susceptibility of the specific Ni-alloy weld to environmentally enhanced cracking.

  3. Mechanical Systems Signal Processing

    E-Print Network [OSTI]

    Ray, Asok

    for 7075-T6 aluminium alloy specimens, where the anomalies accrue from small fatigue crack growth. r 2005

  4. The solar thermal report. Volume 3, Number 5

    SciTech Connect (OSTI)

    NONE

    1982-09-01T23:59:59.000Z

    This report is published by the Jet Propulsion Laboratory for the DOE Solar Thermal Technology Division to provide an account of work sponsored by the Division and to aid the community of people interested in solar thermal technology in gaining access to technical information. Contents include articles entitled the following: Solar system supplies thermal energy for producing chemicals at USS plant; Solar thermal power module designed for small community market; Roof-mounted trough system supplies process heat for Caterpillar plant; Solar thermal update -- 10 MW(e) pilot plant and 3-MW(t) total energy system; Solar steam processes crude oil; New York investigates solar ponds as a source of thermal energy; On-farm solar -- Finding new uses for the sun; and Topical index of solar thermal report articles.

  5. Thermal conductivity measurements of Summit polycrystalline silicon.

    SciTech Connect (OSTI)

    Clemens, Rebecca; Kuppers, Jaron D.; Phinney, Leslie Mary

    2006-11-01T23:59:59.000Z

    A capability for measuring the thermal conductivity of microelectromechanical systems (MEMS) materials using a steady state resistance technique was developed and used to measure the thermal conductivities of SUMMiT{trademark} V layers. Thermal conductivities were measured over two temperature ranges: 100K to 350K and 293K to 575K in order to generate two data sets. The steady state resistance technique uses surface micromachined bridge structures fabricated using the standard SUMMiT fabrication process. Electrical resistance and resistivity data are reported for poly1-poly2 laminate, poly2, poly3, and poly4 polysilicon structural layers in the SUMMiT process from 83K to 575K. Thermal conductivity measurements for these polysilicon layers demonstrate for the first time that the thermal conductivity is a function of the particular SUMMiT layer. Also, the poly2 layer has a different variation in thermal conductivity as the temperature is decreased than the poly1-poly2 laminate, poly3, and poly4 layers. As the temperature increases above room temperature, the difference in thermal conductivity between the layers decreases.

  6. Compliant alkali silicate sealing glass for solid oxide fuel cell applications: Combined stability in isothermal ageing and thermal cycling with YSZ coated ferritic stainless steels

    SciTech Connect (OSTI)

    Chou, Y. S.; Thomsen, Edwin C.; Choi, Jung-Pyung; Stevenson, Jeffry W.

    2012-01-01T23:59:59.000Z

    An alkali-containing silicate glass (SCN-1) is currently being evaluated as a candidate sealing glass for solid oxide fuel cell (SOFC) applications. The glass contains about 17 mole% alkalis (K+Na) and has low glass transition and softening temperatures. It remains vitreous and compliant around 750-800oC after sealing without substantial crystallization, as contrary to conventional glass-ceramic sealants, which experience rapid crystallization after the sealing process. The glassy nature and low characteristic temperatures can reduce residual stresses and result in the potential for crack healing. In a previous study, the glass was found to have good thermal cycle stability and was chemically compatible with YSZ coating during short term testing. In the current study, the compliant glass was further evaluated in a more realistic way in that the sealed glass couples were first isothermally aged for 1000h followed by thermal cycling. High temperature leakage was measured. The chemical compatibility was also investigated with powder mixtures at 700 and 800oC to enhance potential interfacial reaction. In addition, interfacial microstructure was examined with scanning electron microscopy and evaluated with regard to the leakage and chemical compatibility results.

  7. Mode I transverse cracking in an epoxy and a graphite fiber reinforced epoxy

    E-Print Network [OSTI]

    Williams, David Robert

    1981-01-01T23:59:59.000Z

    release rate can be derived from Equation (2) and shown to be: P dc where C = D/P is the compliance (m/N), D being displacement (m) and P being load (N) . Given an algebraic expression for the compliance as a function of crack length, it is possible... lengths to a compliance function suggested by Slepetz and Carlson [11]: C = A *A + A *A + A *(2+A)l(1-A) 3 2 1 2 3 24 where the A. are the coefficients, A is the relative crack length a/w (crack length measured from load line divided by specimen...

  8. Crack healing as a function of pOH- and fracture morphology

    E-Print Network [OSTI]

    Fallon, Jessica Anne

    2005-02-17T23:59:59.000Z

    Crack healing in quartz has been investigated by optical microscopy and interferometry of rhombohedral ( 1) cracks in polished Brazilian quartz prisms that were annealed hydrothermally at temperatures of 250?C and 400?C for 2.4 to 240 hours, fluid... pressure Pf = Pc = 41 MPa, and varying pOH- (from 5.4 to 1.2 at 250?C for fluids consisting of distilled water and NaOH solutions with molalities up to 1). Crack morphologies before and after annealing were recorded for each sample in plane light...

  9. Technique development for field inspection of cracking in seam welded ducts

    SciTech Connect (OSTI)

    Shell, Eric B.; Benson, Craig [Wyle Laboratories, Inc., Dayton, OH 45440 (United States); Liljestrom, Greg C.; Shanahan, Stephen [Wyle Laboratories, Inc., Oklahoma City, OK 73110 (United States)

    2014-02-18T23:59:59.000Z

    The resistance seam weld interfaces between alloyed and pure titanium are an in service concern due to precipitation of titanium hydride and resulting embrittlement and cracking. Several inspection techniques were developed and evaluated for field use to characterize the damage in the fleet. Electromagnetic, ultrasonic, florescent penetrant, thermographic, and radiographic techniques were considered. The ultrasonic and electromagnetic approaches were both found suitable. However, the electromagnetic approach is more desirable for field inspections, due to consistency and ease of use. The electromagnetic inspection procedure is able to discriminate between precursor damage and through cracking with sufficient sensitivity to small cracks.

  10. Ultrasonic ply-by-ply detection of matrix cracks in laminated composites 

    E-Print Network [OSTI]

    Ganpatye, Atul Shridatta

    2005-02-17T23:59:59.000Z

    .......................................... 68 Fig. 2.33 (a) Filtered X-ray image, and (b) ultrasonic image, of cracks in the -452 ply-group of the TAMU-1 specimen.................................................... 69 Fig. 2.34 (a) Filtered X-ray image, and (b) ultrasonic image....................................................... 71 Fig. 2.36 (a) Filtered X-ray image, and (b) ultrasonic image, of cracks in the -452 ply-group of the TAMU-4 specimen.................................................... 72 xi Page Fig. 3.1 Ultrasonic images of cracks in the eight...

  11. Remote reactor repair: GTA (gas tungsten Arc) weld cracking caused by entrapped helium

    SciTech Connect (OSTI)

    Kanne, W.R. Jr.

    1988-01-01T23:59:59.000Z

    A repair patch was welded to the wall of a nuclear reactor tank using remotely controlled thirty-foot long robot arms. Further repair was halted when gas tungsten arc (GTA) welds joining type 304L stainless steel patches to the 304 stainless steel wall developed toe cracks in the heat-affected zone (HAZ). The role of helium in cracking was investigated using material with entrapped helium from tritium decay. As a result of this investigation, and of an extensive array of diagnostic tests performed on reactor tank wall material, helium embrittlement was shown to be the cause of the toe cracks.

  12. Enhanced Productivity of Chemical Processes Using Dense Fluidized Beds

    SciTech Connect (OSTI)

    Sibashis Banerjee; Alvin Chen; Rutton Patel; Dale Snider; Ken Williams; Timothy O'Hern; Paul Tortora

    2008-02-29T23:59:59.000Z

    The work detailed in this report addresses Enabling Technologies within Computational Technology by integrating a “breakthrough” particle-fluid computational technology into traditional Process Science and Engineering Technology. The work completed under this DOE project addresses five major development areas 1) gas chemistry in dense fluidized beds 2) thermal cracking of liquid film on solids producing gas products 3) liquid injection in a fluidized bed with particle-to-particle liquid film transport 4) solid-gas chemistry and 5) first level validation of models. Because of the nature of the research using tightly coupled solids and fluid phases with a Lagrangian description of the solids and continuum description of fluid, the work provides ground-breaking advances in reactor prediction capability. This capability has been tested against experimental data where available. The commercial product arising out of this work is called Barracuda and is suitable for a wide (dense-to-dilute) range of industrial scale gas-solid flows with and without reactions. Commercial applications include dense gas-solid beds, gasifiers, riser reactors and cyclones.

  13. Standard test method for evaluating stress-corrosion cracking of stainless alloys with different nickel content in boiling acidified sodium chloride solution

    E-Print Network [OSTI]

    American Society for Testing and Materials. Philadelphia

    2000-01-01T23:59:59.000Z

    1.1 This test method describes a procedure for conducting stress-corrosion cracking tests in an acidified boiling sodium chloride solution. This test method is performed in 25% (by mass ) sodium chloride acidified to pH 1.5 with phosphoric acid. This test method is concerned primarily with the test solution and glassware, although a specific style of U-bend test specimen is suggested. 1.2 This test method is designed to provide better correlation with chemical process industry experience for stainless steels than the more severe boiling magnesium chloride test of Practice G36. Some stainless steels which have provided satisfactory service in many environments readily crack in Practice G36, but have not cracked during interlaboratory testing using this sodium chloride test method. 1.3 This boiling sodium chloride test method was used in an interlaboratory test program to evaluate wrought stainless steels, including duplex (ferrite-austenite) stainless and an alloy with up to about 33% nickel. It may also b...

  14. MONITORING OF CRACKS ON THE BELL TOWER OF ST. ANASTASIA CATHEDRAL IN ZADAR CROATIA

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    MONITORING OF CRACKS ON THE BELL TOWER OF ST. ANASTASIA CATHEDRAL IN ZADAR CROATIA Davor Uglesi 1 , Uros Bohinc 2 1 D & Z doo, Jerolima Vidulia 7, 23000 Zadar, Croatia 2 ZAG, Dimiceva 12, 1000 Ljubljana

  15. Analysis of cracking in small-diameter BWR piping. Final report

    SciTech Connect (OSTI)

    Eason, E.D.; Shusto, L.M.

    1986-01-01T23:59:59.000Z

    In BWRs, the failure rate from intergranular stress corrosion cracking is lower for small piping than for piping of more than 4-in. diameter. Moreover, for the small piping, repair costs are considerably lower, and leakage has much less impact.

  16. Effect of oxygen potential on high temperature crack growth in alloy 617

    E-Print Network [OSTI]

    Benz, Julian K

    2009-01-01T23:59:59.000Z

    The effect of oxygen partial pressure on crack growth rates in Alloy 617 has been studied using both static and fatigue loading at 650°C. Tests were conducted at a constant stress intensity factor, K, for static loading ...

  17. Modeling the ASR Induced Strains and Cracking of Reinforced Concrete Beams

    E-Print Network [OSTI]

    Zhang, Li

    2013-05-17T23:59:59.000Z

    the number and spacing of cracks of a partly restrained reinforced concrete beam affected by ASR gels. The model is validated with recent experimental results on large scale reinforced concrete specimens. Predictions agree well with the observed number...

  18. Stiffness reduction and stress transfer in composite laminates with transverse matrix cracks

    E-Print Network [OSTI]

    Praveen, Grama Narasimhaprasad

    1994-01-01T23:59:59.000Z

    Cross-ply laminates and angle-ply laminates with transverse plies containing through-width matrix cracks across the thickness of the transverse plies are studied using a variational, strain energy based approach, complementary to that of Hashin...

  19. Cracked lifting lug welds on ten-ton UF{sub 6} cylinders

    SciTech Connect (OSTI)

    Dorning, R.E. [Martin Marietta Energy Systems, Inc., Piketon, OH (United States)

    1991-12-31T23:59:59.000Z

    Ten-ton, Type 48X, UF{sub 6} cylinders are used at the Portsmouth Gaseous Diffusion Plant to withdraw enriched uranium hexafluoride from the cascade, transfer enriched uranium hexafluoride to customer cylinders, and feed enriched product to the cascade. To accomplish these activities, the cylinders are lifted by cranes and straddle carriers which engage the cylinder lifting lugs. In August of 1988, weld cracks on two lifting lugs were discovered during preparation to lift a cylinder. The cylinder was rejected and tagged out, and an investigating committee formed to determine the cause of cracking and recommend remedial actions. Further investigation revealed the problem may be general to this class of cylinder in this use cycle. This paper discusses the actions taken at the Portsmouth site to deal with the cracked lifting lug weld problem. The actions include inspection activities, interim corrective actions, metallurgical evaluation of cracked welds, weld repairs, and current monitoring/inspection program.

  20. Integrating Gas Turbines with Cracking Heaters - Impact on Emissions and Energy Efficiency

    E-Print Network [OSTI]

    Platvoet, E.

    2011-01-01T23:59:59.000Z

    Turbine Exhaust Gas (TEG) contains high levels of oxygen, typically 15 vol. percent, due to gas turbine blade material temperature limits. As such it can be used as an oxidant for combustion in cracking furnaces and reformers. Its high temperature...

  1. Comparison of theory and experiment for elastic-plastic plane-strain crack growth

    E-Print Network [OSTI]

    well to the experimental results obtained on deeply cracked compact specimens. L. Hermann, lng, MS yielding are not yet available, although some discussion of the fully yielded case has been possible 1

  2. A preliminary investigation of the effects of environmentally assisted cracking on natural gas transmission pipelines 

    E-Print Network [OSTI]

    Curbo, Jason Wayne

    2005-08-29T23:59:59.000Z

    Concepts for the development of a model to predict natural gas transmission pipeline lifetime in a corrosive environment are constructed. Primarily, the effects of environmentally assisted cracking (EAC) are explored. Tensile test specimens from a...

  3. Theoretical Simulation of n-Alkane Cracking on Zeolites Joseph A. Swisher,,|

    E-Print Network [OSTI]

    Bell, Alexis

    calculations for propane and butane cracking on MFI reveal that significantly better agreement between reactions, as well as the distribution of the products formed from a specified set of reactants. Impressive

  4. A program to design asphalt concrete overlays to mitigate reflection cracking

    E-Print Network [OSTI]

    Satyanarayana Rao, Sindhu

    2002-01-01T23:59:59.000Z

    of the research are to understand the occurrence and behavior of reflection cracking and for devising ways of mitigating them and to put together an effective and complete package of computer programs to design asphalt concrete overlays. Another primary objective...

  5. The stress field around two parallel edge cracks in a finite body

    E-Print Network [OSTI]

    Hardin, Patrick Wayne

    1993-01-01T23:59:59.000Z

    The goal of this research was to develop a method to represent and analyze the stress field surrounding two edge cracks located in a finite body. The generalized Westergaard equations were utilized to represent the independent stress fields created...

  6. Linear elastic fracture mechanics in anisotropic solids : application to fluid-driven crack propagation

    E-Print Network [OSTI]

    Laubie, Hadrien Hyacinthe

    2013-01-01T23:59:59.000Z

    Fracture mechanics is a field of continuum mechanics with the objective to predict how cracks initiate and propagate in solids. It has a wide domain of application. While aerospace engineers want to make sure a defect in ...

  7. THE EFFECT OF SILICON ON THE ENVIRONMENTAL CRACKING BEHAVIOR OF A HIGH STRENGTH STEEL

    E-Print Network [OSTI]

    Cedeno, M.H.C.

    2010-01-01T23:59:59.000Z

    Low-Alloy, High-Strength Steel, Advanced Research ProjectsTests of High Strength Steels, BISRA Report September 1971.Cracking in High Strength Steels and in Titanium and

  8. Experiment evidence on the temperature dependence of desiccation cracking behavior of clayey soils

    E-Print Network [OSTI]

    Boyer, Edmond

    in analyzing drought effects on buildings, because the presence of cracks changes soil surface properties, leading to dam failures as for the Stockton and Wister dams (Sherard, 1973). In the agricultural field

  9. Evaluation of the filler effects on fatique cracking and permanent deformation of asphalt concrete mixtures 

    E-Print Network [OSTI]

    Izzo, Richard P

    1997-01-01T23:59:59.000Z

    The addition of hydrated lime to asphalt has shown to be beneficial with an improvement in the Theological properties of the binder, as well as resistance to permanent deformation (rutting) and fatigue cracking of asphalt concrete mixtures...

  10. Evaluation of the filler effects on fatique cracking and permanent deformation of asphalt concrete mixtures

    E-Print Network [OSTI]

    Izzo, Richard P

    1997-01-01T23:59:59.000Z

    The addition of hydrated lime to asphalt has shown to be beneficial with an improvement in the Theological properties of the binder, as well as resistance to permanent deformation (rutting) and fatigue cracking of asphalt concrete mixtures...

  11. Aluminum nitride transitional layer for reducing dislocation density and cracking of AIGan epitaxial films

    DOE Patents [OSTI]

    Allerman, Andrew A. (Tijeras, NM); Crawford, Mary H. (Albuquerque, NM); Koleske, Daniel D. (Albuquerque, NM); Lee, Stephen R. (Albuquerque, NM)

    2011-03-29T23:59:59.000Z

    A denticulated Group III nitride structure that is useful for growing Al.sub.xGa.sub.1-xN to greater thicknesses without cracking and with a greatly reduced threading dislocation (TD) density.

  12. Thermal imaging measurement of lateral thermal diffusivity in continuous fiber ceramic composites

    SciTech Connect (OSTI)

    Sun, J. G.; Deemer, C.; Ellingson, W. A.

    2000-02-18T23:59:59.000Z

    Infrared thermal imaging has become a common technique for nondestructive evaluation and measurement of thermal properties in ceramic specimens. Flash thermal imaging can be used to determine two-dimensional through-thickness thermal diffusivity in a planar specimen. In this study, the authors extended the method to determine lateral, or transverse, thermal diffusivity in the specimen. During the flash thermal imaging test, pulsed heat energy is applied to a specimen's back surface, which is partially shielded, and the change of temperature distribution on the front surface is monitored by an infrared thermal imaging system. The temperature distribution represents the effect of both the normal heat transfer through the specimen's thickness and the lateral heat transfer through the interface between the shielded and unshielded back-surface regions. Those temperature distributions are then fitted with a theoretical solution of the heat transfer process to determine the lateral thermal diffusivity at the interface. This technique has been applied to measure lateral thermal diffusivity in a steel plate and a continuous fiber ceramic composite specimen.

  13. Geometry dependence of crack growth resistance curves in thin sheet aluminum alloys

    E-Print Network [OSTI]

    Stricklin, Lance Lee

    1988-01-01T23:59:59.000Z

    GEOMETRY DEPENDENCE OF CRACK GROWTH RESISTANCE CURVES IN THIN SHEET ALUMINUM ALLOYS A Thesis by LANCE LEE STRICKLIN Submitted to the Office of Graduate Studies of Texas ASM University in partial fulfillment of the requirement for the degree... of MASTER OF SCIENCE December 1988 Major Subject: Mechanical Engineering GEOMETRY DEPENDENCE OF CRACK GROWTH RESISTANCE CURVES IN THIN SHEET ALUMINUM ALLOYS A Thesis by LANCE LEE STRICKLIN Approved as to style and content by: Ted L. Anderson...

  14. A quantitative determination of the conditions for hot cracking during welding for aluminum alloys

    E-Print Network [OSTI]

    Steenbergen, James Everett

    1969-01-01T23:59:59.000Z

    A QUANTITATIVE DETERMINATION OF THE CONDITIONS FOR HOT CRACKING DURING WELDING FOR ALUMINUM ALLOYS A Thesis by JAMES EVERETT STEENBERGEN Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE January 1969 Major Subject: Materials Engineering A QUANTITATIVE DETERMINATION OF THE CONDITIONS FOR HOT CRACKING DURING WELDING FOR ALUMINUM ALLOYS A Thesis by JAMES EVERETT STEENBERGEN (Chairman of Committee) ( ead...

  15. Identification of asphalt binder properties that affect cracking performance of hot mixed asphalt concrete pavements

    E-Print Network [OSTI]

    Hastings, Charles Patrick

    1997-01-01T23:59:59.000Z

    Specimen Failing in Indirect Tension Fatigue Cracking as a Function of Time for Texarkana Test Pavements 17 17 19 Figure 10. Figure I l. Figure 12. Texarkana EVA Test Section Texarkana Latex Test Section . Reflective Cracking as a Function... Results for Carbon Black Illustrating Increase in Molecular Size 69 Figure B5. Sherman GPC Results for Control Illustrating Increase in Molecular Size . 70 Page Figure B6. Sherman GPC Results for EVA Illustrating Increase in Molecular Size 70 Figure...

  16. A quantitative determination of the conditions for hot cracking during welding for aluminum alloys 

    E-Print Network [OSTI]

    Steenbergen, James Everett

    1969-01-01T23:59:59.000Z

    A QUANTITATIVE DETERMINATION OF THE CONDITIONS FOR HOT CRACKING DURING WELDING FOR ALUMINUM ALLOYS A Thesis by JAMES EVERETT STEENBERGEN Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE January 1969 Major Subject: Materials Engineering A QUANTITATIVE DETERMINATION OF THE CONDITIONS FOR HOT CRACKING DURING WELDING FOR ALUMINUM ALLOYS A Thesis by JAMES EVERETT STEENBERGEN (Chairman of Committee) ( ead...

  17. Characterization of the plastic strain theory for predicting hot cracking during welding in aluminum alloys 

    E-Print Network [OSTI]

    Walters, Douglas Frederick

    1970-01-01T23:59:59.000Z

    CHARACTERIZATION OF THE PLASTIC STRAIN THEORY FQR PREDICTING HOT CRACKING DURING WELDING IN ALUMINUM ALLOYS A Thesis by DOUGLAS FREDERICK WALTERS Submitted to the Graduate College of Texas A&M University in partial fulfillment... of the requirement for the degree of MASTER OF SCIENCE May 1970 Major Subject: Mechanical Engineering CHARACTERIZATION OF THE PLASTIC STRAIN THEORY FOR PREDICTING HOT CRACKING DURING WELDING IN ALUMINUM ALLOYS A Thesis by DOUGLAS FREDERICK WALTERS Approved...

  18. On grouting using a suspension of ultrafine clay on artificially cracked rock samples

    SciTech Connect (OSTI)

    Ito, Y.; Sakaguchi, T.; Nishiyama, K. [Kumagai Gumi Co., Ltd., Tokyo (Japan). Nuclear and Energy Dept.; Fujiwara, A. [Radioactive Waste Management Center, Tokyo (Japan). Second Research Div.

    1993-12-31T23:59:59.000Z

    Recently there has been increasing social interest in the effective disposal of low-level radioactive wastes. The use of underground rock caverns is considered as a possible repository space. This paper presents a new grouting method which uses a suspension of liquefied ultrafine clay in fractured rock masses. In order to demonstrate the effect to block open cracks, two experiments were carried out on large-sized granite samples with open cracks. The experiments proved the method to be highly effective.

  19. Mechanism of Irradiation Assisted Cracking of Core Components in Light Water Reactors

    SciTech Connect (OSTI)

    Gary S. Was; Michael Atzmon; Lumin Wang

    2003-04-28T23:59:59.000Z

    The overall goal of the project is to determine the mechanism of irradiation assisted stress corrosion cracking (IASCC). IASCC has been linked to hardening, microstructural and microchemical changes during irradiation. Unfortunately, all of these changes occur simultaneously and at similar rates during irradiation, making attribution of IASCC to any one of these features nearly impossible to determine. The strategy set forth in this project is to develop means to separate microstructural from microchemical changes to evaluate each separately for their effect on IASCC. In the first part, post irradiation annealing (PIA) treatments are used to anneal the irradiated microstructure, leaving only radiation induced segregation (RIS) for evaluation for its contribution to IASCC. The second part of the strategy is to use low temperature irradiation to produce a radiation damage dislocation loop microstructure without radiation induced segregation in order to evaluate the effect of the dislocation microstructure alone. A radiation annealing model was developed based on the elimination of dislocation loops by vacancy absorption. Results showed that there were indeed, time-temperature annealing combinations that leave the radiation induced segregation profile largely unaltered while the dislocation microstructure is significantly reduced. Proton irradiation of 304 stainless steel irradiated with 3.2 MeV protons to 1.0 or 2.5 dpa resulted in grain boundary depletion of chromium and enrichment of nickel and a radiation damaged microstructure. Post irradiation annealing at temperatures of 500 ? 600°C for times of up to 45 min. removed the dislocation microstructure to a greater degree with increasing temperatures, or times at temperature, while leaving the radiation induced segregation profile relatively unaltered. Constant extension rate tensile (CERT) experiments in 288°C water containing 2 ppm O2 and with a conductivity of 0.2 mS/cm and at a strain rate of 3 x 10-7 s-1 showed that the IASCC susceptibility, as measured by the crack length per unit strain, decreased with very short anneals and was almost completely removed by an anneal at 500°C for 45 min. This annealing treatment removed about 15% of the dislocation microstructure and the irradiation hardening, but did not affect the grain boundary chromium depletion or nickel segregation, nor did it affect the grain boundary content of other minor impurities. These results indicate that RIS is not the sole controlling feature of IASCC in irradiated stainless steels in normal water chemistry. The isolation of the irradiated microstructure was approached using low temperature irradiation or combinations of low and high temperature irradiations to achieve a stable, irradiated microstructure without RIS. Experiments were successful in achieving a high degree of irradiation hardening without any evidence of RIS of either major or minor elements. The low temperature irradiations to doses up to 0.3 dpa at T<75°C were also very successful in producing hardening to levels considerably above that for irradiations conducted under nominal conditions of 1 dpa at 360°C. However, the microstructure consisted of an extremely fine dispersion of defect clusters of sizes that are not resolvable by either transmission electron microscopy (TEM) or small angle x-ray scattering (SAXS). The microstructure was not stable at the 288°C IASCC test temperature and resulted in rapid reduction of hardening and presumably, annealing of the defect clusters at this temperature as well. Nevertheless, the annealing studies showed that treatments that resulted in significant decreases in the hardening produced small changes in the dislocation microstructure that were confined to the elimination of the finest of loops (~1 nm). These results substantiate the importance of the very fine defect microstructure in the IASCC process. The results of this program provide the first definitive evidence that RIS is not the sole controlling factor in the irradiation assisted stress corrosion cracking of austenitic stain

  20. Catalytic thermal barrier coatings

    DOE Patents [OSTI]

    Kulkarni, Anand A. (Orlando, FL); Campbell, Christian X. (Orlando, FL); Subramanian, Ramesh (Oviedo, FL)

    2009-06-02T23:59:59.000Z

    A catalyst element (30) for high temperature applications such as a gas turbine engine. The catalyst element includes a metal substrate such as a tube (32) having a layer of ceramic thermal barrier coating material (34) disposed on the substrate for thermally insulating the metal substrate from a high temperature fuel/air mixture. The ceramic thermal barrier coating material is formed of a crystal structure populated with base elements but with selected sites of the crystal structure being populated by substitute ions selected to allow the ceramic thermal barrier coating material to catalytically react the fuel-air mixture at a higher rate than would the base compound without the ionic substitutions. Precious metal crystallites may be disposed within the crystal structure to allow the ceramic thermal barrier coating material to catalytically react the fuel-air mixture at a lower light-off temperature than would the ceramic thermal barrier coating material without the precious metal crystallites.