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Note: This page contains sample records for the topic "thermal cracking process" from the National Library of EnergyBeta (NLEBeta).
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We encourage you to perform a real-time search of NLEBeta
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1

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...

2

A heavy oil thermal cracking simulation program  

SciTech Connect (OSTI)

Correlations were developed to simulate the thermal cracking reaction of petroleum vacuum distillation residues through pilot plant data analysis. They use charge properties like specific gravity, viscosity, sulphur content and initial boiling point to give the yield and quality of products as a function of conversion, which is measured in terms of wt.% products with normal boiling point below 350{degrees}C. The mixture is represented with 24 lumps, and kinetic parameters for the reaction feed {r_arrow} products were also found as a function of feedstock properties. Finally, a computer program was developed to simulate fired heater operation for visbreaking and delayed coking units. 3 refs., 10 figs., 1 tab.

Maciel, R. [UNICAMP, Campinas (Brazil); Sugaya, M.F. [Petrobrais, Rio de Janeiro (Brazil)

1996-12-31T23:59:59.000Z

3

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

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

Crack Imaging Reveals Degradation Processes in Nuclear Reactor Structural Materials. High-Resolution Crack Imaging Reveals Degradation Processes in Nuclear Reactor Structural...

4

Thermal cracking in disc brakes Thomas J. Mackin *,1  

E-Print Network [OSTI]

Thermal cracking in disc brakes Thomas J. Mackin *,1 , Steven C. Noe, K.J. Ball, B.C. Bedell, D, or hub, which is connected to the wheel and axle, and an inboard and outboard braking surface

Salvaggio, Carl

5

Process for magnetic beneficiating petroleum cracking catalyst  

DOE Patents [OSTI]

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.

Doctor, Richard D. (Lisle, IL)

1993-01-01T23:59:59.000Z

6

Process for magnetic beneficiating petroleum cracking catalyst  

DOE Patents [OSTI]

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.

Doctor, R.D.

1993-10-05T23:59:59.000Z

7

Hydrogen Crack Growth Resistance of Thermal Power Plant Material Collector  

Science Journals Connector (OSTI)

Abstract The influence of electrolytical hydrogenation on fracture toughness, corrosion crack-growth resistance and fracture micromechanisms of operated 12Cr1MoV steel of thermal power plant superheater collector has been studied. Compact tension specimens were cut from perforated surface of thermal power plant superheater collector dismounted after 178,500 hours of operation. Corrosion crack-growth resistance under tension of previously hydrogenated compact specimens with fatigue cracks was studied. Due to the increased concentration of hydrogen in solution an additional buffer was being created that prevents hydrogen leakage from the specimen through the fracture surface during the experiment. The hydrogenation causes the significant decrease of critical stress intensity factor Kc, during the experiment in 0.1 N NaOH solution as compared with critical stress intensity factor K of non-hydrogenation 12Cr1MoV steel obtained by the 5% secant line method and in comparison with critical stress intensity factor Kc, determined through the J-integral. The areas of ductile crack growth in hydrogenated and non-hydrogenated specimens were found to have similar material fracture micromechanisms with dimples creation of different shape and size. But on the ductile crack growth area in hydrogenated specimens material intergranular fracture mechanisms were found caused by the hydrogen embrittlement which are similar to areas without ridges with the products corrosion traces.

V. Iasnii; P. Maruschak; O. Yasniy; Y. Lapusta

2014-01-01T23:59:59.000Z

8

Solar Thermal Processes  

Science Journals Connector (OSTI)

The use of solar energy for desalination purposes was one of ... The process is based on the use of solar thermal energy to evaporate water, thus separating pure ... brine. In this chapter an overview of solar thermal

M.T. Chaibi; Ali M. El-Nashar

2009-01-01T23:59:59.000Z

9

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

E-Print Network [OSTI]

when the material is subjected to temperature gradients and is therefore relevant to its thermal shock resistance. The present study focuses on the effects of a periodic array of matrix cracks on thermal displacement are used to determine the contributions to the longitudinal thermal resistance due to each crack

Zok, Frank

10

Fracture Modeling of Crack Propagation in Wood and Wood Composites Including Crack Tip Processes and Fiber Bridging Mechanics  

E-Print Network [OSTI]

1 Fracture Modeling of Crack Propagation in Wood and Wood Composites Including Crack Tip Processes and Fiber Bridging Mechanics J. A. Nairn, N. Matsumoto Wood Science & Engineering, Oregon State University wood and wood composites develop process zones often consisting of fibers bridging the crack surfaces

Nairn, John A.

11

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

E-Print Network [OSTI]

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

Shawabkeh, Reyad A.

12

A nanomechanical investigation of the crack tip process zone of marble  

E-Print Network [OSTI]

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 ...

Brooks, Zenzile (Zenzile Z.)

2010-01-01T23:59:59.000Z

13

A probabilistic model to predict the formation and propagation of crack networks in thermal  

E-Print Network [OSTI]

. In the case of cooling systems in nuclear power plants, observations revealed the presence of thermal crazing loading even if thermal fatigue is multiaxial. However, the first simulations on a uniaxial mechanicalA probabilistic model to predict the formation and propagation of crack networks in thermal fatigue

14

Thermal Conversion Process (TCP) Technology  

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

Changing World Technologies' Changing World Technologies' Thermal Conversion Process Commercial Demonstration Plant DOE/EA 1506 Weld County, Colorado December 2004 U.S. DEPARTMENT OF ENERGY GOLDEN FIELD OFFICE 1617 Cole Boulevard Golden, Colorado 80401 Thermal Conversion Process (TCP) Technology Commercial Demonstration - Weld County, CO TABLE OF CONTENTS Environmental Assessment Thermal Conversion Process (TCP) Technology Commercial Demonstration Project Weld County, Colorado SUMMARY............................................................................................................................. S-1 1.0 INTRODUCTION.........................................................................................................1-1 1.1. National Environmental Policy Act and Related Procedures...........................1-1

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

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

E-Print Network [OSTI]

and elasticity in multiphase materials is emphasized. The results for the constriction resistance are comparedThermal resistance of bridged cracks in fiber-reinforced ceramic composites John Dryden Department of Mechanical and Materials Engineering, The University of Western Ontario, London, Ontario, Canada, N6A 5B9

Zok, Frank

17

Continuous Processing of High Thermal Conductivity Polyethylene...  

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

Processing of High Thermal Conductivity Polyethylene Fibers and Sheets Continuous Processing of High Thermal Conductivity Polyethylene Fibers and Sheets Massachusetts Institute of...

18

Solar Thermal Process Heat | Open Energy Information  

Open Energy Info (EERE)

Solar Thermal Process Heat Incentives Retrieved from "http:en.openei.orgwindex.php?titleSolarThermalProcessHeat&oldid267198" Category: Articles with outstanding TODO tasks...

19

Effect of cracks on the thermal resistance of aligned fiber composites Department of Mechanical and Materials Engineering, University of Western Ontario, London,  

E-Print Network [OSTI]

Effect of cracks on the thermal resistance of aligned fiber composites J. Dryden Department are bridged by the fibers, and this crack- ing causes an increase in the longitudinal thermal resistance of the matrix and the fiber, respectively. The thermal resistance of a pristine unit cell is R0 L b2 kz . 4

Zok, Frank

20

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

SciTech Connect (OSTI)

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.

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

Note: This page contains sample records for the topic "thermal cracking process" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Thermal processing systems for TRU mixed waste  

SciTech Connect (OSTI)

This paper presents preliminary ex situ thermal processing system concepts and related processing considerations for remediation of transuranic (TRU)-contaminated wastes (TRUW) buried at the Radioactive Waste Management Complex (RWMC) of the Idaho National Engineering Laboratory (INEL). Anticipated waste stream components and problems are considered. Thermal processing conditions required to obtain a high-integrity, low-leachability glass/ceramic final waste form are considered. Five practical thermal process system designs are compared. Thermal processing of mixed waste and soils with essentially no presorting and using incineration followed by high temperature melting is recommended. Applied research and development necessary for demonstration is also recommended.

Eddy, T.L.; Raivo, B.D.; Anderson, G.L.

1992-01-01T23:59:59.000Z

22

Thermal processing systems for TRU mixed waste  

SciTech Connect (OSTI)

This paper presents preliminary ex situ thermal processing system concepts and related processing considerations for remediation of transuranic (TRU)-contaminated wastes (TRUW) buried at the Radioactive Waste Management Complex (RWMC) of the Idaho National Engineering Laboratory (INEL). Anticipated waste stream components and problems are considered. Thermal processing conditions required to obtain a high-integrity, low-leachability glass/ceramic final waste form are considered. Five practical thermal process system designs are compared. Thermal processing of mixed waste and soils with essentially no presorting and using incineration followed by high temperature melting is recommended. Applied research and development necessary for demonstration is also recommended.

Eddy, T.L.; Raivo, B.D.; Anderson, G.L.

1992-08-01T23:59:59.000Z

23

Thermally activated dislocation creep model for primary water stress corrosion cracking of NiCrFe alloys  

SciTech Connect (OSTI)

There is a growing awareness that awareness that environmentally assisted creep plays an important role in integranular stress corrosion cracking (IGSCC) of NiCrFe alloys in the primary coolant water environment of a pressurized water reactor (PWR). The expected creep mechanism is the thermally activated glide of dislocations. This mode of deformation is favored by the relatively low temperature of PWR operation combined with the large residual stresses that are most often identified as responsible for the SCC failure of plant components. Stress corrosion crack growth rate (CGR) equations that properly reflect the influence of this mechanism of crack tip deformation are required for accurate component life predictions. A phenomenological IGSCC-CGR model, which is based on an apriori assumption that the IGSCC-CGR is controlled by a low temperature dislocation creep mechanism, is developed in this report. Obstacles to dislocation creep include solute atoms such as carbon, which increase the lattice friction force, and forest dislocations, which can be introduced by cold prestrain. Dislocation creep also may be environmentally assisted due to hydrogen absorption at the crack tip. The IGSCC-CGR model developed here is based on an assumption that crack growth occurs by repeated fracture events occurring within an advancing crack-tip creep-fracture zone. Thermal activation parameters for stress corrosion cracking are obtained by fitting the CGR model to IGSCC-CGR data obtained on NiCrFe alloys, Alloy X-750 and Alloy 600. These IGSCC-CGR activation parameters are compared to activation parameters obtained from creep and stress relaxation tests. Recently reported CGR data, which exhibit an activation energy that depends on yield stress and the applied stress intensity factor, are used to benchmark the model. Finally, the effects of matrix carbon concentration, grain boundary carbides and absorbed hydrogen concentration are discussed within context of the model.

Hall, M.M., Jr

1995-12-31T23:59:59.000Z

24

Coupled Thermal-Hydrological-Mechanical Processes in Salt, Hot...  

Office of Environmental Management (EM)

Coupled Thermal-Hydrological-Mechanical Processes in Salt, Hot Granular Salt Consolidation, Constitutive Model and Micromechanics Coupled Thermal-Hydrological-Mechanical Processes...

25

Thermal behavior in the LENS process  

SciTech Connect (OSTI)

Direct laser metal deposition processing is a promising manufacturing technology which could significantly impact the length of time between initial concept and finished part. For adoption of this technology in the manufacturing environment, further understanding is required to ensure robust components with appropriate properties are routinely fabricated. This requires a complete understanding of the thermal history during part fabrication and control of this behavior. This paper will describe research to understand the thermal behavior for the Laser Engineered Net Shaping (LENS) process, where a component is fabricated by focusing a laser beam onto a substrate to create a molten pool in which powder particles are simultaneously injected to build each layer. The substrate is moved beneath the laser beam to deposit a thin cross section, thereby creating the desired geometry for each layer. After deposition of each layer, the powder delivery nozzle and focusing lens assembly is incremented in the positive Z-direction, thereby building a three dimensional component layer additively. It is important to control the thermal behavior to reproducibly fabricate parts. The ultimate intent is to monitor the thermal signatures and to incorporate sensors and feedback algorithms to control part fabrication. With appropriate control, the geometric properties (accuracy, surface finish, low warpage) as well as the materials` properties (e.g., strength, ductility) of a component can be dialed into the part through the fabrication parameters. Thermal monitoring techniques will be described, and their particular benefits highlighted. Preliminary details in correlating thermal behavior with processing results will be discussed.

Griffith, M.L.; Schlienger, M.E.; Harwell, L.D. [and others

1998-08-01T23:59:59.000Z

26

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

E-Print Network [OSTI]

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 ...

Hixon, Jeff

2006-01-01T23:59:59.000Z

27

Integrated two stage coking and steam cracking process and apparatus therefor  

SciTech Connect (OSTI)

The invention relates to an improvement in an integrated, two stage coking and steam cracking process for the production of unsaturated light hydrocarbons. A heavy hydrocarbonaceous oil is first coked in a fluidized bed coking zone. The vaporous conversion product is passed to a dilute phase. High temperature cracking in the presence of steam is carried out on the vaporous coker conversion product by injecting into the vapors a stream of hot coke particles at a sufficient temperature and in sufficient amount to raise the coker vapors to steam cracking temperature and supply the endothermic heat of reaction. Solids are separated from product gas in a gas-solids separation zone such as one or more cyclones and sent to the fluid coking zone and the gas is quenched to stop olefin degradation reactions. According to the improvement, relatively low temperature steam is introduced into contact with the separated solids to superheat the steam and cool the solids. Suitably this is effected in a riser on the cyclone dipleg. The solids, after having given up heat to the steam, pass into the coking zone and the superheated steam passes into the dilute phase and serves as part of the dilution steam therefor. Conservation of fuel and mitigation of coke on reactor walls and equipment are advantages of the process.

Oldweiler, M.E.

1983-10-25T23:59:59.000Z

28

Thermally activated low temperature creep and primary water stress corrosion cracking of NiCrFe alloys  

SciTech Connect (OSTI)

A phenomenological SCC-CGR model is developed based on an apriori assumption that the SCC-CGR is controlled by low temperature creep (LTC). This mode of low temperature time dependent deformation occurs at stress levels above the athermal flow stress by a dislocation glide mechanism that is thermally activated and may be environmentally assisted. The SCC-CGR model equations developed contain thermal activation parameters descriptive of the dislocation creep mechanism. Thermal activation parameters are obtained by fitting the CGR model to SCC-CGR data obtained on Alloy 600 and Alloy X-750. These SCC-CGR activation parameters are compared to LTC activation parameters obtained from stress relaxation tests. When the high concentration of hydrogen at the tip of an SCC crack is considered, the SCC-CGR activation energies and rate sensitivities are shown to be quantitatively consistent with hydrogen reducing the activation energy and increasing the strain rate sensitivity in LTC stress relaxation tests. Stress dependence of SCC-CGR activation energy consistent with that found for the LTC activation energy. Comparisons between temperature dependence of the SCC-CGR stress sensitivity and LTC stress sensitivity provide a basis for speculation on effects of hydrogen and solute carbon on SCC crack growth rates.

Hall, M.M. Jr.

1993-10-01T23:59:59.000Z

29

Continuous Processing of High Thermal Conductivity Fibers and...  

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

We are developing a continuous fabrication process for high thermal conductivity polyethylene (PE) films While high thermal conductivity in (PE) has been shown in isolated...

30

ENVIRONMENTALLY FRIENDLY PROCESSING OF POLYURETHANE FOAM FOR THERMAL INSULATION  

E-Print Network [OSTI]

ENVIRONMENTALLY FRIENDLY PROCESSING OF POLYURETHANE FOAM FOR THERMAL INSULATION CHANJOONG KIM was proposed and evaluated for the application of thermal insulation. For the production of polyurethane foam correspondence should be sent. #12;Key Words: Foam; Polyurethane; Thermal insulation; Nucleation; Growth

Kim, Chanjoong

31

Utilizing Solar Thermal Energy in Textile Processing Units  

Science Journals Connector (OSTI)

This chapter presents the prospects of solar thermal energy utilization in the textile processing units in Pakistan. Various solar thermal technologies suitable for thermal energy production and their application...

Asad Mahmood; Khanji Harijan

2012-01-01T23:59:59.000Z

32

The evolution of solid density within a thermal explosion II. Dynamic proton radiography of cracking and solid consumption by burning  

SciTech Connect (OSTI)

We report proton transmission images obtained subsequent to the laser assisted thermal ignition of a sample of PBX 9501 (a plastic bonded formulation of the explosive nitramine octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX)). We describe the laser assisted thermal ignition technique as a means to synchronize a non-linear thermal ignition event while preserving the subsequent post-ignition behavior. We have obtained dynamic proton transmission images at two spatial magnifications and viewed both the radial and transverse axis of a solid cylindrical sample encased in aluminum. Images have been obtained with 3 to 15 {mu}s temporal resolution and approximately 100 {mu}m spatial resolution at the higher magnification. We observe case expansion from very early in the experiment, until case fragmentation. We observe spatially anisotropic features in the transmission which we attribute to cracking in the solid explosive, in agreement with previous measurements conducted on two dimensional samples with optical viewing. Digital analysis of the images also reveals spatially isotropic features which we attribute to the evolution of the loss of density by burning subsequent to thermal ignition.

Smilowitz, L.; Henson, B. F.; Romero, J. J.; Asay, B. W.; Saunders, A.; Merrill, F. E.; Morris, C. L.; Kwiatkowski, K.; Grim, G.; Mariam, F.; Schwartz, C. L.; Hogan, G.; Nedrow, P.; Murray, M. M.; Thompson, T. N.; Espinoza, C.; Lewis, D.; Bainbridge, J.; McNeil, W.; Rightley, P. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); and others

2012-05-15T23:59:59.000Z

33

Scale control in thermal desalination processes  

SciTech Connect (OSTI)

Thermal desalination processes involve the heating of seawater to form water vapor which is then condensed to produce salt free water. Multiple Effect Evaporation (ME) and Multiple-Stage Flash distillation (MSF) are the two main processes used for thermal distillation. MSF distillation, currently is the dominant process. MSF distillation is run under pressure at relatively high temperatures (90--125 C). Scale formation is one of the most critical problems affecting both processes. In the case of MSF, calcium carbonate, magnesium hydroxide and calcium sulfate are the main scale forming salts. The first two scale forming salts are usually controlled by keeping neutral the pH of the system by the addition of acid. Scale inhibitors are used to prevent calcium sulfate scale. Because of economical reasons, the trend in the industry is to operate systems at as high a temperature and concentration factor as possible in order to increase purified water production at a lower cost. Safety concerns have also increased the need for acid feed elimination as a mean of controlling pH. These practices increased the scaling tendencies in MSF processes and created the need for more effective treatment programs to control scale formation on heat exchangers. A new multi-component inhibitor program that enable operation of MSF systems without the need of acid feed for pH control has been developed. The program prevent scale formation and allows to operate the system under typical or higher concentration factors and temperatures than normally found in MSF evaporators operating with acid feed.

Perez, L.A.; Polizzotti, D.M. [BetzDearborn, Trevose, PA (United States)

1999-11-01T23:59:59.000Z

34

Synthesis report on thermally driven coupled processes  

SciTech Connect (OSTI)

The main purpose of this report is to document observations and data on thermally coupled processes for conditions that are expected to occur within and around a repository at Yucca Mountain. Some attempt is made to summarize values of properties (e.g., thermal properties, hydrologic properties) that can be measured in the laboratory on intact samples of the rock matrix. Variation of these properties with temperature, or with conditions likely to be encountered at elevated temperature in the host rock, is of particular interest. However, the main emphasis of this report is on direct observation of thermally coupled processes at various scales. Direct phenomenological observations are vitally important in developing and testing conceptual models. If the mathematical implementation of a conceptual model predicts a consequence that is not observed, either (1) the parameters or the boundary conditions used in the calculation are incorrect or (2) the conceptual basis of the model does not fit the experiment; in either case, the model must be revised. For example, the effective continuum model that has been used in thermohydrology studies combines matrix and fracture flow in a way that is equivalent to an assumption that water is imbibed instantaneously from fractures into adjacent, partially saturated matrix. Based on this approximation, the continuum-flow response that is analogous to fracture flow will not occur until the effective continuum is almost completely saturated. This approximation is not entirely consistent with some of the experimental data presented in this report. This report documents laboratory work and field studies undertaken in FY96 and FY97 to investigate thermally coupled processes such as heat pipes and fracture-matrix coupling. In addition, relevant activities from past years, and work undertaken outside the Yucca Mountain project are summarized and discussed. Natural and artificial analogs are also discussed to provide a convenient source of material documenting the conceptual and mathematical basis for modeling coupled phenomena. The actual models and codes, and their specific empirical and theoretical bases, will be documented in a separate report to be delivered in FY99.

Hardin, E.L.

1997-10-15T23:59:59.000Z

35

Different process schemes for converting light straight run and fluid catalytic cracking naphthas in a FCC unit for maximum propylene production  

Science Journals Connector (OSTI)

Light straight run (LSR) and fluid catalytic cracking (FCCN) naphthas were cracked in a transported bed reactor (MicroDowner) and in a fixed bed reactor (MAT) over a commercial Y zeolite based catalyst, over a commercial ZSM-5 zeolite based additive, and over a mixture of both at selected conditions. Based on the mechanisms through which naphtha hydrocarbons are converted, we evaluated the best alternatives for processing these streams to produce light olefins and/or to reduce olefins content in commercial gasoline. The experimental set-up allowed us to simulate the cracking behaviour of the different naphtha streams in a fluid catalytic cracking (FCC) unit by different processing schemes. Results indicate that LSR only cracks at high severity, yielding large amounts of dry gas. Despite its high olefins content, FCCN practically does not crack when it is fed together with gas oil feed. When cracking FCCN alone at typical gas oil cracking conditions, olefins are transformed preferentially into naphtha-range isoparaffins and aromatics, and when cracking FCCN at high severity, olefins are transformed preferentially into propylene and butylenes. Finally, cracking naphtha in the stripper produces some propylene and increases the aromatics in the remaining gasoline.

Avelino Corma; FranciscoV Melo; Laurent Sauvanaud; F.J Ortega

2004-01-01T23:59:59.000Z

36

List of Solar Thermal Process Heat Incentives | Open Energy Information  

Open Energy Info (EERE)

Process Heat Incentives Process Heat Incentives Jump to: navigation, search The following contains the list of 204 Solar Thermal Process Heat Incentives. CSV (rows 1 - 204) Incentive Incentive Type Place Applicable Sector Eligible Technologies Active 30% Business Tax Credit for Solar (Vermont) Corporate Tax Credit Vermont Commercial Industrial Photovoltaics Solar Space Heat Solar Thermal Electric Solar Thermal Process Heat Solar Water Heat No APS - Renewable Energy Incentive Program (Arizona) Utility Rebate Program Arizona Commercial Residential Anaerobic Digestion Biomass Daylighting Geothermal Electric Ground Source Heat Pumps Landfill Gas Other Distributed Generation Technologies Photovoltaics Small Hydroelectric Solar Pool Heating Solar Space Heat Solar Thermal Process Heat

37

Continuous Processing of High Thermal Conductivity Polyethylene Fibers and Sheets  

Broader source: Energy.gov [DOE]

Project to develop and validate a continuous manufacturing process for polyethylene fibers and sheets yielding a thermal conductivity value greater than 60 W/m.K.

38

MODELING OF THERMALLY DRIVEN HYDROLOGICAL PROCESSES IN PARTIALLY  

E-Print Network [OSTI]

) incorporation of a full set of thermal-hydrological processes into a numerical simulator, (2) realistic AND BACKGROUND [2] The containment of spent fuel from nuclear power plants in a geological repositoryMODELING OF THERMALLY DRIVEN HYDROLOGICAL PROCESSES IN PARTIALLY SATURATED FRACTURED ROCK Y. W

Jellinek, Mark

39

Thermal processing system concepts and considerations for RWMC buried waste  

SciTech Connect (OSTI)

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.

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

1992-02-01T23:59:59.000Z

40

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

SciTech Connect (OSTI)

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.

Hai Huang; Ben Spencer; Jason Hales

2014-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "thermal cracking process" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Process and apparatus for thermal enhancement  

DOE Patents [OSTI]

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.

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

1984-06-26T23:59:59.000Z

42

THERMAL PROCESSING OF OIL SHALE/SANDS  

E-Print Network [OSTI]

)-based simulation tools to a modified in-situ process for production of oil from oil shale. The simulation tools

Michal Hradisky; Philip J. Smith; Doe Award; No. De-fe

2009-01-01T23:59:59.000Z

43

Thermal Analysis of Novel Underfill Materials with Optimum Processing Characteristics  

E-Print Network [OSTI]

Thermal Analysis of Novel Underfill Materials with Optimum Processing Characteristics Yang Liu,1 Yi evolution. Boron nitride, silica-coated alu- minum nitride, and alumina ceramic powders were used as fillers poly- merization. The effects of the filler type and composition on the thermal and mechanical

Harmon, Julie P.

44

Stress corrosion crack growth in porous sandstones.   

E-Print Network [OSTI]

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...

Ojala, Ira O

45

Fracture criterion for predicting surface cracking of Ti40 alloy in hot forming processes  

Science Journals Connector (OSTI)

Hot compression tests were conducted on Ti40 burn resistant titanium alloy in the temperature range of 900–1 100 °C and strain rate range of 0.01–10 s?1 to investigate its fracture behavior and critical fracture conditions in hot forming. It was observed that the failure of Ti40 alloy is attributed to longitudinal surface cracking due to severe oxidation of element V and the secondary tensile stresses. The critical fracture strain increases with increasing temperature and decreasing strain rate. From these observations and parallel FEM simulations, it was concluded that the critical fracture strain is a function of a single argument Zener-Hollomon parameter, and there is a linear relationship between them. An Oyane criterion successfully predicted the location of crack initiation. The critical fracture values also exhibit a liner relationship with lnZ. Based on these results, a new fracture criterion of Ti40 alloy based on Zener-Hollomon parameter was established.

Xue-min ZHANG; Wei-dong ZENG; Ying SHU; Yi-gang ZHOU; Yong-qing ZHAO; Huan WU; Han-qing YU

2009-01-01T23:59:59.000Z

46

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

SciTech Connect (OSTI)

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

Longzhou Ma

2012-11-30T23:59:59.000Z

47

Coupled Thermal-Hydrological-Mechanical Processes in Salt, Hot Granular  

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

Coupled Thermal-Hydrological-Mechanical Processes in Salt, Hot Coupled Thermal-Hydrological-Mechanical Processes in Salt, Hot Granular Salt Consolidation, Constitutive Model and Micromechanics Coupled Thermal-Hydrological-Mechanical Processes in Salt, Hot Granular Salt Consolidation, Constitutive Model and Micromechanics The report addresses granular salt reconsolidation from three vantage points: laboratory testing, modeling, and petrofabrics. The experimental data 1) provide greater insight and understanding into the role of elevated temperature and pressure regimes on physical properties of reconsolidated crushed salt, 2) can supplement an existing database used to develop a reconsolidation constitutive model and 3) provide data for model evaluation. The constitutive model accounts for the effects of moisture through pressure solution and dislocation creep, with both terms dependent

48

Coupled Thermal-Hydrological-Mechanical Processes in Salt, Hot Granular  

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

Coupled Thermal-Hydrological-Mechanical Processes in Salt, Hot Coupled Thermal-Hydrological-Mechanical Processes in Salt, Hot Granular Salt Consolidation, Constitutive Model and Micromechanics Coupled Thermal-Hydrological-Mechanical Processes in Salt, Hot Granular Salt Consolidation, Constitutive Model and Micromechanics The report addresses granular salt reconsolidation from three vantage points: laboratory testing, modeling, and petrofabrics. The experimental data 1) provide greater insight and understanding into the role of elevated temperature and pressure regimes on physical properties of reconsolidated crushed salt, 2) can supplement an existing database used to develop a reconsolidation constitutive model and 3) provide data for model evaluation. The constitutive model accounts for the effects of moisture through pressure solution and dislocation creep, with both terms dependent

49

Process for fabricating composite material having high thermal conductivity  

DOE Patents [OSTI]

A process 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.

Colella, Nicholas J. (Livermore, CA); Davidson, Howard L. (San Carlos, CA); Kerns, John A. (Livermore, CA); Makowiecki, Daniel M. (Livermore, CA)

2001-01-01T23:59:59.000Z

50

Process management using component thermal-hydraulic function classes  

DOE Patents [OSTI]

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.

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

1999-07-27T23:59:59.000Z

51

Process management using component thermal-hydraulic function classes  

DOE Patents [OSTI]

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.

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

1999-01-01T23:59:59.000Z

52

Thermal acidization and recovery process for recovering viscous petroleum  

DOE Patents [OSTI]

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.

Poston, Robert S. (Winter Park, FL)

1984-01-01T23:59:59.000Z

53

Method and apparatus for thermal processing of semiconductor substrates  

DOE Patents [OSTI]

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.

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

2002-01-01T23:59:59.000Z

54

Method and apparatus for thermal processing of semiconductor substrates  

DOE Patents [OSTI]

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.

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

55

Fracture mechanics and subcritical crack growth approach to model time-dependent failure in brittle rock.  

E-Print Network [OSTI]

??Subcritical crack growth (SCG) takes place when a crack is stressed below its short-term strength. This slow fracturing process may lead to an accelerating crack… (more)

Rinne, Mikael

2008-01-01T23:59:59.000Z

56

Materials Science and Engineering A 490 (2008) 2635 Mechanisms of cracking and delamination within thick thermal barrier  

E-Print Network [OSTI]

. Introduction The maximum temperature capability of thermal barrier systems used in gas turbines is often that characterizes the susceptibility to delamination of thermal barrier coated (TBC) hot-section aero-turbine and sub-surface delaminations, as well as spalls. Estimates of the residual stress gradients made on cross

Hutchinson, John W.

57

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

SciTech Connect (OSTI)

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.

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

1995-09-01T23:59:59.000Z

58

A new mineralogical approach to predict coefficient of thermal expansion of aggregate and concrete  

E-Print Network [OSTI]

the construction allows for accurate prediction of the potential thermal change on crack development and crack width and enhances the overall design process. Siliceous gravel use results in larger crack width than does the limestone and at low temperature... increment between the contacts to the flask volume, the amount of aggregate in the flask, and the thermal characteristics of the aggregate. For measurements made below the freezing point of water, a non-reactive liquid, such as toluene, which does...

Neekhra, Siddharth

2005-02-17T23:59:59.000Z

59

Supporting technology for enhanced oil recovery - EOR thermal processes  

SciTech Connect (OSTI)

This report contains the results of efforts under the six tasks of the Eighth Amendment and Extension of Annex IV, Enhanced Oil Recovery Thermal Processes of the Venezuela/USA Agreement. The report is presented in sections 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.

NONE

1995-03-01T23:59:59.000Z

60

Advanced Reactors Thermal Energy Transport for Process Industries  

SciTech Connect (OSTI)

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.

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

2014-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "thermal cracking process" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Thermal and membrane processe economics: Optimized selection for seawater desalination  

Science Journals Connector (OSTI)

While the fuel cost has increased in the past years, the desalinated water demand has also increased sharply, especially in the deserted areas. The challenge is to be able to meet such future demand, minimizing the water production costs. The desalination concepts have evolved, achieving substantial progress: desalination thermal process is moving from MSF to MED, hybrids involving both thermal and membrane process are more and more implemented. Reduction in cost and the improved economics of desalination plants are essential elements for the development of communities. Energy, capital, and operating costs are key issues of water desalination economics. This will lead to an optimized process selection on a case by case approach: the choice will depend on the specific conditions prevailing on site, such as existing facilities, power and water demand increase, land availability, raw water quality of water to be produced, ratio between power and water production, ratio between thermal and membrane desalination. The presentation will focus on these various aspects of seawater desalination economics.

Jacques Andrianne; Félix Alardin

2003-01-01T23:59:59.000Z

62

Wide-Area Thermal Processing of Light-Emitting Materials  

SciTech Connect (OSTI)

Silicon carbide based materials and devices have been successfully exploited for diverse electronic applications. However, they have not achieved the same success as Si technologies due to higher material cost and higher processing temperatures required for device development. Traditionally, SiC is not considered for optoelectronic applications because it has an indirect bandgap. However, AppliCote Associates, LLC has developed a laser-based doping process which enables light emission in SiC through the creation of embedded p-n junctions. AppliCote laser irradiation of silicon carbide allows two different interaction mechanisms: (1) Laser conversion or induced phase transformation which creates carbon rich regions that have conductive properties. These conductive regions are required for interconnection to the light emitting semiconducting region. (2) Laser doping which injects external dopant atoms into the substrate that introduces deep level transition states that emit light when electrically excited. The current collaboration with AppliCote has focused on the evaluation of ORNL's unique Pulse Thermal Processing (PTP) technique as a replacement for laser processing. Compared to laser processing, Pulse Thermal Processing can deliver similar energy intensities (20-50 kW/cm2) over a much larger area (up to 1,000 cm2) at a lower cost and much higher throughput. The main findings of our investigation; which are significant for the realization of SiC based optoelectronic devices, are as follows: (1) The PTP technique is effective in low thermal budget activation of dopants in SiC similar to the laser technique. The surface electrical conductivity of the SiC samples improved by about three orders of magnitude as a result of PTP processing which is significant for charge injection in the devices; (2) The surface composition of the SiC film can be modified by the PTP technique to create a carbon-rich surface (increased local C:Si ratio from 1:1 to 2.9:1). This is significant as higher thermal and electrical conductivities of the surface layer are critical for a successful development of integrated optoelectronic devices; and (3) PTP provides low thermal budget dopant activation with a controlled depth profile, which can be exploited for high performance device development with selective patterning of the substrate. This project has successfully demonstrated that a low thermal budget annealing technique, such as PTP, is critical to defining the path for low cost electronic devices integrated on glass or polymeric substrates. This project is complimentary to the goals of the Solid State Lighting Program within DOE. It involves new manufacturing techniques for light emitting materials that are potentially much lower cost and energy efficient than existing products. Significant opportunity exists for further exploration of AppliCote's material and device technology in combination with ORNL's PTP technique, modeling, and characterization capabilities.

Duty, C.; Quick, N. (AppliCote Associates, LLC) [AppliCote Associates, LLC

2011-09-30T23:59:59.000Z

63

Characterization of Fatigue Cracking and Healing of Asphalt Mixtures  

E-Print Network [OSTI]

Fatigue cracking is one of the most common distresses of asphalt pavements, whereas healing is a counter process to cracking which alleviates cracking damage and extends fatigue life of asphalt pavements. Most of existing methods to characterize...

Luo, Xue

2012-07-16T23:59:59.000Z

64

Analysis of Zinc 65 Contamination after Vacuum Thermal Process  

SciTech Connect (OSTI)

Radioactive contamination with a gamma energy emission consistent with {sup 65}Zn was detected in a glovebox following a vacuum thermal process. The contaminated components were removed from the glovebox and subjected to examination. Selected analytical techniques were used to determine the nature of the precursor material, i.e., oxide or metallic, the relative transferability of the deposit and its nature. The deposit was determined to be borne from natural zinc and was further determined to be deposited as a metallic material from vapor.

Korinko, Paul S.; Tosten, Michael H.

2013-01-01T23:59:59.000Z

65

Thermally stable booster explosive and process for manufacture  

DOE Patents [OSTI]

A thermally stable booster explosive and process for the manufacture of the explosive. The product explosive is 2,4,7,9-tetranitro-10H-benzo[4,5]furo[3,2-b]indole (TNBFI). A reactant/solvent such as n-methylpyrrolidone (NMP) or dimethyl formamide (DMF) is made slightly basic. The solution is heated to reduce the water content. The solution is cooled and hexanitrostilbene is added. The solution is heated to a predetermined temperature for a specific time period, cooled, and the product is collected by filtration.

Quinlin, William T. (Amarillo, TX); Thorpe, Raymond (Amarillo, TX); Lightfoot, James M. (Amarillo, TX)

2006-03-21T23:59:59.000Z

66

Method for thermal processing alumina-enriched spinel single crystals  

DOE Patents [OSTI]

A process for age-hardening alumina-rich magnesium aluminum spinel to obtain the desired combination of characteristics of hardness, clarity, flexural strength and toughness comprises selection of the time-temperature pair for isothermal heating followed by quenching. The time-temperature pair is selected from the region wherein the precipitate groups have the characteristics sought. The single crystal spinel is isothermally heated and will, if heated long enough pass from its single phase through two pre-precipitates and two metastable precipitates to a stable secondary phase precipitate within the spinel matrix. Quenching is done slowly at first to avoid thermal shock, then rapidly. 12 figs.

Jantzen, C.M.

1995-05-09T23:59:59.000Z

67

Crack propagation in hydrided zircaloy-2  

Science Journals Connector (OSTI)

Transmission electron microscope observations of cracks in thin foils of Zircaloy—2 which contains hydride particles have shown that the fracture process is one of linking up satellite cracks in the hydride ph...

G. Östberg

1968-06-01T23:59:59.000Z

68

Carbon Nanostructures As Thermal Interface Materials: Processing And Properties.  

E-Print Network [OSTI]

??The power density of electronic packages has substantially increased. The thermal interface resistance involves more than 50% of the total thermal resistance in current high-power… (more)

Memon, Muhammad Omar

2011-01-01T23:59:59.000Z

69

Combustion in cracks of PBX 9501  

SciTech Connect (OSTI)

Recent experiments involving the combustion of PBX 9501 explosive under confined conditions reveal the importance of crack and flaws in reaction violence. Experiments on room temperature confined disks of pristine and thermally damaged PBX 9501 reveal that crack ignition depends on hot gases entering existing or pressure induced cracks rather than on energy release at the crack tip. PBX 9501 slot combustion experiments show that the reaction propagation rate in the slot does not depend on the external pressure. We have observed 1500 d s in long slots of highly-confined PBX 9501. We present experiments that examine the combustion of mechanically and thermally damaged samples of PBX 9501.

Berghout, H. L. (Henry L.); Son, S. F. (Steven F.); Bolme, C. A. (Cynthia A.); Hill, L. G. (Larry G.); Asay, B. W. (Blaine W.); Dickson, P. M. (Peter M.); Henson, B. F. (Bryan F.); Smilowitz, L. B. (Laura B.)

2002-01-01T23:59:59.000Z

70

Subcritical crack growth in fibrous materials  

E-Print Network [OSTI]

We present experiments on the slow growth of a single crack in a fax paper sheet submitted to a constant force $F$. We find that statistically averaged crack growth curves can be described by only two parameters : the mean rupture time $\\tau$ and a characteristic growth length $\\zeta$. We propose a model based on a thermally activated rupture process that takes into account the microstructure of cellulose fibers. The model is able to reproduce the shape of the growth curve, the dependence of $\\zeta$ on $F$ as well as the effect of temperature on the rupture time $\\tau$. We find that the length scale at which rupture occurs in this model is consistently close to the diameter of cellulose microfibrils.

Santucci, Stéphane; Deschanel, Stéphanie; Vanel, Loic; Ciliberto, Sergio

2006-01-01T23:59:59.000Z

71

Cracking knuckles  

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

Cracking knuckles Cracking knuckles Name: Renee Knuckles Location: N/A Country: N/A Date: N/A Question: Does cracking your joints especially the knuckles cause arthritis? What are some of the results of doing so? Replies: Cracking knuckles has NEVER been associated with causing arthritis. This concept is as wrong as saying weight lifting makes you short, or playing basketball makes you tall. The "popping" of the knuckles results from forcing joint fluid to very rapidly pass from one side of the joint to the other, where the "sides" are partitioned off by the main bones of the joint. Let me rephrase that: a joint is an area where two or more separate and distinct bones meet. The joint fluid provides a cushioning between the joints so that they don't grate into each other. Cracking your knuckles forces the joint fluid from one part of the joint to another, and the popping sound is just the result of the high pressured rushing of fluid.

72

Advanced thermal processing alternatives for solid waste management  

SciTech Connect (OSTI)

The 1990`s have seen a resurgence of interest in the development of new thermal processing alternatives for municipal solid waste (MSW). Sparked by increasingly stringent environmental regulations, much of this creative energy has been applied to technologies for the gasification of MSW: converting the solid, hard to handle material into a clean, medium to high-Btu fuel gas. Other developers have focussed on full combustion technology but with a {open_quotes}twist{close_quotes} that lowers emissions or reduces cost. A comprehensive study of these new technologies was recently completed under the sponsorship of the National Renewable Energy Laboratory of the U.S. Department of Energy. The study characterized the state-of-the-art among emerging MSW thermal processing technologies that have reached the point of `incipient commercialization.` More than 45 technologies now under development were screened to develop a short list of seven processes that have passed through the idea stage, laboratory and benchscale testing, and have been prototyped at an MSW feed rate of at least several tons per hour. In-depth review of these seven included inspections of operating pilot or prototype units and a detailed analysis of technical, environmental and economic feasibility issues. No attempt was made to select `the best` technology since best can only be defined in the context of the constraints, aspirations and circumstances of a specific, local situation. The basic flowsheet, heat and material balances and available environmental data were summarized to help the reader grasp the underlying technical concepts and their embodiment in hardware. Remaining development needs, as seen by the study team are presented. Economic analysis shows the general balance of capital and operating costs.

Niessen, W.R. [Camp Dresser & McKee Inc., Cambridge, MA (United States)

1997-12-01T23:59:59.000Z

73

Integration of solar thermal energy into processes with heat demand  

Science Journals Connector (OSTI)

An integration of solar thermal energy can reduce the utility cost and the environmental impact. A proper integration of solar thermal energy is required in order to achieve ... objective of this study is to maxi...

Andreja Nemet; Zdravko Kravanja…

2012-06-01T23:59:59.000Z

74

Enhanced oil recovery: miscible flooding; thermal methods; and process implementation. Annual report, October 1, 1979-September 30, 1980  

SciTech Connect (OSTI)

The individual papers in this volume covering miscible flooding, thermal methods, and process implementation were indexed.

Linville, B. (ed.)

1980-01-01T23:59:59.000Z

75

On-line inspection and thermal properties comparison for laser deposition process .  

E-Print Network [OSTI]

??"This thesis is focused on comparing the laser deposition cladding with intended design model and comparing the effect of laser deposition process on thermal properties… (more)

Yang, Yu, 1973-

2007-01-01T23:59:59.000Z

76

Thermal diffusion processes in aqueous sodium chloride solutions  

SciTech Connect (OSTI)

The experimental results for the Soret coefficients are variable, but suggest a trend with NaCl concentration that is consistent with electrolyte solution behavior. The temperature dependence of the Soret coefficients is in approximate agreement with previous measurements obtained using other techniques. In general, the Soret coefficient values are best interpreted based on the expansion of the fluid inclusion migration fields. The high temperature values for {sigma} at 1.0 N NaCl concentration suggest an expansion of the migration field to smaller inclusion sizes, which for a single halite crystal at these conditions, approach a dimension of one micron. The corresponding fluid inclusion size for the polycrystalline material, where grain boundaries retard the migration, is approximately 10 microns. Although the Soret results obtained in the present study provide additional data for high temperature applications in nuclear waste isolation, more experimentation and new equipment design are required in order to obtain data at temperatures above 80{degree}C. The experimental approach utilized in this study is limited in that respect. The almost immeasurable nature of the thermal diffusion process for the brines as examined in the laboratory, suggests that this effect will be insignificant (outside of fluid inclusion migration) in most rock-water interactions associated with a rocksalt nuclear waste repository. Other effects, such as convective fluid transport, pressure solution, and groundwater flow, will be orders-of-magnitude more important in evaluating the critical nature of brine migration, waste canister corrosion, and the potential for leaching radioisotopes from waste repositories.

Cygan, R.T. [Sandia National Labs., Albuquerque, NM (United States); Jarrell, G.D. [ManTech Environmental Technology, Inc., Corvallis, OR (United States)

1992-08-18T23:59:59.000Z

77

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)

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.

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

1997-04-01T23:59:59.000Z

78

Early stages in the development of stress corrosion cracks  

SciTech Connect (OSTI)

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.

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

1993-12-01T23:59:59.000Z

79

Thermal Cracking of Higher Paraffins  

Science Journals Connector (OSTI)

The model was based on the Kossiakoff and Rice theory, that is, including the following five elementary reactions:? initiation, ... ...

H. H. Voge; G. M. Good

1949-02-01T23:59:59.000Z

80

Strain compensation in boron-indium coimplanted laser thermal processed silicon  

E-Print Network [OSTI]

Strain compensation in boron-indium coimplanted laser thermal processed silicon Mark H. Clarka Strain in B-implanted laser thermal processed LTP silicon is reduced by coimplantation of In. Strain in the codoped layer is calculated using lattice constants measured by high-resolution x-ray diffraction

Florida, University of

Note: This page contains sample records for the topic "thermal cracking process" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Corrigenda for Solar Engineering of Thermal Processes, Fourth Ed. J. A. Duffie and W. A. Beckman  

E-Print Network [OSTI]

Corrigenda for Solar Engineering of Thermal Processes, Fourth Ed. J. A. Duffie and W. A. Beckman 2 Last Eqn on page Second Ti should be Ti-1 #12;Corrigenda for Solar Engineering of Thermal Processes "radiation on" to "radiation at solar noon on" Second equation Change G to Gb + Gd Six lines from bottom

Wisconsin at Madison, University of

82

Representation of thermal energy in the design process  

E-Print Network [OSTI]

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. ...

Roth, Shaun

1995-01-01T23:59:59.000Z

83

Technical Letter Report - Analysis of Ultrasonic Data on Piping Cracks at Ignalina Nuclear Power Plant Before and After Applying a Mechanical Stress Improvement Process, JCN-N6319, Task 2  

SciTech Connect (OSTI)

Pacific Northwest National Laboratory (PNNL) is assisting the United States Nuclear Regulatory Commission (NRC) in developing a position on the management of primary water stress corrosion cracking (PWSCC) in piping systems previously analyzed for leak-before-break (LBB). Part of this work involves determining whether inspections alone are sufficient or if inspections plus mitigation techniques are needed. The work described in this report addresses the reliability of ultrasonic phased-array (PA) examinations for inspection of cracks that have been subjected to the mitigation method of mechanical stress improvement process (MSIP). It is believed that stresses imparted during MSIP may make ultrasonic crack responses in piping welds more difficult to detect and accurately characterize. To explore this issue, data were acquired, both before and after applying MSIP, and analyzed from cracked areas in piping at the Ignalina Nuclear Power Plant (INPP) in Lithuania. This work was performed under NRC Project JCN-N6319, PWSCC in Leak-Before-Break Systems.

Anderson, Michael T.; Cumblidge, Stephen E.; Crawford, Susan L.

2008-02-26T23:59:59.000Z

84

ZSM-5- and MgAl2O4-Based Bifunctional Additives for Enhancing the Production of Propene and Removal of SO2 in the Fluid Catalytic Cracking (FCC) Process  

Science Journals Connector (OSTI)

ZSM-5- and MgAl2O4-Based Bifunctional Additives for Enhancing the Production of Propene and Removal of SO2 in the Fluid Catalytic Cracking (FCC) Process† ... The effects of adding the bifunctional additives containing MgAl2O4 and the commercial propene additive ZSM-5/kaolin to the base catalyst in cracking of vacuum gas oil (VGO) were investigated. ... Those additives adsorb SOx and then transfer sulfur back into the riser, where it is released as H2S, which is removed in the usual way (Claus process). ...

Xiaoling Xu; Xiaoli Ran; Qiukai Cui; Chunyi Li; Honghong Shan

2010-01-26T23:59:59.000Z

85

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

SciTech Connect (OSTI)

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.

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

2013-10-15T23:59:59.000Z

86

Overview of the DOE studies of recovery boiler floor tube cracking  

SciTech Connect (OSTI)

Cracking of the stainless steel layer of coextruded 304L/SA210 recovery boiler floor tubes has been observed in an increasing number of black liquor recovery boilers. Because failure of such tubes is a serious safety concern as well as an economic issue, this project was initiated with the objective of identifying alternate materials or process changes that would prevent tube cracking. Tensile stresses are essential for the most likely failure mechanisms, i.e., fatigue or stress corrosion cracking, therefore stresses were measured at room temperature and modeling was used to predict stresses under operating conditions. Laboratory studies have identified conditions under which composite tubes crack due to thermal fatigue and stress corrosion. Floor tube temperature measurements have defined the magnitude and frequency of temperature fluctuations experienced by such tubes, and smelt corrosion studies have measured the degradation rate when molten smelt comes in contact with tubes. Based on these observations, certain materials appear more likely to resist cracking and certain process changes should help avoid conditions that cause composite tube cracking.

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

1998-03-01T23:59:59.000Z

87

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

E-Print Network [OSTI]

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

Paris-Sud XI, Université de

88

DETERMINATION OF THE UAV POSITION BY AUTOMATIC PROCESSING OF THERMAL IMAGES  

E-Print Network [OSTI]

DETERMINATION OF THE UAV POSITION BY AUTOMATIC PROCESSING OF THERMAL IMAGES Wilfried Hartmann.hartmann, sebastian.tilch, henri.eisenbeiss, konrad.schindler)@geod.baug.ethz.ch KEY WORDS: Thermal, UAV, Camera, Calibration, Bundle, Photogrammetry, GPS/INS ABSTRACT: If images acquired from Unmanned Aerial Vehicles (UAVs

Schindler, Konrad

89

Modeling Process Characteristics and Performance of Fixed and Fluidized Bed Regenerative Thermal Oxidizer  

Science Journals Connector (OSTI)

Modeling Process Characteristics and Performance of Fixed and Fluidized Bed Regenerative Thermal Oxidizer ... (7)?Cheng, W.-H.; Chou, M.-S.; Lee, W.-S.; Huang, B.-J. Applications of Low-Temperature Regenerative Thermal Oxidizers to Treat Volatile Organic Compounds. ...

Pietropaolo Morrone; Francesco P. Di Maio; Alberto Di Renzo; Mario Amelio

2006-05-26T23:59:59.000Z

90

Non-thermal Plasma Processing for Dilute VOCs Decomposition Combined with the Catalyst  

Science Journals Connector (OSTI)

Atmospheric pressure non-thermal plasma process combined with the new catalyst for...2...) named as the carbon balance. For better carbon balance, SED of the electric discharge is more than 90 J/L which is pretty...

Tetsuji Oda; Hikaru Kuramochi; Ryo Ono

2009-01-01T23:59:59.000Z

91

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

E-Print Network [OSTI]

1 Energy Efficient Process Heating: Insulation and Thermal Mass Kevin Carpenter and Kelly Kissock-0210 Phone: (937) 229-2852 Fax: (937) 229-4766 Email: Kelly.Kissock@notes.udayton.edu ABSTRACT Open tanks

Kissock, Kelly

92

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

E-Print Network [OSTI]

PROCESS DESIGN AND CONTROL Efficient Conversion of Thermal Energy into Hydrogen: Comparing Two. The performance of energy conversion processes can be evaluated using several types of efficiencies.2 Nowadays Gross,*, Ad Verkooijen, and Signe Kjelstrup, Department of Process & Energy, Delft Uni

Kjelstrup, Signe

93

Applications of the thermal DeNO{sub x} process to FBC boilers  

SciTech Connect (OSTI)

This paper presents graphical and tabular information on Exxon Research and Engineering Company`s proprietary NH{sub 3} based selective non-catalytic nitrogen oxides reduction process. The process is applicable to boilers, incinerators, and fired heaters. Process operating parameters, technology, and equipment are outlined. Thermal performance data and simplified flow diagrams are also presented.

McIntyre, A.D. [Exxon Research & Engineering Company, Florham Park, NJ (United States)

1997-12-31T23:59:59.000Z

94

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

Office of Environmental Management (EM)

Institute 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...

95

Processing and thermal properties of molecularly oriented polymers  

E-Print Network [OSTI]

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 ...

Skow, Erik (Erik Dean)

2007-01-01T23:59:59.000Z

96

Control of thermal processes in a fluidized bed combustor (FBC)  

SciTech Connect (OSTI)

Heat and mass balance equations for the transient process of a fluidized bed furnace are described. The equations involve heat release from char and volatiles combustion, heat consumption during moisture evaporation, and heating of char and circulating particles. Calculations and experimental data for steady-state and unsteady conditions are compared. The results show that the height of the dense bed, the excess-air ratio and kinetic features of the fuel affect the rate of the transient process. The time constant for a disturbance by a change of the air flow rate was found to be smaller than the one for a change of the fuel input.

Munts, V.A.; Filippovskij, N.F.; Baskakov, A.P.; Pavliok, E.J. [Ural State Technical Univ., Ekaterinburg (Russian Federation). Heat Power Dept.; Leckner, B. [Chalmers Univ. of Technology, Gothenburg (Sweden). Dept. of Energy Conversion

1997-12-31T23:59:59.000Z

97

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

E-Print Network [OSTI]

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

Connolly Jr, Harold C.

98

Nonlinear structural crack growth monitoring  

DOE Patents [OSTI]

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.

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

2002-01-01T23:59:59.000Z

99

Indirect thermal liquefaction process for producing liquid fuels from biomass  

SciTech Connect (OSTI)

A progress report on an indirect liquefaction process to convert biomass type materials to quality liquid hydrocarbon fuels by gasification followed by catalytic liquid fuels synthesis has been presented. A wide variety of feedstocks can be processed through the gasification system to a gas with a heating value of 500 + Btu/SCF. Some feedstocks are more attractive than others with regard to producing a high olefin content. This appears to be related to hydrocarbon content of the material. The H/sub 2//CO ratio can be manipulated over a wide range in the gasification system with steam addition. Some feedstocks require the aid of a water-gas shift catalyst while others appear to exhibit an auto-catalytic effect to achieve the conversion. H/sub 2/S content (beyond the gasification system wet scrubber) is negligible for the feedstocks surveyed. The water gas shift reaction appears to be enhanced with an increase in pyrolysis reactor temperature over the range of 1300 to 1700/sup 0/F. Reactor temperature in the Fischer-Tropsch step is a significant factor with regard to manipulating product composition analysis. The optimum temperature however will probably correspond to maximum conversion to liquid hydrocarbons in the C/sub 5/ - C/sub 17/ range. Continuing research includes integrated system performance assessment, alternative feedstock characterization (through gasification) and factor studies for gasification (e.g., catalyst usage, alternate heat transfer media, steam usage, recycle effects, residence time study) and liquefaction (e.g., improved catalysts, catalyst activity characterization).

Kuester, J.L.

1980-01-01T23:59:59.000Z

100

Cracking of Composite Modified Alloy 825 Primary Air Port Tubes  

SciTech Connect (OSTI)

Twenty primary air ports fabricated from modified Alloy 825-based composite tubes underwent a metallurgical examination to document the mode and extent of cracking on the external fireside surface of a kraft recovery boiler. Collectively, the crack features found are most consistent with thermal fatigue, but corrosion fatigue cannot be ruled out. Regardless of the true cracking mechanism, temperature cycling is implicated as a critical factor for crack propagation. on the basis of the relative crack lengths observed, membrane welds and tube weld repairs, and their adjacent heat-affected zones, appear to be more susceptible to cracking than the cladding itself. This work suggests that mills should avoid boiler operating conditions that promote large temperature fluctuations, which can cause Alloy 825-based composite tubes to crack.

Kish, Joseph R. [Paprican; Keiser, James R [ORNL; Singbeil, Douglas [Paprican; Willoughby, Adam W [ORNL; Longmire, Hu Foster [ORNL

2007-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "thermal cracking process" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Composite material having high thermal conductivity and process for fabricating same  

DOE Patents [OSTI]

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.

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

1998-07-21T23:59:59.000Z

102

Composite material having high thermal conductivity and process for fabricating same  

DOE Patents [OSTI]

A process 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.

Colella, Nicholas J. (Livermore, CA); Davidson, Howard L. (San Carlos, CA); Kerns, John A. (Livermore, CA); Makowiecki, Daniel M. (Livermore, CA)

1998-01-01T23:59:59.000Z

103

Thermal Systems Process and Components Laboratory (Fact Sheet), NREL (National Renewable Energy Laboratory), Energy Systems Integration Facility (ESIF)  

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

Systems Process and Systems Process and Components Laboratory may include: * CSP technology developers * Utilities * Certification laboratories * Government agencies * Universities * Other National laboratories Contact Us If you are interested in working with NREL's Thermal Systems Process and Components Laboratory, please contact: ESIF Manager Carolyn Elam Carolyn.Elam@nrel.gov 303-275-4311 Thermal Systems Process and Components Laboratory 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

104

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

DOE Patents [OSTI]

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.

Sheldon, Ray W. (Huntley, MT)

2001-01-01T23:59:59.000Z

105

Process efficiency in polymer extrusion: Correlation between the energy demand and melt thermal stability  

Science Journals Connector (OSTI)

Abstract Thermal stability is of major importance in polymer extrusion, where product quality is dependent upon the level of melt homogeneity achieved by the extruder screw. Extrusion is an energy intensive process and optimisation of process energy usage while maintaining melt stability is necessary in order to produce good quality product at low unit cost. Optimisation of process energy usage is timely as world energy prices have increased rapidly over the last few years. In the first part of this study, a general discussion was made on the efficiency of an extruder. Then, an attempt was made to explore correlations between melt thermal stability and energy demand in polymer extrusion under different process settings and screw geometries. A commodity grade of polystyrene was extruded using a highly instrumented single screw extruder, equipped with energy consumption and melt temperature field measurement. Moreover, the melt viscosity of the experimental material was observed by using an off-line rheometer. Results showed that specific energy demand of the extruder (i.e. energy for processing of unit mass of polymer) decreased with increasing throughput whilst fluctuation in energy demand also reduced. However, the relationship between melt temperature and extruder throughput was found to be complex, with temperature varying with radial position across the melt flow. Moreover, the melt thermal stability deteriorated as throughput was increased, meaning that a greater efficiency was achieved at the detriment of melt consistency. Extruder screw design also had a significant effect on the relationship between energy consumption and melt consistency. Overall, the relationship between the process energy demand and thermal stability seemed to be negatively correlated and also it was shown to be highly complex in nature. Moreover, the level of process understanding achieved here can help to inform selection of equipment and setting of operating conditions to optimise both energy and thermal efficiencies in parallel.

Chamil Abeykoon; Adrian L. Kelly; Javier Vera-Sorroche; Elaine C. Brown; Phil D. Coates; Jing Deng; Kang Li; Eileen Harkin-Jones; Mark Price

2014-01-01T23:59:59.000Z

106

3:2:1 Crack Spread  

Gasoline and Diesel Fuel Update (EIA)

:2:1 Crack Spread :2:1 Crack Spread Figure 1 Source: U.S. Energy Information Administration, based on Thomson Reuters. A crack spread measures the difference between the purchase price of crude oil and the selling price of finished products, such as gasoline and distillate fuel, that a refinery produces from the crude oil. Crack spreads are an indicator of the short-term profit margin of oil refineries because they compare the cost of the crude oil inputs to the wholesale, or spot, prices of the outputs (although they do not include other variable costs or any fixed costs). The 3:2:1 crack spread approximates the product yield at a typical U.S. refinery: for every three barrels of crude oil the refinery processes, it makes two barrels of gasoline and one barrel of distillate

107

Analysis of Dynamic Behavior of a Thermally Coupled Distillation Column Implemented on a Process with Recycles  

Science Journals Connector (OSTI)

Abstract Nowadays, the installation and operation of systems with minimum energy and material consumption is a main objective in the industrial ambit; this goal can be achieved through the implementation of recycle streams to recover raw materials and the use of energy integration techniques to minimize utilities requirements. However, when a process is highly integrated, e.g. processes with recycle streams and energy integration or thermal couplings, systems can present control problems. Several studies for Reactor-Separation-Recycle (RSR) systems using separation systems with conventional distillation columns have been reported, but few works have focused on energy-integrated columns or thermally coupled distillation sequences. This work presents a comparison between the dynamic behavior of a thermally coupled distillation column with side rectifier implemented within a RSR system and that obtained with a conventional distillation sequence.

D. Mascote-Pérez; A. Sánchez-Hijar; N. Ramírez-Corona; A. Jiménez-Gutierrez

2012-01-01T23:59:59.000Z

108

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

E-Print Network [OSTI]

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

Paris-Sud XI, Université de

109

Thermal Processing Techniques to Improve Metal Sulfide Mixed Alcohol Catalyst Performance  

SciTech Connect (OSTI)

Research over several decades by several institutions has shown that alkali-promoted metal sulfide catalysts are capable of producing mixed alcohols from syngas with high selectivity and yield. Unfortunately, process models suggest that syngas to mixed alcohol processes, and especially thermochemical biomass to mixed alcohol processes, require improvements to sulfide catalyst activity and/or selectivity for acceptable economics. These improvements, if incremental, cannot result in increased process complexity, capital expenditure, or catalyst costs. It is well accepted among catalyst researchers that thermal processing techniques like calcining and reduction can have profound effects on the properties and performance of finished catalysts, and that small variations in thermal processing do not usually affect the overall cost of the catalyst. Metal sulfide catalysts are no exception but surprisingly, little attention has been given to the effects of thermal treatment on bulk metal sulfide mixed alcohol catalysts. This presentation will discuss how parameters like temperature, dwell time, metal ratios, and purge gas affect the performance and physical properties of K-Co/Mo catalysts.

Hensley, J.; Menart, M.; Costelow, K.; Thibodeaux, J.; Yung, M.

2011-01-01T23:59:59.000Z

110

Enhanced oil recovery for thermal processes. First amendment and extension to Annex IV  

SciTech Connect (OSTI)

This report contains the result of efforts under the several tasks of the First Amendment and Extension of Annex IV, Enhanced Oil Recovery Thermal processes. The report is presented in six sections (for each of the six tasks) and each section contains one or more reports prepared by various individuals or groups describing the results of efforts under each one of the tasks. Each section has been abstracted and processed for inclusion in the Energy Data Base. A statement of each task, taken from the agreement, is presented on the first page of each section. The tasks are numbered 8-13. The first report on Annex IV, Venezuela-MEM/USE-DOE Fossil Energy Report IV-1, (DOE/BETC/SP-83/15), contains the results from the first seven tasks. That report is dated April 1983, entitled, EOR Thermal Processes.

Peterson, G.; Schwartz, E.

1984-08-01T23:59:59.000Z

111

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

Broader source: Energy.gov [DOE]

This technical brief is a guide to selecting high-temperature metallic materials for use in process heating applications such as burners, electrical heating elements, material handling, load support, and heater tubes, etc.

112

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

E-Print Network [OSTI]

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...

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

2013-01-01T23:59:59.000Z

113

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

SciTech Connect (OSTI)

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.

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

114

Elevated temperature crack propagation  

SciTech Connect (OSTI)

This paper is a summary of two NASA contracts on high temperature fatigue crack propagation in metals. The first evaluated the ability of fairly simple nonlinear fracture parameters to correlate crack propagation. Hastelloy-X specimens were tested under isothermal and thermomechanical cycling at temperatures up to 980 degrees C (1800 degrees F). The most successful correlating parameter was the crack tip opening displacement derived from the J-integral. The second evaluated the ability of several path-independent integrals to correlate crack propagation behavior. Inconel 718 specimens were tested under isothermal, thermomechanical, temperature gradient, and creep conditions at temperatures up to 650 degrees C (1200 degrees F). The integrals formulated by Blackburn and by Kishimoto correlated the data reasonably well under all test conditions.

Orange, T.W.

1994-02-01T23:59:59.000Z

115

Evaluation of cracking in steam generator feedwater piping in pressurized water reactor plants  

SciTech Connect (OSTI)

Cracking in feedwater piping was detected near the inlet to steam generators in 15 pressurized water reactor plants. Sections with cracks from nine plants are examined with the objective of identifying the cracking mechanism and assessing various factors that might contribute to this cracking. Using transmission electron microscopy, fatigue striations are observed on replicas of cleaned crack surfaces. Calculations based on the observed striation spacings gave a cyclic stress value of 150 MPa (22 ksi) for one of the major cracks. The direction of crack propagation was invariably related to the piping surface and not to the piping axis. These two factors are consistent with the proposed concept of thermally induced, cyclic, tensile surface stresses and it is concluded that the overriding factor in the cracking problem was the presence of such undocumented cyclic loads.

Goldberg, A.; Streit, R.D.

1981-05-01T23:59:59.000Z

116

A New Solar Carbon Capture Process: Solar Thermal Electrochemical Photo (STEP) Carbon Capture  

Science Journals Connector (OSTI)

A New Solar Carbon Capture Process: Solar Thermal Electrochemical Photo (STEP) Carbon Capture ... CO2 can be captured from 34% to over 50% solar energy efficiency (depending on the level of solar heat inclusion), as solid carbon and stored, or used as carbon monoxide to be available for a feedstock to synthesize (with STEP generated hydrogen) solar diesel fuel, synthetic jet fuel, or chemical production. ... STEP Iron, a Chemistry of Iron Formation without CO2 Emission: Molten Carbonate Solubility and Electrochemistry of Iron Ore Impurities ...

Stuart Licht; Baohui Wang; Susanta Ghosh; Hina Ayub; Dianlu Jiang; Jason Ganley

2010-07-14T23:59:59.000Z

117

Influence of embedded-carbon nanotubes on the thermal properties of copper matrix nanocomposites processed  

E-Print Network [OSTI]

-level mix- ing, exhibits CNTs homogeneously dispersed in the Cu matrix. Measured thermal conductivity: Metal matrix composites; Nanocomposite; Carbon and graphite; Thermal conductivity Carbon nanotubes (CNTs management applications, due to their extraordinarily low coefficient of thermal expan- sion (CTE) [1

Hong, Soon Hyung

118

PHYSICAL REVIEW E 84, 036104 (2011) Average crack-front velocity during subcritical fracture propagation in a heterogeneous medium  

E-Print Network [OSTI]

PHYSICAL REVIEW E 84, 036104 (2011) Average crack-front velocity during subcritical fracture]. In consequence the slow kinetic crack propagation is usually referred to as subcritical crack growth or the subcritical regime. Statistical physics models suggest that this subcritical regime is governed by a thermally

Schmittbuhl, Jean

119

ensl-00156750,version1-22Jun2007 A dynamical law for slow crack growth in polycarbonate films  

E-Print Network [OSTI]

that subcritical crack growth in paper sheets can be successfully described by a thermally activated mechanismensl-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

Paris-Sud XI, Université de

120

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

SciTech Connect (OSTI)

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.

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

Note: This page contains sample records for the topic "thermal cracking process" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Low resistive p-type GaN using two-step rapid thermal annealing processes  

Science Journals Connector (OSTI)

Two-step thermal annealing processes were investigated for electrical activation of magnesium- doped galliumnitride layers. The samples were studied by room-temperature Hall measurements and photoluminescence spectroscopy at 16 K. After an annealing process consisting of a short-term step at 960?°C followed by a 600?°C dwell step for 5 min a resistivity as low as 0.84 ??cm is achieved for the activated sample which improves the results achieved by standard annealing (800?°C for 10 min) by 25% in resistivity and 100% in free hole concentration.Photoluminescence shows a peak centered at 3.0 eV which is typical for Mg-doped samples with high free hole concentrations.

M. Scherer; V. Schwegler; M. Seyboth; C. Kirchner; M. Kamp; A. Pelzmann; M. Drechsler

2001-01-01T23:59:59.000Z

122

Corrosion-fatigue crack growth behavior of surface crack on AH36 TMCP steel weld in seawater  

SciTech Connect (OSTI)

Fatigue crack growth behavior in seawater of surface crack on the weld was studied with a structural steel, AH36, manufactured by the thermo-mechanical control process (TMCP). Crack growth rate was measured for the surface cracks located in different regions of weld, such as the heat affected zone, the weld metal and the base metal. Influence of the welding condition was investigated with the variation of heat inputs of 80, 120 and 180 kJ/cm. Electrochemical analysis of each region of the weld was also performed to investigate the corrosion behavior between the weld and the base metal.

Kweon, Y.G.; Jeong, H.D.; Chang, R.W. [Research Inst. of Industrial Science and Technology, Pohang (Korea, Republic of). Welding Research Center

1995-12-31T23:59:59.000Z

123

Modeling and Optimization of Direct Chill Casting to Reduce Ingot Cracking  

SciTech Connect (OSTI)

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

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

124

Crack propagation in Hastelloy X  

SciTech Connect (OSTI)

The fatigue and creep crack growth rates of Hastelloy X were examined both in air and impure helium. Creep crack growth rate is higher in air and impure helium at 650/sup 0/C. Initial creep crack growth from the original sharp fatigue crack is by an intergranular mode of fracture. As the cracking accelerates at higher stress intensities, growth is by a mixed mode of both intergranular and transgranular fracture. Fatigue crack growth rate increases with increasing temperature and decreasing frequency for the range of stress intensities reported in the literature and is lower in impure helium than in air.

Weerasooriya, T.; Strizak, J.P.

1980-05-01T23:59:59.000Z

125

Crack Fundamental Element (CFE) for Multi-scale Crack Classification  

Science Journals Connector (OSTI)

With the advance of sensor and information technology, high-resolution 2D image and 3D range data are available to support crack classification. However, crack classification still remains a challenge because sta...

Yuchun Huang; Yichang (James) Tsai

2012-01-01T23:59:59.000Z

126

Reflective Cracking Study: Summary Report  

E-Print Network [OSTI]

Cracking Study: First-level Report on Laboratory ShearStudy: Second-Level Analysis Report. Davis and Berkeley, CA:Cracking Study: First-level Report on HVS Testing on Section

Jones, David; Harvey, John T; Monismith, Carl L.

2008-01-01T23:59:59.000Z

127

Thermal Processing and Characterizations of Dye-Sensitized Solar Cells Based on Nanostructured TiO2  

Science Journals Connector (OSTI)

Thermal Processing and Characterizations of Dye-Sensitized Solar Cells Based on Nanostructured TiO2 ... This work reports an extensive study about the effects of thermal treatments on the performance of TiO2-based dye-sensitized solar cells. ... The current–voltage characteristics were measured using an Advantest R6243 current/voltage unit after a 10 min wait for achieving thermal equilibrium under AM 1.5G, simulated solar light of 100 mW cm–2 and irradiated from a WACOM super solar simulator. ...

Filippo Fabbri; Francesca Detto; Nicola Armani; Norifusa Satoh; Tullo Besagni; Maura Pavesi; Giancarlo Salviati

2013-01-04T23:59:59.000Z

128

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

SciTech Connect (OSTI)

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.

Not Available

1982-12-01T23:59:59.000Z

129

Eco Logic International gas-phase chemical reduction process: The thermal desorption unit. Applications analysis report. Final report  

SciTech Connect (OSTI)

The report details the Superfund Innovative Technology Evaluation of the Eco Logic International`s gas-phase chemical reduction process, with an emphasis on their thermal desorption unit. The Eco Logic process employs a high temperature reactor filled with hydrogen as a means to destroy chlorinated organic wastes. The process is designed around a reduction reaction, which reduces the organic wastes into a high-BTU gas product. The thermal desorption unit is designed to work in conjunction with the Eco Logic Reactor system. It is intended to process soils and sludges, desorbing the organic contaminants into a hydrogen gas stream for subsequent treatment and destruction within the Reactor System. The demonstration program was conducted at the Middleground Island Landfill in Bay City, Michigan during October to December, 1992. The report provides details of the test program, summaries of analytical tests conducted on a variety of process streams, process economics, and case study information.

Sudell, G.

1994-09-01T23:59:59.000Z

130

Thermophilic anaerobic digestion of thermal pretreated sludge: Role of microbial community structure and correlation with process performances  

Science Journals Connector (OSTI)

Abstract Thermal hydrolysis pretreatment coupled with Thermophilic Anaerobic Digestion (TAD) for Waste Activated Sludge (WAS) treatment is a promising combination to improve biodegradation kinetics during stabilization. However, to date there is a limited knowledge of the anaerobic biomass composition and its impact on TAD process performances. In this study, the structure and dynamics of the microbial communities selected in two semi-continuous anaerobic digesters, fed with untreated and thermal pretreated sludge, were investigated. The systems were operated for 250 days at different organic loading rate. 16S rRNA gene clonal analysis and Fluorescence In Situ Hybridization (FISH) analyses allowed us to identify the majority of bacterial and archaeal populations. Proteolytic Coprothermobacter spp. and hydrogenotrophic Methanothermobacter spp. living in strict syntrophic association were found to dominate in TAD process. The establishment of a syntrophic proteolytic pathway was favoured by the high temperature of the process and enhanced by the thermal pretreatment of the feeding sludge. Proteolytic activity, alone or with thermal pretreatment, occurred during TAD as proven by increasing concentration of soluble ammonia and soluble COD (sCOD) during the process. However, the availability of a readily biodegradable substrate due to pretreatment allowed to significant sCOD removals (more than 55%) corresponding to higher biogas production in the reactor fed with thermal pretreated sludge. Microbial population dynamics analysed by FISH showed that Coprothermobacter and Methanothermobacter immediately established a stable syntrophic association in the reactor fed with pretreated sludge in line with the overall improved TAD performances observed under these conditions.

M.C. Gagliano; C.M. Braguglia; A. Gianico; G. Mininni; K. Nakamura; S. Rossetti

2015-01-01T23:59:59.000Z

131

Analysis of composite tube cracking in recovery boiler floors  

SciTech Connect (OSTI)

Cracking of co-extruded (generally identified as composite) floor tubes in kraft black liquor recovery boilers was first observed in Scandinavia, but this problem has now been found in many North American boilers. In most cases, cracking in the outer 304L stainless steel has not progressed into the carbon steel, but the potential for such crack propagation is a cause of concern. A multidimensional study has been initiated to characterize the cracking seen in composite floor tubes, to measure the residual stresses resulting from composite tube fabrication, and to predict the stresses in tubes under operating conditions. The characterization studies include review of available reports and documents on composite tube cracking, metallographic examination of a substantial number of cracked tubes, and evaluation of the dislocation structure in cracked tubes. Neutron and X-ray diffraction are being used to determine the residual stresses in composite tubes from two major manufacturers, and finite element analysis is being used to predict the stresses in the tubes during normal operation and under conditions where thermal fluctuations occur.

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

1996-08-01T23:59:59.000Z

132

Automated Thermal Image Processing for Detection and Classification of Birds and Bats - FY2012 Annual Report  

SciTech Connect (OSTI)

Surveying wildlife at risk from offshore wind energy development is difficult and expensive. Infrared video can be used to record birds and bats that pass through the camera view, but it is also time consuming and expensive to review video and determine what was recorded. We proposed to conduct algorithm and software development to identify and to differentiate thermally detected targets of interest that would allow automated processing of thermal image data to enumerate birds, bats, and insects. During FY2012 we developed computer code within MATLAB to identify objects recorded in video and extract attribute information that describes the objects recorded. We tested the efficiency of track identification using observer-based counts of tracks within segments of sample video. We examined object attributes, modeled the effects of random variability on attributes, and produced data smoothing techniques to limit random variation within attribute data. We also began drafting and testing methodology to identify objects recorded on video. We also recorded approximately 10 hours of infrared video of various marine birds, passerine birds, and bats near the Pacific Northwest National Laboratory (PNNL) Marine Sciences Laboratory (MSL) at Sequim, Washington. A total of 6 hours of bird video was captured overlooking Sequim Bay over a series of weeks. An additional 2 hours of video of birds was also captured during two weeks overlooking Dungeness Bay within the Strait of Juan de Fuca. Bats and passerine birds (swallows) were also recorded at dusk on the MSL campus during nine evenings. An observer noted the identity of objects viewed through the camera concurrently with recording. These video files will provide the information necessary to produce and test software developed during FY2013. The annotation will also form the basis for creation of a method to reliably identify recorded objects.

Duberstein, Corey A.; Matzner, Shari; Cullinan, Valerie I.; Virden, Daniel J.; Myers, Joshua R.; Maxwell, Adam R.

2012-09-01T23:59:59.000Z

133

Fundamental heat transfer processes related to phase change thermal storage media  

SciTech Connect (OSTI)

Research on fundamental heat transfer processes which occur in phase-change thermal storage systems is described. The research encompasses both melting and freezing, and includes both experiment and analysis. The status of four research problems is discussed. One of the freezing problems was focused on investigating, via experiment, the extent to which freezing can be enhanced by the attachment of fins to the external surface of a cooled vertical tube situated in a liquid phase-change medium. Very substantial enhancements were encountered which neutralize the degradation of freezing due to the thermal resistance of the frozen layer and to natural convection in the liquid phase. The second of the freezing problems was analytical in nature and sought to obtain solutions involving both the phase-change medium and the heat transfer fluid used either to add heat to or extract heat from the medium. For freezing on a plane wall, it was possible to obtain a closed-form analytical solution, while for freezing about a coolant-carrying circular tube, a new numerical methodology was devised to obtain finite-difference solutions. For melting, quantitative design-quality heat transfer coefficients were determined experimentally for melting adjacent to a heated vertical tube. These experiments explored the effects of solid-phase subcooling and of open versus closed top containment on the coefficients. A dimensionless correlation enables these results to be used for a wide range of phase-change media. Studies on melting of a phase-change material situated within a circular tube are in progress.

Sparrow, E. M.; Ramsey, J. W.

1981-01-01T23:59:59.000Z

134

Energy Recovery System for Fluid Catalytic Cracking Units  

E-Print Network [OSTI]

This paper describes the power and heat recovery processes and equipment for modern fluid catalytic cracking (FCC) units made possible by improvements in catalyst fines removal technology and the availability of erosion resistant high temperature...

Wen, H.; Lou, S. C.

1982-01-01T23:59:59.000Z

135

Modeling of crack initiation, propagation and coalescence in rocks  

E-Print Network [OSTI]

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 ...

Gonçalves da Silva, Bruno Miguel

2009-01-01T23:59:59.000Z

136

CIRCUMFERENTIAL MFL IN-LINE INSPECTION FOR CRACKS IN PIPELINES  

SciTech Connect (OSTI)

Circumferential MFL is a new implementation of a widely used technology that has potential to provide improved detection and quantification of axially oriented defects such as cracks, seam weld defects, mechanical damage, and groove corrosion. This implementation works by orienting the magnetic field around the pipe rather that along the axis. By orienting the magnetic field around the pipe (the circumferential direction), the axial defects that were magnetically transparent can disrupt more of the magnetic field and can be more easily detected. Initial implementations of circumferential MFL have found that flux leakage from cracks at the interior of the pipe is small, and the signals from cracks are difficult to detect. The objective of this project is to improve detection of cracks by changing the implementation along with using data from overlapping and complementary inspection techniques. Two technology enhancements were investigated: Combining high- and low-magnetization technology for stress detection; and Combining axial and circumferential MFL methods. Although a method combining high- and low-magnetization technology showed promise for characterizing gouges cause by third party excavation equipment, its commercial development was not successful for two reasons. First, the stress diminishes the crack signal, while the opening of the crack increases the signal. The stress-induced changes in flux leakage around cracks were small and any critical information on the severity of cracks and crack-like defects is difficult to distinguish from changes caused by the crack opening and other inspection variables. Second, it is difficult to magnetize pipe material in the circumferential direction. A relatively low, non-uniform magnetization level produced by the circumferential magnetizer makes detection of changes due to stress extremely difficult. This project also examined combining axial and circumferential MFL to improve crack detection and distinguish cracks for axially oriented volumetric defects. While successful results are presented in this report, circumferential MFL can only detect larger cracks. Even with the field aligned properly, circumferential MFL technology has difficulty detecting cracks on the outside surface that have the potential to grow to failure. Circumferential MFL can be used to detect many corrosion, mechanical damage, and crack defects. However, the detection capabilities and sizing accuracies may not be sufficient for all pipeline threats. Inspection tools that use more sophisticated technologies for detecting and sizing defects may have better performance capabilities, but will likely be expensive to operate. Circumferential MFL will be useful in identifying locations for detailed testing. While performance enhancements may be limited, circumferential MFL inspections will be part of the inspection process for many decades.

J.B. Nestleroth

2003-06-01T23:59:59.000Z

137

Analysis of Fatigue Crack Growth under Random Load Sequences Derived from Military In-flight Load Data  

Science Journals Connector (OSTI)

The crack growth process of a crack initiating at a hole of a skin-stringer panel in a fighter aircraft subjected to random variable amplitude loading is investigated in this paper. The generation of synthetic...

C. Mattrand; J. -M. Bourinet; D. Théret

2011-01-01T23:59:59.000Z

138

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

SciTech Connect (OSTI)

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.

Izequeido, Alexandor

2001-04-01T23:59:59.000Z

139

11 - Stresses due to Change of Air Temperature and Superficial Thermal Insulation  

Science Journals Connector (OSTI)

Experience shows that most cracks in mass concrete structures are originally superficial cracks, but some of them may become larger and deeper cracks later on which will reduce the safety and durability of the structure. Thermal insulation is the most efficient measure for preventing superficial cracks of mass concrete structures.

Zhu Bofang

2014-01-01T23:59:59.000Z

140

Characterization of penetration induced thermal runaway propagation process within a large format lithium ion battery module  

Science Journals Connector (OSTI)

Abstract This paper investigates the mechanisms of penetration induced thermal runaway (TR) propagation process within a large format lithium ion battery pack. A 6-battery module is built with 47 thermocouples installed at critical positions to record the temperature profiles. The first battery of the module is penetrated to trigger a TR propagation process. The temperature responses, the voltage responses and the heat transfer through different paths are analyzed and discussed to characterize the underlying physical behavior. The temperature responses show that: 1) Compared with the results of TR tests using accelerating rate calorimetry (ARC) with uniform heating, a lower onset temperature and a shorter TR triggering time are observed in a penetration induced TR propagation test due to side heating. 2) The maximum temperature difference within a battery can be as high as 791.8 °C in a penetration induced TR propagation test. The voltage responses have a 5-stage feature, indicating that the TR happens in sequence for the two pouch cells packed inside a battery. The heat transfer analysis shows that: 1) 12% of the total heat released in TR of a battery is enough to trigger the adjacent battery to TR. 2) The heat transferred through the pole connector is only about 1/10 of that through the battery shell. 3) The fire has little influence on the TR propagation, but may cause significant damage on the accessories located above the battery. The results can enhance our understandings of the mechanisms of TR propagation, and provide important guidelines in pack design for large format lithium ion battery.

Xuning Feng; Jing Sun; Minggao Ouyang; Fang Wang; Xiangming He; Languang Lu; Huei Peng

2015-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "thermal cracking process" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Modeling of interaction between corrosion-induced concrete cover crack and steel corrosion rate.  

E-Print Network [OSTI]

??Chloride-induced corrosion of steel reinforcement in concrete may cause severe damage to RC structures. Longitudinal cover cracks may form during the rust expansion process. Currently,… (more)

Cao, Chong

2012-01-01T23:59:59.000Z

142

Crack-resistant siloxane molding compounds. [Patent application  

DOE Patents [OSTI]

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.

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

1980-11-03T23:59:59.000Z

143

The Application of Reliability-Based Design Factors In Stress Corrosion Cracking Evaluations  

SciTech Connect (OSTI)

First-order reliability methodology (FORM) is used to develop reliability-based design factors for deterministic analyses of stress corrosion cracking. The basic elements of FORM as applied to structural reliability problems are reviewed and then employed specifically to stress corrosion cracking evaluations. Failure due to stress corrosion cracking is defined as crack initiation followed by crack growth to a critical depth. The stress corrosion cracking process is thus represented in terms of a crack initiation time model and a crack growth rate model, with the crack growth rate integrated from the initiation time to the time at which the crack grows to its critical depth. Both models are described by log-normal statistical distribution functions. A procedure is developed to evaluate design factors that are applied to the mean values of the crack initiation time and the crack growth rate for specified temperature and stress conditions. The design factors, which depend on the standard deviations of the statistical distributions, are related to a target reliability, which is inversely related to an acceptable probability of failure. The design factors are not fixed, but are evaluated on a case-to-case basis for each application. The use of these design factors in a deterministic analysis assures that the target reliability will be attained and the corresponding acceptable probability of failure will not be exceeded. An example problem illustrates use of this procedure.

E. Friedman

2001-12-20T23:59:59.000Z

144

Status Report on Studies of Recovery Boiler Composite Floor Tube Cracking  

SciTech Connect (OSTI)

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.

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

145

Insights into Stress Corrosion Cracking Mechanisms from High-Resolution Measurements of Crack-Tip Structures and Compositions  

SciTech Connect (OSTI)

The fundamental basis for mechanistic understanding and modeling of SCC remains in question for many systems. Specific mechanisms controlling SCC can vary with changes in alloy characteristics, applied/residual stress or environmental conditions. The local crack electrochemistry, crack-tip mechanics and material metallurgy are the main factors controlling crack growth. These localized properties are difficult or impossible to measure in active cracks. Nevertheless, it is essential to quantitatively interrogate these crack-tip conditions if mechanistic understanding is to be obtained. A major recent advance has been the ability to investigate SCC cracks and crack tips using high-resolution ATEM techniques. ATEM enables the characterization of SCC cracks including trapped tip solution chemistries, corrosion product/film compositions and structures, and elemental composition gradients and defect microstructures along the crack walls and at the crack tip. A wide variety of methods for imaging and analyses at resolutions down to the atomic level can be used to examine the crack and corrosion film characteristics. Surface films and reaction layers have been examined by cross-sectional TEM techniques, but little work had been conducted on environmentally induced internal cracks until that of Lewis and co-workers [1-3] and the current authors [4-17]. This capability combined with modern ATEM techniques has enabled exciting new insights into corrosion processes occurring at buried interfaces and is being used to identify mechanisms controlling IGSCC in boiling water reactor (BWR) and pressurized water reactor (PWR) components. The objective of this paper is to summarize certain results focused on IGSCC of Fe- base and Ni-base stainless alloys in high-temperature water environments. Representative crack-tip examples will be shown to illustrate specific aspects that are characteristic of SCC in the material/environment combinations. Differences and similarities in crack-tip structures- chemistries will be highlighted comparing Fe-base 316/304SS to Ni-base alloy 600/182 and for tests in oxidizing versus hydrogenated water environments.

Bruemmer, Stephen M.; Thomas, Larry E.

2010-04-05T23:59:59.000Z

146

THERMAL ANALYSIS FOR IN-TANK ION-EXCHANGE COLUMN PROCESS  

SciTech Connect (OSTI)

High Level Waste (HLW) at the Savannah River Site (SRS) is stored in three forms: sludge, saltcake, and supernate. A small column ion-exchange (SCIX) process is being designed to treat dissolved saltcake waste before feeding it to the saltstone facility to be made into grout. The waste is caustic with high concentrations of various sodium salts and lower concentrations of radionuclides. Two cation exchange media being considered are a granular form of crystalline silicotitanate (CST) and a spherical form of resorcinol-formaldehyde (RF) resin. CST is an inorganic material highly selective for cesium that is not elutable. Through this process, radioactive cesium from the salt solution is absorbed into ion exchange media (either CST or RF) which is packed within a flow-through column. A packed column loaded with radioactive cesium generates significant heat from radiolytic decay. If engineering designs cannot handle this thermal load, hot spots may develop locally which could degrade the performance of the ion-exchange media. Performance degradation with regard to cesium removal has been observed between 50 and 80 C for CST [1] and at 65 C for RF resin [2]. In addition, the waste supernate solution will boil around 130 C. If the columns boiled dry, the sorbent material could plug the column and lead to replacement of the entire column module. Alternatively, for organic resins such as RF there is risk of fire at elevated temperatures. The objective of the work is to compute temperature distributions across CST- and RF-packed columns immersed in waste supernate under accident scenarios involving loss of salt solution flow through the beds and, in some cases, loss of coolant system flow. For some cases, temperature distributions are determined as a function of time after the initiation of a given accident scenario and in other cases only the final steady-state temperature distributions are calculated. In general, calculations are conducted to ensure conservative and bounding results for the maximum temperatures achievable using the current baseline column design. This information will assist in SCIX design and facility maintenance.

Lee, S; Frank02 Smith, F

2009-01-05T23:59:59.000Z

147

Structures for dense, crack free thin films  

DOE Patents [OSTI]

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.

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

2011-03-08T23:59:59.000Z

148

Experimental study of slider–disk interaction process with thermal-flying-height controlled slider  

Science Journals Connector (OSTI)

Thermal flying height (TFC) controlled slider has been introduced in hard disk drive recently. Flying height at the read/write elements of ... protrusion. Interactions between the TFC slider and disk can be very ...

Yansheng Ma; Bo Liu

2011-06-01T23:59:59.000Z

149

Analysis of particle behavior in High-Velocity Oxy-Fuel thermal spraying process  

Science Journals Connector (OSTI)

This paper analyzes the behavior of coating particle as well as the gas flow both of inside and outside the High-Velocity Oxy-Fuel (HVOF) thermal spraying gun by using quasi-one-dimensional analysis and numerical...

Hiroshi Katanoda; Kazuyasu Matsuo

2003-08-01T23:59:59.000Z

150

Solar-Thermal Processing of Methane to Produce Hydrogen and Syngas  

Science Journals Connector (OSTI)

A solar-thermal aerosol flow reactor has been constructed, installed, and tested with the High-Flux Solar Furnace (HFSF) at the National Renewable Energy Laboratory (NREL). Experiments were successfully carried out for the dissociation of methane to ...

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

2001-07-27T23:59:59.000Z

151

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

E-Print Network [OSTI]

discharges can be made more economically attrac tank holding several thousand gallons of water tive by incorporating thermal energy storage in a maintained at 128-130?F. This scald tank is con heat recovery system. Thermal energy storage can stantly... the ultimate energy end use. of wasting this hot water to the plant drain, a heat A project conducted by the Georgia Tech exchanger was installed at the Gold Kist plant to Engineering Experiment Station to demonstrate preheat scald tank makeup water...

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

1980-01-01T23:59:59.000Z

152

Modeling the thermal-hydrologic processes in a large-scale underground heater test in partially saturated fractured tuff  

SciTech Connect (OSTI)

The Drift Scale Test (DST) is being conducted in an underground facility at Yucca Mountain, Nevada, to probe the coupled thermal, hydrological, mechanical, and chemical processes likely to occur in the fractured rock mass around a potential high-level nuclear waste repository. Thermal-hydrological processes in the DST have been simulated using a three-dimensional numerical model. The model incorporates the realistic test configuration and all available site-specific measurements pertaining to the thermal and hydrological properties of the unsaturated fractured tuff of the test block. The modeled predictions were compared to the extensive set of measured data collected in the first year of this 8-year-long test. The mean error between the predictions and measurement at 12 months of heating for over 1600 temperature sensors is about 2 degrees C. Heat-pipe signature in the temperature data, indicating two-phase regions of liquid-vapor counterflow, is seen in both the measurements and simulated results. The redistribution of moisture content in the rock mass (resulting from vaporization and condensation) was probed by periodic air-injection testing and geophysical measurements. Good agreement also occurred between the model predictions and these measurements. The general agreement between predictions from the numerical simulations and the measurements of the thermal test indicates that our fundamental understanding of the coupled thermal-hydrologic processes at Yucca Mountain is sound. However, effects of spatial heterogeneity from discrete fractures that are observed in the temperature data are not matched by simulations from the numerical model, which treat the densely spaced fractures as a continuum.

Birkholzer, J.T.; Tsang, Y.W.

1999-06-24T23:59:59.000Z

153

Enhanced-oil-recovery thermal processes, annex IV. Venezuela-MEM/USA-DOE fossil-energy report IV-1  

SciTech Connect (OSTI)

The Agreement between the United States and Venezuela was designed to further energy research and development in six areas. This report focuses on Annex IV - Enhanced-Oil-Recovery Thermal Processes which was divided into seven tasks. This report will discuss the information developed within Task I related to the Department of Energy providing data on the performance of insulated oil-well tubulars. Surface generated steam has been traditionally used in thermal enhanced oil recovery processes. In past years the tubing through which the steam is injected into the reservoir has been bare with relatively high heat losses. In recent years however various materials and designs for insulating the tubing to reduce heat losses have been developed. Evaluation of several of these designs in an instrumented test tower and in an oil field test environment was undertaken. These tests and the resulting data are presented.

Peterson, G.; Schwartz, E.

1983-04-01T23:59:59.000Z

154

Iron(III) Oxides from Thermal ProcessesSynthesis, Structural and Magnetic Properties, Mössbauer Spectroscopy Characterization, and Applications  

Science Journals Connector (OSTI)

Structural and magnetic properties, methods of synthesis, and applications of seven iron(III) oxide polymorphs, including rare beta, epsilon, amorphous, and high-pressure forms, are reviewed. ... Their discoveries as well as the majority of formation processes are connected with thermal transformations of iron-bearing materials in an oxidizing atmosphere. ... Iron(III) oxide in all its forms is one of the most used metal oxides with various applications in many scientific and industrial fields. ...

Radek Zboril; Miroslav Mashlan; Dimitris Petridis

2002-02-28T23:59:59.000Z

155

Determination of Thermal Contact Conductance of Metal Tabs for Battery Ultrasonic Welding Process  

SciTech Connect (OSTI)

A new experimental apparatus and data analysis algorithm were used to determine the thermal contact conductance between 0.2-mm-thick pure aluminum battery tabs as a function of contact pressure from 3.6 to 14.4 MPa. Specimens were sandwiched between one optically transparent and one infrared (IR) transparent glass windows, and heated up from one side by an intense short pulse of flash light. The temperature transient on the other side was measured by an IR camera. In order to determine the thermal contact conductance, two experiment configurations having different number of Al specimen layers were used. Numerical heat conduction simulations showed that the thermal contact conductance strongly depended on the ratio of the maximum temperature rise between the two configurations. Moreover, this ratio was not sensitive to the uncertainties of other thermal properties. Through the simulation results, a simple correlation between the gap conductance and the ratio was established. Therefore, once the ratio of the temperature rise between two configurations was experimentally measured, the thermal contact conductance could be readily determined from the correlation. The new method was fast and robust. Most importantly, the data analysis algorithm improved the measurement accuracy by considerably reducing the uncertainties associated with the thermophysical properties of materials and measurement system.

Chen, Jian [ORNL] [ORNL; Zhang, Wei [ORNL] [ORNL; Yu, Zhenzhen [ORNL] [ORNL; Feng, Zhili [ORNL] [ORNL

2012-01-01T23:59:59.000Z

156

Fluid catalytic cracking of heavy petroleum fractions  

SciTech Connect (OSTI)

A process is claimed for fluid catalytic cracking of residuum and other heavy oils comprising of gas oil, petroleum residue, reduced and whole crudes and shale oil to produce gasoline and other liquid products which are separated in various streams in a fractionator and associated vapor recovery equipment. The heat from combustion of coke on the coked catalyst is removed by reacting sulfur-containing coke deposits with steam and oxygen in a separate stripper-gasifier to produce a low btu gas stream comprising of sulfur compounds, methane, carbon monoxide, hydrogen, and carbon dioxide at a temperature of from about 1100/sup 0/F. To about 2200/sup 0/F. The partially regenerated catalyst then undergoes complete carbon removal in a regeneration vessel. The regenerated catalyst is recycled for re-use in the cracking of heavy petroleum fractions. The liquid products are gasoline, distillates, heavy fuel oil, and light hydrocarbons.

McHenry, K.W.

1981-06-30T23:59:59.000Z

157

The effects of stress and fluid pressure on the anisotropy of interconnected cracks  

Science Journals Connector (OSTI)

......compressive stress, as it hinders the process of crack closure (Fig. 1a). Crack...decreasing the anisotropy. These two competing processes explain the rise in the anisotropy parameters...effective pressure, in 70th Ann. Int. Mtg SEG, Exp. Abs., pp. 1826-1829....

S. R. Tod

2002-04-01T23:59:59.000Z

158

Description of Thermal and Micro-Structural Processes in Generalized Continua: Zhilin's  

E-Print Network [OSTI]

and its Modifications Elena Ivanova and Elena Vilchevskaya Abstract The method of description of thermal, Russia e-mail: elenaivanova239@post.ru E. Vilchevskaya Institute for Problems in Mechanical Engineering transitions and structural transformations, plastic flow, dynamics of bulk solids, dynamics of granular media

Ivanova, Elena A.

159

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

E-Print Network [OSTI]

device in order to meet the utility's mandate. The first part of this study looks at the effects of adding propylene glycol to a static-water ice thermal storage tank, in the pursuit of increasing storage capacity. The effects of glycol addition...

Abraham, Michaela Marie

1993-01-01T23:59:59.000Z

160

A Low-Temperature Thermal Process for the Decomposition of Water  

Science Journals Connector (OSTI)

...indeed to become the energy carrier of the future...primary heat or solar energy into electricity would...and potentially even converters of solar to thermal energy. We present here a...the top layer of the ocean to meteorological events...

Bernard M. Abraham; Felix Schreiner

1973-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "thermal cracking process" from the National Library of EnergyBeta (NLEBeta).
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161

Analysis of cracking of co-extruded recovery boiler floor tubes  

SciTech Connect (OSTI)

Cracking of the stainless steel layer in co-extruded 304L/SA210 tubing used in black liquor recovery boilers is being found in an ever-increasing number of North American pulp and paper mills. Because of the possibility of a tube failure, this is a significant safety issue, and, because of the extra time required for tube inspection and repair, this can become an economic issue as well. In a project funded by the U.S. Department of Energy and given wide support among paper companies, boiler manufacturers, and tube fabricators, studies are being conducted to determine the cause of the cracking and to identify alternate materials and/or operating procedures to prevent tube cracking. Examination of cracked tubes has permitted characterization of crack features, and transmission electron microscopy is providing information about the thermal history, particularly cyclic thermal exposures, that tubes have experienced. Neutron and x-ray diffraction techniques are being used to determine the residual stresses in as-fabricated tube panels and exposed tubes, and finite element modeling is providing information about the stresses the tubes experience during operation. Laboratory studies are being conducted to determine the susceptibility of the co-extruded 304L/SA210 tubes to stress corrosion cracking, thermal fatigue, and corrosion in molten smelt. This paper presents the current status of these studies. On the basis of all of these studies, recommendations for means to prevent tube cracking will be offered.

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

1997-08-01T23:59:59.000Z

162

FOREIGN INVESTMENT: Commerce Cracks Down  

Science Journals Connector (OSTI)

FOREIGN INVESTMENT: Commerce Cracks Down ... U.S. companies "will have to learn to live with" some form of mandatory federal controls on direct overseas investments "for at least a few years." ...

1968-09-02T23:59:59.000Z

163

Peridynamic model for fatigue cracking.  

SciTech Connect (OSTI)

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.

Silling, Stewart A.; Abe Askari (Boeing)

2014-10-01T23:59:59.000Z

164

Atmospheric Pollutant Removal by Non?Thermal Plasmas: Basic Data Needs for Understanding and Optimization of the Process  

Science Journals Connector (OSTI)

Since fifteen years an increasing interest has been devoted to removal of atmospheric pollutant by non?thermal plasmas achieved using e?beams or pulsed discharges for the nitrous oxides the so?called de?NOx process or for Volatils Organic Compounds the so?called de?VOC process. However the physical and chemical mechanisms involved are not easy to understand: molecules or gas mixtures are quite complex and the transient plasma created by the type of discharge often used dielectric barrier or corona ones is non homogeneous in space. In this paper is discussed some data needs for understanding of the NO?removal process and the destruction of some selected VOC molecules TCE and TCA by pulsed discharge plasmas. Some experimental studies performed to get insight into the discharge plasma kinetic involved in the pollutant removal are presented in particular about the hydroxyl radical OH which play an important role in this kinetic.

S. Pasquiers; M. Cormier; O. Motret

2002-01-01T23:59:59.000Z

165

Cracking behavior of cored structures  

SciTech Connect (OSTI)

The effects of compositional gradients, are considered based on a thermodynamic analysis, referred to as the Cahn-Hillard analysis, which describes the degree to which a local surface energy is modified by the presence of a composition gradient. The analysis predicts that both ductile and brittle fracture mechanisms are enhanced by the presence of a composition gradient. Data on stress corrosion cracking and fatigue crack growth in selected FCC alloys are used to illustrate the significance of microsegregation on mechanical properties.

Wahid, A.; Olson, D.L.; Matlock, D.K. (Colorado School of Mines, Golden, CO (United States). Center for Welding and Joining Research); Kelly, T.J. (General Electric Aircraft Engines, Evendale, OH (United States))

1991-01-01T23:59:59.000Z

166

Fraunhofer-Center fr Silizium-Photovoltaik CSP CRACK INVESTIGATION OF ENCAPSULATED  

E-Print Network [OSTI]

© Fraunhofer-Center für Silizium-Photovoltaik CSP CRACK INVESTIGATION OF ENCAPSULATED SOLAR CELLS UNDER THERMAL AND MECHANICAL STRESSES Martin Sander Fraunhofer Center for Silicon Photovoltaics CSP-5999, martin.sander@csp.fraunhofer.de Workshop "Impact of mechanical and thermal loads on the long term

167

A comparison of thermal decomposition energy and nitrogen content of nitrocellulose in non-fat process of linters by DSC and EA  

Science Journals Connector (OSTI)

Investigations of nitrogen content and thermal decomposition activation energy (E a) of two different kinds of nitrocellulose (NC) products, NMNC and MNC from the non-fat and original processes of...

C. -P. Lin; C. -M. Shu

2009-02-01T23:59:59.000Z

168

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

DOE Patents [OSTI]

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.

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

2003-01-01T23:59:59.000Z

169

Modelling thermal processes in buildings using an object-oriented approach and Modelica  

Science Journals Connector (OSTI)

Most of today’s modelling and simulation concepts originate from the times and methods of analog computers. Usually, it is assumed that the model must be expressed in an explicit state-space form. Consequently, the topology of the system gets lost and any future extension and reuse of the model is tedious and error-prone. In other words, it is the modeller’s task to consider the computational order of the operations during a simulation. In this paper we discuss the re-implementation of a passive-solar- building simulator in an object-oriented environment; it was originally built in the non-object-oriented simulation environment of Matlab–Simulink. The former simulator was designed to resemble a real physical test chamber with regard to the thermal and solar radiation flows. However, due to the lack of object orientation in Matlab–Simulink it was very difficult to apply any configuration modifications and extensions. We start with a brief description of the mathematical modelling which includes thermal dynamics and solar radiation. Then the implementation in Modelica is presented. So, a much superior environment in comparison with Matlab-Simulink was obtained, giving us the possibility of high-level modular and object-oriented modelling. The model is also extremely efficient in multidisciplinary projects in which control-engineering specialists (our group) cooperate with specialists from civil engineering, because civil engineers can more easily understand graphical and textual models in Modelica than schemes in Simulink. We expect that such a model will fulfil and significantly improve several model properties in comparison to the Matlab–Simulink implementation, i.e., a better understanding of the influences of thermal and radiation flows on comfortable living conditions, a model-based control-system design, which will enable the harmonization of active and passive energy resources, important energy savings, and a very suitable environment for education in modelling, simulation and control.

Anton Sodja; Borut Zupan?i?

2009-01-01T23:59:59.000Z

170

Degradation of Structural Alloys Under Thermal Insulation  

E-Print Network [OSTI]

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...

McIntyre, D. R.

1984-01-01T23:59:59.000Z

171

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

E-Print Network [OSTI]

of terrestrial solar cells as compared to classical furnace or pulsed laser annealing. Unfortunately, drawbacks695 Polyx multicrystalline silicon solar cells processed by PF+5 unanalysed ion implantation with classical furnace annealing or with classical diffusion process. Revue Phys. Appl. 22 (1987) 695-700 JUILLET

Paris-Sud XI, Université de

172

Environmental stress cracking of plastics under dynamic conditions  

E-Print Network [OSTI]

The objective of this study was to find out if dynamic conditions have any effect on the phenomenon of environmental stress cracking (ESC). Dynamic conditions in this study include thermal shock, mechanical shock, and vibrations. Injection blow molded... resistance of blow molded polyethylene containers. The experimental data indicated that each of the dynamic conditions accelerated the ESC. Therefore, the results obtained from the static tests cannot be used to predict the service life of the containers...

Suresh, Mitta

1992-01-01T23:59:59.000Z

173

Weld solidification cracking in 304 to 304L stainless steel  

SciTech Connect (OSTI)

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.

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

174

Weld solidification cracking in 304 to 204L stainless steel  

SciTech Connect (OSTI)

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.

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

175

Evaluation of cracking in feedwater piping adjacent to the steam generators in Nine Pressurized Water Reactor Plants  

SciTech Connect (OSTI)

Cracking in ASTM A106-B and A106-C feedwater piping was detected near the inlet to the steam generators in a number of pressurized water reactor plants. We received sections with cracks from nine of the plants with the objective of identifying the cracking mechanism and assessing various factors that might contribute to this cracking. Variations were observed in piping surface irregularities, corrosion-product, pit, and crack morphology, surface elmental and crystal structure analyses, and steel microstructures and mechanical properties. However, with but two exceptions, namely, arrest bands and major surface irregularities, we were unable to relate the extent of cracking to any of these factors. Tensile and fracture toughness (J/sub Ic/ and tearing modulus) properties were measured over a range of temperatures and strain rates. No unusual properties or microstructures were observed that could be related to the cracking problem. All crack surfaces contained thick oxide deposits and showed evidence of cyclic events in the form of arrest bands. Transmission electron microscopy revealed fatigue striations on replicas of cleaned crack surfaces from one plant and possibly from three others. Calculations based on the observed striation spacings gave a value of ..delta..sigma = 150 MPa (22 ksi) for one of the major cracks. The direction of crack propagation was invariably related to the piping surface and not to the piping axis. These two factors are consistent with the proposed concept of thermally induced, cyclic, tensile surface stresses. Although surface irregularities and corrosion pits were sources for crack initiation and corrosion may have contributed to crack propagation, it is proposed that the overriding factor in the cracking problem is the presence of unforeseen cyclic loads.

Goldberg, A.; Streit, R.D.; Scott, R.G.

1980-06-25T23:59:59.000Z

176

Crack propagation driven by crystal growth  

SciTech Connect (OSTI)

Crystals that grow in confinement may exert a force on their surroundings and thereby drive crack propagation in rocks and other materials. We describe a model of crystal growth in an idealized crack geometry in which the crystal growth and crack propagation are coupled through the stress in the surrounding bulk solid. Subcritical crack propagation takes place during a transient period, which may be very long, during which the crack velocity is limited by the kinetics of crack propagation. When the crack is sufficiently large, the crack velocity becomes limited by the kinetics of crystal growth. The duration of the subcritical regime is determined by two non-dimensional parameters, which relate the kinetics of crack propagation and crystal growth to the supersaturation of the fluid and the elastic properties of the surrounding material.

A. Royne; Paul Meaking; A. Malthe-Sorenssen; B. Jamtveit; D. K. Dysthe

2011-10-01T23:59:59.000Z

177

Method for fabrication of crack-free ceramic dielectric films  

DOE Patents [OSTI]

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.

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

2014-02-11T23:59:59.000Z

178

Optimization and heat integration of hollow fiber based thermal swing adsorption process for CO2 capture from flue gas  

Science Journals Connector (OSTI)

Abstract This work studies the optimization of a hollow fiber contactor operated in a rapid temperature swing adsorption (RTSA) mode for CO2 capture from flue gas. A hollow fiber contactor enables rapid heat and mass transfer and an efficient heat integration whereby parasitic loads on power plants can be reduced significantly compared to the traditional thermal swing adsorption processes. In this paper we employ a dynamic optimization strategy to predict the optimal operating conditions of a hollow fiber RTSA process for different process design objectives. The objective function considered was to maximize the feed throughput of the process with constraints for the required CO2 purity and recovery. Furthermore, the external heat and cold utilities must be minimized. The optimization requires a dynamic heat integration i.e. redistributing the hot and cold stream outlet between different parts of a cycle which is challenging and unconventional. This has been performed using a binary decision variable which switches the outlet water stream between hot and cold tanks. We also show that a multi- objective optimization approach can be employed to determine the optimal trade-off between heat duty and process throughput. Optimization was performed using a single discretization approach within gPROMS.

Subramanian Swernath; Fateme Rezaei; Jayashree Kalyanaraman; Ryan. P. Lively; Matthew J. Realff; Yoshiaki Kawajiri

2014-01-01T23:59:59.000Z

179

To Crack or Not to Crack: Strain in High Temperature Superconductors  

E-Print Network [OSTI]

Strain in High Temperature Superconductors Arno GodekeCrack: Strain in High Temperature Superconductors MotivationCrack: Strain in High Temperature Superconductors How do Nb

Godeke, Arno

2008-01-01T23:59:59.000Z

180

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

SciTech Connect (OSTI)

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.

Kolarik, Robert V.

2005-11-11T23:59:59.000Z

Note: This page contains sample records for the topic "thermal cracking process" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

An AHP (Analytic Hierarchy Process)/ANP (Analytic Network Process)-based multi-criteria decision approach for the selection of solar-thermal power plant investment projects  

Science Journals Connector (OSTI)

Abstract In this paper the AHP (Analytic Hierarchy Process) and the ANP (Analytic Network Process) are applied to help the managing board of an important Spanish solar power investment company to decide whether to invest in a particular solar-thermal power plant project and, if so, to determine the order of priority of the projects in the company's portfolio. Project management goes through a long process, from obtaining the required construction permits and authorizations, negotiating with different stakeholders, complying with complex legal regulations, to solving the technical problems associated with plant construction and distribution of the energy generated. The whole process involves high engineering costs. The decision approach proposed in this paper consists of three phases. In the first two phases, the managing board must decide whether to accept or reject a project according to a set of criteria previously identified by the technical team. The third phase consists of establishing a priority order among the projects that have proven to be economically profitable based on project risk levels and execution time delays. This work analyzes the criteria that should be taken into account to accept or reject proposals for investment, as well as the risks used to prioritize some projects over others.

Pablo Aragonés-Beltrán; Fidel Chaparro-González; Juan-Pascual Pastor-Ferrando; Andrea Pla-Rubio

2014-01-01T23:59:59.000Z

182

The Chemistry of the Thermal DeNOx Process: A Review of the Technology's Possible Application to control of NOx from Diesel Engines  

SciTech Connect (OSTI)

This paper presents a review of the Thermal DeNOx process with respect to its application to control of NOx emissions from diesel engines. The chemistry of the process is discussed first in empirical and then theoretical terms. Based on this discussion the possibilities of applying the process to controlling NOx emissions from diesel engines is considered. Two options are examined, modifying the requirements of the chemistry of the Thermal DeNOx process to suit the conditions provided by diesel engines and modifying the engines to provide the conditions required by the process chemistry. While the former examination did not reveal any promising opportunities, the latter did. Turbocharged diesel engine systems in which the turbocharger is a net producer of power seem capable of providing the conditions necessary for NOx reduction via the Thermal DeNOx reaction.

Lyon, Richard

2001-08-05T23:59:59.000Z

183

Assessing the Power Generation Solution by Thermal-chemical Conversion of Meat Processing Industry Waste  

Science Journals Connector (OSTI)

Abstract The paper presents a waste to energy conversion solution using a pyro-air-gasification process applied to biodegradable residues from meat processing industry integrated with small scale thermodynamic cycle for power generation. The solution of air- gasification at atmospheric pressure is based on experimental research and engineering computation developed during the study. The input data, such as: waste chemical composition, low/high heating value and proximate analysis, correspond to real waste products, sampled directly from the industrial processing line. Separate drying as first stage pre-treatment and integrated partial drying inside the reactor was used. The syngas low heating value of about 4.3 MJ/Nm3 is insured by its combustible fraction (H2– 12.2%, CO – 19.2%, CH4 – 1.6%). According to syngas composition the thermodynamic cycle was chosen – Otto gas engine. For a given waste feed-in flow considered in our computation of about 110 kg/h the power output obtained is about 50 kWel. The global energy efficiency of the unit is about 15%. The results offer answers to energy recovery waste disposal for residues with characteristics that are not suitable for classic incineration or limit the energy efficiency of the process making it non-economical (the average humidity of the raw waste is about 42% in mass). The research focused on waste to energy conversion process energy efficiency, waste neutralization and power generation.

Cosmin Marculescu; Florin Alexe

2014-01-01T23:59:59.000Z

184

Innovative Approach to Establish Root Causes for Cracking in Aggressive Reactor Environments  

SciTech Connect (OSTI)

The research focuses on the high-resolution characterization of degradation microstructures and microchemistries in specimens tested under controlled conditions for the environment and for the material where in-service complexities can be minimized. Thermodynamic and kinetic modeling of crack-tip processes is employed to analyze corrosion-induced structures and gain insights into degradation mechanisms. Novel mechanistic ''fingerprinting'' of crack-tip structures is used to isolate causes of environmental cracking in tandem with quantitative measurements of crack growth. Sample preparation methods and advanced analytical techniques are used to characterize corrosion/oxidation reactions and crack-tip structures at near atomic dimensions in order to gain insight into fundamental environmental cracking mechanisms. Reactions at buried interfaces, not accessible by conventional approaches, are being systematically interrogated. Crack-growth experiments in high-temperature water environments are evaluating and isolating the effects of material condition (matrix strength, grain boundary composition and precipitation) on stress corrosion cracking (SCC). The fundamental understanding of crack advance mechanisms will establish the basis to design new corrosion-resistant alloys for current light-water reactors and advanced reactor systems.

Bruemmer, Stephen M.; Thomas, Larry E.; Vetrano, John S.; Simonen, Edward P.

2003-10-31T23:59:59.000Z

185

A Kinetic model of crack fusion  

Science Journals Connector (OSTI)

......Research Note A Kinetic model of crack fusion Zbigniew Czechowski Institute of Geophysics...presents a kinetic approach to the problem of fusion of cracks. A kinetic equation for the...repetitive episodes of seismicity. crack fusion|kinetic model|seismicity| References......

Zbigniew Czechowski

1991-02-01T23:59:59.000Z

186

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

SciTech Connect (OSTI)

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.

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

187

Response of Surface Cracks in Tubular Members During Global Buckling and Instability  

Science Journals Connector (OSTI)

Abstract Beam-columns in compression are subject to potential buckling. If the axial load is combined with a global bending moment, member instability may occur. One situation where this can occur is for pipelines on the seabed, where thermal strains induce significant compression in the pipeline due to constrained expansion. This may lead to upheaval buckling or snaking. In this condition one should also assess how a weld defect in the buckle zone will evolve. If the crack is located on the compressive side of the cross section, the crack remains closed. If the crack is located on the side where beam bending eventually leads to tension, fracture may develop. This has not been studied sufficiently in the past, and is the topic of the present paper. Here the interesting case of initial compression, with closure of the crack, is followed by a transition to tension and opening of the crack when the transverse displacement increases in the post-buckling regime. Simple cases of tubular beam-columns with surface cracks are investigated for cracks growing in a ductile manner. The simulations are based on shell and linespring finite elements.

Bjørn Skallerud

2014-01-01T23:59:59.000Z

188

Rapid Thermal Processing of High Efficiency n-Type Silicon Solar Cells with Al Back Junction  

SciTech Connect (OSTI)

In this paper we report on the design, fabrication and modeling of 49 cm{sup 2}, 200-{micro}m thick, 1-5 {Omega}-cm, n- and p-type <111> and <100> screen-printed silicon solar cells. A simple process involving RTP front surface phosphorus diffusion, low frequency PECVD silicon nitride deposition, screen-printing of Al metal and Ag front grid followed by co-firing of front and back contacts produced cell efficiencies of 15.4% on n-type <111> Si, 15.1% on n-type <100> Si, 15.8% on p-type <111> Si and 16.1% on p-type <100> Si. Open circuit voltage was comparable for n and p type cells and was also independent of wafer orientation. High fill factor values (0.771-0.783) for all the devices ruled out appreciable shunting which has been a problem for the development of co-fired n-type <100> silicon solar cells with Al back junction. Model calculations were performed using PC1D to support the experimental results and provide guidelines for achieving >17% n-type silicon solar cells by rapid firing of Al back junction.

Ebong, A.; Upadhyaya, V.; Rounsaville, B.; Kim, D. S.; Meemongkolkiat, V.; Rohatgi, A.; Al-Jassim, M. M.; Jones, K. M.; To, B.

2006-01-01T23:59:59.000Z

189

Insights Gained from Ultrasonic Testing of Piping Welds Subjected to the Mechanical Stress Improvement Process  

SciTech Connect (OSTI)

Pacific Northwest National Laboratory (PNNL) is assisting the United States Nuclear Regulatory Commission (NRC) in developing a position on the management of primary water stress corrosion cracking (PWSCC) in leak-before-break piping systems. Part of this involves determining whether inspections alone, or inspections plus mitigation, are needed. This work addresses the reliability of ultrasonic testing (UT) of cracks that have been mitigated by the mechanical stress improvement process (MSIP). The MSIP has been approved by the NRC (NUREG-0313) since 1986 and modifies residual stresses remaining after welding with compressive, or neutral, stresses near the inner diameter surface of the pipe. This compressive stress is thought to arrest existing cracks and inhibit new crack formation. To evaluate the effectiveness of the MSIP and the reliability of ultrasonic inspections, flaws were evaluated both before and after MSIP application. An initial investigation was based on data acquired from cracked areas in 325-mm-diameter piping at the Ignalina Nuclear Power Plant (INPP) in Lithuania. In a follow-on exercise, PNNL acquired and evaluated similar UT data from a dissimilar metal weld (DMW) specimen containing implanted thermal fatigue cracks. The DMW specimen is a carbon steel nozzle-to-safe end-to-stainless steel pipe section that simulates a pressurizer surge nozzle. The flaws were implanted in the nozzle-to-safe end Alloy 82/182 butter region. Results are presented on the effects of MSIP on specimen surfaces, and on UT flaw responses.

Anderson, Michael T.; Cinson, Anthony D.; Crawford, Susan L.; Diaz, Aaron A.; Moran, Traci L.

2010-12-01T23:59:59.000Z

190

Non-thermal atmospheric pressure plasma: Screening for gentle process conditions and antibacterial efficiency on perishable fresh produce  

Science Journals Connector (OSTI)

Abstract Fresh fruits and vegetables, destined to be eaten raw or minimally processed only, harbor the risk of conveying pathogenic microorganisms. Factors such as weather conditions, which favor survival or growth of microorganisms, and improper handling during cultivation or in the postharvest chain, can contribute to outbreaks of food-borne illness. Application of chemical sanitizers or physical treatments often shows a limited efficiency or does not meet consumer acceptance. Availability of gentle and effective techniques for disinfection of fresh produce, therefore, is highly desirable. Non-thermal gas plasma (NTP) treatment is a promising novel technique to reduce the microbial load on fresh fruits and vegetables. However, knowledge on practical applicability of NTP for fresh fruits and vegetables is very limited. In this study, chlorophyll fluorescence imaging (CFI) was used to elucidate suitable process parameters for application of an atmospheric pressure plasma-jet (kINPen 09, INP Greifswald, Germany) on corn salad, a perishable leafy green. Keeping a distance of 17 mm to the plasma-jet, corn salad leaves could be treated for up to 60 s at a fixed power (8 W) and 5 L min? 1 of argon mixed with 0.1% oxygen. Surface temperature on leaves did never exceed 35.2 °C. Antibacterial tests were performed on corn salad, cucumber, apple, and tomato and achieved an inactivation of artificially inoculated Escherichia coli DSM 1116 of 4.1 ± 1.2, 4.7 ± 0.4, 4.7 ± 0, and 3.3 ± 0.9 log units, respectively, after 60 s treatment time. Additional tests with a dielectric barrier discharge plasma and indirect plasma treatment within a remote exposure reactor, fed by a microwave induced plasma torch, did not result in equivalent levels of quality retention as observed using the plasma-jet. Industrial relevance Development of gentle non-thermal disinfection methods aims to provide the industry with new tools to actively improve the microbial status of fresh produce beyond the preventive benefits of good hygiene practices and the limited efficacy of post-harvest washing. The presented study shows how cold plasma can be applied to heat-sensitive lettuce leaves without detrimental effects to product quality. The additional microbiological tests offer insights into the antibacterial capacity of cold plasma on different produce surfaces. The results contribute to prompt the development of appropriate large-scale plasma sources to establish a new plasma-based sanitation technique for fresh fruits and vegetables, which should also be implementable into running process lines.

Matthias Baier; Mandy Görgen; Jörg Ehlbeck; Dietrich Knorr; Werner B. Herppich; Oliver Schlüter

2014-01-01T23:59:59.000Z

191

Acetaldehyde removal using an atmospheric non-thermal plasma combined with a packed bed: Role of the adsorption process  

Science Journals Connector (OSTI)

Abstract This work is an attempt in order to help towards understanding the influence of the adsorption process on the removal of a VOC (acetaldehyde, CH3CHO) using cyclic non thermal plasma (NTP) combined with a packed-bed of a catalyst support, ?-Al2O3. In the first part, the results obtained by placing the saturated alumina pellets inside the plasma discharge zone are discussed, in terms of acetaldehyde removal, CO and CO2 production. In the second part, adsorption of CH3CHO, CO, CO2 and O3 was carried out, from single and multicomponent mixtures of the different compounds. The results showed that (i) the adsorption capacities followed the order CH 3 CHO ? ? ? CO 2 ? > ? CO ; (ii) O3 was decomposed on the alumina surface; (iii) CO oxidation occurred on the surface when O3 was present. In the third part, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) was used to follow the alumina surface during acetaldehyde adsorption. DRIFTS measurements demonstrated that besides the bands of molecularly adsorbed acetaldehyde, several absorptions appeared on the spectra showing the intermediate surface transformation of acetaldehyde already at 300 K. Finally, the relationship between the adsorption results and the NTP combined with a packed-bed process is discussed.

C. Klett; X. Duten; S. Tieng; S. Touchard; P. Jestin; K. Hassouni; A. Vega-González

2014-01-01T23:59:59.000Z

192

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

SciTech Connect (OSTI)

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.

Kelkar, Sharad [Los Alamos National Laboratory

2011-01-01T23:59:59.000Z

193

Supporting technology for enhanced oil recovery: Third ammendment and extension to Annex IV enhanced oil recovery thermal processes  

SciTech Connect (OSTI)

This report contains the results of efforts under the seven tasks of the Third 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 tasks) and each section contains one or more reports prepared by various individuals or groups describing the results of effort 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 25 through 31. The first, second, and third reports on Annex IV, ((Venezuela-MEM/USA-DOE Fossil Energy Report IV-1, IV-2, and IV-3 (DOE/BETC/SP-83/15, DOE/BC-84/6/SP, and DOE/BC-86/2/SP)) contain the results from the first 24 tasks. Those reports are dated April 1983, August 1984, and March 1986. Selected papers have been processed for inclusion in the Energy Data Base.

Peterson, G.; Munoz, J.D.

1987-07-01T23:59:59.000Z

194

Coolant Sub-Channel and Smeared-Cracking Models in BISON | Department of  

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

Coolant Sub-Channel and Smeared-Cracking Models in BISON Coolant Sub-Channel and Smeared-Cracking Models in BISON Coolant Sub-Channel and Smeared-Cracking Models in BISON January 29, 2013 - 10:45am Addthis Coolant Sub-Channel and Smeared-Cracking Models in BISON A single-pin coolant sub-channel model was implemented in BISON, the pin-scale simulation code. This enables BISON to compute the heat transfer coefficient and coolant temperature as a function of axial position along the fuel pin (rather than requiring this information to be supplied by the user). At present, the model is only applicable to pressurized water reactor coolant conditions, but modifications to include boiling water reactor (BWR) coolant conditions are in progress. A preliminary UO2 thermal and irradiation creep model has been implemented in BISON and is

195

Novel integration options of concentrating solar thermal technology with fossil-fuelled and CO2 capture processes  

Science Journals Connector (OSTI)

Concentrating solar thermal (CST) technology has been commercially proven in utility-scale power plants that have been in operation since the 1980’s. CST uses reflecting surfaces to focus solar energy onto collectors, generating extreme heat than can be used for a variety of purposes. The current focus of CST is large-scale electrical power generation. However, new applications, such as solar fuels, are quickly gaining momentum. One key shortcoming of CST technology is its sensitivity to disruptions in sunlight availability over time. CST systems require either thermal energy storage or backup systems to operate during heavy cloud periods or at night. On the other hand, fossil-based energy systems have high availability and reliability, but they generate substantial CO2 emissions compared to equivalent CST processes. A novel solution would combine the benefits of CST technology and of fossil-fueled energy systems. Such a solar-fossil hybrid system would guarantee energy availability in the absence of sunlight or stored solar energy. The addition of carbon capture to these systems could reduce their carbon intensity to almost zero. This paper introduces three important solar-fossil hybrid energy systems: (1) Integrated Solar Combined Cycle (ISCC), (2) Solar-assisted post-combustion capture (SAPCAP), and (3) Solar gasification with CO2 capture. These novel concepts have great potential to overcome the inherent limitations of their component technologies and to achieve superior greenhouse gas mitigation techno-economic performance in large-scale applications. The paper describes the features of the three solar-fossil hybrid systems described earlier, discusses its advantages and disadvantages, and provides examples of applications. The goal of this manuscript is to introduce experts in the CCS and CST fields to the opportunities of integration between these technologies and their potential benefits.

Guillermo Ordorica-Garcia; and Alfonso Vidal Delgado; Aranzazu Fernandez Garcia

2011-01-01T23:59:59.000Z

196

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

SciTech Connect (OSTI)

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.

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

197

Stiffness reduction and stress transfer in composite laminates with transverse matrix cracks  

E-Print Network [OSTI]

-staggered cracking. Laminates with staggered cracks showed a greater reduction in effective modulus at lower crack densities. The crack opening displacements at different crack densities were normalized in a way as to compare with the solution for an isolated crack...

Praveen, Grama Narasimhaprasad

2012-06-07T23:59:59.000Z

198

Modeling Thermal-Hydrologic Processes for a Heated Fractured Rock System: Impact of a Capillary-Pressure Maximum  

E-Print Network [OSTI]

drift-scale thermal test at Yucca Mountain, Nevada. Lawrencemechanical analyses of the Yucca Mountain Drift Scale Test–waste repository at Yucca Mountain, Nevada. The modeling

Sun, Y.; Buscheck, T. A.; Lee, K. H.; Hao, Y.; James, S. C.

2010-01-01T23:59:59.000Z

199

Thermal energy recovery of low grade waste heat in hydrogenation process; Återvinning av lågvärdig spillvärme från en hydreringsprocess.  

E-Print Network [OSTI]

?? The waste heat recovery technologies have become very relevant since many industrial plants continuously reject large amounts of thermal energy during normal operation which… (more)

Hedström, Sofia

2014-01-01T23:59:59.000Z

200

A NOVEL TECHNIQUE TO GENERATE SHARP CRACKS IN METALLIC/CERAMIC FUNCTIONALLY GRADED  

E-Print Network [OSTI]

materials with high fracture toughness and elevated temperature resistance. Ideally, the ceramic side of the FGM provides thermal and corrosion resistance while the metallic side gives the necessary strengthA NOVEL TECHNIQUE TO GENERATE SHARP CRACKS IN METALLIC/CERAMIC FUNCTIONALLY GRADED MATERIALS

Paulino, Glaucio H.

Note: This page contains sample records for the topic "thermal cracking process" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

ABSTRACT. The stress-relief cracking (SRC) susceptibility of single-pass welds  

E-Print Network [OSTI]

steel, HCM2S, has been evaluated and compared to 2.25Cr-1Mo steel using Gleeble thermal simulation and pressure vessels for chemical and fossil power plants. Many components in these power plants oper- ate techniques. HCM2S was found to be more susceptible to stress-relief cracking than 2.25Cr-1Mo steel. Simulated

DuPont, John N.

202

The effect of aqueous environments upon the initiation and propagation of fatigue cracks in low-alloy steels  

SciTech Connect (OSTI)

The effect of elevated temperature aqueous environments upon the initiation and propagation of fatigue cracks in low-alloy steels is discussed in terms of the several parameters which influence such behavior. These parameters include water chemistry, impurities within the steels themselves, as well as factors such as the water flow rate, loading waveform and loading rates. Some of these parameters have similar effects upon both crack initiation and propagation, while others exhibit different effects in the two stages of cracking. In the case of environmentally-assisted crack (EAC) growth, the most important impurities within the steel are metallurgical sulfide inclusions which dissolve upon contact with the water. A ``critical`` concentration of sulfide ions at the crack tip can then induce environmentally-assisted cracking which proceeds at significantly increased crack growth rates over those observed in air. The occurrence, or non-occurrence, of EAC is governed by the mass-transport of sulfide ions to and from the crack-tip region, and the mass-transport is discussed in terms of diffusion, ion migration, and convection induced within the crack enclave. Examples are given of convective mass-transport within the crack enclave resulting from external free stream flow. The initiation of fatigue cracks in elevated temperature aqueous environments, as measured by the S-N fatigue lifetimes, is also strongly influenced by the parameters identified above. The influence of sulfide inclusions does not appear to be as strong on the crack initiation process as it is on crack propagation. The oxygen content of the environment appears to be the dominant factor, although loading frequency (strain rate) and temperature are also important factors.

James, L.A. [Westinghouse Electric Corp., West Mifflin, PA (United States). Bettis Atomic Power Lab.; Van Der Sluys, W.A. [Babcock and Wilcox Co., Alliance, OH (United States)

1996-01-01T23:59:59.000Z

203

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

E-Print Network [OSTI]

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 in solar energy. Solar energy is widely affordable and has the capability to meet household demand over

Paris-Sud XI, Université de

204

Fatigue crack growth testing of sub-clad defects  

SciTech Connect (OSTI)

Fatigue crack growth tests were performed on four-point bend specimens with cracklike defects intentionally placed in A302B low-alloy pressure vessel steel clad with 308/309L weld-deposited stainless steel. The defects were placed in the base metal under the cladding by machining a cavity from the side opposite the cladding, electric-discharge machining a very sharp flaw, fatigue precracking the flaw, and then filling up the cavity by a weld repair process. The specimens were stress relieved before fatigue testing. The specimens were fatigue cycled at positive load ratios until the defects broke through to the surface. The specimens were then fractured at liquid nitrogen temperatures to reveal the fracture surfaces. Seven different sub-clad flaw specimens were tested in room temperature air and each test provides a record of cycles to defect breakthrough. Changes in defect size and shape as a function of applied load cycles were obtained by beach-marking the crack at various stages of the load history. The results provide a set of embedded defect data which can be used for qualifying fatigue crack growth analysis procedures such as those in Section XI of the ASME boiler and Pressure Vessel Code. A comparison between calculated and measured values shows that the ASME B and PV Section XI fatigue crack growth procedures conservatively predict cycles to defect breakthrough for small sub-clad defects.

Jones, D.P.; Leax, T.R. [Bechtel Bettis, Inc., West Mifflin, PA (United States). Bettis Atomic Power Lab.

1999-08-01T23:59:59.000Z

205

Fundamentals of Petroleum Residue Cracking Gasification for Coproduction of Oil and Syngas  

Science Journals Connector (OSTI)

Fundamentals of Petroleum Residue Cracking Gasification for Coproduction of Oil and Syngas ... Thus, the terminology of heavy oil or heavy residue can be also used to indicate all such heavy petroleum oils. ... Notwithstanding, for the RCG process it is ideal to develop the catalyst that has moderate cracking activity for heavy residues or heavy oils but meanwhile good activity for catalyzing the deposited coke gasification so that the gasification can be at reasonably low temperatures to maintain the catalytic activity for cracking heavy fractions. ...

Yuming Zhang; Deping Yu; Wangliang Li; Yin Wang; Shiqiu Gao; Guangwen Xu

2012-10-23T23:59:59.000Z

206

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...

207

Biomaterials 24 (2003) 52095221 Crack blunting, crack bridging and resistance-curve fracture  

E-Print Network [OSTI]

Biomaterials 24 (2003) 5209­5221 Crack blunting, crack bridging and resistance-curve fracture focused on a description of the fracture toughness properties of dentin in terms of resistance-curve (R-curve) behavior, i.e., fracture resistance increasing with crack extension, particularly in light of the relevant

Ritchie, Robert

208

Method for making dense crack free thin films  

DOE Patents [OSTI]

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.

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

2007-01-16T23:59:59.000Z

209

Electrochemical aspects of stress-corrosion cracking in. cap alpha. -brass  

SciTech Connect (OSTI)

This paper considers a number of aspects of the stress-corrosion cracking of brass from the point of view of the localized electrochemical processes occurring at the tip of a propagating crack. The principal system examined is the intergranular SCC of 70-30 brass in near-neutral ammoniacal solutions, for which a detailed mechanism is developed. In addition, the effects of nitrite ions in promoting SCC of both brass and copper are considered.

Burstein, G T; Newman, R C

1981-01-01T23:59:59.000Z

210

Effect of Desiccation Cracks on Earth Embankments  

E-Print Network [OSTI]

............................................................................. 4 1.4 Methodology ........................................................................................ 6 1.5 Summary .............................................................................................. 8 1.6 Layout... geometry recorded in literature ..... 17 2.5 Desiccation crack behavior during drying-wetting cycles ................... 29 2.6 Flow through a single crack ................................................................. 30 2.7 Flow through a...

Khandelwal, Siddharth

2012-07-11T23:59:59.000Z

211

Strain energy density: Distance criterion for the initiation of hydrogen-induced cracking of Alloy X-750  

SciTech Connect (OSTI)

A criterion for initiation of subcritical crack growth at blunt notches and sharp defects was developed and applied to hydrogen- induced cracking of the Ni-base superalloy X-750. Onset of crack growth is shown to occur when a critical strain energy density is attained at a distance from the notch and crack tips characteristic of the microstructure along the prospective crack path. Rising load crack growth initiation data were obtained using homogeneous hydrogen precharged notched and fatigue precracked bend specimens. Notch root radius, grain size and hydrogen concentration were varied. Crack growth initiation loads were dependent on both notch root radius and bulk precharged hydrogen concentration. These data were shown to be correlated using a critical strain energy at-a-distance (SEDAD) criterion. Furthermore, an elastic-plastic analysis of the strain energy distributions showed that the critical strain energy density value is attained at one grain diameter from the notch and fatigue precrack tips. Mechanical and microstructural aspects of crack growth process and relevance to hydrogen-induced cracking are discussed.

Hall, M.M. Jr.; Symons, D.M.; Kearns, J.J.

1991-12-31T23:59:59.000Z

212

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

SciTech Connect (OSTI)

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.

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

2014-01-09T23:59:59.000Z

213

MASSIVELY PARALLEL FULLY COUPLED IMPLICIT MODELING OF COUPLED THERMAL-HYDROLOGICAL-MECHANICAL PROCESSES FOR ENHANCED GEOTHERMAL SYSTEM RESERVOIRS  

SciTech Connect (OSTI)

Development of enhanced geothermal systems (EGS) will require creation of a reservoir of sufficient volume to enable commercial-scale heat transfer from the reservoir rocks to the working fluid. A key assumption associated with reservoir creation/stimulation is that sufficient rock volumes can be hydraulically fractured via both tensile and shear failure, and more importantly by reactivation of naturally existing fractures (by shearing) to create the reservoir. The advancement of EGS greatly depends on our understanding of the dynamics of the intimately coupled rock-fracture-fluid system and our ability to reliably predict how reservoirs behave under stimulation and production. In order to increase our understanding of how reservoirs behave under these conditions, we have developed a physics-based rock deformation and fracture propagation simulator by coupling a discrete element model (DEM) for fracturing with a continuum multiphase flow and heat transport model. In DEM simulations, solid rock is represented by a network of discrete elements (often referred as particles) connected by various types of mechanical bonds such as springs, elastic beams or bonds that have more complex properties (such as stress-dependent elastic constants). Fracturing is represented explicitly as broken bonds (microcracks), which form and coalesce into macroscopic fractures when external load is applied. DEM models have been applied to a very wide range of fracturing processes from the molecular scale (where thermal fluctuations play an important role) to scales on the order of 1 km or greater. In this approach, the continuum flow and heat transport equations are solved on an underlying fixed finite element grid with evolving porosity and permeability for each grid cell that depends on the local structure of the discrete element network (such as DEM particle density). The fluid pressure gradient exerts forces on individual elements of the DEM network, which therefore deforms and fractures. Such deformation/fracturing in turn changes the permeability, which again changes the evolution of fluid pressure, coupling the two phenomena. The intimate coupling between fracturing and fluid flow makes the meso-scale DEM simulations necessary, as these methods have substantial advantages over conventional continuum mechanical models of elastic rock deformation. The challenges that must be overcome to simulate EGS reservoir stimulation, preliminary results, progress to date and near future research directions and opportunities will be discussed.

Robert Podgorney; Hai Huang; Derek Gaston

2010-02-01T23:59:59.000Z

214

Cool Bottom Processes on the Thermally Pulsing Asymptotic Giant Branch and the Isotopic Composition of Circumstellar Dust Grains  

Science Journals Connector (OSTI)

We examine the effects of cool bottom processing (CBP) on the isotopic ratios 18O/16O, 17O/16O, 14N/15N, 26Al/27Al, C/O, and N/O in the convective envelope during the thermally pulsing asymptotic giant branch (TP-AGB) phase of evolution in a 1.5 M? initial mass star of solar initial composition. We use a parametric model that treats extra mixing by introducing mass flow between the convective envelope and the underlying radiative zone. The parameters of this model are the mass circulation rate () and the maximum temperature (TP) experienced by the circulating material. The effects of nuclear reactions in the flowing matter were calculated using a set of static structures of the radiative zone selected from particular times in a complete stellar evolution calculation. The compositions of the flowing material were obtained, and the resulting changes in the envelope determined. No major shifts in the star's energy budget occur from the imposed CBP if log TP 26Al were essentially independent of the time chosen if log TP > 7.6. Abundant 26Al was produced by CBP for log TP > 7.65. While 26Al/27Al depends on TP, the other isotopic ratios depend dominantly on the circulation rate. The relationship is shown between models of CBP as parameterized by a diffusion formalism within the stellar evolution model and those using the mass-flow formalism employed here. They are shown to be effectively equivalent. In general, the CBP treatment readily permits calculation of envelope compositions as affected by different degrees of extra mixing, based on stellar structures computed by normal stellar evolution models. Using these results, the isotopic ratios under conditions of C/O 1 are compared with the data on circumstellar dust grains. It is found that the 18O/16O, 17O/16O, and 26Al/27Al observed for oxide grains formed at C/O 15N/14N, 12C/13C, and 26Al/27Al in carbide grains (C/O > 1) require that many of their stellar sources must have had 14N/15N at least a factor of 4 lower than the solar value. This allows a self-consistent description of all these isotopes in most SiC grains. The rare grains with 12C/13C

Kenneth M. Nollett; M. Busso; G. J. Wasserburg

2003-01-01T23:59:59.000Z

215

The Co-cracking Experiment and Application Route of Waste Plastics and Heavy Oil  

Science Journals Connector (OSTI)

Abstract The co-cracking experiment of waste plastics and heavy oil was done in the condition of 400 °C and pressure not higher than 2.0 MPa. The experimental results showed that the yield of heavy oil and coke decreased but the light oil and gas yield increased with the increasing amount of waste plastics. The products of heavy oil's solidifying point, flash point, viscosity and density decreased and had a good pour point depression effect. Heavy oil containing heat conduction oil and solvent contributed to heat transfer, melting and transport and had the effect of dissolution and co-cracking. It would have a good prospect when the co-cracking of waste plastics and heavy oil was applied to the combination processes of visbreaking and delayed coking and catalytic cracking and delayed coking.

Shikui Wu; Kaixiong Xu; Lusen Jiang; Li Wang

2014-01-01T23:59:59.000Z

216

Fracture behavior of surface cracked wide plates of high strength steel containing overmatched repair welds  

SciTech Connect (OSTI)

This paper presents the experimental results of tests conducted using surface cracked wide plates containing overmatched repair weld joints. The deformation and fracture characteristics of the repair welded wideplates notched at the original weld deposit, repair weld and HAZ regions are discussed. The aim of this work was to investigate the effects of strength mis-match and notch position on the fracture performance of such complex weldments. Furthermore, the predictions of crack driving force using the Engineering Treatment Model for mis-matched welds (ETM-MM) procedure was compared with the results of the wide plates containing semielliptical surface cracks. For this study, 1/2K weld joints were prepared on 30 nm thick pipeline steel X65 plates by using a SAW process, resulting in 50% overmatching. Repair was performed at the cap side of the original joint up to half depth of plate thickness with a GMA welding process under hyperbaric conditions, leading to 41% yield strength overmatching. In order to assess the fracture behavior of these welds, surface cracked (semielliptic defects) wide plates containing original and repair welds were tested in tension at {minus}10 C. The surface cracked wide plate tests results have confirmed that overmatched repair weld metal can exert a significant effect on the deformation and fracture behavior of the wide plates. Wide plates containing root cracks clearly showed a shielding effect of the overmatched repair weld since it prevented development of through thickness ligament yielding.

Junghans, E.; Kocak, M.; Schwalbe, K.H. [GKSS Research Center, Geesthacht (Germany). Inst. of Materials Research

1996-12-01T23:59:59.000Z

217

Microstructural and Microchemical Characterization of Dual Step Aged Alloy X-750 and its Relationship to Environmentally Assisted Cracking  

SciTech Connect (OSTI)

When exposed to deaerated high purity water, Alloy X-750 is susceptible to both high temperature (> 249 C) intergranular stress corrosion cracking (IGSCC) and intergranular low temperature (< 149 C) fracture (LTF). However, the microstructural and microchemical factors that govern environmentally assisted cracking (EAC) susceptibility are poorly understood. The present study seeks to characterize the grain boundary microstructure and microchemistry in order to gain a better mechanistic understanding of stress corrosion crack initiation, crack growth rate, and low temperature fracture. Light microscopy, scanning electron microscopy, transmission electron microscopy, orientation imaging microscopy, scanning Auger microscopy, and thermal desorption spectroscopy were performed on selected heats of Alloy X-750 AH. These data were correlated to EAC tests performed in 338 C deaerated water. Results show that grain boundary MC-type [(Ti,Nb)C] carbides and increased levels of grain boundary phosphorus correlate with an increase in LTF susceptibility but have little effect on the number of initiation sites or the SCC crack growth rate. Thermal desorption data show that multiple hydrogen trapping states exist in Alloy X-750 condition AH. Moreover, it appears that exposure to high temperature (> 249 C), hydrogen deaerated water increases the hydrogen concentration in strong hydrogen trap states and degrades the resistance of the material to low temperature fracture. These findings are consistent with a hydrogen embrittlement based mechanism of LTF where intergranular fracture occurs ahead of a crack tip and is exacerbated by phosphorus segregation to grain boundaries and grain boundary hydrogen trap states.

G.A. Young; N. Lewis; M. Hanson; W. Matuszyk; B. Wiersma; S. Gonzalez

2001-05-08T23:59:59.000Z

218

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

E-Print Network [OSTI]

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 ...

Shim, JongMin, 1975-

2005-01-01T23:59:59.000Z

219

Development of processing techniques for advanced thermal protection materials. Annual progress report, 1 June 1994-31 May 1995  

SciTech Connect (OSTI)

The main purpose of this work has been in the development and characterization of materials for high temperature applications. Thermal Protection Systems (TPS) are constantly being tested, and evaluated for increased thermal shock resistance, high temperature dimensional stability, and tolerance to environmental effects. Materials development was carried out through the use of many different instruments and methods, ranging from extensive elemental analysis to physical attributes testing. The six main focus areas include: (1) protective coatings for carbon/carbon composites; (2) TPS material characterization; (3) improved waterproofing for TPS; (4) modified ceramic insulation for bone implants; (5) improved durability ceramic insulation blankets; and (6) ultra-high temperature ceramics. This report describes the progress made in these research areas during this contract period.

Selvaduray, G.S.

1995-06-01T23:59:59.000Z

220

Stress corrosion cracking of power boiler drums  

Science Journals Connector (OSTI)

This paper deals with the study, analysis and technical diagnosis fundamentals concerning damage induced by stress corrosion cracking. The main repair and safe operation methods for power boiler drums are described; this work being based on plant experience.

Alecsandru Pavel; Alexandru Pelle; Alexandru Epure; Cornel Radulescu; Petric? Baciu; Alexandru Bogdan; Mihai Stefanescu

1991-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "thermal cracking process" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Parallel interacting edge cracks under pure bending  

E-Print Network [OSTI]

. Once the applicability of the Williams' equations, have been proved or disproved, the power of the singularity represented by the first term of equation 1. 1 and the polynomial expansion can be truncated in order to extract information... of Williams' approach for the case of cracked bodies under pure bending is demonstrated. Four point bending load is applied on specimens with either a vertical or a slant crack giving Mode I or Mixed Mode I ? II respectively. The existence...

Moran, Ivan

1991-01-01T23:59:59.000Z

222

Studies on fruit cracking of tomatoes  

E-Print Network [OSTI]

STUDIES ON FRUIT CRACKING OF TOMATOES A Thesis Sam Don Cotner Submitted to the Graduate College of' ths Texas A&M University in partial fulfillment of the requirements i' or the degree of MASTER OF SCIENCE January~ 1966 Major Subject...: Horticulture STUDlES ON FRUIT CRACKING OF TOMATOES A Thesis Sam Dcn Cotnsr Approved as to style and content by; (Chairman of tes Member (Head o Department) mbsr) January 1966 TABLE OF CONTENTS Chapter I. INTRODUCTION . II. REVIEW OF LITERATURE Page...

Cotner, Sam Don

1966-01-01T23:59:59.000Z

223

Proceedings of the ASME Heat Transfer Division. Volume 4: Natural convection within a horizontal circular cylinder heated from below and cooled from above; Numerical methods for coupled fluid-thermal-structural interaction; Thermal analysis in waste processing and disposal; Heat transfer in fire and combustion systems; HTD-Volume 335  

SciTech Connect (OSTI)

The first two sections as listed in the title contain 7 papers. The third section on thermal analysis contains 18 papers arranged into the following topical areas: Thermal treatment and municipal wastes; Thermal hydraulics in hazardous and nuclear waste processing and disposal; and Waste processing. Heat transfer in fire and combustion systems contains 17 papers arranged into the following topical sections: Soot/radiation; Combustion systems; Multiphase combustion; and Flames and fires. Most papers have been processed separately for inclusion on the data base.

Pepper, D.W. [ed.] [Univ. of Nevada, Las Vegas, NV (United States); Douglass, R.W. [ed.] [Idaho National Engineering Lab., Idaho Falls, ID (United States); Heinrich, J.C. [ed.] [Univ. of Arizona, Tucson, AZ (United States)] [and others

1996-12-31T23:59:59.000Z

224

Hydrogen-induced cracking along the fusion boundary of dissimilar metal welds  

SciTech Connect (OSTI)

Presented here are the results from a series of experiments in which dissimilar metals welds were made using the gas tungsten arc welding process with pure argon or argon-6% hydrogen shielding gas. The objective was to determine if cracking near the fusion boundary of dissimilar metal welds could be caused by hydrogen absorbed during welding and to characterize the microstructures in which cracking occurred. Welds consisted of ER308 and ER309LSi austenitic stainless steel and ERNiCr-3-nickel-based filler metals deposited on A36 steel base metal. Cracking was observed in welds made with all three filler metals. A ferrofluid color metallography technique revealed that cracking was confined to regions in the weld metal containing martensite. Microhardness indentations indicated that martensitic regions in which cracking occurred had hardness values from 400 to 550 HV. Cracks did not extend into bulk weld metal with hardness less than 350 HV. Martensite formed near the fusion boundary in all three filler metals due to regions of locally increased base metal dilution.

Rowe, M.D.; Nelson, T.W.; Lippold, J.C. [Ohio State Univ., Columbus, OH (United States)

1999-02-01T23:59:59.000Z

225

Crack-Size Effects on Cyclic and Monotonic Crack Growth in Polycrystalline Alumina: Quantification of the Role of Grain Bridging  

E-Print Network [OSTI]

-prediction methodologies, it is necessary in many materials that the subcritical crack-growth and toughness propertiesCrack-Size Effects on Cyclic and Monotonic Crack Growth in Polycrystalline Alumina: Quantification propagation has been quantitatively examined in a 99.5% pure alumina. Fatigue-crack growth properties for both

Ritchie, Robert

226

Investigation of Thermal Decomposition as the Kinetic Process That Causes the Loss of Crystalline Structure in Sucrose Using a Chemical Analysis Approach (Part II)  

Science Journals Connector (OSTI)

Investigation of Thermal Decomposition as the Kinetic Process That Causes the Loss of Crystalline Structure in Sucrose Using a Chemical Analysis Approach (Part II) ... In the fast heating method, initial decomposition components, glucose (0.365%) and 5-HMF (0.003%), were found in the sucrose sample coincident with the onset temperature of the first endothermic peak. ... Three sample pans of sucrose were loaded in the DSC cell; one pan was placed on the sample platform, and the others were placed on the bottom of the DSC cell. ...

Joo Won Lee; Leonard C. Thomas; John Jerrell; Hao Feng; Keith R. Cadwallader; Shelly J. Schmidt

2010-12-22T23:59:59.000Z

227

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

SciTech Connect (OSTI)

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.

Edward Levy

2012-06-29T23:59:59.000Z

228

Assessing thermal energy storage technologies of concentrating solar plants for the direct coupling with chemical processes. The case of solar-driven biomass gasification  

Science Journals Connector (OSTI)

Abstract Dynamic simulation, design improvements and control issues in solar power plants might compete with special considerations on energy storing techniques. In order to provide the stability in production of power or chemical commodities in spite of discontinuity in the source of energy, i.e., sun, overall concerns in the details of solar power plant, competition and comparison of common storing technologies should be taken into account to ensure the effectiveness and continuity of the supply. This research activity is aimed at extending the study from the power generation purpose to the solar-supplied chemical commodities production, highlighting the limitations of certain well-established thermal energy storage techniques when concentrating solar is directly coupled with chemical processes. The (intrinsically dynamic and closed-loop) simulation of solar power plants and direct thermal energy storage technologies is performed for the direct thermal energy storage technologies and, only for the case of thermocline, it is coupled with computational fluid-dynamic (CFD) studies for the proper assessment of molten salt and steam temperature trends. To investigate benefits/restrictions of the storage technologies, the solar steam generation is integrated with the gasification of biomasses for syngas production. Also, first-principles dynamic model for the biomass gasifier is provided.

Flavio Manenti; Andres R. Leon-Garzon; Zohreh Ravaghi-Ardebili; Carlo Pirola

2014-01-01T23:59:59.000Z

229

“Petroleum Gas Oil?Ethanol” Blends Used as Feeds: Increased Production of Ethylene and Propylene over Catalytic Steam-Cracking (CSC) Hybrid Catalysts. Different Behavior of Methanol in Blends with Petroleum Gas Oil  

Science Journals Connector (OSTI)

“Petroleum Gas Oil?Ethanol” Blends Used as Feeds: Increased Production of Ethylene and Propylene over Catalytic Steam-Cracking (CSC) Hybrid Catalysts. ... Recently developed hybrid catalysts used in the catalytic steam cracking (CSC, formerly called selective deep catalytic cracking or SDCC(1, 2) and also thermal catalytic cracking or TCC(3, 4)) of hydrocarbon heavy feedstocks (naphthas and gas oils) are very efficient in the production of light olefins, particularly ethylene and propylene with a product propylene-to-ethylene ratio close to 1.0. ...

A. Muntasar; R. Le Van Mao; H. T. Yan

2010-03-22T23:59:59.000Z

230

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

SciTech Connect (OSTI)

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

Kumar Sridharan; Mark Anderson; Todd Allen; Michael Corradini

2012-01-30T23:59:59.000Z

231

Thermal spray coatings on Yankee dryers  

SciTech Connect (OSTI)

Several failure investigations and recent research on thermal spray coatings on Yankee dryer surfaces show at least three modes of environmentally induced degradation. Corrosion may occur with the ingress of certain chemicals into coating pores. Erosion or corrosion is manifested by streaks at local sites of high doctor blade loading. Erosion and cracking occur due to coating parameters, thermal stress, and differential expansion. While most of the results described in this paper are from investigations of molybdenum, stainless steel coatings also are discussed.

Bowers, D.F. (Packer Engineering, Inc., Naperville, IL (United States))

1994-08-01T23:59:59.000Z

232

E-Print Network 3.0 - axially cracked pressure Sample Search...  

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

Collection: Engineering 2 MATERIAL POINT METHOD CALCULATIONS WITH EXPLICIT CRACKS, FRACTURE PARAMETERS, AND CRACK Summary: under axial impact with a crack in the central disk....

233

E-Print Network 3.0 - anomolous fatigue crack Sample Search Results  

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

Science ; Engineering 6 Cracking Resistance of Asphalt Rubber Mix Versus Summary: vs. Fracture Mechanics Conventional Fatigue Testing Crack initiation Fracture Mechanics Crack......

234

Interfacial and near interfacial crack growth phenomena in metal bonded alumina  

E-Print Network [OSTI]

studies looking at subcritical crack growth at interfaces,An understanding of subcritical crack growth is important,the amount of subcritical crack growth data that could be

Kruzic, Jamie Joseph

2002-01-01T23:59:59.000Z

235

Process-circuit and layout solutions for steam-turbine units and performance efficiency of thermal power plants  

Science Journals Connector (OSTI)

Criteria for evaluating process-circuit and layout solutions adopted in designing steam-turbine units are presented together with their values for a number of steam-turbine units produced by the Ural Turbine Work...

A. A. Gol’dberg; T. L. Shibaev

2014-12-01T23:59:59.000Z

236

Thermal Transients During Processing of 3003 Al-H18 Multilayer Build by Very High-Power Ultrasonic Additive Manufacturing  

Science Journals Connector (OSTI)

Previous investigations suggested a gradient in bond microstructure along the height of a “build” made by very high power ultrasonic additive manufacturing—a rapid prototyping process that is based...

M. R. Sriraman; Matt Gonser; Daniel Foster…

2012-02-01T23:59:59.000Z

237

De-alloying and stress-corrosion cracking. Final report  

SciTech Connect (OSTI)

This research program has had two major areas of focus that are related: (1) alloy corrosion and (2) the role of selective dissolution in the stress corrosion cracking of alloy systems. These interrelated issues were examined using model systems such as Ag-Au and Cu-Au by conventional electrochemical techniques, in situ scanning tunneling microscopy (STM), in situ small angle neutron scattering (SANS), ultrahigh speed digital photography of fracture events, and computer simulations. The STM and SANS work were specifically aimed at addressing a roughening transition known to occur in alloy systems undergoing corrosion at electrochemical potentials greater than the so-called critical potential. Analytical models of de-alloying processes including the roughening transition were developed that specifically include curvature effects that are important in alloy corrosion processes. Stress-corrosion experiments were performed on the same model systems using rapid optical and electrochemical techniques on 50 {micro}m--250 {micro}m thick sheets and small diameter wires. The primary goal of this work was to develop a fundamental understanding of the corrosion and electrochemistry of alloys and the stress-corrosion cracking processes these alloys undergo. Computer simulations and analytical work identified surface stress and an important parameter in environmentally assisted fracture. The major results of the research on this program since the summer of 1993 are briefly summarized.

Sieradzki, K.

1998-09-01T23:59:59.000Z

238

Crack detection using resonant ultrasound spectroscopy  

DOE Patents [OSTI]

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.

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

1994-10-04T23:59:59.000Z

239

Influence of non-thermal atmospheric pressure plasma on cellular structures and processes in human keratinocytes (HaCaT)  

Science Journals Connector (OSTI)

Background The use of non-thermal atmospheric pressure plasma in dermatology to improve the healing of chronic wounds is a promising application. The antimicrobial properties of physical plasma offer on the one hand the killing of bacteria, which are often a problem in chronic wounds. On the other hand, plasma can activate cells which are involved in the wound closure. Objective To guarantee a safe application it is essential to understand basic interactions between physical plasma and human skin cells. Methods In our study, human keratinocytes (HaCaT cells) were directly plasma treated with a dielectric barrier discharge (DBD) plasma source and effects on viability, DNA, cell cycle, intracellular concentration of reactive oxygen species and induction of apoptosis were observed. Results A treatment time-dependent loss of recovered adherent HaCaT cells after 24 h and a linear increase of DNA damage were observed, which was no longer evident 24 h after plasma stimulation, except for long treatment times. An accumulation of HaCaT cells in G2/M phase and a decrease in the G1 phase was caused by DBD plasma. The increasing formation of intracellular ROS is also attributed to plasma treatment. In contrast to other studies we did not find clear evidences for apoptosis in adherent HaCaT cells. A culture medium exchange subsequently after plasma treatment weakened the observed effects. Conclusion DBD plasma treatment resulted in oxidative stress in human keratinocytes which is related to deficient cell performance.

Susanne Blackert; Beate Haertel; Kristian Wende; Thomas von Woedtke; Ulrike Lindequist

2013-01-01T23:59:59.000Z

240

Development of CFD-Based Simulation Tools for In-Situ Thermal Processing of Oil Shale/Sands  

SciTech Connect (OSTI)

In our research, we are taking the novel approach of developing and applying high performance computing, computational fluid dynamics (CFD)-based simulation tools to a modified in-situ process for production of oil from oil shale. The simulation tools being developed capture the relevant physical processes and data from a large-scale system. The modified in-situ application is a pilot-scale heat transfer process inside Red Leaf Resourcesâ?? EcoShale capsule. We demonstrate the need to understand fluid flow behavior in the convective channels of the rubblized shale bed as convective heating greatly decreases the time required to heat the oil shale to the production temperature when compared with conductive heating alone. We have developed and implemented a geometry creation strategy for a representative section of the EcoShale capsule, developed a meshing approach to deal with the complicated geometry and produce a well-behaved mesh, analyzed the effects of boundary conditions on the simulation results, and devised a new operator splitting solution algorithm that reduces computational costs by taking advantage of the differing convective and conductive time scales occurring in the simulation. These simulation tools can be applied to a wide range of processes involving convective fluid flow heating in rubblized beds.

None

2012-04-30T23:59:59.000Z

Note: This page contains sample records for the topic "thermal cracking process" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Evaluation of the MMCLIFE 3.0 code in predicting crack growth in titanium aluminide composites  

SciTech Connect (OSTI)

Crack growth and fatigue life predictions made with the MMCLIFE 3.0 code are compared to test data for unidirectional, continuously reinforced SCS-6/Ti-14Al-21Nb (wt pct) composite laminates. The MMCLIFE 3.0 analysis package is a design tool capable of predicting strength and fatigue performance in metal matrix composite (MMC) laminates. The code uses a combination of micromechanic lamina and macromechanic laminate analyses to predict stresses and uses linear elastic fracture mechanics to predict crack growth. The crack growth analysis includes a fiber bridging model to predict the growth of matrix flaws in 0{degree} laminates and is capable of predicting the effects of interfacial shear stress and thermal residual stresses. The code has also been modified to include edge-notch flaws in addition to center-notch flaws. The model was correlated with constant amplitude, isothermal data from crack growth tests conducted on 0- and 90{degree} SCS-6/Ti-14-21 laminates. Spectrum fatigue tests were conducted, which included dwell times and frequency effects. Strengths and areas for improvement for the analysis are discussed.

Harmon, D. [Boeing Co., St. Louis, MO (United States); Larsen, J.M. [Materials and Mfg. Directorate, Wright-Patterson AFB, OH (United States). Air Force Research Lab.; Peralta, A.; Hall, J.A. [Allied Signal Engines, Phoenix, AZ (United States)

1999-02-01T23:59:59.000Z

242

Linking Grain Boundary Structure and Composition to Intergranular Stress Corrosion Cracking of Austenitic Stainless Steels  

SciTech Connect (OSTI)

Grain boundary structure and composition is assessed in austenitic stainless steels along with its influence on intergranular stress corrosion cracking (IGSCC) in high-temperature water. Brief examples are presented illustrating effects of grain boundary character and segregation on behavior in specific light-water-reactor environments. Although grain boundary engineering can produce an increased fraction of special boundaries in austenitic stainless alloys, practical benefits depend on the boundary orientation distribution. It is critical to recognize that only coherent sigma 3s appear to be resistant to SCC and the behavior of other low sigma boundaries is uncertain. Grain boundary composition can have a dominant effect on IGSCC under certain conditions, but altered interfacial chemistry is not required for cracking. In high-potential oxidizing environments, IGSCC susceptibility is a direct function of the boundary Cr concentration. Non-equilibrium thermal segregation of Cr and Mo is often present in millannealed stainless steels and may influence cracking susceptibility. This initial grain boundary composition alters subsequent radiation-induced segregation and delays irradiation-assisted SCC susceptibility to higher doses. Other alloying elements and impurities in 300-series stainless steels have been seen to enrich grain boundaries, but few have any significant impact on IGSCC susceptibility. One exception is Si that strongly segregates during irradiation. recent results suggest that Si may accelerate crack propagation in both low- and high-potential water environments. Critical research is still needed to isolate individual grain boundary characteristics and quantitatively link to IGSCC.

Bruemmer, Stephen M.

2004-08-10T23:59:59.000Z

243

Fatigue Enhancement of Undersized, Drilled Crack-Arrest Holes  

E-Print Network [OSTI]

Fatigue cracks occur in steel bridges from repeated loads. If allowed to continue to grow, eventually the fatigue cracks will require either expensive repairs or reduction of traffic loads on the bridge, or they may lead ...

Simmons, Gary Gene

2013-12-31T23:59:59.000Z

244

Dynamical fracture instabilities due to local hyperelasticity at crack tips  

Science Journals Connector (OSTI)

... a crack propagating through a brittle material increases, a dynamical instability leads to an increased roughening of the fracture surface. Cracks moving at low speeds create atomically flat mirror-like ...

Markus J. Buehler; Huajian Gao

2006-01-19T23:59:59.000Z

245

Reflective cracking of shear keys in multi-beam bridges  

E-Print Network [OSTI]

strength to resist cracking from vehicular loads, but uneven temperature changes and shrinkage strains cause high tensile stresses in the shear key regions and lead to reflective cracking. The analyses showed the highest stresses were often times near...

Sharpe, Graeme Peter

2009-06-02T23:59:59.000Z

246

Catalytic cracking of a Gippsland reduced crude on zeolite catalysts  

SciTech Connect (OSTI)

Cracking reactions of a Gippsland reduced crude have been investigated at 520[degrees]C over HY and HZSM-5. Gasolines with similar characteristics can be obtained on both zeolites, although the mechanistic routes to these products are quite distinct. Changes in aromatic product selectivities are consistent with the zeolite pore geometries. Minor quantities of aromatics are formed via hydrogen transfer processes involving product olefins and naphthenes over the faujasite and the cyclization (and to a lesser extent oligomerization) of olefinic species on the pentasil. Dehydrogenation of naphthenic species in the feedstock is also important for aromatic formation. While paraffins are formed via hydrogen transfer processes together with cracking and isomerization of feed paraffins on HY, only the latter route can explain formation of saturated species on HZSM-5. The removal of linear paraffins from the GRC was traced as a function of conversion on HY. It was found that the relative reactivity of the linear paraffins increased monotonically with paraffin chain length. 43 refs., 11 figs., 8 tabs.

Guerzoni, F.N.; Abbot, J. (Univ. of Tasmania (Australia))

1994-06-01T23:59:59.000Z

247

Keep Customers—and Energy—From Slipping Through the Cracks  

Broader source: Energy.gov [DOE]

The most successful energy efficiency upgrade programs have customers who are willing and able to implement energy efficiency upgrades. This may seem like an obvious statement; however, many upgrade programs are struggling to reach their upgrade goals because they allow initially excited customers to slip through the cracks by not guiding them through the entire upgrade process.

248

Task 3.9 -- Catalytic tar cracking. Semi-annual report, January 1--June 30, 1995  

SciTech Connect (OSTI)

Tar produced in the gasification of coal is deleterious to the operation of downstream equipment including fuel cells, gas turbines, hot-gas stream cleanup filters, and pressure swing adsorption systems. Catalytic cracking of tars to smaller hydrocarbons can be an effective means to remove these tars from gas streams and, in the process, generate useful products, e.g., methane gas, which is crucial to the operation of molten carbonate fuel cells. The objectives of this project are to investigate whether gasification tars can be cracked by synthetic nickel-substituted micamontmorillonite, zeolite, or dolomite material; and whether the tars can be cracked selectively by these catalysts to produce a desired liquid and/or gas stream. Results to date are presented in the cited papers.

Young, B.C.; Timpe, R.C.

1995-12-31T23:59:59.000Z

249

A review of test results on parabolic dish solar thermal power modules with dish-mounted rankine engines and for production of process steam  

SciTech Connect (OSTI)

This paper presents results of development testing of various solar thermal parabolic dish modules and assemblies. Most of the tests were at modules and assemblies that used a dish-mounted, organic Rankine cycle turbine for production of electric power. Some tests were also run on equipment for production of process steam or for production of electricity using dish-mounted reciprocating steam engines. These tests indicate that early modules achieve efficiencies of about 18 percent in converting sunlight to electricity (excluding the inverter but including parasitics). A number of malfunctions occurred. The performance measurements, as well as the malfunctions and other operating experience, provided information that should be of value in developing systems with improved performance and reduced maintenance.

Jaffe, L.D.

1988-11-01T23:59:59.000Z

250

Digital radiographic systems detect boiler tube cracks  

SciTech Connect (OSTI)

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.

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

2008-06-15T23:59:59.000Z

251

NORTHWESTERN UNIVERSITY Autonomous Crack Comparometer Phase II  

E-Print Network [OSTI]

program between the two universities. Thanks are also given to the staff of the Infrastructure Technology Institute and in particular Dan Marron for all his advice and assistance during the project. I would like that daily and weekly weather related crack displacements are greater than those produced by dynamic events

252

CRACKING OF PIc NUCLEAR CONTAINMENT STRUCTURES  

E-Print Network [OSTI]

CRACKING OF PIc NUCLEAR CONTAINMENT STRUCTURES By Sami H. Rizkalla,l Sidney H. Simmonds': and James structures for some Canadian nuclear reactors consist of a heavy concrete base, a cylindrical wall, a ring the design accident pressure. This would result in the walls and dome of the containment being stressed

253

Thermal neutron capture cross-section to {sup 113}Cd isomer for the study of s-process origin of {sup 115}Sn  

SciTech Connect (OSTI)

The astrophysical origin of a p-nucleus {sup 115}Sn has remained still an open question. The nucleus {sup 115}Sn may be produced by a weak branch of the s-process through a beta-unstable isomer in {sup 113}Cd. However, a neutron capture cross-section to this isomer has not been measured with high accuracy at any energy. A neutron capture cross-section for the {sup 112}Cd(n,gamma){sup 113}Cd{sup m} reaction has been measured with neutrons provided from a nuclear reactor. The nucleus {sup 115}Sn may be produced by a nucleosynthesis flow through {sup 113}Cd{sup m} in the s-process. We have obtained the thermal neutron capture cross-section of 0.028+-0.009[b] and the resonance integral of 1.1+-0.3[b] using a cadmium difference method. The cross-section ratio of the isomer to the ground state has been calculated as a function of the incident neutron energy, E, by using a statistical model. The calculated ratios are almost constant over a wide range of E<100 keV. We have evaluated the s-process contribution to the solar abundance of {sup 115}Sn using the classical steady-flow model. This calculated result has shown that the production through {sup 113}Cd{sup m} may be minor contribution to {sup 115}Sn.

Hayakawa, Takehito; Shizuma, Toshiyuki [Kansai Photon Science Institute, Japan Atomic Energy Agency, Kizu, Kyoto 619-0215 (Japan); Chiba, Satoshi; Hatsukawa, Yuichi; Iwamoto, Nobuyuki; Shinohara, Nobuo; Harada, Hideo [Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan); Kajino, Toshitaka [National Astronomical Observatory, Osawa, Mitaka, Tokyo 181-8588 (Japan)

2010-06-01T23:59:59.000Z

254

Feedback algorithm for simulation of multi-segmented cracks  

SciTech Connect (OSTI)

In this paper, a method for obtaining a three dimensional crack model from a radiographic image is discussed. A genetic algorithm aiming at close simulation of crack's shape is presented. Results obtained with genetic algorithm are compared to those achieved in authors' previous work. The described algorithm has been tested on both simulated and real-life cracks.

Chady, T.; Napierala, L. [Department of Electrical and Computer Engineering, Faculty of Electrical Engineering, West Pomeranian University of Technology, al. Piastow 17, 70-310 Szczecin (Poland)

2011-06-23T23:59:59.000Z

255

ESTABLISHEMENT OF CRACK INDEXES BY ELECTRICAL APPARENT RESISTIVITY DATA  

E-Print Network [OSTI]

ESTABLISHEMENT OF CRACK INDEXES BY ELECTRICAL APPARENT RESISTIVITY DATA A. Samouelian (1,2), I is indeed well adapted to recognize the electrical resistant signature of crack filled by air during-destructive geophysical methods permits a 3D temporal monitoring of the cracking patterns. Electrical resis- tivity

Boyer, Edmond

256

Fracture toughness and fatigue crack growth characteristics of nanotwinned copper  

E-Print Network [OSTI]

fracture and subcritical fatigue crack growth life. Possible mechanistic origins of these trends and the resistance to stable subcritical crack growth under mono- tonic and cyclic loading, especially at lowerFracture toughness and fatigue crack growth characteristics of nanotwinned copper A. Singh a,1 , L

Suresh, Subra

257

Dynamic crack response to a localized shear pulse perturbation in brittle amorphous materials: on crack surface roughening  

Science Journals Connector (OSTI)

Linear Elastic Fracture Mechanics (LEFM) provides a coherent framework to evaluate quantitatively the energy flux released at the tip of a growing crack. However, the way in which the crack chooses its path in re...

D. Bonamy; K. Ravi-Chandar

2005-07-01T23:59:59.000Z

258

Development of Spatio-Temporal Wavelet Post Processing Techniques for Application to Thermal Hydraulic Experiments and Numerical Simulations  

E-Print Network [OSTI]

for Re=2.06E5 .................... 55 xiv Page Figure 34 Zoom of 1D Wavelet transform after the SEO for Re=2.06E5 ....................... 56 Figure 35 1D Wavelet transform semblance plot of low frequency pressure signals before and after the SEO... fields of straddling PTV ?t sensitivity study for times (a) 0.001s, (b) 0.0005s, (c) 0.00033s, and (d) 0.00025s at z=3.0? ........................ 75 Figure 56 Sensitivity study to the number of image pairs used in averaging process...

Salpeter, Nathaniel

2012-07-16T23:59:59.000Z

259

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

E-Print Network [OSTI]

. Cracks Follow Capillary Channels . . 3. Warping stress coefficients (from Bradbury). , 4. Cracks follow capillary channels. 5. Schematic representation of the slab instrumentation. . . . 6. Weather data on the day the bike trail concrete was laid... the curling stresses caused by temperature differentials through the slab, and are used to find the total stress due to bending, in a slab. The Bradbury curling coefficient (Figure 3) was developed by Bradbury in 1938 based on Westergaard analysis. Bradbury...

Vepakomma, Shilpa

2012-06-07T23:59:59.000Z

260

Evolving crack patterns in thin films with the extended finite element method  

E-Print Network [OSTI]

-exist in the film. To describe subcritical crack growth, we prescribe a kinetic law that relates the crack velocity is susceptible to subcritical cracking, obeying a kinetic law that relates the velocity of each crack to its Elsevier Science Ltd. All rights reserved. Keywords: Crack patterns; Subcritical cracking; Thin films

Suo, Zhigang

Note: This page contains sample records for the topic "thermal cracking process" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

EMAT based inspection of natural gas pipelines for SSC cracks  

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

EMAT-Based Inspection of Natural Gas EMAT-Based Inspection of Natural Gas Pipelines for Stress Corrosion Cracks FY2004 Report Venugopal K. Varma, Raymond W. Tucker, Jr., and Austin P. Albright Oak Ridge National Laboratory Oak Ridge, Tennessee 37831 1 This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name,

262

Cleavage crack-tip deformation in single-crystal zinc  

Science Journals Connector (OSTI)

Dislocation distribution ahead of a cleavage crack tip in single crystal Zn is observed by using the etch pit technique. The results show that the distribution has the feature predicted by the DFZ models, and both X1, the distance from the crack tip to the first dislocation and N0, the total number of dislocations ahead of the crack tip, agree with Majumdar and Burns's DFZ theory. The problems of dislocation emission from the crack tip and dislocation shielding effects on the crack tip are also discussed based on the experimental results.

Fu Ran; Q Y Long; T Y Zhang; C W Lung

1989-01-01T23:59:59.000Z

263

In-situ repairs of pipelines using metal arc welding under oil (MAW-UO) aided by eddy current crack detection  

Science Journals Connector (OSTI)

Metal arc welding under oil (MAW-UO) is a new process developed to make in-situ internal repairs of in-service oil industry pipelines tanks and vessels without the need to evacuate the service from the containing fluid. High nickel alloy welding wires were used to produce a tough relatively soft austenitic weld metal; with reduced weld metal hardness porosity residual strain and cracking susceptibility. Eddy current sensors were able to detect cracks under oil which then can be repaired in-situ using MAW-UO. The in-situ under oil crack detection and arc weld repair process will be described.

2012-01-01T23:59:59.000Z

264

Chemical analysis of HfO{sub 2}/Si (100) film systems exposed to NH{sub 3} thermal processing  

SciTech Connect (OSTI)

Nitrogen incorporation in HfO{sub 2}/SiO{sub 2} films utilized as high-k gate dielectric layers in advanced metal-oxide-semiconductor field effect transistors has been investigated. Thin HfO{sub 2} blanket films deposited by atomic layer deposition on either SiO{sub 2} or NH{sub 3} treated Si (100) substrates have been subjected to NH{sub 3} and N{sub 2} anneal processing. Several high resolution techniques including electron microscopy with electron energy loss spectra, grazing incidence x-ray diffraction, and synchrotron x-ray photoelectron spectroscopy have been utilized to elucidate chemical composition and crystalline structure differences between samples annealed in NH{sub 3} and N{sub 2} ambients as a function of temperature. Depth profiling of core level binding energy spectra has been obtained by using variable kinetic energy x-ray photoelectron spectroscopy with tunable photon energy. An 'interface effect' characterized by a shift of the Si{sup 4+} feature to lower binding energy at the HfO{sub 2}/SiO{sub 2} interface has been detected in the Si 1s spectra; however, no corresponding chemical state change has been observed in the Hf 4f spectra acquired over a broad range of electron take-off angles and surface sensitivities. The Si 2p spectra indicate Si-N bond formation beneath the HfO{sub 2} layer in the samples exposed to NH{sub 3} anneal. The NH{sub 3} anneal ambient is shown to produce a metastable Hf-N bond component corresponding to temperature driven dissociation kinetics. These findings are consistent with elemental profiles across the HfO{sub 2}/Si(100) interface determined by electron energy loss spectroscopy measurements. X-ray diffraction measurements on similarly treated films identify the structural changes resulting from N incorporation into the HfO{sub 2} films.

Lysaght, Patrick S.; Barnett, Joel; Bersuker, Gennadi I.; Woicik, Joseph C.; Fischer, Daniel A.; Foran, Brendan; Tseng, Hsing-Huang; Jammy, Raj [Front End Process Division, SEMATECH, 2706 Montopolis Drive, Austin, Texas 78741-6499 (United States); National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Physical Characterization Laboratory, Advanced Technology Development Facility, 2706 Montopolis Drive, Austin, Texas 78741-6499 (United States); Front End Process Division, SEMATECH, 2706 Montopolis Drive, Austin, Texas 78741-6499 (United States)

2007-01-15T23:59:59.000Z

265

Tar evolution in a two stage fluid bed–plasma gasification process for waste valorization  

Science Journals Connector (OSTI)

Abstract This work focuses on systematic studies of the plasma reforming of newly evolved vapors from a fluid bed gasifier, and on the resulting evolution of individual gaseous cracking products to hydrogen-rich syngas. The aim of this study is to compare some previously developed mechanisms of thermal cracking and to identify the main elementary reactions and the most sensible ones for tar decomposition in a two-stage process. Evaluation of plasma chemistry is performed by a comparison between experimental data and thermal kinetic predicted results. Distribution analysis of condensable organics shows that for all the representative species, the levels of tars are distinct in the first stage and almost negligible after the plasma treatment. Under the given reaction conditions, the organic cracking products such as methane and C2-species are completely converted to carbon monoxide and hydrogen, and no soot significantly formed. Oxygen atoms initially formed from CO2 were identified as the major active species involved in the oxidative decomposition of hydrocarbon intermediates and soot precursors. As a result, a two-stage system shows better reforming results, large treatment capacity and almost complete carbon conversion.

Massimiliano Materazzi; Paola Lettieri; Luca Mazzei; Richard Taylor; Chris Chapman

2014-01-01T23:59:59.000Z

266

The Stress Corrosion Crack Growth Rate of Alloy 600 Heat Affected Zones Exposed to High Purity Water  

SciTech Connect (OSTI)

Grain boundary chromium carbides improve the resistance of nickel based alloys to primary water stress corrosion cracking (PWSCC). However, in weld heat affected zones (HAZ's), thermal cycles from fusion welding can solutionize beneficial grain boundary carbides, produce locally high residual stresses and strains, and promote PWSCC. The present research investigates the crack growth rate of an A600 HAZ as a function of test temperature. The A600 HAZ was fabricated by building up a gas-tungsten-arc-weld deposit of EN82H filler metal onto a mill-annealed A600 plate. Fracture mechanics based, stress corrosion crack growth rate testing was performed in high purity water between 600 F and 680 F at an initial stress intensity factor of 40 ksi {radical}in and at a constant electrochemical potential. The HAZ samples exhibited significant SCC, entirely within the HAZ at all temperatures tested. While the HAZ samples showed the same temperature dependence for SCC as the base material (HAZ: 29.8 {+-} 11.2{sub 95%} kcal/mol vs A600 Base: 35.3 {+-} 2.58{sub 95%} kcal/mol), the crack growth rates were {approx} 30X faster than the A600 base material tested at the same conditions. The increased crack growth rates of the HAZ is attributed to fewer intergranular chromium rich carbides and to increased plastic strain in the HAZ as compared to the unaffected base material.

George A. Young; Nathan Lewis

2003-04-05T23:59:59.000Z

267

Inuence of foreign-object damage on crack initiation and early crack growth during high-cycle fatigue of Ti6Al4V  

E-Print Network [OSTI]

; Ti±6Al±4V 1. Introduction The high-cycle fatigue (HCF) of aircraft gas-turbine engine components has of small surface fatigue cracks in a Ti±6Al±4V alloy, processed for typical turbine blade applications microcracks in the damaged zone (seen only at the higher impact velocities). Furthermore, the eect of residual

Ritchie, Robert

268

Improve corrosion control in refining processes  

SciTech Connect (OSTI)

New guidelines show how to control corrosion and environmental cracking of process equipment when processing feedstocks containing sulfur and/or naphthenic acids. To be cost competitive refiners must be able to process crudes of opportunity. These feedstocks when processed under high temperatures and pressures and alkaline conditions can cause brittle cracks and blisters in susceptible steel-fabricated equipment. Even with advances in steel metallurgy, wet H{sub 2}S cracking continues to be a problem. New research data shows that process conditions such as temperature, pH and flowrate are key factors in the corrosion process. Before selecting equipment material, operators must understand the corrosion mechanisms present within process conditions. Several case histories investigate the corrosion reactions found when refining naphthenic crudes and operating amine gas-sweetening systems. These examples show how to use process controls, inhibitors and/or metallurgy to control corrosion and environmental cracking, to improve material selection and to extend equipment service life.

Kane, R.D.; Cayard, M.S. [CLI International, Houston, TX (United States)

1995-11-01T23:59:59.000Z

269

Static strength assessment of cracked tubular joints  

SciTech Connect (OSTI)

Results from a number of investigations on the ultimate capacity of cracked tubular joints are available. A comparison of the results with predictions from parametric equations for the static strength capacity of intact joints indicates that the presence of a defect can have a significant influence on the joint capacity. The data, which were obtained from experiments on small-scale and large-scale tests and numerical analyses, are assessed in this paper. A range of tubular joint geometries containing surface and through-thickness cracks are considered. The data are assessed with respect to characteristic static strength predictions and fracture mechanics predictions based on the use of the Failure Assessment Diagram approach. Finally, an outline of current research in this area is presented.

Stacey, A.; Sharp, J.V. [Health and Safety Executive, London (United Kingdom). Offshore Safety Div.; Nichols, N.W. [AEA Technology, Culham (United Kingdom)

1996-12-01T23:59:59.000Z

270

Features of hydrotreating catalytic cracking feed and heavy slow coking gas oils  

SciTech Connect (OSTI)

A possible means of more extensive processing of crude oil is the use, in catalytic cracking, of heavy coking gas oils (HCGOs), a feature of which is a higher content of polycyclic aromatic compounds and resins by comparison with straight-run vacuum distillates. The presence of these compounds in catalytic cracking feed causes a reduction in the product yield and increased coke formation. Therefore, one of the problems of hydrotreating feedstock of this kind is the hydrogenation of polycyclic arenes. Processes of extensive desulphurization and denitration occur in parallel, since the sulphur and nitrogen compounds of HCGO are chiefly condensed benzoderivatives of thiophene, pyridine and carbazole, and largely concentrated in heavy aromatic and resinous fractions. The composition of the saturated part of the cracking feed plays a large role in achieving the optimum yields of gaseous and gasoline fractions. Thus an increase in the proportion of cyclanes in the feed raises the gasoline yield. In this way, an investigation of the hydrocarbon conversions during the hydrotreatment of cracking feed is of great importance. The present paper sets out the results for studying the change in the group-structural characteristics of the hydrogenation products of a mixture containing 30% HCGOs according to data of {sup 1}H and {sup 13}C NMR spectroscopy. 7 refs., 7 figs., 1 tab.

Yefremov, N.I.; Kushnarev, D.F.; Frolov, P.A.; Chagovets, A.N.; Kalabin, G.A.

1993-12-31T23:59:59.000Z

271

Thermal Recovery Methods  

SciTech Connect (OSTI)

Thermal Recovery Methods describes the basic concepts of thermal recovery and explains the injection patterns used to exploit reservoir conditions. Basic reservoir engineering is reviewed with an emphasis on changes in flow characteristics caused by temperature. The authors discuss an energy balance for steam and combustion drive, and they explain in situ reactions. Heat loss, combustion drive, and steam displacement also are examined in detail, as well as cyclic steam injection, downhole ignition, well heating, and low-temperature oxidation. Contents: Thermal processes; Formation and reservoir evaluations; Well patterns and spacing; Flow and process equations; Laboratory simulation of thermal recovery; Heat loss and transmission; Displacement and production; Equipment; Basic data for field selection; Laboratory evaluation of combustion characteristics; Thermal properties of reservoirs and fluids.

White, P.D.; Moss, J.T.

1983-01-01T23:59:59.000Z

272

Computational simulations of latent heat thermal energy storage systems - with innovative and first-principles based simulation for the underlying unsteady melting (and solidification) processes.  

E-Print Network [OSTI]

?? This thesis develops an effective modeling and simulation procedure for a specific thermal energy storage system commonly used and recommended for various applications (such… (more)

Gumaste, Rohan Achyut

2011-01-01T23:59:59.000Z

273

Room-temperature thermally induced relaxation effect in a two-dimensional cyano-bridged Cu-Mo bimetal assembly and thermodynamic analysis of the relaxation process  

SciTech Connect (OSTI)

We observed a photo-switching effect in [Cu{sup II}(1,4,8,11-tetraazacyclodecane)]{sub 2}[Mo{sup IV}(CN){sub 8}]{center_dot}10H{sub 2}O by irradiation with 410-nm light around room temperature using infrared spectroscopy. This photo-switching is caused by the photo-induced charge transfer from Mo{sup IV} to Cu{sup II}. The photo-induced phase thermally relaxed to the initial phase with a half-life time of 2.7 Multiplication-Sign 10{sup 1}, 6.9 Multiplication-Sign 10{sup 1}, and 1.7 Multiplication-Sign 10{sup 2} s at 293, 283, and 273 K, respectively. The relaxation process was analyzed using Hauser's equation, k=k{sub 0}exp[-(E{sub a}+E{sub a}{sup *}{gamma}) /k{sub B}T], where k is the rate constant of relaxation, k{sub 0} is the frequency factor, E{sub a} is the activation energy, E{sub a}{sup *} is the additional activation energy due to the cooperativity, and {gamma} is the fraction of the photo-induced phase. k{sub 0}, E{sub a}, and E{sub a}{sup *} were evaluated as 1.28 Multiplication-Sign 10{sup 7}{+-} 2.6 s{sup -1}, 4002 {+-} 188 cm{sup -1}, and 546 {+-} 318 cm{sup -1}, respectively. The value of E{sub a} is much larger than that of the relaxation process for the typical light-induced spin crossover effect (E{sub a} Almost-Equal-To 1000 cm{sup -1}). Room-temperature photo-switching is an important issue in the field of optical functional materials. The present system is useful for the demonstration of high-temperature photo-switching material.

Umeta, Yoshikazu; Ozaki, Noriaki [Department of Chemistry, School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Tokoro, Hiroko [Department of Chemistry, School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); NEXT, JSPS, 8 Ichibancho, Chiyoda-ku, Tokyo 102-8472 (Japan); Ohkoshi, Shin-ichi [Department of Chemistry, School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); CREST, JST, K's Gobancho, 7 Gobancho, Chiyoda-ku, Tokyo 102-0076 (Japan)

2013-04-15T23:59:59.000Z

274

Solar-thermal reaction processing  

DOE Patents [OSTI]

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.

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

2014-03-18T23:59:59.000Z

275

Method and apparatus for generating a natural crack  

DOE Patents [OSTI]

A method and apparatus for generating a measurable natural crack includes forming a primary notch in the surface of a solid material. A nonsustained single pressure pulse is then generated in the vicinity of the primary notch, reuslting in the formation of a shock wave which travels through the material. The shock wave creates a measurable natural crack within the material which extends from the primary notch. The natural crack formed possesses predictable geometry, location and orientation.

Fulton, F.J.; Honodel, C.A.; Holman, W.R.; Weingart, R.C.

1982-05-06T23:59:59.000Z

276

Factors Affecting the Hydrogen Environment Assisted Cracking Resistance of an AL-Zn-Mg-(Cu) Alloy  

SciTech Connect (OSTI)

Precipitation hardenable Al-Zn-Mg alloys are susceptible to hydrogen environment assisted cracking (HEAC) when exposed to aqueous environments. In Al-Zn-Mg-Cu alloys, overaged tempers are used to increase HEAC resistance at the expense of strength but overaging has little benefit in low copper alloys. However, the mechanism or mechanisms by which overaging imparts HEAC resistance is poorly understood. The present research investigated hydrogen uptake, diffusion, and crack growth rate in 90% relative humidity (RH) air for both a commercial copper bearing Al-Zn-Mg-Cu alloy (AA 7050) and a low copper variant of this alloy in order to better understand the factors which affect HEAC resistance. Experimental methods used to evaluate hydrogen concentrations local to a surface and near a crack tip include nuclear reaction analysis (NRA), focused ion beam, secondary ion mass spectroscopy (FIB/SIMS) and thermal desorption spectroscopy (TDS). Results show that overaging the copper bearing alloys both inhibits hydrogen ingress from oxide covered surfaces and decreases the apparent hydrogen diffusion rates in the metal.

G.A. Young; J.R. Scully

2002-04-09T23:59:59.000Z

277

Vibration Diagnosis of Elastic Shafts with A Transverse Crack.  

E-Print Network [OSTI]

??Detection of the shaft crack in a rotating machine is one of the most challenging problems in equipment predictive maintenance. In the available literature, various… (more)

Cai, ZHONGYI

2011-01-01T23:59:59.000Z

278

White-Etching Crack Failure Overview, Tomography Analysis, and...  

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

White-Etching Crack Failure Overview, Tomography Analysis, and Test Development Presented by Aaron Greco of Argonne National Laboratory at the Wind Turbine Tribology Seminar 2014....

279

Investigation of White Etching Crack (WEC) Formation Mechanisms...  

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

Investigation of White Etching Crack (WEC) Formation Mechanisms Under Non-hydrogen Charged Test Conditions Presented by Alex Richardson, Afton Chemical (representing University of...

280

Hot Rolling Scrap Reduction through Edge Cracking and Surface...  

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

properties as a routine part of design. OEMs design typically with linear elastic fracture mechanics, isotropic crack direction criteria (maximum tensile stress) In...

Note: This page contains sample records for the topic "thermal cracking process" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Crack initiation and crack growth resistance of Ti-48Al-2Cr sheet material  

SciTech Connect (OSTI)

The present paper reports on the fracture toughness tests conducted on Ti-48Al-2Cr sheet material with near-gamma microstructure produced by hot rolling. Compact tension specimens were sectioned from sheet material and tested at room temperature to determine the fracture toughness and crack growth resistance curves. The deformation and fracture behavior were studied on tested specimens.

Dogan, B.; Schwalbe, K.H. [GKSS Research Centre, Geesthacht (Germany)] [GKSS Research Centre, Geesthacht (Germany); Clemens, H. [Plansee AG, Reutte (Austria)] [Plansee AG, Reutte (Austria)

1998-03-03T23:59:59.000Z

282

An evaluation of crack front effect on threshold and crack propagation  

SciTech Connect (OSTI)

That a through-thickness crack may exhibit over the entire fatigue crack propagation (FCP) regime morphological variations such as curvature, deviation and deflection appears to be very common. This effect is hereafter referred to as the crack front effect (CFE). It includes the practical consequence that when CFE occurs, local crack length, and hence the surface and the through-thickness data derived, tend to differ. Apparently, the difference should not be significant a least for thin specimens, for which data acquisition on one face suffices, and therefore, problems resulting from CFE can be neglected in certain cases. The authors became involved in the CFE problem while studying hysteresis effects in the threshold regime, particularly when post-threshold non-propagation was observed on the surface. In brief, the specimens had a section thickness of 4mm, i.e., relatively thin (B/W = 0.066), and according to the ASIM test recommendations the surface data should have been accurate. The major questions which arose were, however, whether surface and through-thickness effects are comparable, and how reliable surface observations are. Pure copper was chosen as the material since it exhibits a mixed mode fracture path, and thus should be inherently prone to yield CFE.

Vaidya, W.V.

1989-01-01T23:59:59.000Z

283

Stress Corrosion Cracking of the Drip Shield, the Waste Package Outer Barrier, and the Stainless Steel Structural Material  

SciTech Connect (OSTI)

Stress corrosion cracking is one of the most common corrosion-related causes for premature breach of metal structural components. Stress corrosion cracking is the initiation and propagation of cracks in structural components due to three factors that must be present simultaneously: metallurgical susceptibility, critical environment, and static (or sustained) tensile stresses. This report was prepared according to ''Technical Work Plan for: Regulatory Integration Modeling and Analysis of the Waste Form and Waste Package'' (BSC 2004 [DIRS 171583]). The purpose of this report is to provide an evaluation of the potential for stress corrosion cracking of the engineered barrier system components (i.e., the drip shield, waste package outer barrier, and waste package stainless steel inner structural cylinder) under exposure conditions consistent with the repository during the regulatory period of 10,000 years after permanent closure. For the drip shield and waste package outer barrier, the critical environment is conservatively taken as any aqueous environment contacting the metal surfaces. Appendix B of this report describes the development of the SCC-relevant seismic crack density model (SCDM). The consequence of a stress corrosion cracking breach of the drip shield, the waste package outer barrier, or the stainless steel inner structural cylinder material is the initiation and propagation of tight, sometimes branching, cracks that might be induced by the combination of an aggressive environment and various tensile stresses that can develop in the drip shields or the waste packages. The Stainless Steel Type 316 inner structural cylinder of the waste package is excluded from the stress corrosion cracking evaluation because the Total System Performance Assessment for License Application (TSPA-LA) does not take credit for the inner cylinder. This document provides a detailed description of the process-level models that can be applied to assess the performance of Alloy 22 (used for the waste package outer barrier) and Titanium Grade 7 (used for the drip shield) that are subjected to the effects of stress corrosion cracking. The use of laser peening or other residual stress mitigation techniques is considered as a means of mitigating stress corrosion cracking in the waste package final closure lid weld.

G. Gordon

2004-10-13T23:59:59.000Z

284

Nickel electroplating of steam generator tubes (kiss sleeving process)  

SciTech Connect (OSTI)

This process, the nickel electroplating of steam generator tubes, has been jointly developed under a Belgatom (Laborelec) and Framatome agreement with shared experience gained by both companies, industrial applications being under the responsibility of Framatome. Application of the coating in zones where residual stresses or cracks are present prevents contact between the primary water and the tube, which stops the stress corrosion process. In the Doel 2 plant, 91 tubes have been plated since 1985, and different sets of parameters have been used for comparison purposes. Among these tubes, 9 have been preventively plugged because of defective plating, 9 have been pulled out for laboratory examinations, 2 just after plating and 7 after 1 or 2 yr of service. There are 73 plated tubes still in service. From the tests that were performed, it was possible to select an optimized set of parameters guaranteeing the following properties: bridging of existing cracks and good behavior of the coating in relevant zones, good adhesion to the Inconel tube, high ductility, low residual stresses, thermal shock resistance, corrosion resistance, erosion resistance, and low cobalt content. The licensability of this process is being completed. It is based first on the leak-before-break concept to determine the characteristics of the nickel plating, thickness in particular, and second on the inspectability of ultrasonic testing methods.

Michaut, B.

1988-01-01T23:59:59.000Z

285

E-Print Network 3.0 - applications crack growth Sample Search...  

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

that the critical crack-tip opening angle (CTOA) value measured on the specimen... fracture changes a Mode-I type of crack growth to a mixed-mode IIII type of crack growth. It...

286

Fatigue of polycrystalline silicon for MEMS applications: Crack growth and stability under resonant loading conditions  

E-Print Network [OSTI]

S.B. , 1999. Subcritical crack growth in silicon MEMS. J.appearance of subcritical crack growth in the absence ofbe mistaken for subcritical fatigue-crack growth when the

Muhlstein, C.L.; Howe, R.T.; Ritchie, R.O.

2001-01-01T23:59:59.000Z

287

Propagating solitary waves along a rapidly moving crack front  

Science Journals Connector (OSTI)

... Much recent research has focused on crack front coherence and roughening. Simplified models (mode III) of fracture as well as more general models of ... the cumulative effect of numerous asperities would be to cause a crack front to continually roughen. We point out that despite this possibility of increasing roughness, the propagating nature of ...

Eran Sharon; Gil Cohen; Jay Fineberg

2001-03-01T23:59:59.000Z

288

Fracture mechanics analysis of slow crack growth in polyethylene  

E-Print Network [OSTI]

Slow crack growth in polyethylene is often the limiting factor in long-term service of plastic pipe or other structural applications. A new test method and analysis method was developed to study slow crack growth in polyethylene. Two high density...

Self, Robert Alan

1997-01-01T23:59:59.000Z

289

The Influence of Crystallographic Orientation on Crack Tip Displacements of  

E-Print Network [OSTI]

consists of 212 randomly shaped, sized and oriented grains, loaded monotonically in uniaxial tension to a maximum load of 0.9Rp0.2 (240 MPa). The influence that a random grain structure imposes on a Stage I crack will preferably follow the slip plane where the crack tip opening displacement is highest, we show

Cizelj, Leon

290

Prediction of pure water stress corrosion cracking (PWSCC) in nickel base alloys using crack growth rate models  

SciTech Connect (OSTI)

The Ford/Andresen slip dissolution SCC model, originally developed for stainless steel components in BWR environments, has been applied to Alloy 600 and Alloy X-750 tested in deaerated pure water chemistry. A method is described whereby the crack growth rates measured in compact tension specimens can be used to estimate crack growth in a component. Good agreement was found between model prediction and measured SCC in X-750 threaded fasteners over a wide range of temperatures, stresses, and material condition. Most data support the basic assumption of this model that cracks initiate early in life. The evidence supporting a particular SCC mechanism is mixed. Electrochemical repassivation data and estimates of oxide fracture strain indicate that the slip dissolution model can account for the observed crack growth rates, provided primary rather than secondary creep rates are used. However, approximately 100 cross-sectional TEM foils of SCC cracks including crack tips reveal no evidence of enhanced plasticity or unique dislocation patterns at the crack tip or along the crack to support a classic slip dissolution mechanism. No voids, hydrides, or microcracks are found in the vicinity of the crack tips creating doubt about classic hydrogen related mechanisms. The bulk oxide films exhibit a surface oxide which is often different than the oxides found within a crack. Although bulk chromium concentration affects the rate of SCC, analytical data indicates the mechanism does not result from chromium depletion at the grain boundaries. The overall findings support a corrosion/dissolution mechanism but not one necessarily related to slip at the crack tip.

Thompson, C.D.; Krasodomski, H.T.; Lewis, N.; Makar, G.L.

1995-02-22T23:59:59.000Z

291

Methods applied to investigate the major VCE that occured in the TOTAL refinery's Fluid Catalytic Cracking Unit at La Mede,  

E-Print Network [OSTI]

95-35 Methods applied to investigate the major �VCE that occured in the TOTAL refinery's Fluid.V.C.E, occured in the Gas Plant of the TOTAL refinery's Fluid Catalytic Cracking ünit at La Mede, France sources: control room hard copy and electronically stored records: no deviation of process operating

Paris-Sud XI, Université de

292

Crack Propagation Fracture Toughness of Several Wood Species Elijah Wilson, Meisam Shir Mohammadi, and John A. Nairn  

E-Print Network [OSTI]

1 Crack Propagation Fracture Toughness of Several Wood Species Elijah Wilson, Meisam Shir Mohammadi, and John A. Nairn Wood Science & Engineering, Oregon State University, Corvallis, OR, USA Abstract In materials with process zones, such as fiber bridging zones in wood, it is crucial to characterize fracture

Nairn, John A.

293

E-Print Network 3.0 - assisted cracking resistance Sample Search...  

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

crack... and the time-dependent, environmentally-assisted, crack initiation and subcritical growth in the oxide layer... of exploring these prin- ciples is seen in Figure 5....

294

The significance of crack-resistance curves to the mixed-mode fracture toughness of human cortical bone  

E-Print Network [OSTI]

in the presence of subcritical crack growth. It involvesgrowth (not crack initiation). As a result, stable (subcritical)

Zimmermann, Elizabeth A.

2010-01-01T23:59:59.000Z

295

The probabilistic life time prediction model of oil pipeline due to local corrosion crack  

Science Journals Connector (OSTI)

Abstract A four-stage probabilistic damage model is proposed basis of cross-scale damage processes to deal with the local corrosion crack of oil pipeline. At first, some key parameters for life time prediction were determined; then the probabilistic damage model is formulated and numerically calculated by using Monte Carlo Simulation (MCS). Furthermore, the model is used to deal with an example in order to check its validity. The results show that the life-span of this pipeline is nearly 20.55 years, and the pipe wall thickness, operating pressure difference and corrosion electric current density are the three key parameters to determine the span-life of this pipeline; the longest examination and repair period should be less than 4.71 years for safety when the surface crack length of 10 mm can be detected reliably.

Jun Hu; Yangyang Tian; Haipeng Teng; Lijun Yu; Maosheng Zheng

2014-01-01T23:59:59.000Z

296

The selective catalytic cracking of Fischer-Tropsch liquids to high value transportation fuels. Final report  

SciTech Connect (OSTI)

Amoco Oil Company, investigated a selective catalytic cracking process (FCC) to convert the Fischer-Tropsch (F-T) gasoline and wax fractions to high value transportation fuels. The primary tasks of this contract were to (1) optimize the catalyst and process conditions of the FCC process for maximum conversion of F-T wax into reactive olefins for later production of C{sub 4}{minus}C{sub 8} ethers, and (2) use the olefin-containing light naphtha obtained from FCC processing of the F-T wax as feedstock for the synthesis of ethers. The catalytic cracking of F-T wax feedstocks gave high conversions with low activity catalysts and low process severities. HZSM-5 and beta zeolite catalysts gave higher yields of propylene, isobutylene, and isoamylenes but a lower gasoline yield than Y zeolite catalysts. Catalyst selection and process optimization will depend on product valuation. For a given catalyst and process condition, Sasol and LaPorte waxes gave similar conversions and product selectivities. The contaminant iron F-T catalyst fines in the LaPorte wax caused higher coke and hydrogen yields.

Schwartz, M.M.; Reagon, W.J.; Nicholas, J.J.; Hughes, R.D.

1994-11-01T23:59:59.000Z

297

7 -ATOMIC PROCESSES Atomic processes can be  

E-Print Network [OSTI]

1 7 - ATOMIC PROCESSES Atomic processes can be: 1. Scattering 2. Absorption/Thermal Emission scattering, although the results won't change much when this condition is relaxed. #12;2 Absorption/Thermal Emission Free-free (continuum) ("Bremsstrahlung") Emission/Absorption Bound-Bound & Bound-Free Processes

Sitko, Michael L.

298

Factors Affecting the Hydrogen Environment Assisted Cracking Resistance of an Al-Zn-Mg-(Cu) Alloy  

SciTech Connect (OSTI)

It is well established that Al-Zn-Mg-(Cu) aluminum alloys are susceptible to hydrogen environment assisted cracking (HEAC) when exposed to aqueous environments. In Al-Zn-Mg-Cu alloys, overaged tempers are commonly used to increase HEAC resistance at the expense of strength. Overaging has little benefit in low copper alloys. However, the mechanism or mechanisms by which overaging imparts HEAC resistance is poorly understood. The present research investigated hydrogen uptake, diffusion, and crack growth rate in 90% relative humidity (RH) air for both a commercial copper bearing Al-Zn-Mg-Cu alloy (AA 7050) and a low copper variant of this alloy in order to better understand the factors which affect HEAC resistance. Experimental methods used to evaluate hydrogen concentrations local to a surface and near a crack tip include nuclear reaction analysis (NRA), focused ion beam, secondary ion mass spectroscopy (FIB/SIMS) and thermal desorption spectroscopy (TDS). When freshly bared coupons of AA 7050 are exposed to 90 C, 90% RH air, hydrogen ingress follows inverse-logarithmic-type kinetics and is equivalent for underaged (HEAC susceptible) and overaged (HEAC resistant) tempers. However, when the native oxide is allowed to form (24 hrs in 25 C, 40% RH lab air) prior to exposure to 90 C, 90% RH air, underaged alloy shows significantly greater hydrogen ingress than the overaged alloy. Humid air is a very aggressive environment producing local ({approx}1{micro}m) hydrogen concentrations in excess of 10,000 wt. ppm at 90 C. In the copper bearing alloy, overaging also effects the apparent diffusivity of hydrogen. As AA 7050 is aged from underaged {yields} peak aged {yields} overaged, the activation energy for hydrogen diffusion increases and the apparent diffusivity for hydrogen decreases, In the low copper alloy, overaging has little effect on hydrogen diffusion. Comparison of the apparent activation energies for hydrogen diffusion and for K independent (stage II) crack growth rate in 90% RH air between 25 and 90 C indicates that hydrogen transport kinetics are responsible for the decreased crack growth rate of overaged AA 7050 relative to the peak aged temper.

G.A. Young; J.R. Scully

2001-09-12T23:59:59.000Z

299

Neutron stars - thermal emitters  

E-Print Network [OSTI]

Confronting theoretical models with observations of thermal radiation emitted by neutron stars is one of the most important ways to understand the properties of both, superdense matter in the interiors of the neutron stars and dense magnetized plasmas in their outer layers. Here we review the theory of thermal emission from the surface layers of strongly magnetized neutron stars, and the main properties of the observational data. In particular, we focus on the nearby sources for which a clear thermal component has been detected, without being contaminated by other emission processes (magnetosphere, accretion, nebulae). We also discuss the applications of the modern theoretical models of the formation of spectra of strongly magnetized neutron stars to the observed thermally emitting objects.

Potekhin, A Y; Pons, J A

2014-01-01T23:59:59.000Z

300

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

E-Print Network [OSTI]

Engineering Laboratory / Värme- och strömningsteknik tel. 3223 ; ron.zevenhoven@abo.fi Kylteknik ("KYL") Refrigeration course # 424503.0 v. 2014 �A 424503 Refrigeration / Kylteknik 12.11.2014�bo Akademi Univ - Thermal voltage part for T-E) see ---- boundaries in the figures below The energy input occurs at the point where

Zevenhoven, Ron

Note: This page contains sample records for the topic "thermal cracking process" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Thermomechanical measurements on thermal microactuators.  

SciTech Connect (OSTI)

Due to the coupling of thermal and mechanical behaviors at small scales, a Campaign 6 project was created to investigate thermomechanical phenomena in microsystems. This report documents experimental measurements conducted under the auspices of this project. Since thermal and mechanical measurements for thermal microactuators were not available for a single microactuator design, a comprehensive suite of thermal and mechanical experimental data was taken and compiled for model validation purposes. Three thermal microactuator designs were selected and fabricated using the SUMMiT V{sup TM} process at Sandia National Laboratories. Thermal and mechanical measurements for the bent-beam polycrystalline silicon thermal microactuators are reported, including displacement, overall actuator electrical resistance, force, temperature profiles along microactuator legs in standard laboratory air pressures and reduced pressures down to 50 mTorr, resonant frequency, out-of-plane displacement, and dynamic displacement response to applied voltages.

Baker, Michael Sean; Epp, David S.; Serrano, Justin Raymond; Gorby, Allen D.; Phinney, Leslie Mary

2009-01-01T23:59:59.000Z

302

Author's personal copy Effect of fluid salinity on subcritical crack propagation in calcite  

E-Print Network [OSTI]

Author's personal copy Effect of fluid salinity on subcritical crack propagation in calcite Fatma Accepted 22 October 2012 Available online 31 October 2012 Keywords: Subcritical crack growth Calcite Salt Damage The slow propagation of cracks, also called subcritical crack growth, is a mechanism of fracturing

303

A three-dimensional validation of crack curvature in muscovite mica  

SciTech Connect (OSTI)

Experimental and computational efforts focused on characterizing crack tip curvature in muscovite mica. Wedge-driven cracks were propagated under monochromatic light. Micrographs verified the subtle curvature of the crack front near the free surface. A cohesive approach was employed to model mixed-mode fracture in a three-dimensional framework. Finite element calculations captured the crack curvature observed in experiment.

J. C. Hill; J. W. Foulk III; P. A. Klein; E. P. Chen

2001-01-07T23:59:59.000Z

304

EFFECT OF VISCOUS GRAIN BRIDGING ON CYCLIC FATIGUE-CRACK GROWTH IN MONOLITHIC CERAMICS  

E-Print Network [OSTI]

, toughness, creep, and subcritical crack growth [1± 10]. Under quasi-static loading, subcritical crack growthEFFECT OF VISCOUS GRAIN BRIDGING ON CYCLIC FATIGUE-CRACK GROWTH IN MONOLITHIC CERAMICS AT ELEVATED allow for consistent crack-growth monitoring in these materials at high temperatures, and even

Ritchie, Robert

305

Cyclic fatigue-crack propagation in sapphire in air and simulated physiological environments  

E-Print Network [OSTI]

for the first time in sapphire for both modes of subcritical cracking. It was found that growth rates were on the subcritical crack-growth prop- erties of sapphire. In general, crack growth in many polycrystalline ce- ramics loads. This article describes an investigation of subcritical crack growth in sapphire under both mon

Ritchie, Robert

306

Research on the evolvement of morphology of coking coal during the coking process  

Science Journals Connector (OSTI)

Abstract The evolvement of morphology and structure of the coal with different metamorphic degrees during coking process in the vertical furnace was investigated by infrared Image detector. Moreover, the temperature distribution in the radial direction and the crack formation were also studied in heating process. The results show that the amount of crack and the shrinkage level of char decrease with the coal rank rising. In addition, the initial temperature of crack formation for char increases with the coal rank rising.

Xiangyun Zhong; Shiyong Wu; Yang Liu; Zhenning Zhao; Yaru Zhang; Jinfeng Bai; Jun Xu; Bai Xi

2013-01-01T23:59:59.000Z

307

Environmentally Assisted Cracking of Ni-Base Alloys [Corrosion and  

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

LWRs > Environmentally Assisted LWRs > Environmentally Assisted Cracking of Ni-Base Alloys Capabilities Materials Testing Environmentally Assisted Cracking (EAC) of Reactor Materials Corrosion Performance/Metal Dusting Overview Light Water Reactors Fatigue Testing of Carbon Steels and Low-Alloy Steels Environmentally Assisted Cracking of Ni-Base Alloys Irradiation-Induced Stress Corrosion Cracking of Austenitic Stainless Steels Steam Generator Tube Integrity Program Air Oxidation Kinetics for Zr-based Alloys Fossil Energy Fusion Energy Metal Dusting Publications List Irradiated Materials Steam Generator Tube Integrity Other Facilities Work with Argonne Contact us For Employees Site Map Help Join us on Facebook Follow us on Twitter NE on Flickr Corrosion and Mechanics of Materials Light Water Reactors

308

Irradiation-Induced Stress Corrosion Cracking of Austenitic Stainless  

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

Environmentally Assisted Environmentally Assisted Cracking of Ni-Base Alloys Capabilities Materials Testing Environmentally Assisted Cracking (EAC) of Reactor Materials Corrosion Performance/Metal Dusting Overview Light Water Reactors Fatigue Testing of Carbon Steels and Low-Alloy Steels Environmentally Assisted Cracking of Ni-Base Alloys Irradiation-Induced Stress Corrosion Cracking of Austenitic Stainless Steels Steam Generator Tube Integrity Program Air Oxidation Kinetics for Zr-based Alloys Fossil Energy Fusion Energy Metal Dusting Publications List Irradiated Materials Steam Generator Tube Integrity Other Facilities Work with Argonne Contact us For Employees Site Map Help Join us on Facebook Follow us on Twitter NE on Flickr Corrosion and Mechanics of Materials Light Water Reactors Bookmark and Share

309

Automated crack control analysis for concrete pavement construction  

E-Print Network [OSTI]

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...

Jang, Se Hoon

2005-11-01T23:59:59.000Z

310

Delayed hydride cracking behavior for ZIRCALOY-2 tubing  

Science Journals Connector (OSTI)

The delayed hydride cracking (DHC) behavior for ZIRCALOY-2 tubing was characterized at temperatures ranging from 93 °C to 288 °C. Testing was performed on the three types of pressure tubes that were used in th...

F. H. Huang; W. J. Mills

1991-09-01T23:59:59.000Z

311

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...

312

SAFT Imaging of Transverse Cracks in Austenitic and Dissimilar Welds  

Science Journals Connector (OSTI)

Up to now there is no sufficient technique to detect transverse cracks in austenitic and dissimilar welds which recently are of increasing interest in the integrity surveillance of nuclear power plants as well as...

Christian Höhne; Sanjeevareddy Kolkoori…

2013-03-01T23:59:59.000Z

313

Failure analysis of a cracked diesel engine clutch spring plate  

Science Journals Connector (OSTI)

A diesel engine clutch spring plate used in a truck cracked when testing was being performed. The crack initiated from the middle of the thickness direction of the plate and propagated toward the front and the back of the plate. Fractographic studies indicate that brittle intergranular fracture was the dominant failure mechanism. Many parallel band structures were observed along the radial direction of the plate in the intergranular fracture region; a high density of secondary cracks and fine intergranular particles were found in this banded region. Metallurgical examinations indicated segregation of elongated MnS inclusions and the presence of granular vanadium carbides along the radial direction of the plate, at the location of the crack origin. Segregation of the elongated MnS inclusions leads to a reduction in toughness, and the combined segregation of inclusions and impurity elements at grain boundaries result in weakening of the boundaries. These conditions led to the intergranular brittle fracture of the clutch spring plate.

Zhiwei Yu; Xiaolei Xu

2008-01-01T23:59:59.000Z

314

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

SciTech Connect (OSTI)

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.

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

2014-03-10T23:59:59.000Z

315

Transformations of the Micro-Domain Structure of Polyimide Films during Thermally Induced Chemical Conversion:? Characterization via Thermodynamics of Irreversible Processes  

Science Journals Connector (OSTI)

To find ?ys? and ??uo uniquely interrelated is a hallmark of the model developed here. ... Rows obsd. in the process are attributed to surface diffusion processes conducted by local stresses in oriented surface layers. ...

Hanns-Georg Kilian; Sergei Bronnikov; Tatiana Sukhanova

2003-11-14T23:59:59.000Z

316

Failure Analysis of Cracked FS-85 Tubing and ASTAR-811C End Caps  

SciTech Connect (OSTI)

Failure analyses were performed on cracked FS-85 tubing and ASTAR-811C and caps which had been fabricated as components of biaxial creep specimens meant to support materials testing for the NR Space program. During the failure analyses of cracked FS-85 tubing, it was determined that the failure potentially could be due to two effects: possible copper contamination from the EDM (electro-discharge machined) recast layer and/or an insufficient solution anneal. to prevent similar failures in the future, a more formal analysis should be done after each processing step to ensure the quality of the material before further processing. During machining of the ASTAR-811FC rod to form end caps for biaxial creep specimens, linear defects were observed along the center portion of the end caps. These defects were only found in material that was processed from the top portion of the ingot. The linear defects were attributed to a probable residual ingot pipe that was not removed from the ingot. During the subsequent processing of the ingot to rod, the processing temperatures were not high enough to allow self healing of the ingot's residual pipe defect. To prevent this from occurring in the future, it is necessary to ensure that complete removal of the as-melted ingot pipe is verified by suitable non-destructive evaluation (NDE).

ME Petrichek

2006-02-09T23:59:59.000Z

317

Energy and environmental research emphasizing low-rank coal: Task 3.9 catalytic tar cracking  

SciTech Connect (OSTI)

Tar produced in the gasification of coal is deleterious to the operation of downstream equipment, including fuel cells, gas turbines, hot-gas stream cleanup filters, and pressure-swing absorption systems. Catalytic cracking of tars to smaller hydrocarbons can be an effective means of removing these tars from gas streams and, in the process, generating useful products, such as methane gas, which is crucial to operation of molten carbonate fuel cells. Aerosol tars are not readily removed from gas streams by conventional means and, as a consequence, often end up plugging filters or fouling fuel cells, turbines, or sorbents. Catalytic cracking of these tars to molecular moieties of C{sub 10} or smaller would prevent the problems commonly attributed to the tars. As an example, the moving Bourdon fixed-bed gasifier, by virtue of its efficient countercurrent heat exchange and widespread commercial use, may offer the lowest-cost integrated gasification combined-cycle (IGCC) system if tar generation and wastewater contamination can be minimized. We evaluate the potential of selected catalysts to minimize tar accumulation and maximize char conversion to useful liquid and/or gaseous products. Owing to the potential for production of extremely toxic nickel carbonyl gas, care must be exercised in the use of a NISMM catalyst for cracking tars at high temperatures in reducing atmospheres such as those produced by coal gasification. We observed a fifty percent or more of tar produced during steam gasification of Beulah lignite at temperatures of 400{degrees}-800+{degrees}C when cracked by either dolomite or zeolite maintained at a temperature of 50{degrees}C-100{degrees}C below that of the reactor.

Timpe, R.C.

1995-09-01T23:59:59.000Z

318

J-integral values for cracks in conventional fatigue specimens  

SciTech Connect (OSTI)

Comprehensive S-N fatigue data has been developed worldwide using conventional low-cycle fatigue tests. Such tests use smooth unnotched specimens subjected to controlled axial deflection or strain ranges. The tests must be run in the plastic regime in order to achieve the required cycles-to-failure. Recent developments have highlighted the need to understand and interpret the significance of the resulting strain range vs. cycles to failure data in terms of crack initiation and propagation. Since conventional fatigue tests are conducted in the plastic regime, linear elastic fracture mechanics cannot be used to accurately quantify crack growth in such tests. Elastic-plastic J-integral theory, however, has been shown to provide excellent correlations of crack growth in the elastic, elastic-plastic and grossly-plastic regimes for a wide range of geometric and loading conditions. The authors are applying this theory to the low-cycle fatigue specimen crack behavior. As cracks progress in conventional fatigue specimens, bending becomes significant. Since fatigue testing machines are quite stiff relative to the small fatigue specimens, the ends of the specimen are constrained to remain parallel, and this reduces bending in the cracked cross-section. Three-dimensional finite element elastic-plastic analyses are required to include these constraints in the J-integral solutions.

O`Donnell, T.P.; O`Donnell, W.J. [O`Donnell Consulting Engineers, Pittsburgh, PA (United States)

1996-12-01T23:59:59.000Z

319

Research on mechanisms of stress corrosion cracking in Zircaloy  

SciTech Connect (OSTI)

The results of internal gas pressurization tests, primarily at 320/sup 0/C, on cladding tubes from two suppliers, Supplier A and Supplier B, are presented. The two lots show a substantial difference in iodine SCC susceptibility so a test matrix is used to resolve the relative contributions of surface condition, residual stress, and texture. Additional tests with constant deflection split-ring specimens and with unstressed cladding segments are used to understand crack initiation and the early crack growth stages of SCC. The difference in SCC susceptibility is due to crystallographic texture. Other variables such as surface finish, stress relief temperature, and residual stress have little or no effect. Mechanical properties, crack initiation, and crack propagation all depend on texture. Both initiation and propagation features are analyzed by scanning electron microscopy. A mechanism for crack initiation consistent with most observations in this study and with the work of other investigators is proposed. At 320/sup 0/C, lifetime is crack initiation limited while several tests at 390/sup 0/C indicate that lifetime is less initiation limited at higher temperature. 31 figures, 9 tables.

Knorr, D.B.; Pelloux, R.M.

1981-06-01T23:59:59.000Z

320

Thermal treatment  

Science Journals Connector (OSTI)

Thermal treatment can be regarded as either a pre-treatment of waste prior to final disposal, or as a means of valorising waste by recovering energy. It includes both the burning of mixed MSW in municipal inciner...

Dr. P. White; Dr. M. Franke; P. Hindle

1995-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "thermal cracking process" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

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

SciTech Connect (OSTI)

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.

Lienert, Thomas J [Los Alamos National Laboratory

2010-12-09T23:59:59.000Z

322

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

E-Print Network [OSTI]

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

Cizelj, Leon

323

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

DOE Patents [OSTI]

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.

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

2003-02-11T23:59:59.000Z

324

Matrix fatigue cracking mechanisms of alpha(2) TMC for hypersonic applications  

SciTech Connect (OSTI)

The objective of this work was to understand matrix cracking mechanisms in a unidirectional alpha[sub 2] TMC in possible hypersonic applications. A (0)[sub 8] SCS-6/Ti-24Al-11Nb (at. percent) TMC was first subjected to a variety of simple isothermal and nonisothermal fatigue cycles to evaluate the damage mechanisms in simple conditions. A modified ascent mission cycle test was then performed to evaluate the combined effects of loading modes. This cycle mixes mechanical cycling at 150 and 483 C, sustained loads, and a slow thermal cycle to 815 C. At low cyclic stresses and strains more common in hypersonic applications, environment-assisted surface cracking limited fatigue resistance. This damage mechanism was most acute for out-of-phase nonisothermal cycles having extended cycle periods and the ascent mission cycle. A simple linear fraction damage model was employed to help understand this damage mechanism. Time-dependent environmental damage was found to strongly influence out-of-phase and mission life, with mechanical cycling damage due to the combination of external loading and CTE mismatch stresses playing a smaller role. The mechanical cycling and sustained loads in the mission cycle also had a smaller role.

Gabb, T.P.; Gayda, J.

1994-02-01T23:59:59.000Z

325

Matrix fatigue cracking in {alpha}{sub 2} titanium matrix composites for hypersonic applications  

SciTech Connect (OSTI)

The objective of this work was to understand matrix cracking mechanisms in a unidirectional {alpha}{sub 2} titanium matrix composite (TMC) in possible hypersonic applications. A [0]{sub 8} SCS-6/Ti-24Al-11Nb (atomic %) TMC was first subjected to a variety of simple isothermal and nonisothermal fatigue cycles to evaluate the damage mechanisms in simple conditions. A modified ascent mission cycle test was then performed to evaluate the combined effects of loading modes. This cycle mixes mechanical cycling at 150 and 483 C, sustained loads, and a slow thermal cycle to 815 C. At low cyclic stresses and strains more common in hypersonic applications, environment-assisted surface cracking limited fatigue resistance. This damage mechanism was most acute for out-of-phase nonisothermal cycles having extended cycle periods and the ascent mission cycle. A simple linear fraction damage model was employed to help understand this damage mechanism. Time-dependent environmental damage was found to strongly influence out-of-phase and mission life, with mechanical cycling damage due to the combination of external loading and CTE mismatch stresses playing a smaller role. The mechanical cycling and sustained loads in the mission cycle also had a smaller role.

Gabb, T.P.; Gayda, J. [NASA Lewis Research Center, Cleveland, OH (United States)

1996-12-31T23:59:59.000Z

326

Thermal plasmonic interconnects in graphene  

Science Journals Connector (OSTI)

As one emerging plasmonic material, graphene can support surface plasmons at infrared and terahertz frequencies with unprecedented properties due to the strong interactions between graphene and low-frequency photons. Since graphene surface plasmons exist in the infrared and terahertz regime, they can be thermally pumped (excited) by the infrared evanescent waves emitted from an object. Here we show that thermal graphene plasmons can be efficiently excited and have monochromatic and tunable spectra, thus paving a way to harness thermal energy for graphene plasmonic devices. We further demonstrate that “thermal information communication” via graphene surface plasmons can be potentially realized by effectively harnessing thermal energy from various heat sources, e.g., the waste heat dissipated from nanoelectronic devices. These findings open up an avenue of thermal plasmonics based on graphene for different applications ranging from infrared emission control, to information processing and communication, to energy harvesting.

Baoan Liu; Yongmin Liu; Sheng Shen

2014-11-10T23:59:59.000Z

327

7 -ATOMIC PROCESSES Atomic processes can be  

E-Print Network [OSTI]

1 7 - ATOMIC PROCESSES Atomic processes can be: 1. Scattering 2. Absorption/Thermal Emission scattering, although the results won't change much when this condition is relaxed. Absorption/Thermal Emission Free-free (continuum) ("Bremsstrahlung") Emission/Absorption #12;2 Bound-Bound & Bound

Sitko, Michael L.

328

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

E-Print Network [OSTI]

SiO2 film. An optimal process window had been previously identified at a total pressure of 5 Torr, but also quantitative metrology for the film deposition process. © 1999 American Vacuum Society. S0734-211X the wafer. Radiative heating of the wafer was achieved through a quartz window by an array of halogen lamps

Rubloff, Gary W.

329

Statistical simulation of small fatigue crack nucleation and coalescence in a lamellar TiAl alloy  

SciTech Connect (OSTI)

This article examines the possibility of fatigue failure as the result of fatigue crack nucleation and coalescence at stress ranges below the fatigue limit and the large crack threshold where fatigue cracks are expected not to grow. By representing the material as a two-dimensional array of beam elements, the nucleation of nonpropagating small cracks at various material locations is modeled via a statistical approach that considers fatigue crack nucleation by accumulation of damage at randomly distributed weak regions. Once nucleated, the fatigue cracks do not propagate but extend only by linking with fatigue cracks subsequently formed in the contiguous elements. Result of the computer simulation suggests that fatigue failure by crack nucleation and coalescence is feasible, but the cycles-to-coalescence is much longer than the cycles-to-initiation for the first crack. Implications of the results in fatigue life assessment based on the Kitagawa diagram are discussed for TiAl alloys.

Chan, K.S. [Southwest Research Inst., San Antonio, TX (United States); Wittowsky, B. [Proctor and Gamble European Service GmbH, Euskirchen (Germany); Pfuff, M. [GKSS Research Center, Geesthacht (Germany)

1999-05-01T23:59:59.000Z

330

Measure the Crack Instead of Construction Vibrations by Charles H. Dowding, Ph.D., P.E.  

E-Print Network [OSTI]

Measure the Crack Instead of Construction Vibrations by Charles H. Dowding, Ph.D., P.E. Figure 1 to address fears of vibration-induced cracking by directly measuring crack response. Relatively inexpensive. HOUSE AND CRACK RESPONSE TO VIBRATIONS Crack measurement concepts are illustrated by the response

331

Integrated Modeling for Intelligent Battery Thermal Management  

Science Journals Connector (OSTI)

Effective thermal management is crucial to the optimal operation of lithium ion batteries and its health management. However, the thermal behaviors of batteries are governed by complex chemical process whose parameters will degrade over time and different ... Keywords: integrated modeling, distributed parameter system, battery thermal management, intelligent learning

Zhen Liu; Han-Xiong Li

2013-10-01T23:59:59.000Z

332

Coding the cracks | Argonne Leadership Computing Facility  

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

is able to calculate and solve these processes in a single day, standard high-performance computing clusters typically available to university researchers could take six months...

333

FITNESS-FOR-SERVICE ASSESSMENT FOR A RADIOACTIVE WASTE TANK THAT CONTAINS STRESS CORROSION CRACKS  

SciTech Connect (OSTI)

Radioactive wastes are confined in 49 underground storage tanks at the Savannah River Site. The tanks are examined by ultrasonic (UT) methods for thinning, pitting, and stress corrosion cracking in order to assess fitness-for-service. During an inspection in 2002, ten cracks were identified on one of the tanks. Given the location of the cracks (i.e., adjacent to welds, weld attachments, and weld repairs), fabrication details (e.g., this tank was not stress-relieved), and the service history the degradation mechanism was stress corrosion cracking. Crack instability calculations utilizing API-579 guidance were performed to show that the combination of expected future service condition hydrostatic and weld residual stresses do not drive any of the identified cracks to instability. The cracks were re-inspected in 2007 to determine if crack growth had occurred. During this re-examination, one indication that was initially reported as a 'possible perpendicular crack <25% through wall' in 2002, was clearly shown not to be a crack. Additionally, examination of a new area immediately adjacent to other cracks along a vertical weld revealed three new cracks. It is not known when these new cracks formed as they could very well have been present in 2002 as well. Therefore, a total of twelve cracks were evaluated during the re-examination. Comparison of the crack lengths measured in 2002 and 2007 revealed that crack growth had occurred in four of the nine previously measured cracks. The crack length extension ranged from 0.25 to 1.8 inches. However, in all cases the cracks still remained within the residual stress zone (i.e., within two to three inches of the weld). The impact of the cracks that grew on the future service of Tank 15 was re-assessed. API-579 crack instability calculations were again performed, based on expected future service conditions and trended crack growth rates for the future tank service cycle. The analysis showed that the combined hydrostatic and weld residual stresses do not drive the identified cracks to instability. This tank expected to be decommissioned in the near future. However, if these plans are delayed, it was recommended that a third examination of selected cracks in the tank be performed in 2014.

Wiersma, B; James Elder, J; Rodney Vandekamp, R; Charles Mckeel, C

2009-04-23T23:59:59.000Z

334

Influence of cracking on the diffusion properties of cement-based materials. Part I: Influence of continuous cracks on the steady-state regime  

SciTech Connect (OSTI)

The influence of traversing cracks on the steady-state diffusion properties of concrete was studied. The effect of both anisotropic and isotropic crack networks was first theoretically assessed using an analytical approach. To simplify the transport equations, cracks were assumed to be of uniform size and evenly distributed on a one- or two-dimensional grid. Results of the theoretical analysis were then compared to experimental data. Both series of results indicate that cracking can markedly alter the diffusion properties of the material and favor the penetration (or the leaching) of drifting species. A simple method to predict the effect of cracking on the concrete diffusivity is proposed. Predictions are made on the basis of two parameters: the crack density and the mean crack aperture. This method can provide a first estimate of the diffusion properties of severely damaged concrete elements.

Gerard, B.; Marchand, J.

2000-01-01T23:59:59.000Z

335

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

SciTech Connect (OSTI)

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.

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

1987-08-01T23:59:59.000Z

336

Characterization of geothermal reservoir crack patterns using shear-wave  

Open Energy Info (EERE)

geothermal reservoir crack patterns using shear-wave geothermal reservoir crack patterns using shear-wave splitting Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Characterization of geothermal reservoir crack patterns using shear-wave splitting Details Activities (1) Areas (1) Regions (0) Abstract: Microearthquakes recorded by a downhole, three-component seismic network deployed around the Coso, California, geothermal reservoir since 1992 display distinctive shear-wave splitting and clear polarization directions. From the polarizations the authors estimated three predominant subsurface fracture directions, and from the time delays of the split waves they determined tomographically the 3-D fracture density distribution in the reservoir. Author(s): Lou, M.; Rial, J.A. Published: Geophysics, 3/1/1997

337

Shear-wave splitting and reservoir crack characterization: the Coso  

Open Energy Info (EERE)

Shear-wave splitting and reservoir crack characterization: the Coso Shear-wave splitting and reservoir crack characterization: the Coso geothermal field Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Shear-wave splitting and reservoir crack characterization: the Coso geothermal field Details Activities (1) Areas (1) Regions (0) Abstract: This paper aims to improve current understanding of the subsurface fracture system in the Coso geothermal field, located in east-central California. The Coso reservoir is in active economic development, so that knowledge of the subsurface fracture system is of vital importance for an accurate evaluation of its geothermal potential and day-to-day production. To detect the geometry and density of fracture systems we applied the shear-wave splitting technique to a large number of

338

Stress-corrosion cracking in BWR and PWR piping  

SciTech Connect (OSTI)

Intergranular stress-corrosion cracking of weld-sensitized wrought stainless steel piping has been an increasingly ubiquitous and expensive problem in boiling-water reactors over the last decade. In recent months, numerous cracks have been found, even in large-diameter lines. A number of potential remedies have been developed. These are directed at providing more resistant materials, reducing weld-induced stresses, or improving the water chemistry. The potential remedies are discussed, along with the capabilities of ultrasonic testing to find and size the cracks and related safety issues. The problem has been much less severe to date in pressurized-water reactors, reflecting the use of different materials and much lower coolant oxygen levels.

Weeks, R.W.

1983-07-01T23:59:59.000Z

339

Cracking a Cold Case and Enduring Mystery | Department of Energy  

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

Cracking a Cold Case and Enduring Mystery Cracking a Cold Case and Enduring Mystery Cracking a Cold Case and Enduring Mystery July 1, 2013 - 3:04pm Addthis Chris Brandon of the ROMACONS project collects a sample of ancient Roman concrete drilled from a breakwater in Pozzuoli Bay, near Naples, Italy. The breakwater dates back to roughly 37 B.C. | Photo courtesy of J.P. Oleson. Chris Brandon of the ROMACONS project collects a sample of ancient Roman concrete drilled from a breakwater in Pozzuoli Bay, near Naples, Italy. The breakwater dates back to roughly 37 B.C. | Photo courtesy of J.P. Oleson. Charles Rousseaux Charles Rousseaux Senior Writer, Office of Science What are the key facts? Modern concrete buildings -- most made with Portland cement -- are built to last for a hundred or so years. But Roman concrete has withstood

340

Stress intensity factors for small fatigue cracks in tubular joints  

SciTech Connect (OSTI)

Some simple fracture mechanics models are presented for estimating stress intensity factors for small surface fatigue cracks in welded tubular joints. Model predictions are compared with large-scale experimental results for the cases of in-plane and out-of-plane bending in multi-brace tubular nodes. It is demonstrated that reasonably accurate predictions of the stress intensity factor are possible using a modified flat plate solution if the effects of weld geometry, load shedding and crack shape are adequately accounted for.

Monahan, C.C. [Memorial Univ. of Newfoundland, St. Johns, Newfoundland (Canada). Centre for Cold Ocean Resources Engineering; Dover, W.D. [University College, London (United Kingdom)

1995-12-31T23:59:59.000Z

Note: This page contains sample records for the topic "thermal cracking process" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Model of crack propagation in a clay soil  

E-Print Network [OSTI]

of independent variables for maximum R to determine A for crack de th, 2 Number of variables in model (p) R Variables in model 0. 703913 0. 916176 0. 988151 0. 997207 0. 999328 H*CLrH*M~CL H, H*M, H~M*CL H, CL, H*M, H*M*CL H, CL, H"M, H*CL, H...: Agricultural Engineering MODEL OF CRACK PROPAGATION IN A CLAY SOIL A Thesis by PATRICK EDWIDGE CARRIERE Approved as to style and content by: John L. Nieber (Chairman of Committee) Donald L. Reddell (Member) Kirk W, Brown (Member ) Wilbert H...

Carriere, Patrick Edwidge

2012-06-07T23:59:59.000Z

342

Waste package degradation from thermal and chemical processes in performance assessments for the Yucca Mountain disposal system for spent nuclear fuel and high-level radioactive waste  

Science Journals Connector (OSTI)

Abstract This paper summarizes modeling of waste container degradation in performance assessments conducted between 1984 and 2008 to evaluate feasibility, viability, and assess compliance of a repository for spent nuclear fuel and high-level radioactive waste at Yucca Mountain, Nevada. As understanding of the Yucca Mountain disposal system increased, modeling of container degradation evolved from a component of the source term in 1984 to a separate module describing both container and drip shield degradation in 2008. A thermal module for evaluating the influence of higher heat loads from more closely packed, large waste packages was also introduced. In addition, a module for evaluating drift chemistry was added in later \\{PAs\\} to evaluate the potential for localized corrosion of the outer barrier of the waste container composed of Alloy 22, a highly corrosion-resistant nickel–chromium–tungsten–molybdenum alloy. The uncertainty of parameters related to container degradation contributed significantly to the estimated uncertainty of performance measures (cumulative release in assessments prior to 1995 and individual dose, thereafter).

Rob P. Rechard; Joon H. Lee; Ernest L. Hardin; Charles R. Bryan

2014-01-01T23:59:59.000Z

343

AQUIFER THERMAL ENERGY STORAGE  

E-Print Network [OSTI]

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

Tsang, C.-F.

2011-01-01T23:59:59.000Z

344

A sintering model for thermal barrier coatings R.G. Hutchinson a  

E-Print Network [OSTI]

Turbine blades in the high-pressure, high-temperature stages of gas turbines are manufactured from creep model is developed for the progressive sintering of ceramic columns in a thermal barrier coating made. Explicit calculations are reported for the evolution of sintering within an array of mud-cracked columns

Fleck, Norman A.

345

E-Print Network 3.0 - assisted crack growth Sample Search Results  

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

cal crack growth by stress... for the first time in sapphire for both modes of subcritical cracking. It was found that growth rates were... growth rates could be closely...

346

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

E-Print Network [OSTI]

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...

Ackerson, Jason Paul

2013-11-20T23:59:59.000Z

347

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

SciTech Connect (OSTI)

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.

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

2012-02-13T23:59:59.000Z

348

Design of a turbomachine set for a fluid catalytic cracking plant and its shop-testing under full-load conditions  

SciTech Connect (OSTI)

In fluid catalytic cracking plants, heavy hydrocarbons are converted into low-boiling point products. Starting from a concise description of the energy recovery system, this paper details the design features of a turbo machine set for an FCC plant, with the emphasis on the design of the four-stage 12,000 kW process gas expander. 6 refs.

Turanskyj, L.; Woelk, G.U.

1982-04-01T23:59:59.000Z

349

Non-thermal plasma enhanced heavy oil upgrading  

Science Journals Connector (OSTI)

Abstract A process was proposed for upgrading heavy oil using non-thermal plasma technology in a conventional thermal cracking system under atmospheric pressure. Results from a comparison of the reactivity of a N2, H2 and CH4 plasma showed that the plasma can increase the trap oil yield significantly. The trap oil yield increased by ?9% when the N2 plasma was applied and showed a further increase of ?19% when the H2 or CH4 plasma was applied. A detailed study on the H2 plasma-enhanced upgrading process was carried out and the results showed that the trap oil yields of the plasma-on runs can be 8–33% higher than those of the plasma-off runs, depending on experimental conditions. Compared with the plasma-off runs, trap oil from the plasma-on runs had a higher (H/C)atomic but less heteroatoms (S and N). Over-balanced hydrogen in the products from plasma-on runs revealed the H2 plasma reactivity, which was further demonstrated by an increase in the substitution and condensation indices of trap oil from the plasma-on runs. Although thermal cracking was mainly involved whether the plasma was applied or not, the electrical field for generating the plasma and the generated plasma may assist with hydrocarbon bond cleavage. This was shown by the increased trap oil yield with the N2 plasma and the hydrogen and carbon residue distribution. Compared with the feedstock, more aromatic and ?-hydrogen (HA and H?, respectively) and less ?- and ?-hydrogen (H? and H?, respectively) were present in the residues, which agrees with the bond dissociation energy data. Similarly, the amounts of saturated (Cs) and alkyl (Cp) carbons in the residues were significantly lower than those in the feedstock while the amount of aromatic carbons (Ca) in the residues was higher than the feedstock. The changes in hydrogen and carbon distribution were more significant for the plasma-on runs. This implies that mainly side chain losses and bridged bond breakage are involved in the processes. This was demonstrated further by the molecular weight distribution. In general, the molecular weight of the residues was lower than that of the feedstock, especially for residues from the plasma-on runs. However, compared with the feedstock, the residues contained less saturated, aromatic and resin fractions but more asphaltene and toluene insoluble fractions. This implies that intra-molecular condensation was more significant than inter-molecular condensation, especially in the plasma-on runs. This should be attributed to the higher stabilization ability of the H2 plasma for fragments or radicals and gas (plasma) flow by which the fragments or radicals are separated rapidly.

Haigang Hao; Bao S. Wu; Jianli Yang; Qiang Guo; Yong Yang; Yong W. Li

2014-01-01T23:59:59.000Z

350

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

SciTech Connect (OSTI)

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.

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

351

EARLY-AGE CRACKING REVIEW: MECHANISMS, MATERIAL PROPERTIES,  

E-Print Network [OSTI]

://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

Bentz, Dale P.

352

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

353

Predicting overload-affected fatigue crack growth in steels  

SciTech Connect (OSTI)

The ability of semi-empirical crack closure models to predict the effect of overloads on fatigue crack growth in low-alloy steels has been investigated. With this purpose, the CORPUS model developed for aircraft metals and spectra has been checked first through comparisons between the simulated and observed results for a low-alloy steel. The CORPUS predictions of crack growth under several types of simple load histories containing overloads appeared generally unconservative which prompted the authors to formulate a new model, more suitable for steels. With the latter approach, the assumed evolution of the crack opening stress during the delayed retardation stage has been based on experimental results reported for various steels. For all the load sequences considered, the predictions from the proposed model appeared to be by far more accurate than those from CORPUS. Based on the analysis results, the capability of semi-empirical prediction concepts to cover experimentally observed trends that have been reported for sequences with overloads is discussed. Finally, possibilities of improving the model performance are considered.

Skorupa, M.; Skorupa, A.; Ladecki, B. [Univ. of Mining and Metallurgy, Krakow (Poland). Dept. of Mechanical Engineering and Robotics

1996-12-01T23:59:59.000Z

354

Cracks and Atoms** By Dominic Holland* and Michael Marder  

E-Print Network [OSTI]

Cracks and Atoms** By Dominic Holland* and Michael Marder 1. Introduction Many materials scientists the atomic scale on the mechanical response of materials. On the one hand, there is a reluctance to believe that the invisible atomic scale is important for macroscopic mechanical deformation. Out of sight, out of mind

Texas at Austin. University of

355

Corrosion pitting and environmentally assisted small crack growth  

Science Journals Connector (OSTI)

...of pit geometry and the local pit chemistry. In addition, the pit may have significant microtopographical...these can be found in the work of Burns et al. [29] in relation to...that cracks may initiate near the pit mouth, but the specific location...

2014-01-01T23:59:59.000Z

356

Incipient Crack Detection in Composite Wind Turbine Blades  

SciTech Connect (OSTI)

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.

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

357

A new approach to the subcritical cracking of ceramic Pierre Ladev`eze,a,1  

E-Print Network [OSTI]

A new approach to the subcritical cracking of ceramic fibers Pierre Ladev`eze,a,1 , Martin Geneta a Cachan Cedex, France Abstract A new modeling approach to subcritical crack propagation (i.e. static fa, the result comes down to the widely-used Paris-like subcritical crack propagation law. For the general case

358

Average crack front velocity during subcritical fracture propagation in a heterogeneous medium  

E-Print Network [OSTI]

Average crack front velocity during subcritical fracture propagation in a heterogeneous medium relaxation tests, exploring subcritical to critical regimes. Transparency of the material (PMMA) allows kinetic crack propagation is usually referred to as sub-critical crack growth or sub- critical regime

Paris-Sud XI, Université de

359

On the physics of moisture-induced cracking in metal-glass ,,copper-silica... interfaces  

E-Print Network [OSTI]

September 2007 Environmentally dependent subcritical crack growth, or stress-corrosion cracking, along on the moisture content in gaseous environments. Water and several organic liquids, namely n-butanol, methanol, additionally, subcritical crack growth17 and cyclically induced fracture18 at or near these interfaces when

Ritchie, Robert

360

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

E-Print Network [OSTI]

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

Volinsky, Alex A.

Note: This page contains sample records for the topic "thermal cracking process" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Influence of Impurity Segregation on Temper Embrittlement and on Slow Fatigue Crack  

E-Print Network [OSTI]

of segregated impurity atoms (temper embrittlement) and hydrogen atoms, evolved from crack tip surface reactions with water vapor in the moist air environment (hydrogen embrittlement). The signifi- cance of crack closureInfluence of Impurity Segregation on Temper Embrittlement and on Slow Fatigue Crack Growth

Ritchie, Robert

362

Brittle fracture in a periodic structure with internal potential energy. Spontaneous crack propagation  

Science Journals Connector (OSTI)

...with the crack speed-energy relation is presented...crack-related dynamic Green's function. For anisotropic...crack-related dynamic Green's function Note that...absence of the internal energy was considered in [14] without evaluation of the Green's function (also see...

2014-01-01T23:59:59.000Z

363

MICRO-METER MEASUREMENT OF CRACKS TO COMPARE BLAST AND ENVIRONMENTAL EFFECTS.  

E-Print Network [OSTI]

to development of a new approach to vibration monitoring called autonomous crack measurement (ACM vibration time histories. Measurements reported herein show that weather- induced response of cracksMICRO-METER MEASUREMENT OF CRACKS TO COMPARE BLAST AND ENVIRONMENTAL EFFECTS. Charles H Dowding

364

White(etching!matter!in!bearing!steel! Part1:!Controlled(cracking!of!52100!steel!  

E-Print Network [OSTI]

! 1! White(etching!matter!in!bearing!steel! Part1:!Controlled(cracking!of!52100!steel! ! W!phenomena!such!as!the!appearance!of!"white(etching!areas"!or!"white(etching! cracks",!crack!particular!kind!of!microstructural!damage!in!the!form!of!regions!of!the! structure,! which! appear! white! in

Cambridge, University of

365

ensl-00138774,version1-27Mar2007 Slow crack growth: models and experiments  

E-Print Network [OSTI]

the subcritical growth of a single crack in thin sheets of paper. A good agreement between the theoreticalensl-00138774,version1-27Mar2007 Slow crack growth: models and experiments S. Santucci, L. Vanel, S'Italie, 69364 Lyon Cedex 07, France March 28, 2007 Abstract The properties of slow crack growth in brittle

Paris-Sud XI, Université de

366

J Am Cerom Soc 73 [4]893-903 (1990) Cyclic Fatigue-Crack Propagation in  

E-Print Network [OSTI]

InternationalScience Center, Thousand Oaks, California 91360 The subcritical growth of fatigue cracks under variable-amplitude cyclic loading, crack-growth rates show transient accelera- tions following low overloads, again analogous to behavior commonly observed in ductile metals. Cyclic crack-growth rates

Ritchie, Robert

367

Biomaterials 28 (2007) 49014911 Stresscorrosion crack growth of SiNaKMgCaPO bioactive  

E-Print Network [OSTI]

Elsevier Ltd. All rights reserved. Keywords: Stress corrosion; Bioactive glass; Subcritical crack growthBiomaterials 28 (2007) 4901­4911 Stress­corrosion crack growth of Si­Na­K­Mg­Ca­P­O bioactive Available online 21 August 2007 Abstract This paper describes research on the stress­corrosion crack growth

Ritchie, Robert

368

Fluid Catalytic Cracking Power Recovery Computer Simulation  

E-Print Network [OSTI]

re covery available in new plants results in the air string being almost self sustaining, 8S far as direct input power. With some processes, it is possible to produce excess power on the order of 1,000 to 9,000 HP. Waste heat recovery in the form...

Samurin, N. A.

1979-01-01T23:59:59.000Z

369

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

E-Print Network [OSTI]

to make lasting repairs to the Watts Towers. 15 REFERENCES [1] LSTC. "LS-DYNA KEYWROD MANUAL." DYNA Support. Livermore Software Technology Corporation, n.d. Web. 5 Apr. 2013.

Spencer, Matthew T

2013-02-06T23:59:59.000Z

370

Estimation of Damage to the Collector of a Water Economizer by Thermal Fatigue Cracks  

Science Journals Connector (OSTI)

We study defects formed on the outer and inner surfaces of the input collector of water economizer of a TPP-312 boiler at the...

R. Ya. Kosarevych; O. Z. Student; Ya. D. Onyshchak; A. D. Markov…

2004-01-01T23:59:59.000Z

371

Thermal Shock-resistant Cement  

SciTech Connect (OSTI)

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.

Sugama T.; Pyatina, T.; Gill, S.

2012-02-01T23:59:59.000Z

372

Ultrasonic Flaw Detection of Cracks and Machined Flaws as Observed Through Austenitic Stainless Steel Piping Welds  

SciTech Connect (OSTI)

Piping welds in the pressure boundary of light water reactors (LWRs) are subject to a volumetric examination based on Section XI of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code. Due to access limitations and high background radiation levels, the technique used is primarily ultrasonic rather than radiographic. Many of the austenitic welds in safety-related piping systems provide limited access to both sides of the weld, so a far-side examination is necessary. Historically, far-side inspections have performed poorly because of the coarse and elongated grains that make up the microstructures of austenitic weldments. The large grains cause the ultrasound to be scattered, attenuated, and redirected. Additionally, grain boundaries or weld geometry may reflect coherent ultrasonic echoes, making flaw detection and discrimination a more challenging endeavor. Previous studies conducted at the Pacific Northwest National Laboratory (PNNL) on ultrasonic far-side examinations in austenitic piping welds involved the application of conventional transducers, use of low-frequency Synthetic Aperture Focusing Techniques (SAFT), and ultrasonic phased-array (PA) methods on specimens containing implanted thermal fatigue cracks and machined reflectors [1-2]. From these studies, PA inspection provided the best results, detecting nearly all of the flaws from the far side. These results were presented at the Fifth International Conference on NDE in Relation to Structural Integrity for Nuclear and Pressurised Components in 2006. This led to an invitation to examine field-removed specimens containing service-induced intergranular stress corrosion cracks (IGSCC) at the Electric Power Research Institute’s (EPRI) Nondestructive Evaluation (NDE) Center, in Charlotte, North Carolina. Results from this activity are presented.

Anderson, Michael T.; Cinson, Anthony D.; Crawford, Susan L.; Cumblidge, Stephen E.; Diaz, Aaron A.

2009-07-01T23:59:59.000Z

373

Reactor Thermal-Hydraulics  

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

Thermal-Hydraulics Thermal-Hydraulics Dr. Tanju Sofu, Argonne National Laboratory In a power reactor, the energy produced in fission reaction manifests itself as heat to be removed by a coolant and utilized in a thermodynamic energy conversion cycle to produce electricity. A simplified schematic of a typical nuclear power plant is shown in the diagram below. Primary coolant loop Steam Reactor Heat exchanger Primary pump Secondary pump Condenser Turbine Water Although this process is essentially the same as in any other steam plant configuration, the power density in a nuclear reactor core is typically four orders of magnitude higher than a fossil fueled plant and therefore it poses significant heat transfer challenges. Maximum power that can be obtained from a nuclear reactor is often limited by the

374

Thermalization through parton transport  

E-Print Network [OSTI]

A radiative transport model is used to study kinetic equilibration during the early stage of a relativistic heavy ion collision. The parton system is found to be able to overcome expansion and move toward thermalization via parton collisions. Scaling behaviors show up in both the pressure anisotropy and the energy density evolutions. In particular, the pressure anisotropy evolution shows an approximate alpha_s scaling when radiative processes are included. It approaches an asymptotic time evolution on a time scale of 1 to 2 fm/c. The energy density evolution shows an asymptotic time evolution that decreases slower than the ideal hydro evolution. These observations indicate that partial thermalization can be achieved and viscosity is important for the evolution during the early longitudinal expansion stage of a relativistic heavy ion collision.

Bin Zhang

2009-09-03T23:59:59.000Z

375

EFFECT OF UNBROKEN LIGAMENTS ON STRESS CORROSION CRACKING BEHAVIOR OF ALLOY 82H WELDS  

SciTech Connect (OSTI)

Previously reported stress corrosion cracking (SCC) rates for Alloy 82H gas-tungsten-arc welds tested in 360 C water showed tremendous variability. The excessive data scatter was attributed to the variations in microstructure, mechanical properties and residual stresses that are common in welds. In the current study, however, re-evaluation of the SCC data revealed that the large data scatter was an anomaly due to erroneous crack growth rates inferred from crack mouth opening displacement (CMOD) measurements. Apparently, CMOD measurements provided reasonably accurate SCC rates for some specimens, but grossly overestimated rates in others. The overprediction was associated with large unbroken ligaments that often form in welds in the wake of advancing crack fronts. When ligaments were particularly large, they prevented crack mouth deflection, so apparent crack incubation times (i.e. period of time before crack advance commences) based on CMOD measurements were unrealistically long. During the final states of testing, ligaments began to separate allowing the crack mouth to open rather quickly. This behavior was interpreted as a rapid crack advance, but it actually reflects the ligament separation rate, not the SCC rate. Revised crack growth rates obtained in this study exhibit substantially less scatter than that previously reported. The effects of crack orientation and fatigue flutter loading on SCC rates in 82H welds are also discussed.

Mills, W.J. and Brown, C.M.

2003-02-20T23:59:59.000Z

376

Characteristics of lead induced stress corrosion cracking of alloy 690 in high temperature  

SciTech Connect (OSTI)

Slow strain rate tests (SSRT) were conducted on alloy 690 in various lead chloride solutions and metal lead added to 100 ppm chloride solution at 288 C. The corrosion potential (rest potential) for the alloy was measured with SSRT tests. The cracking was observed by metallographic examination and electron probe micro analyzer. Also, the corrosion behavior of the alloy was evaluated by anodic polarized measurement at 30 C. Resulting from the tests, cracking was characterized by cracking behavior, crack length and crack growth rate, and lead effects on cracking. The cracking was mainly intergranular in mode, approximately from 60 um to 450 um in crack length, and approximately 10{sup {minus}6} to 10{sup {minus}7} mmS-1 in crack velocity. The cracking was evaluated through the variation the corrosion potential in potential-time and lead behavior during SSRTs. The lead effect in corrosion was evaluated through active to passive transition behavior in anodic polarized curves. The corrosion reactions in the cracking region were confirmed by electron probe microanalysis. Alloy 690 is used for steam generation tubes in pressurized water reactors.

Chung, K.K. [Korea Inst. of Nuclear Safety, Taejon (Korea, Republic of); Lim, J.K. [Chonbuk National Univ., Chonju (Korea, Republic of); Watanabe, Yutaka; Shoji, Tetsuo [Tohoku Univ., Sendai (Japan). Research Inst. for Fracture Technology

1996-10-01T23:59:59.000Z

377

Advanced thermal barrier coating system development. Technical progress report, June 1, 1996--July 31, 1996  

SciTech Connect (OSTI)

An improved thermal barrier coating system with good reliability and thermal performance is described. The report discusses the coating process, manufacturing, repair, deposition, and microstructure of the coatings.

NONE

1996-08-07T23:59:59.000Z

378

Adaptive Restoration of Airborne Daedalus AADS1268 ATM Thermal Data  

SciTech Connect (OSTI)

To incorporate the georegistration and restoration processes into airborne data processing in support of U.S. Department of Energy's nuclear emergency response task, we developed an adaptive restoration filter for airborne Daedalus AADS1268 ATM thermal data based on the Wiener filtering theory. Preliminary assessment shows that this filter enhances the detectability of small weak thermal anomalies in AADS1268 thermal images.

D. Yuan; E. Doak; P. Guss; A. Will

2002-01-01T23:59:59.000Z

379

Selective thermal and photooxidation of hydrocarbons in zeolites by oxygen  

DOE Patents [OSTI]

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.

Frei, H.; Blatter, F.; Sun, H.

1999-06-22T23:59:59.000Z

380

Fatigue and Creep Crack Propagation behaviour of Alloy 617 in the Annealed and Aged Conditions  

SciTech Connect (OSTI)

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.

Julian K. Benz; Richard N. Wright

2013-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "thermal cracking process" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

On the application of bees algorithm to the problem of crack detection of beam-type structures  

Science Journals Connector (OSTI)

In this paper, the application of the bees algorithm (BA) to the problem of crack detection in beams is introduced. A numerical as well as an experimental study is designed to predict a single open edge-crack in cantilever beams. The crack is modeled ... Keywords: Bees algorithm, Cantilever beam, Crack detection, Modal testing, Particle swarm optimization

S. Moradi; P. Razi; L. Fatahi

2011-12-01T23:59:59.000Z

382

Environmentally assisted cracking of light-water reactor materials  

SciTech Connect (OSTI)

Environmentally assisted cracking (EAC) of lightwater reactor (LWR) materials has affected nuclear reactors from the very introduction of the technology. Corrosion problems have afflicted steam generators from the very introduction of pressurized water reactor (PWR) technology. Shippingport, the first commercial PWR operated in the United States, developed leaking cracks in two Type 304 stainless steel (SS) steam generator tubes as early as 1957, after only 150 h of operation. Stress corrosion cracks were observed in the heat-affected zones of welds in austenitic SS piping and associated components in boiling-water reactors (BRWs) as early as 1965. The degradation of steam generator tubing in PWRs and the stress corrosion cracking (SCC) of austenitic SS piping in BWRs have been the most visible and most expensive examples of EAC in LWRs, and the repair and replacement of steam generators and recirculation piping has cost hundreds of millions of dollars. However, other problems associated with the effects of the environment on reactor structures and components am important concerns in operating plants and for extended reactor lifetimes. Cast duplex austenitic-ferritic SSs are used extensively in the nuclear industry to fabricate pump casings and valve bodies for LWRs and primary coolant piping in many PWRs. Embrittlement of the ferrite phase in cast duplex SS may occur after 10 to 20 years at reactor operating temperatures, which could influence the mechanical response and integrity of pressure boundary components during high strain-rate loading (e.g., seismic events). The problem is of most concern in PWRs where slightly higher temperatures are typical and cast SS piping is widely used.

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

1996-02-01T23:59:59.000Z

383

Chapter 5 - Gasification Processes  

Science Journals Connector (OSTI)

Publisher Summary There is a broad range of reactor types that are used in the practical realization of the gasification process. For most purposes, these reactor types can be grouped into one of three categories: moving-bed gasifiers, fluid-bed gasifiers, and entrained-flow gasifiers. Moving-bed processes are the oldest processes, and two processes in particular, the producer gas process and the water gas process, have played an important role in the production of synthesis gas from coal and coke. In moving bed processes, there are the sasol-lurgi dry bottom process, British Gas/Lurgi (BGL) slagging gasifier, that are detailed in the chapter along with their applications. Following this, fluid-bed processes are discussed in which the blast has two functions: that of blast as a reactant and that of the fluidizing medium for the bed. The best known fluid-bed gasifiers that have no tar problem are regenerators of catalytic cracking units that often operate under reducing, that is, gasification conditions that can be found in many refineries. HRL process, BHEL gasifier, circulating fluidized-bed (CFB) processes, the KBR transport gasifier, agglomerating fluid-bed processes, the Pratt & Whitney Rocketdyne (PWR) gasifier, the GEE gasification process, the Shell Gasification Process (SGP), Lurgi’ s Multi-Purpose Gasification process (MPG), etc. are the various processes discussed in the chapter.

Christopher Higman; Maarten van der Burgt

2008-01-01T23:59:59.000Z

384

Direct Observation and Image-Based Simulation of Three-Dimensional Tortuous Crack Evolution inside Opaque Materials  

Science Journals Connector (OSTI)

We present a combined novel methodology to study the three-dimensional complex geometry of a tortuous crack and identify the essential features of the crack and its propagation inside a heterogeneous material. We find that some severe damage events occur unexpectedly below a local mode-I crack within the sample; we realize that the severe plastic zone of the local mode-I crack is shifted down by another unseen crack segment hidden behind, which is responsible for the unusual damage phenomenon observed. We also find that the crack grows fast at some locations but slowly at some other locations along the crack front; we recognize that the crack-tip fields are reduced by neighboring hidden crack segments, which accounts for the retarded propagation of some part of the crack front. The feasibility and power of the proposed methodology highlights the potential of a new way to study fracture mechanisms in real materials.

Lihe Qian; Hiroyuki Toda; Kentaro Uesugi; Masakazu Kobayashi; Toshiro Kobayashi

2008-03-21T23:59:59.000Z

385

Mixed-mode, high-cycle fatigue-crack growth thresholds in I. A comparison of large-and short-crack behavior  

E-Print Network [OSTI]

) in a Ti±6Al±4V turbine blade alloy with a bimodal microstructure. Speci®cally, the eect of combined mode I machined to within $200 lm of the precrack tip. For such short cracks, wherein the magnitude of crack, particularly in association with fretting fatigue in the blade dovetail/disk contact section [3]. For fatigue

Ritchie, Robert

386

To Crack or Not to Crack: Strain in High TemperatureSuperconductors  

SciTech Connect (OSTI)

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.

Godeke, Arno

2007-08-22T23:59:59.000Z

387

Assessment of Crack Detection in Heavy-Walled Cast Stainless Steel Piping Welds Using Advanced Low-Frequency Ultrasonic Methods  

SciTech Connect (OSTI)

Studies conducted at the Pacific Northwest National Laboratory in Richland, Washington, have focused on assessing the effectiveness and reliability of novel approaches to nondestructive examination (NDE) for inspecting coarse-grained, cast stainless steel reactor components. The primary objective of this work is to provide information to the U.S. Nuclear Regulatory Commission on the effectiveness and reliability of advanced NDE methods as related to the inservice inspection of safety-related components in pressurized water reactors (PWRs). This report provides progress, recent developments, and results from an assessment of low frequency ultrasonic testing (UT) for detection of inside surface-breaking cracks in cast stainless steel reactor piping weldments as applied from the outside surface of the components. Vintage centrifugally cast stainless steel piping segments were examined to assess the capability of low-frequency UT to adequately penetrate challenging microstructures and determine acoustic propagation limitations or conditions that may interfere with reliable flaw detection. In addition, welded specimens containing mechanical and thermal fatigue cracks were examined. The specimens were fabricated using vintage centrifugally cast and statically cast stainless steel materials, which are typical of configurations installed in PWR primary coolant circuits. Ultrasonic studies on the vintage centrifugally cast stainless steel piping segments were conducted with a 400-kHz synthetic aperture focusing technique and phased array technology applied at 500 kHz, 750 kHz, and 1.0 MHz. Flaw detection and characterization on the welded specimens was performed with the phased array method operating at the frequencies stated above. This report documents the methodologies used and provides results from laboratory studies to assess baseline material noise, crack detection, and length-sizing capability for low-frequency UT in cast stainless steel piping.

Anderson, Michael T.; Crawford, Susan L.; Cumblidge, Stephen E.; Denslow, Kayte M.; Diaz, Aaron A.; Doctor, Steven R.

2007-03-01T23:59:59.000Z

388

Effects of stress ratio and fiber orientation on fatigue crack growth behavior in APAL  

SciTech Connect (OSTI)

A new hybrid composite (APAL; Aramid Patched Aluminum Alloy), consisting of 2024-T3 aluminum alloy plate sandwiched between aramid/epoxy prepregs (HK 285/RS 1222), was developed. Fatigue crack growth behavior was examined at stress ratios of R = 0.2, 0.5 using two kinds of APAL with different fiber orientation (0{degree}/90{degree} and {+-} 45{degree} for crack direction). The APAL showed superior fatigue crack growth resistance, which may be attributed to the crack bridging effect imposed by the intact fibers in the crack wave. The magnitude of crack bridging was estimated quantitatively and determined by a new technique on the basis of the compliances of 2024-T3 aluminum alloy and APAL specimens. The crack growth rate of the APAL specimens was reduced significantly as comparison to the monolithic aluminum alloy and was not adequately correlated with the conventional stress intensity factor range ({Delta}K). It was found that the crack growth rate was successfully correlated with the effective stress intensity factor range ( {Delta}K{sub eff} = K{sub br} {minus} K{sub cl}) allowing for the crack closure and the crack bridging. The relation between da/dN and {Delta}K{sub eff} was plotted within a narrow scatter band regardless at loading line of 2024-T3 aluminum alloy, two kinds of the APAL (APAL 0{degree}/90{degree}, APAL {+-} 45{degree}) and two kinds of stress ratios (R = 0.2, 0.5).

Oh, S.W.; Park, W.J. [Dong-A Univ., Pusan (Korea, Republic of). Dept. of Mechanical Engineering; Yoon, H.K.; Lee, K.G. [Dong-Eui Univ., Pusan (Korea, Republic of). Dept. of Mechanical Engineering; Cho, J.M.; Lee, K.B. [Han Kuk Fiber Glass Co. Ltd., Kyungnam (Korea, Republic of)

1993-12-31T23:59:59.000Z

389

Finite element analysis of a crack tip in silicate glass: No evidence for a plastic zone  

Science Journals Connector (OSTI)

Recently, the claim was made that cracks in silicate glasses propagate by the nucleation, growth, and coalescence of cavities at crack tips, which is the same way as in metals but at a much smaller scale. This hypothesis for crack growth is based in part on the measurement of surface displacements near the tip of an emerging crack, which is the point at which a crack front intersects the side surface of the specimen. Surface displacements measured by atomic force microscopy were less than theoretically predicted. The difference between the theoretical and experimental displacements was attributed to a plastic zone surrounding the tip of the moving crack. In this paper, we show that the theoretical analysis used earlier was based on an incorrect assumption about the functional dependence of the displacement with distance from the crack tip. We use a full three-dimensional finite element analysis combined with an asymptotic solution of the crack geometry to obtain a solution to the surface displacement problem. We show that the calculated displacements are fully consistent with those experimentally measured by using an atomic force microscope. No divergence from elastic behavior is observed. Our results support the view that crack propagation in glass is entirely brittle. No evidence for plasticity at the crack tips is obtained.

T. Fett, G. Rizzi, D. Creek, S. Wagner, J. P. Guin, J. M. López-Cepero, and S. M. Wiederhorn

2008-05-15T23:59:59.000Z

390

Acoustic Emission Detection and Prediction of Fatigue Crack Propagation in Composite Patch Repairs Using Neural Networks  

SciTech Connect (OSTI)

An aircraft is subjected to severe structural and aerodynamic loads during its service life. These loads can cause damage or weakening of the structure especially for aging military and civilian aircraft, thereby affecting its load carrying capabilities. Hence composite patch repairs are increasingly used to repair damaged aircraft metallic structures to restore its structural efficiency. This paper presents the results of Acoustic Emission (AE) monitoring of crack propagation in 2024-T3 Clad aluminum panels repaired with adhesively bonded octagonal, single sided boron/epoxy composite patch under tension-tension fatigue loading. Crack propagation gages were used to monitor crack initiation. The identified AE sensor features were used to train neural networks for predicting crack length. The results show that AE events are correlated with crack propagation. AE system was able to detect crack propagation even at high noise condition of 10 Hz loading; that crack propagation signals can be differentiated from matrix cracking signals that take place due to fiber breakage in the composite patch. Three back-propagation cascade feed forward networks were trained to predict crack length based on the number of fatigue cycles, AE event number, and both the Fatigue Cycles and AE events, as inputs respectively. Network using both fatigue cycles and AE event number as inputs to predict crack length gave the best results, followed by Network with fatigue cycles as input, while network with just AE events as input had a greater error.

Okafor, A. Chukwujekwu; Singh, Navdeep; Singh, Navrag [Structural Health Monitoring and NDE Laboratory, Department of Mechanical and Aerospace Engineering, University of Missouri-Rolla, 1870 Miner Circle Rolla MO 65409-0050 (United States)

2007-03-21T23:59:59.000Z

391

Stress Corrosion Cracking and Non-Destructive Examination of Dissimilar Metal Welds and Alloy 600  

SciTech Connect (OSTI)

The United States Nuclear Regulatory Commission (USNRC) has conducted research since 1977 in the areas of environmentally assisted cracking and assessment and reliability of non-destructive examination (NDE). Recent occurrences of cracking in Alloy 82/182 welds and Alloy 600 base metal at several domestic and overseas plants have raised several issues relating to both of these areas of NRC research. The occurrences of cracking were identified by the discovery of boric acid deposits resulting from through-wall cracking in the primary system pressure boundary. Analyses indicate that the cracking has occurred due to primary water stress corrosion cracking (PWSCC) in Alloy 82/182 welds. This cracking has occurred in two different locations: in hot leg nozzle-to-safe end welds and in control rod drive mechanism (CRDM) nozzle welds. The cracking associated with safe-end welds is important due to the potential for a large loss of reactor coolant inventory, and the cracking of CRDM nozzle base metal and welds, particularly circumferential cracking of CRDM nozzle base metal, is important due to the potential for a control rod to eject resulting in a loss of coolant accident. The industry response in the U.S. to this cracking is being coordinated through the Electric Power Research Institute's Materials Reliability Project (EPRI-MRP) in a comprehensive, multifaceted effort. Although the industry program is addressing many of the issues raised by these cracking occurrences, confirmatory research is necessary for the staff to evaluate the work conducted by industry groups. Several issues requiring additional consideration regarding the generic implications of these isolated events have been identified. This paper will discuss the recent events of significant cracking in domestic and foreign plants, discuss the limitations of NDE in detecting SCC, identify deficiencies in information available in this area, discuss the USNRC approach to address these issues, and discuss the development of an international cooperative effort. (authors)

Jackson, Deborah A. [U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001 (United States)

2002-07-01T23:59:59.000Z

392

The Thermal Expansion, Elastic and Fracture Properties of Porous Cordierite at Elevated Temperatures  

SciTech Connect (OSTI)

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.

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

393

Seasonal thermal energy storage  

SciTech Connect (OSTI)

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.

Allen, R.D.; Kannberg, L.D.; Raymond, J.R.

1984-05-01T23:59:59.000Z

394

Effect of disorder on temporal fluctuations in drying-induced cracking  

Science Journals Connector (OSTI)

We investigate by means of computer simulations the effect of structural disorder on the statistics of cracking for a thin layer of material under uniform and isotropic drying. For this purpose, the layer is discretized into a triangular lattice of springs with a slightly randomized arrangement. The drying process is captured by reducing the natural length of all springs by the same factor, and the amount of quenched disorder is controlled by varying the width ? of the distribution of the random breaking thresholds for the springs. Once a spring breaks, the redistribution of the load may trigger an avalanche of breaks, not necessarily as part of the same crack. Our computer simulations revealed that the system exhibits a phase transition with the amount of disorder as control parameter: at low disorders, the breaking process is dominated by a macroscopic crack at the beginning, and the size distribution of the subsequent breaking avalanches shows an exponential form. At high disorders, the fracturing proceeds in small-sized avalanches with an exponential distribution, generating a large number of microcracks, which eventually merge and break the layer. Between both phases, a sharp transition occurs at a critical amount of disorder ?c=0.40±0.01, where the avalanche size distribution becomes a power law with exponent ?=2.6±0.08, in agreement with the mean-field value ?=5/2 of the fiber bundle model. Moreover, good quality data collapses from the finite-size scaling analysis show that the average value of the largest burst ??max? can be identified as the order parameter, with ?/?=1.4 and 1/??1.0, and that the average ratio ?m2/m1? of the second m2 and first moments m1 of the avalanche size distribution shows similar behavior to the susceptibility of a continuous transition, with ?/?=1, 1/??0.9. These results suggest that the disorder-induced transition of the breakup of thin layers is analogous to a continuous phase transition.

Gabriel Villalobos; Ferenc Kun; José D. Muñoz

2011-10-11T23:59:59.000Z

395

Thermal unobtainiums? The perfect thermal conductor and  

E-Print Network [OSTI]

contribute to thermal resistance · Isotopically pure diamond has highest thermal conductivity of any material materials: disordered layered crystals Conclude with some thoughts on promising, high-risk, research even in a computer model. #12;Thermal resistance is created by Umklapp scattering (U

Braun, Paul

396

Thermal Imaging Control of Furnaces and Combustors  

SciTech Connect (OSTI)

The object if this project is to demonstrate and bring to commercial readiness a near-infrared thermal imaging control system for high temperature furnaces and combustors. The thermal imaging control system, including hardware, signal processing, and control software, is designed to be rugged, self-calibrating, easy to install, and relatively transparent to the furnace operator.

David M. Rue; Serguei Zelepouga; Ishwar K. Puri

2003-02-28T23:59:59.000Z

397

Ocean Thermal Energy Conversion LUIS A. VEGA  

E-Print Network [OSTI]

Ocean Thermal Energy Conversion LUIS A. VEGA Hawaii Natural Energy Institute, School of Ocean depths of 20 m (surface water) and 1,000 m. OTEC Ocean Thermal Energy Conversion, the process Energy Conversion. At first, OTEC plantships providing electricity, via submarine power cables, to shore

398

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)

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.

Brevick, Jerald R. [Ohio State University

2014-06-13T23:59:59.000Z

399

Beryllium Manufacturing Processes  

SciTech Connect (OSTI)

This report is one of a number of reports that will be combined into a handbook on beryllium. Each report covers a specific topic. To-date, the following reports have been published: (1) Consolidation and Grades of Beryllium; (2) Mechanical Properties of Beryllium and the Factors Affecting these Properties; (3) Corrosion and Corrosion Protection of Beryllium; (4) Joining of Beryllium; (5) Atomic, Crystal, Elastic, Thermal, Nuclear, and other Properties of Beryllium; and (6) Beryllium Coating (Deposition) Processes and the Influence of Processing Parameters on Properties and Microstructure. The conventional method of using ingot-cast material is unsuitable for manufacturing a beryllium product. Beryllium is a highly reactive metal with a high melting point, making it susceptible to react with mold-wall materials forming beryllium compounds (BeO, etc.) that become entrapped in the solidified metal. In addition, the grain size is excessively large, being 50 to 100 {micro}m in diameter, while grain sizes of 15 {micro}m or less are required to meet acceptable strength and ductility requirements. Attempts at refining the as-cast-grain size have been unsuccessful. Because of the large grain size and limited slip systems, the casting will invariably crack during a hot-working step, which is an important step in the microstructural-refining process. The high reactivity of beryllium together with its high viscosity (even with substantial superheat) also makes it an unsuitable candidate for precision casting. In order to overcome these problems, alternative methods have been developed for the manufacturing of beryllium. The vast majority of these methods involve the use of beryllium powders. The powders are consolidated under pressure in vacuum at an elevated temperature to produce vacuum hot-pressed (VHP) blocks and vacuum hot-isostatic-pressed (HIP) forms and billets. The blocks (typically cylindrical), which are produced over a wide range of sizes (up to 183 cm dia. by 61 cm high), may be cut or machined into parts or be thermomechanically processed to develop the desired microstructure, properties, and shapes. Vacuum hot-isostatic pressing and cold-isostatic pressing (CIP) followed by sintering and possibly by a final HIP'ing (CIP/Sinter/HIP) are important in their use for the production of near net-shaped parts. For the same starting powder, a HIP'ed product will have less anisotropy than that obtained for a VHP'ed product. A schematic presentation illustrating the difference between VHP'ing and HIP'ing is shown in Figure I-1. The types of powders and the various beryllium grades produced from the consolidated powders and their ambient-temperature mechanical properties were presented in the consolidation report referred to above. Elevated-temperature properties and the effect of processing variables on mechanical properties are described in the mechanical properties report. Beryllium can also be deposited as coatings as well as freestanding forms. The microstructure, properties, and various methods used that are related to the deposition of beryllium are discussed in the report on beryllium coatings.

Goldberg, A

2006-06-30T23:59:59.000Z

400

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....

Note: This page contains sample records for the topic "thermal cracking process" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Conductive Thermal Interaction in Evaporative Cooling Process  

E-Print Network [OSTI]

It has long been recognized that evaporative cooling is an effective and logical substitute for mechanical cooling in hot-arid climates. This paper explores the application of evaporative coolers to the hot-humid climates using a controlled...

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

1990-01-01T23:59:59.000Z

402

Method For Brazing And Thermal Processing  

DOE Patents [OSTI]

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.

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

403

ACR process for ethylene  

SciTech Connect (OSTI)

Describes how the advanced cracking reactor process, which is ready for a logical commercial application, offers total liquids feedstock flexibility from light naphthenes through vacuum gas oils in the same production unit. Several processes are presently being developed which are aimed at maintaining olefin selectivity when cracking the heaviest feeds. Addresses the problems posed by such heavy feedstocks. The following trends favor the ACR process in the 1980s: natural gas price decontrol; limited natural gas reserves; few new domestic LPG-based ethylene plants will be built; an economic recovery will create the need for more ethylene capacity; modest increases in ''real'' crude oil prices; plentiful supplies of vacuum gas oil at prices making it an attractive ethylene feedstock; and increasing supplies of light naphtha at prices making it an attractive ethylene feedstock as well. Predicts that these factors will swing the preferred feedstocks for ethylene manufacture back to crude oil distillates before the end of the decade. Argues that in this environment, the ACR process can deliver the lowest cost ethylene in the industry. ACR has full-range feedstock flexibility, high selectivity to ethylene, and less sensitivity to feedstock costs and co-product credits.

Baldwin, R.L.; Kamm, G.R.

1983-01-01T23:59:59.000Z

404

The component interaction network approach for modeling of complex thermal systems  

Science Journals Connector (OSTI)

A practical approach for the thermal modeling of complex thermal systems, called the component interaction network (CIN) is presented. Its stages are explained: description of the thermal system as a set of non-overlapping components and their interactions ... Keywords: Component interaction network, Electric furnace, Experimental validation, Heat transfer, Rapid thermal processing, Thermal modeling

K. El Khoury; G. Mouawad; G. El Hitti; M. Nemer

2013-11-01T23:59:59.000Z

405

Energy Recovery Efficiency and Cost Analysis of VOC Thermal Oxidation Pollution Control Technology  

Science Journals Connector (OSTI)

Respective cost models were derived for recuperative thermal oxidizer (TO) and regenerative thermal oxidizer (RTO). ... In a thermal oxidation process, VOC-laden air is thermally treated (oxidized/decomposed) at temperatures about 730?850 °C. ... Choi and Yi(4) worked on the simulation and optimization of regenerative thermal oxidizers. ...

Aruna S. K. Warahena; Yew Khoy Chuah

2009-06-24T23:59:59.000Z

406

VacuumProcesses  

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

Processes Processes Manufacturing Technologies The vacuum processing capabilities in the Thin Film, Vacuum, & Packaging Laboratory encompass several areas. Capabilities include vacuum, inert gas and hydrogen firing; thermal desorption mass spectroscopy; vacuum out- gassing rate measurement; ion beam milling; and cermet densification. Capabilities * Expertise in the development of cleaning processes and materials characterization of vacuum materials and components * Vacuum and hydrogen firing of components for oxide reduction and cleaning of vacuum components * Large scale cleaning processes, vapor degreasing and vacu- um firing for large vol- ume components * Thermal desorption mass spectroscopy of material and components with controlled tem- perature ramp rates to 1500°C in a UHV

407

Significance of crack opening monitoring for determining the growth behavior of hydrofractures  

SciTech Connect (OSTI)

A method for determining the size of a crack induced by hydraulic fracturing is presented. The procedure is based on the measurement of the crack opening displacement and the fracture mechanics approach. The proposed method has been tested by conducting laboratory small-scale hydraulic fracturing tests on a granite. It is shown from the preliminary tests that the method provides a reasonable prediction of experimentally observed crack sizes.

Hashida, Toshiyuki; Sato, Kazushi; Takahashi, Hideaki

1993-01-28T23:59:59.000Z

408

Exergy in the Thermal Systems Analysis  

Science Journals Connector (OSTI)

Exergy analysis has been developed as a result ... imperfection of industrial thermal processes. Precursors of exergy analysis were Gouy [1] and Stodola ... due to the thermodynamic irrevesibility. The term exergy

J. Szargut

1999-01-01T23:59:59.000Z

409

Laser perforation of screen vacuum thermal insulation  

Science Journals Connector (OSTI)

This paper presents the results of the process of laser perforation of screen vacuum thermal insulation and shows that it has high efficiency. The use of various types of IR lasers...

Sysoev, V K; Vyatlev, P A; Zakharchenko, A V

2007-01-01T23:59:59.000Z

410

Stress-corrosion cracking of steels in ammonia with consideration given to OTEC design: a survey  

SciTech Connect (OSTI)

Carbon steel, alloy steel, and high-strength, quenched and tempered steel, when under applied or residual stress and especially when cold formed and/or welded without subsequent thermal stress relief, are subject to failure by stress-corrosion cracking (SCC) in air-contaminated dry ammonia. Water as well as hydrazine when present in small amounts have been shown to be effective inhibitors in an all steel system. Galvanic corrosion between dissimilar metals and/or accelerated failure by SCC of stressed steel as a result of galvanic coupling may be of concern. Where water has proven effective as an inhibitor of SCC in an all steel system, it may not be adequate in a mixed metal system. With aluminum tubes, the tube sheet will either have to be solid aluminum, aluminum clad steel or some nonconductive coating will be necessary to effectively remove the cathodic alloy from the galvanic circuit. Research is required to determine the severity of the coupling effect between dissimilar alloys in ammonia under OTEC conditions; especially the possibility of accelerated SCC failures of stressed steel where the presence of an inhibitor in the ammonia may not be sufficient to override the galvanic coupling effect.

Teel, R.B.

1980-03-01T23:59:59.000Z

411

Evaluation of low-cycle fatigue crack growth and subsequent ductile fracture for cracked pipe experiments using cyclic J-integral  

SciTech Connect (OSTI)

Piping for LWR power plants is required to satisfy the Leak-Before-Break concept for postulated (not actual) defects. With this in mind, numerous research has so far been conducted on the fatigue crack growth under cyclic loading, and on the ductile crack growth under excessive loading. Study on cracked pipe fracture under cyclic loading gains much attention from the viewpoint of the Leak-Before-Break concept for seismic loading that accompanies large-scale yielding. An evaluation method based on cyclic J-integral was newly developed to predict the low-cycle fatigue crack growth and the subsequent ductile fracture for cyclic loading that accompanies large-scale yielding. Cyclic J-integral was introduced to describe the crack growth up to failure. The method was applied to 4-inch diameter circumferentially through-wall-cracked carbon steel base metal pipes and welded pipe joints subjected to cyclic 4-point bending at room temperature and high temperature of approximately 300 C. Fatigue crack growth behavior and failure life were successfully predicted by the proposed approach.

Miura, Naoki; Fujioka, Terutaka; Kashima, Koichi [CRIEPI, Tokyo (Japan); Miyazaki, Katsumasa; Kanno, Satoshi; Hayashi, Makoto; Ishiwata, Masayuki; Gotoh, Nobuho [Hitachi, Ltd., Ibaraki (Japan)

1996-12-01T23:59:59.000Z

412

E-Print Network 3.0 - assisted fatigue crack Sample Search Results  

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

and Grain-Boundary Adhesion Summary: unless they experience environmentally assisted subcritical growth during cyclic loading.7 Fatigue-crack... (moist air and dry N2). The...

413

Low Alloy Steel Susceptibility to Stress Corrosion Cracking in Hydraulic Fracturing Environment.  

E-Print Network [OSTI]

??The pipelines used for hydraulic fracturing (aka. "fracking") are often operating at a pressure above 10000psi and thus are highly susceptible to Stress Corrosion Cracking… (more)

Anyanwu, Ezechukwu John

2014-01-01T23:59:59.000Z

414

Simulation of the ultrasonic array response from real branched cracks using an efficient finite element method  

SciTech Connect (OSTI)

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.

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

415

Subcritical crack growth, initiation, and arrest in columnar freshwater and sea ice.  

E-Print Network [OSTI]

??A study was conducted to determine if slow stable sub-critical crack growth may occur in ice. The Double Torsion fracture toughness geometry was used to… (more)

Parsons, Bruce L.

1989-01-01T23:59:59.000Z

416

Welding Hot Cracking of Side Shell of Drilling-Well Oil Storage Ship  

Science Journals Connector (OSTI)

...Cracks were found in the weld metal (WM) of weld-section of side shell of drilling-well oil storage ship when performing post weld radiographic...

Zhi-wei Yu; Xiao-lei Xu

2014-11-01T23:59:59.000Z

417

Fracture of Hydrided Zircaloy-4 Sheet under Through-Thickness Crack Growth Conditions  

SciTech Connect (OSTI)

The failure of thin-wall components such as fuel cladding may be caused by crack initiation on the component surface and subsequent crack growth through its thickness. This study has determined the fracture toughness of hydrided cold-worked stress relieved Zircaloy-4 sheet subject to through-thickness crack growth at 25 deg. C. The experimental approach utilizes a novel procedure in which a narrow linear strip of brittle hydride blister across the specimen width creates a well-defined pre-crack upon initial loading. The subsequent crack growth resistance is then characterized by four-point bending of the specimen and an elastic-plastic fracture mechanics analysis. At room temperature, the through-thickness fracture toughness (K{sub Q}) is sensitive to the orientation of the hydride platelets, and K{sub Q} {approx_equal} 25 MPavm for crack growth through a mixed in-plane/out-of-plane hydride field. In contrast, K{sub Q} is much higher ({approx_equal} 75 MPavm) when the hydride platelets are oriented predominantly in the plane of the sheet (and therefore normal to both the crack plane and the crack growth direction). The implication of these fracture toughness values to the fracture strain behavior of hydrided Zircaloy-4 under through-thickness crack growth conditions is illustrated. (authors)

Raynaud, P.A.; Koss, D.A. [Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802 (United States); Motta, A.T. [Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, PA 16802 (United States); Chan, K.S. [Southwest Research Institute, San Antonio, TX 78238 (United States)

2007-07-01T23:59:59.000Z

418

Thermal treatment for VOC control  

SciTech Connect (OSTI)

Catalytic and thermal oxidation are well-established technologies for controlling volatile organic compounds (VOCs). Oxidation destroys pollutants, rather than capturing them. Oxidation units can destroy nearly 100% of VOC and toxic emissions targeted by the Clean Air Act Amendments of 1990--some systems attain destruction efficiencies over 99.99%. To assist in the design of these systems, an engineer will often look a/t the heat of combustion of the gas stream, along with the type of pollutant, to best determine the correct type of oxidation device to use. The paper discusses catalytic and thermal oxidation, energy recovery, and equipment for these processes.

Cloud, R.A. [Huntington Environmental Systems, Schaumburg, IL (United States)

1998-07-01T23:59:59.000Z

419

Temperature and environmentally assisted cracking in low alloy steel  

SciTech Connect (OSTI)

Environmental assisted cracking (EAC) can be defined as the propagation of fatigue cracks in water at rates from 3 to over 40 times the growth rates in air. For low alloy steels with sulfur contents > 0.0125% by weight, EAC is normal behavior in the 240 to 290C range. However, literature yields mixed results for low alloy steels with compositions just below this sulfur level; some reports indicate EAC while others do not. Also, several authors have reported an increased tendency toward EAC when the water temperatures were lowered. In the present work, five ASTM A 508 Class 2 forgings with ladle and check analyses that ranged from 0.010 to 0.019 wt% S were tested in high purity deaerated water in the temperature range of 93 to 260C. At 260C these forgings did not exhibit EAC, reinforcing earlier results for two similar forgings. This broad sampling indicates strong resistance to EAC for this class of forging at 260C. On the other hand, EAC occurred consistently in the three of these forgings that were tested below 204C, provided the test conditions (loading frequency, {Delta}K, and R) were high enough to produce a high baseline fatigue crack growth rate (FCGR), where the baseline FCGR is that expected in air. At 149C, EAC occurred at test conditions that combined to yield a baseline FCGR greater than {approx}2E-6 mm/s. At 204, 121, and 93C, this critical crack growth rate appeared to shift to lower baseline values. The EAC that occurred at lower temperatures was a factor of 3 to 12 times higher than baseline air rates, which was not as strong as the effect for higher sulfur steels at 240 to 290C. Also, no plateau in the growth rates occurred as it does with the higher sulfur steels. In another approach, EAC was induced at 93 and at 260C by raising the dissolved oxygen content of the water from <10 to >15 ppb.

Auten, T.A.; Monter, J.V.

1995-04-01T23:59:59.000Z

420

Physics-Based Stress Corrosion Cracking Component Reliability  

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

Physics-Based Stress Corrosion Physics-Based Stress Corrosion Cracking Component Reliability Model cast in an R7-Compatible Cumulative Damage Framework Draft Report Supporting Technology Inputs to the Risk- Informed Safety Margin Characterization Pathway of the DOE Light Water Reactor Sustainability Program Stephen D. Unwin Kenneth I. Johnson Robert F. Layton Peter P. Lowry Scott E. Sanborn Mychailo B. Toloczko PNNL-20596 July 2011 Physics-Based SCC Reliability Model in a Cumulative Damage Framework 2 Physics-Based SCC Reliability Model in a Cumulative Damage Framework 3 Table of Contents Executive Summary............................................................................... 4 1. Introduction .......................................................................... 5

Note: This page contains sample records for the topic "thermal cracking process" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Thermal Pretreatment For TRU Waste Sorting  

SciTech Connect (OSTI)

Japan Atomic Energy Agency conducted a study on thermal treatment of TRU waste to develop a removal technology for materials that are forbidden for disposal. The thermal pretreatment in which hot nitrogen and/or air is introduced to the waste is a process of removing combustibles, liquids, and low melting point metals from PVC wrapped TRU waste. In this study, thermal pretreatment of simulated waste was conducted using a desktop thermal treatment vessel and a laboratory scale thermal pretreatment system. Combustibles and low melting point metals are effectively separated from wastes by choosing appropriate temperature of flowing gases. Combustibles such as papers, PVC, oil, etc. were removed and low melting point metals such as zinc, lead, and aluminum were separated from the simulated waste by the thermal pretreatment. (authors)

Sasaki, T.; Aoyama, Y.; Miyamoto, Y.; Yamaguchi, H. [Japan Atomic Energy Agency, Tokai-mura, Ibaraki (Japan)

2008-07-01T23:59:59.000Z

422

Thermal Management of Solar Cells  

E-Print Network [OSTI]

a better thermal conductance and when ceramic particles areor ceramic fillers that enhances thermal conductivity. Solid

Saadah, Mohammed Ahmed

2013-01-01T23:59:59.000Z

423

Ceramics in non-thermal plasma discharge for hydrogen generation.  

E-Print Network [OSTI]

??Recent interest in hydrogen as an energy source has resulted in development of new technologies such as non-thermal plasma processing of natural gas. We report… (more)

Vintila, Ramona Roxana

2005-01-01T23:59:59.000Z

424

Prediction of PWSCC in nickel base alloys using crack growth rate models  

SciTech Connect (OSTI)

The Ford/Andresen slip-dissolution SCC model, originally developed for stainless steel components in BWR environments, has been applied to Alloy 600 and Alloy X-750 tested in deaerated pure water chemistry. A method is described whereby the crack growth rates measured in compact tension specimens can be used to estimate crack growth in a component. Good agreement was found between model prediction and measured SCC in X-750 threaded fasteners over a wide range of temperatures, stresses, and material conditions. Most data support the basic assumption of this model that cracks initiate early in life. The evidence supporting a particular SCC mechanism is mixed. Electrochemical repassivation data and estimates of oxide fracture strain indicate that the slip-dissolution model can account for the observed crack growth rates, provided primary rather than secondary creep rates are used. However, approximately 100 cross-sectional TEM foils of SCC cracks including crack tips reveal no evidence of enhanced plasticity or unique dislocation patterns at the crack tip or along the crack to support a classic slip-dissolution mechanism. No voids, hydrides, or microcracks are found in the vicinity of the crack tips creating doubt about classic hydrogen related mechanisms. The bulk oxide films exhibit a surface oxide which is often different than the oxides found within a crack. Although bulk chromium concentration affects the rate of SCC, analytical data indicates the mechanism does not result from chromium depletion at the grain boundaries. The overall findings support a corrosion/dissolution mechanism but not one necessarily related to slip at the crack tip.

Thompson, C.D.; Krasodomski, H.T.; Lewis, N.; Makar, G.L. [Knolls Atomic Power Lab., Schenectady, NY (United States)

1995-12-31T23:59:59.000Z

425

Fatigue and environmentally assisted cracking in light water reactors  

SciTech Connect (OSTI)

Fatigue and stress corrosion cracking (SCC) for low-alloy steel used in piping and in steam generator and reactor pressure vessels have been investigated. Fatigue data were obtained on medium-sulfur-content A533-Gr B and A106-Gr B steels in high-purity (HP) deoxygenated water, in simulated pressurized water reactor water, and in air. Analytical studies focused on the behavior of carbon steels in boiling water reactor (BWR) environments. Crack-growth rates of composite fracture-mechanics specimens of A533-Gr B/Inconel-182/Inconel-600 (plated with nickel) and homogeneous specimens of A533-Gr B steel were determined under small-amplitude cyclic loading in HP water with {approx}300 pbb dissolved oxygen. Radiation-induced segregation and irradiation-assisted SCC of Type 304 SS after accumulation of relatively high fluence also have been investigated. Microchemical and microstructural changes in HP and commercial-purity Type 304 SS specimens from control-blade absorber tubes used in two operating BWRs were studied by Auger electron spectroscopy and scanning electron microscopy, and slow-strain-rate tensile tests were conducted on tubular specimens in air and in simulated BWR water at 289{degrees}C.

Kassner, T.F.; Ruther, W.E.; Chung, H.M.; Hicks, P.D.; Hins, A.G.; Park, J.Y.; Shack, W.J.

1992-03-01T23:59:59.000Z

426

Thermal insulation constructal optimization for steel rolling reheating furnace wall based on entransy dissipation extremum principle  

Science Journals Connector (OSTI)

Analogizing with the heat conduction process, the entransy dissipation extremum principle for thermal insulation process can be described as: for a ... heat loss) with certain constraints, the thermal insulation ...

HuiJun Feng; LinGen Chen; ZhiHui Xie; FengRui Sun

2012-12-01T23:59:59.000Z

427

Validation of the state-space model of fatigue crack growth in ductile alloys under variable-amplitude load via comparison of the crack-opening stress data  

Science Journals Connector (OSTI)

A state-space model of fatigue crack growth in ductile alloys under variable-amplitude load was presented by Patankar and Ray (Patankar...International Journal of Fracture, 90, 235--249; Patankar and Ray (2000).

Ravindra Patankar; Rong Qu

2005-02-01T23:59:59.000Z

428

DEVELOPMENT AND CONSTRUCTION OF LOW-CRACKING HIGH-PERFORMANCE CONCRETE (LC-HPC) BRIDGE DECKS: FREE SHRINKAGE TESTS, RESTRAINED RING TESTS, CONSTRUCTION EXPERIENCE, AND CRACK SURVEY RESULTS  

E-Print Network [OSTI]

The development, construction, and evaluation of low-cracking high-performance concrete (LC-HPC) bridge decks are described based on laboratory test results and experiences gained during the construction of 13 LC-HPC bridge ...

Yuan, Jiqiu

2011-12-31T23:59:59.000Z

429

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

430

Adsorption and Desorption of Hydrocarbons on a Supported Nickel Cracking Catalyst  

Science Journals Connector (OSTI)

...Hydrocarbons on a Supported Nickel Cracking Catalyst A. K. Galwey A study has been made...a high area supported nickel cracking catalyst. Measurements have been made of (i...adsorbed, after standard preparation of the catalyst, when a known volume of each hydrocarbon...

1963-01-01T23:59:59.000Z

431

Sorption and Diffusion of Simple Paraffins in Silica-Alumina Cracking Catalyst  

Science Journals Connector (OSTI)

...Paraffins in Silica-Alumina Cracking Catalyst R. M. Barrer T. Gabor Sorption and...propane in the silica-alumina cracking catalyst previously employed in similar measurements...behaviour in the micropore structure of the catalyst, for the species studied. The ratio...

1960-01-01T23:59:59.000Z

432

TRANSIENT FATIGUE-CRACK GROWTH BEHAVIOR FOLLOWING VARIABLE-AMPLITUDE LOADING IN A  

E-Print Network [OSTI]

TRANSIENT FATIGUE-CRACK GROWTH BEHAVIOR FOLLOWING VARIABLE-AMPLITUDE LOADING IN A MONOLITHIC-crack growth behavior following variable-amplitude loading sequences has been investigated in a hot-toughened ceramics [13] following various variable-amplitude loading sequences. Transient retardations, involving

Ritchie, Robert

433

Statistical fracture modeling: crack path and fracture criteria with application to homogeneous and  

E-Print Network [OSTI]

Statistical fracture modeling: crack path and fracture criteria with application to homogeneous; accepted 23 January 2002 Abstract Analysis has been performed on fracture initiation near a crack in a brittle material with strength described by Weibull statistics. This nonlocal fracture model allows

Ritchie, Robert

434

Hot cracking in tungsten inert gas welding of magnesium alloy AZ91D  

E-Print Network [OSTI]

Hot cracking in tungsten inert gas welding of magnesium alloy AZ91D W. Zhou*, T. Z. Long and C. K ductility, and the HAZ was found to be the `weakest link'. Keywords: Magnesium alloy, AZ91D, TIG welding, Hot cracking, Liquation, Fracture Introduction Magnesium alloys have high strength/weight ratio

Zhou, Wei

435

Brittle fracture in a periodic structure with internal potential energy. Spontaneous crack propagation  

E-Print Network [OSTI]

Spontaneous brittle fracture is studied based on the recently introduced model (Mishuris and Slepyan, Brittle fracture in a periodic structure with internal potential energy. Proc. Roy. Soc. A, in press). A periodic structure is considered, where only the prospective crack-path layer is specified as a discrete set of alternating initially stretched and compressed bonds. A bridged crack destroying initially stretched bonds may propagate under a certain level of the internal energy without external sources. The general analytical solution with the crack speed $-$ energy relation is presented in terms of the crack-related dynamic Green's function. For the anisotropic two-line chain and lattice considered earlier in quasi-statics, the dynamic problem is examined in detail. The crack speed is found to grow unboundedly as the energy approaches its upper limit. It is revealed that the spontaneous fracture can occur in the form of a pure bridged, partially bridged or fully open crack depending on the internal energy level. Generally, the steady-state mode of the crack propagation is found to be realised, whereas an irregular growth, clustering and the crack speed oscillations are detected in a vicinity of the lower bound of the energy.

Mark Ayzenberg-Stepanenko; Gennady Mishuris; Leonid Slepyan

2014-02-12T23:59:59.000Z

436

DEVELOPMENT OF NONLINEAR TIME REVERSED ACOUSTICS (NLTRA) FOR APPLICATIONS TO CRACK DETECTION IN SOLIDS  

E-Print Network [OSTI]

of Nondestructive Evaluation (NDE) exhibit extremely high sensitivity to the presence of cracks. Time Reverse stones and long-distance communication in the ocean. The Nondestructive Evaluation (NDE) applications,4] and detection of cracks in a thin air-filled hollow cylinder [5]. A review of TRA applications to NDE is given

437

Autonomous Crack Displacement Monitoring of a Residence Near a Quarry David E. Kosnik, Northwestern University  

E-Print Network [OSTI]

Autonomous Crack Displacement Monitoring of a Residence Near a Quarry David E. Kosnik, Northwestern remote mon- itoring of cracks in interior and exterior walls of a residence near a limestone quarry for construction and raw materials. For instance, neighbors of road aggregate quarries often perceive

438

Autonomous Remote Crack Displacement Monitoring of a Residence Near a Limestone  

E-Print Network [OSTI]

Autonomous Remote Crack Displacement Monitoring of a Residence Near a Limestone Quarry, Naples a limestone quarry. The object is to quantitatively compare crack re- sponse to blast-induced ground motion for construction and raw materials. For instance, neighbors of road aggregate quarries often perceive

439

Fatigue failure in thin-film polycrystalline silicon is due to subcritical cracking within the oxide layer  

E-Print Network [OSTI]

Fatigue failure in thin-film polycrystalline silicon is due to subcritical cracking within with stress-induced surface oxide thicken- ing and moisture-assisted subcritical cracking in the amor- phous

Ritchie, Robert

440

Bilateral propagation of a spontaneous two-dimensional anti-plane shear crack under the influence of cohesion  

Science Journals Connector (OSTI)

......cracks, the calculations of the time- dependent fault motions and the corresponding seismograms as the crack propagates, pro- ceed much as in the cases of uniform extension. The principal differences are that, whereas the coordinates of the edges can be......

A. K. Chatterjee; L. Knopoff

1983-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "thermal cracking process" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Spectroscopic studies on the formation of coke on individual Fluid Catalytic Cracking particles: the effect of poisoning metal compounds.  

E-Print Network [OSTI]

??The formation of coke on individual Fluid Catalytic Cracking (FCC) catalyst particles was studied using UV/Vis microspectroscopy and confocal fluorescence microscopy, with n-hexane cracking as… (more)

Goetze, J.G.

2013-01-01T23:59:59.000Z

442

HEATS: Thermal Energy Storage  

SciTech Connect (OSTI)

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.

None

2012-01-01T23:59:59.000Z

443

Holographic thermalization patterns  

E-Print Network [OSTI]

We investigate the behaviour of various correlators in N=4 super Yang Mills theory, taking finite coupling corrections into account. In the thermal limit we investigate the flow of the quasinormal modes as a function of the 't Hooft coupling. Then by using a specific model of holographic thermalization we investigate the deviation of the spectral densities from their thermal limit in an out-of-equilibrium situation. The main focus lies on the thermalization pattern with which the various plasma constituents of different energies approach their final thermal distribution as the coupling constant decreases from the infinite coupling limit. All results point towards the weakening of the usual top down thermalization pattern.

Stefan Stricker

2014-03-11T23:59:59.000Z

444

Holographic thermalization patterns  

E-Print Network [OSTI]

We investigate the behaviour of various correlators in N=4 super Yang Mills theory, taking finite coupling corrections into account. In the thermal limit we investigate the flow of the quasinormal modes as a function of the 't Hooft coupling. Then by using a specific model of holographic thermalization we investigate the deviation of the spectral densities from their thermal limit in an out-of-equilibrium situation. The main focus lies on the thermalization pattern with which the various plasma constituents of different energies approach their final thermal distribution as the coupling constant decreases from the infinite coupling limit. All results point towards the weakening of the usual top down thermalization pattern.

Stricker, Stefan

2014-01-01T23:59:59.000Z

445

Hydride-phase formation and its influence on fatigue crack propagationbehavior in a Zircaloy-4 alloy  

SciTech Connect (OSTI)

The hydride-phase formation and its influence on the fatigue behavior of a Zircaloy-4 alloy charged with hydrogen gas are investigated. First, the microstructure and fatigue crack propagation rate of the alloy in the as-received condition are studied. Second, the formation and homogeneous distribution of delta zirconium hydride ( -ZrH2) in the bulk, and its effect on the fatigue crack propagation rate are presented. The results show that in the presence of hydrides the zirconium alloy exhibits reduced toughness and enhanced crack growth rates. Finally, the influence of a pre-existing fatigue crack in the specimen and the subsequent hydride formation were investigated. The residual lattice strain profile around the fatigue crack tip was measured using neutron diffraction. The combined effects of residual strains and hydride precipitation on the fatigue behavior are discussed.

Garlea, Elena [University of Tennessee, Knoxville (UTK); Choo, H. [University of Tennessee, Knoxville (UTK); Wang, G Y [University of Tennessee, Knoxville (UTK); Liaw, Peter K [University of Tennessee, Knoxville (UTK); Clausen, B [Los Alamos National Laboratory (LANL); Brown, D. W. [Los Alamos National Laboratory (LANL); Park, Jae-Sung [University of Tennessee, Knoxville (UTK); Rack, P. D. [University of Tennessee, Knoxville (UTK); Kenik, Edward A [ORNL

2010-01-01T23:59:59.000Z

446

Fatigue crack propagation in a quasi one-dimensional elasto-plastic model  

E-Print Network [OSTI]

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.

Tomás M. Guozden; Eduardo A. Jagla

2012-06-27T23:59:59.000Z

447

Characterization of elevated temperature crack growth in Hastelloy-X using integral parameters  

SciTech Connect (OSTI)

Linear elastic fracture mechanics approaches are not suitable for prediction of fatigue crack growth in the nonlinear regime at elevated temperatures. The objective of this paper is to investigate the ability of the integral parameters by Blackburn (J*), by Kishimoto et al. ({cflx J}), and by Atluri et al. ({Delta}Tp*, {Delta}Tp) to correlate crack growth data of Hastelloy-X at elevated temperatures under nominally elastic and nominally plastic loading. Crack growth is analyzed using a finite element method, and the integral parameters are computed from the results of analysis. The experimental crack growth rates are correlated with these parameters. It is found that J*, {cflx J}, and {Delta}Tp* can correlate crack growth data within an acceptable accuracy.

Kim, K.S. [Pohang Univ. of Science and Technology (Korea, Republic of). Dept. of Mechanical Engineering; Van Stone, R.H. [General Electric Aircraft Engines, Cincinnati, OH (United States)

1995-07-01T23:59:59.000Z

448

Review of industry efforts to manage pressurized water reactor feedwater nozzle, piping, and feedring cracking and wall thinning  

SciTech Connect (OSTI)

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.

Shah, V.N.; Ware, A.G.; Porter, A.M.

1997-03-01T23:59:59.000Z

449

Non-thermal Plasma Chemistry Non-thermal Thermal  

E-Print Network [OSTI]

automotive industry optics biomedical technology environmental technology Plasma Technology Quote from: Pla-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

Greifswald, Ernst-Moritz-Arndt-Universität

450

Underground Coal Thermal Treatment  

SciTech Connect (OSTI)

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.

P. Smith; M. Deo; E. Eddings; A. Sarofim; K. Gueishen; M. Hradisky; K. Kelly; P. Mandalaparty; H. Zhang

2011-10-30T23:59:59.000Z

451

Monitoring Thermal Fatigue Damage In Nuclear Power Plant Materials Using Acoustic Emission  

SciTech Connect (OSTI)

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.

Meyer, Ryan M.; Ramuhalli, Pradeep; Watson, Bruce E.; Pitman, Stan G.; Roosendaal, Timothy J.; Bond, Leonard J.

2012-04-26T23:59:59.000Z

452

A continuing investigation into the stress field around two parallet-edge cracks in a finite body  

E-Print Network [OSTI]

,7 ........................................................................................... 5 2.1 Two Parallel Edge Cracks in a Four Point Bending Member.............................. 7 2.2 Westergaard Stress Functions and Resulting Stress Intensity Factors for a Crack with Applied Tractions Along Its Faces... .................................................................... 31 4.2 Mesh Created for Numerical Model (Zoomed in on Crack Interaction Region) ............................................................................................. 32 5.1 Open Mode Stress Intensity Factor Percent...

Gilman, Justin Patrick

2005-02-17T23:59:59.000Z

453

Thin Film Cracking Modulated by Underlayer Creep by J. Liang, R. Huang, J.H. Prvost, and Z. Suo  

E-Print Network [OSTI]

: subcritical decohesion at the crack tip, and creep in the underlayer. In a thin-film microbridge over for the growth rate per temperature cycle of a channel crack in a brittle film, induced by ratcheting plasticThin Film Cracking Modulated by Underlayer Creep by J. Liang, R. Huang, J.H. Prévost, and Z. Suo

Huang, Rui

454

Effect of Surface Morphology on Crack Growth at a Sol-Gel Reinforced Epoxy/Aluminum Interface  

E-Print Network [OSTI]

the measurements of the critical energy-release rate, subcritical crack-growth kinetics, and threshold energyEffect of Surface Morphology on Crack Growth at a Sol-Gel Reinforced Epoxy/Aluminum Interface Jiong. Keywords: ADCB wedge test; Crack growth; Durability; Epoxy=aluminum; Sol-gel coating; Surface pretreatment

Chaudhury, Manoj K.

455

Thermal contact resistance  

E-Print Network [OSTI]

This work deals with phenomena of thermal resistance for metallic surfaces in contact. The main concern of the work is to develop reliable and practical methods for prediction of the thermal contact resistance for various ...

Mikic, B. B.

1966-01-01T23:59:59.000Z

456

Thermal Neutron Scattering  

Science Journals Connector (OSTI)

... of its title. It is not for the nuclear physicist, nor even for the neutron physicist, but for the student of solids and liquids. "Thermal ... physicist, but for the student of solids and liquids. "Thermal neutron ...

G. E. BACON

1968-11-09T23:59:59.000Z

457

Thermal-mechanical fatigue behavior of nickel-base superalloys. Final Report  

SciTech Connect (OSTI)

The main achievements of a 36-month research program are presented. The main objective was to gain more insight into the problem of crack growth under thermal mechanical fatigue (TMF) conditions. This program was conducted at M.I.T. for the period of September 1982 to September 1985. The program was arranged into five technical tasks. Under Task I, the literature of TMF data was reviewed. The goal was to identify the crack propagation conditions in aircraft engines (hot section) and to assess the validity of conventional fracture mechanics parameters to address TMF crack growth. The second task defined the test facilities, test specimen and the testing conditions needed to establish the effectiveness of data correlation parameters identified in Task I. Three materials (Inconel X-750, Hastelloy-X, and B-1900) were chosen for the program. Task II was accomplished in collaboration with Pratt and Whitney Aircraft engineers. Under Task III, a computerized testing system to measure the TMF behavior (LCF and CG behaviors) of various alloys systems was built. The software used to run isothermal and TMF tests was also developed. Built around a conventional servohydraulic machine, the system is capable of push-pull tests under stress or strain and temperature controlled conditions in the temperature range of 25C to 1050C. A crack propagation test program was defined and conducted under Task IV. The test variables included strain range, strain rate (frequency) and temperature. Task V correlated and generalized the Task IV data for isothermal and variable temperature conditions so that several crack propagation parameters could be compared and evaluated. The structural damage (mode of cracking and dislocation substructure) under TMF cycling was identified and contrasted with the isothermal damage to achieve a sound fundamental mechanistic understanding of TMF.

Pelloux, R.M.; Marchand, N.

1986-03-01T23:59:59.000Z

458

SRNL SHELF LIFE STUDIES - SCC STUDIES AT ROOM TEMPERTURE [stress corrosion cracking  

SciTech Connect (OSTI)

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.

Mickalonis, J.; Duffey, J.

2014-11-12T23:59:59.000Z

459

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]

???????????..?????????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...

Ju, Jaehyung

2006-10-30T23:59:59.000Z

460

Thermal neutron detection system  

DOE Patents [OSTI]

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.

Peurrung, Anthony J. (Richland, WA); Stromswold, David C. (West Richland, WA)

2000-01-01T23:59:59.000Z

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