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Note: This page contains sample records for the topic "thermal cracking visbreaking" 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
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1

U.S. Refinery Thermal Cracking, Visbreaking Downstream Charge ...  

U.S. Energy Information Administration (EIA)

U.S. Refinery Thermal Cracking, Visbreaking Downstream Charge Capacity as of January 1 (Barrels per Stream Day)

2

Guam Refinery Thermal Cracking/Visbreaking Downstream Charge ...  

U.S. Energy Information Administration (EIA)

Guam Refinery Thermal Cracking/Visbreaking Downstream Charge Capacity as of January 1 (Barrels per Stream Day)

3

Puerto Rico Refinery Thermal Cracking/Visbreaking Downstream ...  

U.S. Energy Information Administration (EIA)

Puerto Rico Refinery Thermal Cracking/Visbreaking Downstream Charge Capacity as of January 1 (Barrels per Stream Day)

4

Thermal Cracking Visbreaking Downstream Charge Capacity  

U.S. Energy Information Administration (EIA)

-No Data Reported; --= Not Applicable; NA = Not Available; W = Withheld to avoid disclosure of individual company data. Notes: See Definitions ...

5

Guam Refinery Thermal Cracking/Other (including Gas Oil ...  

U.S. Energy Information Administration (EIA)

Guam Refinery Thermal Cracking/Other (including Gas Oil) Downstream Charge Capacity as of January 1 (Barrels per Stream Day)

6

U.S. Refinery Thermal Cracking, Fluid Coking Downstream Charge ...  

U.S. Energy Information Administration (EIA)

U.S. Refinery Thermal Cracking, Fluid Coking Downstream Charge Capacity as of January 1 (Barrels per Stream Day)

7

Vacuum Distillation  

U.S. Energy Information Administration (EIA) Indexed Site

Day) Process: Vacuum Distillation Thermal Cracking Thermal Cracking: Coking Thermal Cracking: Delayed Coking Thermal Cracking: Fluid Coking Thermal Cracking: Visbreaking Thermal...

8

U.S. Refinery Thermal Cracking, Other (including Gas Oil ...  

U.S. Energy Information Administration (EIA)

U.S. Refinery Thermal Cracking, Other (including Gas Oil) Downstream Charge Capacity as of January 1 (Barrels per Stream Day)

9

Thermal stress cracking and enhancement of heat extraction from fractured geothermal reservoirs  

DOE Green Energy (OSTI)

The effects of thermal stress cracking, upon heat extraction were studied. Very fundamental approximate analyses were performed to elucidate the mechanics of thermal stress cracking, and the main results are summarized.

Murphy, H.D.

1978-01-01T23:59:59.000Z

10

Thermal Cracking of Large-Diameter 706 Ingots  

Science Conference Proceedings (OSTI)

responsible for the cracking. The most plausible scenario is that residual stresses generated by ... Analysis of Heat Up for Homogenization. Finite Element Model.

11

Effect of Thermal-Mechanical Treatment on the Fatigue Crack ...  

Science Conference Proceedings (OSTI)

that fatigue crack propagation (FCP) resistance without holding time has no significant difference between three alloys with 718Plus being the best and 718 the...

12

Thermal stress cracking and the enhancement of heat extraction from fractured geothermal reservoirs  

DOE Green Energy (OSTI)

Given sufficient time, the extraction of heat from geothermal reservoirs formed by the hydraulic fracturing of competent rock will eventually result in the formation of thermal stress cracks in the reservoir. These cracks penetrate the rock in a manner such that the penetration-to-spacing ratio is approximately one. The penetration depends upon the extent of cooling and the square root of time. Initially then, the cracks are closely spaced and penetrate but little, so that a crazing pattern is apparent; but with increasing time some of these cracks, now more widely spaced, grow deeper. Eventually these larger cracks attain a critical aperture such that significant rates of water flow can be established within them and thus the newly created heat transfer area becomes useful for heat extraction. At the same time that cracks are forming within the main reservoir, thermal cracking also occurs in the wellbores that communicate with the reservoir. These cracks eventually convey water to and from the reservoir, thus leading to a decrease in the flow impedances that are often concentrated in the wellbore regions.

Murphy, H.D.

1978-04-01T23:59:59.000Z

13

Enhanced heat extraction from hot-dry-rock geothermal reservoirs due to interacting secondary thermal cracks. Final report  

DOE Green Energy (OSTI)

How the fluid circulating through the main hydraulic fracture and the thermally-induced secondary, growing, interacting cracks affects the time-varying temperature, deformations, stresses, thermal crack geometry, water flow rates through the main and thermal cracks, reservoir coolant outlet temperature, and reservoir thermal power of the cracked geothermal reservoir is investigated. First, a simplified version of the proposed hot-dry-rock reservoir is considered. A closed-form solution of the rock temperature without thermal crack was found and substituted into SAP-IV computer code to calculate the stresses. These stresses being superposed with earth stresses and fluid pressure were used in conjunction with the fracture mechanics criterion to determine the initiation of secondary thermal crack. After the initiation of secondary thermal crack, the rock temperature was then calculated by a two-dimensional heat conduction program AYER. The detailed procedures for carrying out these steps are listed. Solutions developed are applied to studying the time-varying temperature field, thermal stresses and crack geometry produced, and additional heat power generated in the reservoir. Conclusions were discussed and summarized. (MHR)

Hsu, Y.C.

1979-04-01T23:59:59.000Z

14

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.

15

Engineering methods for predicting productivity and longevity of hot-dry-rock geothermal reservoir in the presence of thermal cracks. Technical completion report  

DOE Green Energy (OSTI)

Additional heat extraction from geothermal energy reservioirs depends on the feasibility to extend the main, hydraulic fracture through secondary thermal cracks of the adjacent hot rock. When the main, hydraulic fracture is cooled sufficiently, these secondary thermal cracks are produced normal to the main fracture surface. As such, both the heat transfer surface area and heat energy available to the fluid circulating through the main, hydraulic fracture system increase. Methods for predicting the productivity and longevity of a geothermal reservoir were developed. A question is whether a significant long-term enhancement of the heat extraction process is achieved due to these secondary thermal cracks. In short, the objectives of this investigation are to study how the main, hydraulic fracture can be extended through these secondary thermal cracks of the rock, and to develop methods for predicting the productivity and longevity of a geothermal reservoir.

Hsu, Y.C.; Lu, Y.M.; Ju, F.D.; Dhingra, K.C.; Lu, Y.M.; Ju, F.D.; Dhingra, K.C.

1978-01-01T23:59:59.000Z

16

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

17

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

Science Conference Proceedings (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

18

Materials Reliability Program: Computer-Based NDE Training for Thermal Fatigue Cracking (MRP-36, Revision 2)  

Science Conference Proceedings (OSTI)

This product comes packaged together and contains both #1022875, Materials Reliability Program: NDE Technology for Detection of Thermal Fatigue Damage in Piping, (MRP-23, Revision 1) and Product #1024915, Computer-Based NDE Training for Thermal ...

2012-11-20T23:59:59.000Z

19

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

Science Conference Proceedings (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

20

Acoustic emission from thermal-gradient cracks in UO$sub 2$  

SciTech Connect

A feasibility study has been conducted to evaluate the potential use of acoustic emission to monitor thermal-shock damage in direct electrical heating of UO$sub 2$ pellets. In the apparatus used for the present tests, two acoustic- emission sensors were placed on extensions of the upper and lower electrical feedthroughs. Commercially available equipment was used to accumulate acoustic- emission data. The accumulation of events displayed on a cathode-ray-tube screen indicates the total number of acoustic-emission events at a particular location within the pellet stack. These tests have indicated that acoustic emission can be used to monitor thermal-shock damage in UO$sub 2$ pellets subjected to direct- electrical heating. 8 references. (auth)

Kennedy, C.R.; Kupperman, D.S.; Wrona, B.J.

1975-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "thermal cracking visbreaking" 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

Quench Cracking Characterization of Superalloys Using Fracture ...  

Science Conference Proceedings (OSTI)

When the on-cooling thermal stress. (load) accumulated to a certain point, quench cracking happened abruptly. Based on the precrack length, the thermal stress...

22

Electrochemical Interpretation of a Stress Corrosion Cracking of Thermally Treated Ni base Alloys in a Lead Contaminated Water  

SciTech Connect

Since the PbSCC(Lead stress corrosion cracking) of alloy 600 tubing materials was reported by Copson and Dean in 1965, the effect of lead on a corrosion film and cracking morphology have been continually debated. An electrochemical interaction of lead with the alloying elements of SG tubings was studied and the corrosion products were analyzed. It was found that lead enhanced the anodic dissolution of alloy 600 and alloy 690 in the electrochemical test. The lead preferentially dissolved the Cr from the corrosion film of alloy 600 and alloy 690 in alkaline water. The lead ion seemed to penetrate into the TG crack tip and react with the corrosion film. A selective Cr depletion was observed to weaken the stability of the passive film on the alloys. Whereas passivity of Ni became stable in lead containing solution, Cr and Fe passivity became unstable.

Hwang, Seong Sik; Lim, Yun Soo; Kim, Hong Pyo; Kim, Joung Soo; Thomas, Larry E.

2007-08-20T23:59:59.000Z

23

PICEP: Pipe Crack Evaluation Program  

Science Conference Proceedings (OSTI)

We describe a computer program that calculates the crack-opening area, the critical (stable) crack length and the two-phase flow rate through cracks in ductile stainless steel pipes and steam generator tubes. The program is useful in performing leak-before-break calculations in order to demonstrate detectable leak rates prior to a through-wall flaw reaching critical size. Necessary input to the code includes a definition of material properties, loads, thermal-hydraulic conditions, pipe geometry, and crack orientation. User information is provided in the report.

Norris, D.; Okamoto, A.; Chexal, B.; Griesbach, T.

1984-08-01T23:59:59.000Z

24

Shale oil cracking. 1. Kinetics  

DOE Green Energy (OSTI)

Experiments were conducted to determine kinetics for thermal cracking of shale oil vapor over shale. Cracking temperatures of 504 to 610/sup 0/C and residence times of 2 to 11 seconds were used. A first-order Arrhenius rate expression and stoichiometry were obtained. Also observed were changes in the oil quality. Cracking decreased the H/C ratio, increased the nitrogen content, and decreased the pour point of the oil. Gas-phase oil cracking is contrasted to liquid-phase oil coking as a loss mechanism in oil-shale retorting.

Burnham, A.K.; Taylor, J.R.

1979-10-01T23:59:59.000Z

25

Cracking knuckles  

NLE Websites -- All DOE Office Websites (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.

26

Hydrogen Assisted Cracking  

Science Conference Proceedings (OSTI)

Environmentally Assisted Cracking (EAC): Laboratory Research and Field Experiences: Hydrogen Assisted Cracking Program Organizers: Suresh Divi, TIMET

27

Thermal Cracking - Energy Information Administration  

U.S. Energy Information Administration (EIA)

-No Data Reported; --= Not Applicable; NA = Not Available; W = Withheld to avoid disclosure of individual company data. Notes: See Definitions ...

28

Creep Crack Growth  

Science Conference Proceedings (OSTI)

Table 3   Creep crack growth constants b and m for various ferritic steels...and Banerji, ??Creep Crack Growth Behavior

29

PICEP: Pipe Crack Evaluation Program (Revision 1): Special report  

Science Conference Proceedings (OSTI)

This report describes software for calculating single- or two-phase flow through cracks in pipes and steam generator tubes. Options are available for calculating the crack-opening area and the critical (stable) crack length. The program is useful in performing leak-before-break analysis to demonstrate detectable leak rates prior to crack growth instability. Input to the code includes material properties, loads, thermal-hydraulic conditions, pipe geometry, and crack type and orientation. Theory and user information are provided in this report. 16 refs., 7 figs.

Norris, D.M.; Chexal, B.

1987-12-01T23:59:59.000Z

30

Post Production Heavy Oil Operations: A Case for Partial Upgrading  

E-Print Network (OSTI)

The transportation of heavy oil is a pressing problem. Various methods have been devised to mitigate the reluctance to flow of these highly dense and viscous oils. This study is focused on evaluating a case for post-production partial upgrading of heavy oil. Specifically, we analyze the impact of visbreaking, a mild thermal cracking method, on the economic and energy demands of the post-production process. Using conservative modeling techniques and principles we find significant cost and energy savings can potentially result out of visbreaking. Cost savings result as a consequence of reduced diluent usage. Even the most conservative modeling scenario under consideration exhibits significant cost savings in the form of reduced diluent usage; these savings not only offset operational costs but provide short payback periods on capital expenditures. Additionally, the lower gravity blend resulting from visbreaking can also bring about energy and cost savings in pipeline transportation and positively impact the heavy oil value chain from the producer to a refinery or regional upgrading facility. From this basic analysis of the potential of visbreaking, we can recommend investing resources to study its viability in the field. Using this analysis as a tipping off point and with a detailed look at the chemistry of the oil in question it is possible to make a very viable case for visbreaking. In a similar vein, this analysis can serve as a guide in making a case for other partial upgrading methods as well.

Lokhandwala, Taher

2012-12-01T23:59:59.000Z

31

Environmentally Assisted Cracking: Nuclear  

Science Conference Proceedings (OSTI)

About this Symposium. Meeting, Materials Science & Technology 2014. Symposium, Environmentally Assisted Cracking: Nuclear. Sponsorship. Organizer(s)...

32

Cracks Cleave Crystals  

E-Print Network (OSTI)

The problem of finding what direction cracks should move is not completely solved. A commonly accepted way to predict crack directions is by computing the density of elastic potential energy stored well away from the crack tip, and finding a direction of crack motion to maximize the consumption of this energy. I provide here a specific case where this rule fails. The example is of a crack in a crystal. It fractures along a crystal plane, rather than in the direction normally predicted to release the most energy. Thus, a correct equation of motion for brittle cracks must take into account both energy flows that are described in conventional continuum theories and details of the environment near the tip that are not.

Michael Marder

2004-03-05T23:59:59.000Z

33

Environmentally assisted cracking in light water reactors.  

DOE Green Energy (OSTI)

This report summarizes work performed by Argonne National Laboratory on fatigue and environmentally assisted cracking (EAC) in light water reactors (LWRs) from January to December 2002. Topics that have been investigated include: (a) environmental effects on fatigue crack initiation in carbon and low-alloy steels and austenitic stainless steels (SSs), (b) irradiation-assisted stress corrosion cracking (IASCC) of austenitic SSs in BWRs, (c) evaluation of causes and mechanisms of irradiation-assisted cracking of austenitic SS in PWRs, and (d) cracking in Ni-alloys and welds. A critical review of the ASME Code fatigue design margins and an assessment of the conservation in the current choice of design margins are presented. The existing fatigue {var_epsilon}-N data have been evaluated to define the effects of key material, loading, and environmental parameters on the fatigue lives of carbon and low-alloy steels and austenitic SSs. Experimental data are presented on the effects of surface roughness on fatigue crack initiation in these materials in air and LWR environments. Crack growth tests were performed in BWR environments on SSs irradiated to 0.9 and 2.0 x 10{sup 21} n x cm{sup -2}. The crack growth rates (CGRs) of the irradiated steels are a factor of {approx}5 higher than the disposition curve proposed in NUREG-0313 for thermally sensitized materials. The CGRs decreased by an order of magnitude in low-dissolved oxygen (DO) environments. Slow-strain-rate tensile (SSRT) tests were conducted in high-purity 289 C water on steels irradiated to {approx}3 dpa. The bulk S content correlated well with the susceptibility to intergranular SCC in 289 C water. The IASCC susceptibility of SSs that contain >0.003 wt. % S increased drastically. bend tests in inert environments at 23 C were conducted on broken pieces of SSRT specimens and on unirradiated specimens of the same materials after hydrogen charging. The results of the tests and a review of other data in the literature indicate that IASCC in 289 C water is dominated by a crack-tip grain-boundary process that involves S. An initial IASCC model has been proposed. A crack growth test was completed on mill annealed Alloy 600 in high-purity water at 289 C and 320 C under various environmental and loading conditions. The results from this test are compared with data obtained earlier on several other heats of Alloy 600.

Chopra, O. K.; Chung, H. M.; Clark, R. W.; Gruber, E. E.; Shack, W. J.; Soppet, W. K.; Strain, R. V.

2007-11-06T23:59:59.000Z

34

LPG storage vessel cracking experience  

SciTech Connect

In order to evaluate liquefied petroleum gas (LPG) handling and storage hazards, Caltex Petroleum Corp. (Dallas) surveyed several installations for storage vessel cracking problems. Cracking was found in approximately one-third of the storage vessels. In most cases, the cracking appeared to be due to original fabrication problems and could be removed without compromising the pressure containment. Several in-service cracking problems found were due to exposure to wet hydrogen sulfide. Various procedures were tried in order to minimize the in-service cracking potential. One sphere was condemned because of extensive subsurface cracking. This article's recommendations concern minimizing cracking on new and existing LPG storage vessels.

Cantwell, J.E. (Caltex Petroleum Corp., P.O. Box 619500, Dallas, TX (US))

1988-10-01T23:59:59.000Z

35

LPG storage vessel cracking experience  

SciTech Connect

As part of an overall company program to evaluate LPG handling and storage hazards the authors surveyed several installations for storage vessel cracking problems. Cracking was found in approximately one third of the storage vessels. In most cases the cracking appeared due to original fabrication problems and could be removed without compromising the pressure containment. Several in-service cracking problems due to exposure to wet hydrogen sulfide were found. Various procedures were tried in order to minimize the in-service cracking potential. One sphere was condemned because of extensive subsurface cracking. Recommendations are made to minimize cracking on new and existing LPG storage vessels.

Cantwell, J.E.

1988-01-01T23:59:59.000Z

36

Prediction of Reflection Cracking in Hot Mix Asphalt Overlays  

E-Print Network (OSTI)

Reflection cracking is one of the main distresses in hot-mix asphalt (HMA) overlays. It has been a serious concern since early in the 20th century. Since then, several models have been developed to predict the extent and severity of reflection cracking in HMA overlays. However, only limited research has been performed to evaluate and calibrate these models. In this dissertation, mechanistic-based models are calibrated to field data of over 400 overlay test sections to produce a design process for predicting reflection cracks. Three cracking mechanisms: bending, shearing traffic stresses, and thermal stress are taken into account to evaluate the rate of growth of the three increasing levels of distress severity: low, medium, and high. The cumulative damage done by all three cracking mechanisms is used to predict the number of days for the reflection crack to reach the surface of the overlay. The result of this calculation is calibrated to the observed field data (severity and extent) which has been fitted with an S-shaped curve. In the mechanistic computations, material properties and fracture-related stress intensity factors are generated using efficient Artificial Neural Network (ANN) algorithms. In the bending and shearing traffic stress models, the traffic was represented by axle load spectra. In the thermal stress model, a recently developed temperature model was used to predict the temperature at the crack tips. This process was developed to analyze various overlay structures. HMA overlays over either asphalt pavement or jointed concrete pavement in all four major climatic zones are discussed in this dissertation. The results of this calculated mechanistic approach showed its ability to efficiently reproduce field observations of the growth, extent, and severity of reflection cracking. The most important contribution to crack growth was found to be thermal stress. The computer running time for a twenty-year prediction of a typical overlay was between one and four minutes.

Tsai, Fang-Ling

2010-12-01T23:59:59.000Z

37

Corrosion Fatigue Crack Growth and Stress-Corrosion Cracking in ...  

Science Conference Proceedings (OSTI)

Abstract Scope, The high stress ratio (R=0.85) corrosion fatigue crack growth kinetics and stress-corrosion cracking resistance of sensitized (70-175 C up to...

38

Blunt-crack band propagation in finite-element analysis for concrete structures. [LMFBR  

SciTech Connect

The knowledge of concrete fracture is needed in nuclear reactor safety. The question of safety arises from the potential of concrete to crack under thermal loading. It has been postulated that structural concrete could be exposed to very high temperature, which may result from hot reactor coolant or even core debris coming in direct contact with the concrete. The utilization of the blunt crack approach for simulating concrete cracking in a general-purpose code is explored. The difficulties encountered in establishing the proper direction of crack propagation in an arbitrary discretization are described. Crack propagation is considered within the context of two types of solution techniques: (1) implicit solution of the static crack advance, and (2) explicit time integration using a dynamic relaxation technique to simulate the static crack advance. Also, in both solution techniques an elastic model is used to characterize the concrete.

Pfeiffer, P.A.; Bazant, Z.P.; Marchertas, A.H.

1983-01-01T23:59:59.000Z

39

Analysis of Cracked Pipe Weldments  

Science Conference Proceedings (OSTI)

EPRI estimation formulas for predicting loads necessary for crack initiation and instability can facilitate leak-before-break analysis of cracked nuclear piping. Finite-element calculations carried out in this study verified the accuracy of these formulas for analyzing through-the-wall cracks in bimetallic weldments.

1987-02-01T23:59:59.000Z

40

Catalytic cracking process  

Science Conference Proceedings (OSTI)

Processes and apparatus for providing improved catalytic cracking, specifically improved recovery of olefins, LPG or hydrogen from catalytic crackers. The improvement is achieved by passing part of the wet gas stream across membranes selective in favor of light hydrocarbons over hydrogen.

Lokhandwala, Kaaeid A. (Union City, CA); Baker, Richard W. (Palo Alto, CA)

2001-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "thermal cracking visbreaking" 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

Analysis of Crack Growth Data  

Science Conference Proceedings (OSTI)

Table 3   Methods for calculating crack growth rates...the derivative at the midpoint of a data set. These methods use

42

Environmentally Assisted Cracking of Materials  

Science Conference Proceedings (OSTI)

Development of Alternating Current Potential Drop (ACPD) method for the detection of Primary Water Stress Corrosion Cracking initiation in Stainless Steels and...

43

Environmentally Assisted Cracking of Materials  

Science Conference Proceedings (OSTI)

In-Situ Repairs of Oil Industry Pipelines, Tanks and Vessels by Welding Using Metal Arc Welding Under Oil (MAW-UO) Interpretation of Crack Initiation and...

44

Hydrogen sulfide stress corrosion cracking in materials for geothermal power  

DOE Green Energy (OSTI)

Studies to evaluate the performance of alloys used in geothermal power systems are reported. Alloys which are commercially available and those which have modified metallurgical structures and/or composition modifications were tested to determine the corrosive effects of the H/sub 2/S and thermal environments in geothermal fluids. Hydrogen embrittlement and sulfide stress corrosion cracking were tested. Test results showing the effects of alloy composition, tempering temperatures, fluid temperature and salt content, and ageing on sulfide stress cracking are tabulated. (LCL)

Hehemann, R.F.; Troiano, A.R.; Abu-Khater, B.; Ferrigno, S.

1976-01-01T23:59:59.000Z

45

Effect of Thermomechanical Processing on Fatigue Crack ...  

Science Conference Proceedings (OSTI)

gechanical driving force such as crack opening distance (COD) . However, at hold time loading, the crack growth rate is drastically decreased with an increase of...

46

Stress corrosion cracking of austenitic stainless steel core internal welds.  

SciTech Connect

Microstructural analyses by several advanced metallographic techniques were conducted on austenitic stainless steel mockup and core shroud welds that had cracked in boiling water reactors. Contrary to previous beliefs, heat-affected zones of the cracked Type 304L, as well as 304 SS core shroud welds and mockup shielded-metal-arc welds, were free of grain-boundary carbides, which shows that core shroud failure cannot be explained by classical intergranular stress corrosion cracking. Neither martensite nor delta-ferrite films were present on the grain boundaries. However, as a result of exposure to welding fumes, the heat-affected zones of the core shroud welds were significantly contaminated by oxygen and fluorine, which migrate to grain boundaries. Significant oxygen contamination seems to promote fluorine contamination and suppress thermal sensitization. Results of slow-strain-rate tensile tests also indicate that fluorine exacerbates the susceptibility of irradiated steels to intergranular stress corrosion cracking. These observations, combined with previous reports on the strong influence of weld flux, indicate that oxygen and fluorine contamination and fluorine-catalyzed stress corrosion play a major role in cracking of core shroud welds.

Chung, H. M.; Park, J.-H.; Ruther, W. E.; Sanecki, J. E.; Strain, R. V.; Zaluzec, N. J.

1999-04-14T23:59:59.000Z

47

Intergranular Stress Corrosion Cracking (IGSCC) Mechanism of ...  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, Materials Science & Technology 2012. Symposium, Environmentally Assisted Cracking of Materials. Presentation Title...

48

Weldability Tests for Evaluating Cracking Susceptibility  

Science Conference Proceedings (OSTI)

Table 2   Weldability tests used to evaluate susceptibility to cracking...used to evaluate susceptibility to cracking Test Fields of use Controllable variables Type of data Specialized equipment Relative cost Lehigh restraint test Weld metal hot and cold cracking, root cracking,

49

Origin of undesirable cracks during layer transfer  

E-Print Network (OSTI)

We investigate the origin of undesirable transverse cracks often observed in thin films obtained by the layer transfer technique. During this process, two crystals bonded to each other containing a weak plan produced by ion implantation are heated to let a thin layer of one of the material on the other. The level of stress imposed on the film during the heating phase due to the mismatch of thermal expansion coefficients of the substrate and the film is shown to be the relevant parameter of the problem. In particular, it is shown that if the film is submitted to a tensile stress, the microcracks produced by ion implantation are not stable and deviate from their straight trajectory making the layer transfer process impossible. However, if the compressive stress exceeds a threshold value, after layer transfer, the film can buckle and delaminate, leading to transverse cracks induced by bending. As a result, we show that the imposed stress \\sigma_m - or equivalently the heating temperature - must be within the ran...

Ponson, Laurent; Atwater, Harry; Ravichandran, Guruswami; Bhattacharya, Kaushik

2008-01-01T23:59:59.000Z

50

Aspects of Stress Corrosion Cracking Relevant to Irradiation-Assisted Stress Corrosion Cracking (IASCC)  

Science Conference Proceedings (OSTI)

This report provides a comprehensive survey of crack initiation issues in irradiation-assisted stress corrosion cracking (IASCC). It considers microcracking on smooth specimens and the transition from microcracking to stable crack propagation.

2002-05-02T23:59:59.000Z

51

Stable crack growth estimates based on effective crack length and crack-opening displacements  

SciTech Connect

A method was developed for estimating the amount of stable crack growth that has occurred in a fracture toughness specimen that were loaded into the plastic range and for which only a monotonically increasing load-displacement curve was measured. The method was applied to data from several pressure vessel steels. The resulting J vs ..delta..a values compare favorably with a resistance curve obtained by the multiple specimen heat-tinting technique for A533, Grade B, Class 1 steel. The method for estimating stable crack growth uses several existing concepts heretofore mainly used separately. These concepts include an approximate expression for J for the compact specimen proposed by Andrews, the effective crack length concept of McCabe and Landes, the UK representation of the crack profile as a pair of straight lines intersecting at a hinge point, and Well's expression, J = m sigma/sub y/delta, for relating the crack-opening displacement to the value of J. The value of the constraint factor, m, at the advancing crack tip is estimated by means of a relation between ductility and fracture toughness. When calculated with respect to the COD at the original fatigue crack tip, the constraint factor, m/sub o/, is found to have a value consistently close to 2.0 for compact and precracked Charpy specimens. The method of estimation requires no auxiliary load-deflection measurements or calculations, and so permits single specimen estimates of stable crack growth to be made without the necessity of making high precision unloading compliance measurements.

Merkle, J.G.; Hudson, C.E.

1979-01-01T23:59:59.000Z

52

Predicting the Behavior of Small Fatigue Cracks - Programmaster.org  

Science Conference Proceedings (OSTI)

are effective at providing crack propagation resistance in many materials and composites, these mechanisms result in a crack size dependence (i.e., small crack...

53

Assessment of Cracks in Stress Concentration Regions with Localized Plastic Zones  

SciTech Connect

Marty brittle fracture evaluation procedures include plasticity corrections to elastically computed stress intensity factors. These corrections, which are based on the existence of a plastic zone in the vicinity of the crack tip, can overestimate the plasticity effect for a crack embedded in a stress concentration region in which the elastically computed stress exceeds the yield strength of the material in a localized zone. The interactions between the crack, which acts to relieve the high stresses driving the crack, plasticity effects in the stress concentration region, and the nature and source of the loading are examined by formulating explicit flaw finite element models for a crack emanating from the root of a notch located in a panel subject to an applied tensile stress. The results of these calculations provide conditions under which a crack-tip plasticity correction based on the Irwin plastic zone size overestimates the plasticity effect. A failure assessment diagram (FAD) curve is used to characterize the effect of plasticity on the crack driving force and to define a less restrictive plasticity correction for cracks at notch roots when load-controlled boundary conditions are imposed. The explicit flaw finite element results also demonstrate that stress intensity factors associated with load-controlled boundary conditions, such as those inherent in the ASME Boiler and Pressure Vessel Code as well as in most handbooks of stress intensity factors, can be much higher than those associated with displacement-controlled conditions, such as those that produce residual or thermal stresses. Under certain conditions, the inclusion of plasticity effects for cracks loaded by displacement-controlled boundary conditions reduces the crack driving force thus justifying the elimination of a plasticity correction for such loadings. The results of this study form the basis for removing unnecessary conservatism from flaw evaluation procedures that utilize plasticity corrections.

Friedman, E.

1998-11-25T23:59:59.000Z

54

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

55

Stress Corrosion Cracking of Brass: A Comparative Study on ...  

Science Conference Proceedings (OSTI)

Environmentally Assisted Cracking of Carbon Steel in High Temperature Geothermal Well Evaluation of the Susceptibility to Hydrogen Assisted Cracking in...

56

On the Fatigue Crack Propagation Behavior of Superalloys at ...  

Science Conference Proceedings (OSTI)

ON THE FATIGUE CRACK PROPAGATION BEHAVIOR. OF SUPERALLOYS AT ... the FCP resistance of superalloys ... lead to poor crack propagation behavior.

57

Environmental Effects on Fatigue Crack Growth Rates in Sour ...  

Science Conference Proceedings (OSTI)

Environmentally Assisted Cracking of Carbon Steel in High Temperature Geothermal Well Evaluation of the Susceptibility to Hydrogen Assisted Cracking in...

58

Environmental Cracking Resistance of High Nickel Alloys (CRAs  

Science Conference Proceedings (OSTI)

Environmentally Assisted Cracking of Carbon Steel in High Temperature Geothermal Well Evaluation of the Susceptibility to Hydrogen Assisted Cracking in...

59

On Modeling Hydrogen-Induced Intergranular Cracking under ...  

Science Conference Proceedings (OSTI)

Environmentally Assisted Cracking of Carbon Steel in High Temperature Geothermal Well Evaluation of the Susceptibility to Hydrogen Assisted Cracking in...

60

Corrosion and Cracking of Carbon Steel in Fuel Grade Ethanol  

Science Conference Proceedings (OSTI)

Environmentally Assisted Cracking of Carbon Steel in High Temperature Geothermal Well Evaluation of the Susceptibility to Hydrogen Assisted Cracking in...

Note: This page contains sample records for the topic "thermal cracking visbreaking" 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

Evaluation of the Susceptibility to Hydrogen Assisted Cracking in ...  

Science Conference Proceedings (OSTI)

Environmentally Assisted Cracking of Carbon Steel in High Temperature Geothermal Well Evaluation of the Susceptibility to Hydrogen Assisted Cracking in...

62

Intergranular Cracking of Brass Sprinkler Heads  

Science Conference Proceedings (OSTI)

Symposium, Charles R. Morin Memorial Symposium on Failure Analysis and Prevention. Presentation Title, Intergranular Cracking of Brass Sprinkler Heads.

63

Vacuum State/Refiner/Location  

U.S. Energy Information Administration (EIA) Indexed Site

Vacuum Vacuum State/Refiner/Location Barrels per Atmospheric Crude Oil Distillation Capacity Barrels per Operating Idle Operating Idle Downstream Charge Capacity Thermal Cracking Delayed Fluid Coking Visbreaking Other/Gas Calendar Day Stream Day Distillation Coking Oil Table 3. Capacity of Operable Petroleum Refineries by State as of January 1, 2013 (Barrels per Stream Day, Except Where Noted) ......................................................... Alabama 120,100 0 130,000 0 48,000 32,000 0 0 0 Goodway Refining LLC 4,100 0 5,000 0 0 0 0 0 0 ....................................................................................................................................................................................................

64

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

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

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

65

CRACK GROWTH RESPONSE OF ALLOY 690 IN SIMULATED PWR PRIMARY WATER  

SciTech Connect

The stress corrosion crack growth response of three extruded alloy 690 CRDM tube heats was investigated in several thermomechanical conditions. Extremely low propagation rates (< 1 x 10{sup -9} mm/s) were observed under constant stress intensity factor (K) loading at 325-350 C in the as-received, thermally treated (TT) materials despite using a variety of transitioning techniques. Post-test observation of the crack-growth surfaces revealed only isolated intergranular (IG) cracking. One-dimensional cold rolling to 17% reduction and testing in the S-L orientation did not promote enhanced stress corrosion rates. However, somewhat higher propagation rates were observed in a 30% cold-rolled alloy 690TT specimen tested in the T-L orientation. Cracking of the cold-rolled material was promoted on grain boundaries oriented parallel to the rolling plane with the % IG increasing with the amount of cold rolling.

Toloczko, Mychailo B.; Bruemmer, Stephen M.

2009-12-01T23:59:59.000Z

66

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

DOE Green Energy (OSTI)

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

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

2009-08-01T23:59:59.000Z

67

Modeling of solar receiver for cracking of liquid petroleum gas  

SciTech Connect

The paper presents the model of an industrial solar receiver/reactor for thermal cracking of liquid petroleum gas (LPG) at the typical temperature range of 800--850 C. The concentrated solar radiation enters the receiver located on the ground and provided with a compound parabolic concentrator (CPC) at the ceiling. This is achieved with a reflecting solar tower. The radiative model uses the classical concept of equivalent gray plane to represent a panel of 40 cracking tubes placed in parallel of a refractory wall of the receiver. The radiative flux distribution on each wall is calculated and the chemistry in each reactor tube is evaluated until convergence is achieved. The design of an industrial size receiver, its behavior, and performance have been evaluated using this model. The computer program based on this model was run for a variety of flow conditions, feed compositions, and pressures.

Segal, A.; Epstein, M. [Weizmann Inst. of Science, Rehovot (Israel). Solar Research Facilities Unit

1997-02-01T23:59:59.000Z

68

Hydrocarbon Processing`s refining processes `96  

Science Conference Proceedings (OSTI)

The paper compiles information on the following refining processes: alkylation, benzene reduction, benzene saturation, catalytic cracking, catalytic reforming, coking, crude distillation, deasphalting, deep catalytic cracking, electrical desalting, ethers, fluid catalytic cracking, hydrocracking, hydrogenation, hydrotreating, isomerization, resid catalytic cracking, treating, and visbreaking. The application, products, a description of the process, yield, economics, installation, and licensor are given for each entry.

NONE

1996-11-01T23:59:59.000Z

69

The influence of cracks in rotating shafts  

E-Print Network (OSTI)

In this paper, the influence of transverse cracks in a rotating shaft is analysed. The paper addresses the two distinct issues of the changes in modal properties and the influence of crack breathing on dynamic response during operation. Moreover, the evolution of the orbit of a cracked rotor near half of the first resonance frequency is investigated. The results provide a possible basis for an on-line monitoring system. In order to conduct this study, the dynamic response of a rotor with a breathing crack is evaluated by using the alternate frequency/time domain approach. It is shown that this method evaluates the nonlinear behaviour of the rotor system rapidly and efficiently by modelling the breathing crack with a truncated Fourier series. The dynamic response obtained by applying this method is compared with that evaluated through numerical integration. The resulting orbit during transient operation is presented and some distinguishing features of a cracked rotor are examined.

Jean-Jacques Sinou; A. W. Lees

2008-01-19T23:59:59.000Z

70

Status Review of Initiation of Environmentally Assisted Cracking and Short Crack Growth  

Science Conference Proceedings (OSTI)

This report reviews current knowledge of environmentally assisted cracking EAC initiation and short crack growth by stress corrosion cracking, strain-induced corrosion cracking, and, to a lesser extent, corrosion fatigue in nickel base alloys, austenitic stainless steels, and carbon and low-alloy steels exposed to typical pressurized water reactor PWR and boiling water reactor BWR aqueous environments. The document identifies key gaps in knowledge and recommends areas where additional experimental work i...

2005-12-06T23:59:59.000Z

71

Stress Corrosion Cracking - Programmaster.org  

Science Conference Proceedings (OSTI)

Oct 28, 2013 ... Atomic Ordering in Alloy 690 and Its Effect on Long-term Structural Stability and Stress Corrosion Cracking Susceptibility: Michael Kaufman1;...

72

Creep Crack Growth Behaviour of Alloy 718  

Science Conference Proceedings (OSTI)

its creep crack growth is controlled by stress intensity factor regardless of load level .... energy. Since vacancies diffuse from a low strain energy position to a high...

73

Evaluation of Stress-Corrosion Cracking  

Science Conference Proceedings (OSTI)

Table 3   Stress-corrosion cracking of selected material systems...chlorides, seawater Oil/gas production and transmission, oil refining,

74

Crystallographic Orientation Dependence of Fatigue Crack ...  

Science Conference Proceedings (OSTI)

In the present study, fatigue crack propagation behavior of rolled AZ31B magnesium ... Alloy Design for Enhancing the Fracture Resistance of Heat Treated High...

75

Sulfide Stress Cracking in Steels - A Review  

Science Conference Proceedings (OSTI)

Symposium, Corrosion and Corrosion Protection of Materials in the Oil and Gas Industry. Presentation Title, Sulfide Stress Cracking in Steels - A Review.

76

Environmentally Assisted Cracking Susceptibility Assessment of AP ...  

Science Conference Proceedings (OSTI)

Presentation Title, Environmentally Assisted Cracking Susceptibility Assessment of AP 1000 Reactor Coolant Pump Flywheel Retainer Ring A289 18Cr-18Mn...

77

Discontinuous surface cracks during stress corrosion cracking of stainless steel single crystal  

E-Print Network (OSTI)

Discontinuous surface cracks during stress corrosion cracking of stainless steel single crystal L Keywords: A. Stainless steel B. SEM C. Stress corrosion a b s t r a c t Single crystal 321 stainless steel, and the river-markings exhibited microshear facets along the {1 1 1} plane. Interaction between the main crack

Volinsky, Alex A.

78

Development of a Low Thermal Expansion, Crack Growth Resistant ...  

Science Conference Proceedings (OSTI)

significant commercial usage in industries as diverse as gas turbine engine static ... Manufacturing and fabricating simplicity, and compatibility of heat treatments...

79

Characterization of Environment-Dependent Fatigue Crack Growth ...  

Science Conference Proceedings (OSTI)

at high frequency levels to fully environment-dependent at very low frequency ... environment-dependent crack growth process, crack increment per cycle is...

80

Computational Weld Mechanics of Hot Crack Nucleation in Nickel ...  

Science Conference Proceedings (OSTI)

Abstract Scope, Computational weld mechanics (CWM) is used to estimate the likelihood of hot crack nucleation in a welded joint. A hot crack nucleates when...

Note: This page contains sample records for the topic "thermal cracking visbreaking" 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

The Effect of Microstructure on the Fatigue Crack Growth Resistance ...  

Science Conference Proceedings (OSTI)

GROWTH RESISTANCE OF NICKEL BASE SUF'RRALLOYS. Randy Bowman ... damage are most resistant to crack growth. ... crack propagation. (FCP) was...

82

High cycle fatigue and fatigue crack propagation behavior of ...  

Science Conference Proceedings (OSTI)

And fatigue crack propagation rates of modified A7075 showed slightly lower. Those superior fatigue strength and resistance of fatigue crack propagation of...

83

Characterization of Elevated Temperature Fatigue Crack Growth Rates  

Science Conference Proceedings (OSTI)

temperature fatigue and the crack growth rates may be adequately correlated with the ... During creep crack growth the use of rate dependent elastic/plastic frac-.

84

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

85

Stress corrosion cracking of type 304L stainless steel core shroud welds.  

SciTech Connect

Microstructural analyses by advanced metallographic techniques were conducted on mockup welds and a cracked BWR core shroud weld fabricated from Type 304L stainless steel. heat-affected zones of the shroud weld and mockup shielded-metal-arc welds were free of grain-boundary carbide, martensite, delta ferrite, or Cr depletion near grain boundaries. However, as a result of exposure to welding fumes, the heat-affected zones of the welds were significantly contaminated by fluorine and oxygen which migrate to grain boundaries. Significant oxygen contamination promotes fluorine contamination and suppresses classical thermal sensitization, even in Type 304 steels. Results of slow-strain-rate tensile tests indicate that fluorine exacerbates the susceptibility of irradiated steels to intergranular stress corrosion cracking. These observations, combined with previous reports on the strong influence of weld flux, indicate that oxygen and fluorine contamination and fluorine-catalyzed stress corrosion play a major role in cracking of Type 304L stainless steel core shroud welds.

Chung, H. M.; Park, J.-H.; Sanecki, J. E.; Zaluzec, N. J.; Yu, M. S.; Yang, T. T.

1999-10-26T23:59:59.000Z

86

A thermal active restrained shrinkage ring test to study the early age concrete behaviour of massive structures  

Science Conference Proceedings (OSTI)

In massive concrete structures, cracking may occur during hardening, especially if autogenous and thermal strains are restrained. The concrete permeability due to this cracking may rise significantly and thus increase leakage (in tank, nuclear containment...) and reduce the durability. The restrained shrinkage ring test is used to study the early age concrete behaviour (delayed strains evolution and cracking). This test shows, at 20 {sup o}C and without drying, for a concrete mix which is representative of a French nuclear power plant containment vessel (w/c ratio equal to 0.57), that the amplitude of autogenous shrinkage (about 40 {mu}m/m for the studied concrete mix) is not high enough to cause cracking. Indeed, in this configuration, thermal shrinkage is not significant, whereas this is a major concern for massive structures. Therefore, an active test has been developed to study cracking due to restrained thermal shrinkage. This test is an evolution of the classical restrained shrinkage ring test. It allows to take into account both autogenous and thermal shrinkages. Its principle is to create the thermal strain effects by increasing the temperature of the brass ring (by a fluid circulation) in order to expand it. With this test, the early age cracking due to restrained shrinkage, the influence of reinforcement and construction joints have been experimentally studied. It shows that, as expected, reinforcement leads to an increase of the number of cracks but a decrease of crack widths. Moreover, cracking occurs preferentially at the construction joint.

Briffaut, M. [LMT/ENS Cachan/CNRS UMR8535/UPMC/PRES UniverSud Paris, Cachan (France); Institut de radioprotection et de surete nucleaire, Fontenay-aux-Roses (France); Benboudjema, F. [LMT/ENS Cachan/CNRS UMR8535/UPMC/PRES UniverSud Paris, Cachan (France); Torrenti, J.M., E-mail: jean-michel.torrenti@lcpc.f [Universite Paris Est, Laboratoire central des ponts et chaussees, Paris (France); Nahas, G. [LMT/ENS Cachan/CNRS UMR8535/UPMC/PRES UniverSud Paris, Cachan (France); Institut de radioprotection et de surete nucleaire, Fontenay-aux-Roses (France)

2011-01-15T23:59:59.000Z

87

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

DOE Green Energy (OSTI)

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

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

2000-09-17T23:59:59.000Z

88

Subcritical Crack Growth Processes in SiC/SiC Ceramic Matrix Composites  

Science Conference Proceedings (OSTI)

Ceramic matrix composites have the potential to operate at high-temperatures and are, therefore being considered for a variety of advanced energy technologies such as combustor liners in land based gas turbo/generators, heat exchangers and advanced fission and fusion reactors. Ceramic matrix composites exhibit a range of crack growth mechanisms driven by a range of environmental and nuclear conditions. The crack growth mechanisms include: 1) fiber relaxation by thermal (FR) and irradiation (FIR) processes, 2) fiber stress-rupture (SR), 3) interface removal (IR) by oxidation, and 4) oxidation embrittlement (OE) resulting from glass formation including effects of glass viscosity. Analysis of these crack growth processes has been accomplished with a combination experimental/modeling effort. Dynamic, high-temperature, in situ crack growth measurements have been made in variable Ar + O2 environments while a PNNL developed model has been used to extrapolate this data and to add radiation effects. In addition to the modeling effort, a map showing these mechanisms as a function of environmental parameters was developed. This mechanism map is an effective tool for identifying operating regimes and predicting behavior. The process used to develop the crack growth mechanism map was to: 1) hypothesize and experimentally verify the operative mechanisms, 2) develop an analytical model for each mechanism, and 3) define the operating regime and boundary conditions for each mechanism. A map for SiC/SiC composites has been developed for chemical and nuclear environments as a function of temperature and time.

Jones, Russell H.; Henager, Charles H.

2005-07-01T23:59:59.000Z

89

Thermal spray coatings on Yankee dryers  

SciTech Connect

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

90

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

Science Conference Proceedings (OSTI)

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

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

1996-02-01T23:59:59.000Z

91

Numerical modeling of crack reorientation and link-up  

Science Conference Proceedings (OSTI)

The FRANC3D/BES software system has been used to simulate the reorientation and link-up of hydraulic fractures in three-dimensional (3D) problems. The adopted technique only needs to discretize the body surface and the crack surface. The crack propagation ... Keywords: FRANC3D/BES, crack propagation, multiple cracks

C. Y. Dong; C. J. de Pater

2002-11-01T23:59:59.000Z

92

Optimal control of fluid catalytic cracking processes  

Science Conference Proceedings (OSTI)

An investigation was made of the applicability of optimal control theory to the design of control systems for non-linear, multivariable chemical processes. A hypothetical fluid catalytic cracking process was selected as a typical representative of such ...

L. A. Gould; L. B. Evans; H. Kurihara

1970-09-01T23:59:59.000Z

93

Linking Grain Boundary Microstructure to Stress Corrosion Cracking of Cold Rolled Alloy 690 in PWR Primary Water  

SciTech Connect

Grain boundary microstructures and microchemistries are examined in cold-rolled alloy 690 tubing and plate materials and comparisons are made to intergranular stress corrosion cracking (IGSCC) behavior in PWR primary water. Chromium carbide precipitation is found to be a key aspect for materials in both the mill annealed and thermally treated conditions. Cold rolling to high levels of reduction was discovered to produce small IG voids and cracked carbides in alloys with a high density of grain boundary carbides. The degree of permanent grain boundary damage from cold rolling was found to depend directly on the initial IG carbide distribution. For the same degree of cold rolling, alloys with few IG precipitates exhibited much less permanent damage. Although this difference in grain boundary damage appears to correlate with measured SCC growth rates, crack tip examinations reveal that cracked carbides appeared to blunt propagation of IGSCC cracks in many cases. Preliminary results suggest that the localized grain boundary strains and stresses produced during cold rolling promote IGSCC susceptibility and not the cracked carbides and voids.

Bruemmer, Stephen M.; Olszta, Matthew J.; Toloczko, Mychailo B.; Thomas, Larry E.

2012-10-01T23:59:59.000Z

94

Effect of Hot Cracks on EAC Crack Initiation and Growth in Nickel ...  

Science Conference Proceedings (OSTI)

No crack initiation/extension from hot cracks occured in any weld metals, which is ... Applicability of Lean Grade of Duplex Stainless Steels in Nuclear Power Plants .... Wear of Zircaloy-4 Grid Straps Due to Fretting and Periodic Impact with RV...

95

Thermal Sprays and Ceramic Coatings Assessments: Laboratory and Field Evaluations of Ceramic and Thermal Sprays Coatings  

Science Conference Proceedings (OSTI)

This report includes assessments of Ceramic and Thermal Spray coatings both by laboratory evaluation and analysis of field samples. The field samples are presented as case studies describing the condition of the material solution applied. Several thermal sprays and ceramic coatings were tested and analyzed for their ability to mitigate fireside corrosion, reduce slagging and it's propensity to have circumferential cracking occur due to cyclic temperature variations. In addition, the case studies provide ...

2010-12-31T23:59:59.000Z

96

VarPetrRef 1 VARIETY AND THE EVOLUTION OF REFINERY PROCESSING  

E-Print Network (OSTI)

. Catalytic reforming followed as a means of upgrading the octane of gasoline range materials principally): Catalytic reforming, Isomerization, Alkylation, Catalytic polymerization, MTBE and Hydrotreating. The last Distillation Visbreaking Hydrotreating Hydrocracking Thermal Reforming Alkylation MTBE Catalytic Reform ing

Paris-Sud XI, Université de

97

TRANSPORT THROUGH CRACKED CONCRETE: LITERATURE REVIEW  

SciTech Connect

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

Langton, C.

2012-05-11T23:59:59.000Z

98

Adsorbent-treated cat cracked gasoline in motor fuels  

SciTech Connect

A methof is described for supressing carburetor deposit formation of motor fuels containing untreated cat cracked gasoline by blending adsorbent-treated cat cracked gasoline into the motor fuel. Up to about 50 percent by weight of the total composition is adsorbent treated cat cracked gasoline, but preferably from about 5 to about 25 percent by weight of the total composition is adsorbent treated cat cracked gasoline. In a preferred embodiment a standard reference fuel capable of providing a predetermined level of carburetor deposit formation is provided by the addition of either adsorbent-treated cat cracked gasoline, untreated cat cracked gasoline, or aromatic amines to a base fuel.

Thomas, S.P.

1980-09-30T23:59:59.000Z

99

STRESS CORROSION CRACKING IN TEAR DROP SPECIMENS  

SciTech Connect

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

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

2009-05-01T23:59:59.000Z

100

Materials Reliability Program: Input for Pressurized Thermal Shock Rulemaking (MRP-248)  

Science Conference Proceedings (OSTI)

The Pressurized Thermal Shock (PTS) rule addresses the risk of a nuclear power plant reactor vessel failing due to propagation of a crack through the vessel wall. If a plant has an emergency cool-down event that superimposes a large thermal transient stress on a large pressure stress in the presence of a pre-existing flaw, it is possible that a crack could initiate and propagate through the vessel wall. The resistance of a vessel to crack initiation and propagation declines as the vessel ages. As a resul...

2008-12-23T23:59:59.000Z

Note: This page contains sample records for the topic "thermal cracking visbreaking" 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

THERMAL RECOVERY  

NLE Websites -- All DOE Office Websites (Extended Search)

THERMAL RECOVERY Thermal recovery comprises the techniques of steamflooding, cyclic steam stimulation, and in situ combustion. In steamflooding, high-temperature steam is injected...

102

Crack detection using resonant ultrasound spectroscopy  

DOE Patents (OSTI)

This invention is comprised of a method and apparatus 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.

Migliori, A.; Bell, T.M.

1992-12-31T23:59:59.000Z

103

Stress corrosion cracking behavior of Alloy 600 in high temperature water  

Science Conference Proceedings (OSTI)

SCC susceptibility of Alloy 600 in deaerated water at 360 C (statically loaded U-bend specimens) is dependent on microstructure and whether the material was cold-worked and annealed (CWA) or hot-worked and annealed (HWA). All cracking was intergranular, and materials lacking grain boundary carbides were most susceptible to SCC initiation. CWA tubing materials are more susceptible to SCC initiation than HWA ring-rolled forging materials with similar microstructures (optical metallography). In CWA tubing materials, one crack dominated and grew to a visible size. HWA materials with a low hot-working finishing temperature (980 C) and a high-temperature final anneal (>1040 C), with grain boundaries that are fully decorated, developed only microcracks in all specimens. These materials did not develop large, visually detectable cracks, even after more than 300 weeks exposure. A low-temperature thermal treatment (610 C for 7h), which reduces or eliminates SCC in Alloy 600, did not eliminate microcrack formation in high temperature processed HWA materials. Conventional metallographic and analytical electron microscopy (AEM) were done on selected materials to identify the factors responsible for the observed differences in cracking behavior. Major difference between high-temperature HWA and low-temperature HWA and CWA materials was that the high temperature processing and final annealing produced predominantly ``semi-continuous`` dendritic M{sub 7}C{sub 3} carbides along grain boundaries with a minimal amount of intragranular carbides. Lower temperature processing produced intragranular M7C3 carbides, with less intergranular carbides.

Webb, G.L.; Burke, M.G.

1995-07-01T23:59:59.000Z

104

Accelerated Fatigue Crack Growth Behavior of PWA 1480 Single ...  

Science Conference Proceedings (OSTI)

3 456. 610. 1520 30. AK . AKrss. MPa v'?! Fig. 10 Fatigue crack growth rate as a function of AKrss and AK. Prediction of the Microscopic Crack Behavior: An...

105

Reading of cracked optical discs using iterative learning control  

Science Conference Proceedings (OSTI)

Optical discs, including Compact Discs (CDs), Digital Versatile Discs (DVDs), and Blu-ray Discs (BDs), can get cracked during storage and usage. Such cracks commonly lead to discontinuities in the data track, potentially preventing reading of the data ...

Maarten Steinbuch; Koos Van Berkel; George Leenknegt; Tom Oomen; Jeroen Van De Wijdeven

2009-06-01T23:59:59.000Z

106

Stress Corrosion Cracking of Steel In Concentrated Nitrate ...  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, Materials Science & Technology 2011. Symposium, Environmentally Assisted Cracking of Materials. Presentation Title, Stress...

107

Interaction between Local Strains and Stress Corrosion Cracks ...  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, Materials Science & Technology 2013. Symposium, Environmentally Assisted Cracking (EAC): Laboratory Research and Field...

108

Stress Corrosion Cracking Observation in API G-105 Grade Drill ...  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, Materials Science & Technology 2011. Symposium, Environmentally Assisted Cracking of Materials. Presentation Title, Stress...

109

Environmentally Assisted Cracking of Stainless Steels and Nickel ...  

Science Conference Proceedings (OSTI)

Oct 10, 2012 ... Intergranular Stress Corrosion Cracking (IGSCC) Mechanism of Structural Component Materials in Pressurized Water Reactors : Young Suk...

110

stress corrosion cracking of iron and nickel based alloys  

Science Conference Proceedings (OSTI)

This Table of Contents is from Chemistry and Electrochemistry of Corrosion and Stress Corrosion Cracking published by TMS.

111

Girth Weld Cracking at Ethanol Terminal Facilities - Programmaster ...  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, Materials Science & Technology 2013. Symposium, Failure Analysis and Prevention. Presentation Title, Girth Weld Cracking at...

112

Latent Cracking of Tantalum - Titanium Welds Due to Hydrogen ...  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, Materials Science & Technology 2012. Symposium, Environmentally Assisted Cracking of Materials. Presentation Title, Latent...

113

Molecular Dynamics of Fatigue Crack Growth in Nanocrystalline ...  

Science Conference Proceedings (OSTI)

Experimental techniques are prohibitive due to limitations of nano samples and advanced microscopic manipulators. In this study, crack propagation under...

114

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

E-Print Network (OSTI)

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

Gibbs, Jonathan Paul

2011-01-01T23:59:59.000Z

115

The influence of crack-imbalance orientation and orbital evolution for an extended cracked Jeffcott rotor  

E-Print Network (OSTI)

Vibration peaks occurring at rational fractions of the fundamental rotating critical speed, here named Local Resonances, facilitate cracked shaft detection during machine shut-down. A modified Jeffcott-rotor on journal bearings accounting for gravity effects and oscillating around nontrivial equilibrium points is employed. Modal parameter selection allows this linear model to represent first mode characteristics of real machines. Orbit evolution and vibration patterns are analyzed, yielding useful results. Crack detection results indicate that, instead of 1x and 2x components, analysis of the remaining local resonances should have priority; this is due to crack-residual imbalance interaction and to 2x multiple induced origins. Therefore, local resonances and orbital evolution around 1/2, 1/3 and 1/4 of the critical speed are emphasized for various crack-imbalance orientations.

Julio Gomez-Mancilla; Jean-Jacques Sinou; V. R. Nosov; Fabrice Thouverez; A. Zambrano

2008-01-19T23:59:59.000Z

116

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

E-Print Network (OSTI)

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

Gibbs, Jonathan Paul

117

Honeywords: making password-cracking detectable  

Science Conference Proceedings (OSTI)

We propose a simple method for improving the security of hashed passwords: the maintenance of additional ``honeywords'' (false passwords) associated with each user's account. An adversary who steals a file of hashed passwords and inverts the hash function ... Keywords: authentication, chaffing, honeywords, login, password cracking, password hashes, passwords

Ari Juels, Ronald L. Rivest

2013-11-01T23:59:59.000Z

118

Fuzzy modeling of fluidized catalytic cracking unit  

Science Conference Proceedings (OSTI)

The paper deals with the fuzzy system identification of reactor-regenerator-stripper-fractionator's (RRSF) section of a fluidized catalytic cracking unit (FCCU). The fuzzy system identification based on the data collected from an operating refinery of ... Keywords: Dynamic fuzzy model, FCCU models, Fuzzy clustering, Fuzzy inference systems, Fuzzy models, Hybrid learning, Mountain clustering, Supervised learning, Unsupervised learning

Mohammad Fazle Azeem; Nesar Ahmad; M. Hanmandlu

2007-01-01T23:59:59.000Z

119

Cracked rotor vibrations by multifractal analysis  

E-Print Network (OSTI)

Multifractal analysis has been used to diagnoze cracked and healthy rotors. Is has been shown that the complexity and regularity criteria of the dynamical systems defined by the multiple scaling of the time series can indicate the damages of the rotating shaft.

Grzegorz Litak; Jerzy T. Sawicki

2008-04-15T23:59:59.000Z

120

Strip edge cracking simulation in cold rolling  

SciTech Connect

This research work focuses on a specific defect which occurs during cold rolling of steel strips: edge-serration. Investigations on the industrial processes have led to the conclusion that this defect is the result of the edge-trimming and cold rolling sequences. The aim of this research work is to analyze the effect of the cutting process and the cold rolling on cracks occurrence, especially on strip edges.This study is performed using an experimental testing stand called Upsetting Rolling Test (URT). It allows to reproduce cold rolling contact parameters such as forward slip, reduction ratio and friction coefficients. Specimens sampled near trimmed industrial strip edges are deformed using the URT stand. Two sets of specimens with different stress states, obtained by annealing, are submitted to two reduction passes with extreme forward slips.Scanning electron microscopy observations added to 3D optical surface profiler topographies show that on one hand, forward slip has a major effect on cracks opening. On the other hand, cracks opening decreases according to high roll strip speed gradient. Concerning the heat-treated specimens, no crack appeared after all reduction passes, showing a large influence of the cutting process and consequently of the local stress state in the vicinity of the burnish and fracture regions.

Hubert, C.; Dubar, L.; Dubar, M.; Dubois, A. [Univ Lille Nord de France, F-59000 Lille (France); UVHC, TEMPO EA 4542, F-59313 Valenciennes (France)

2011-01-17T23:59:59.000Z

Note: This page contains sample records for the topic "thermal cracking visbreaking" 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

Segmentation of cracks in shale rock  

Science Conference Proceedings (OSTI)

In this paper the use of morphological connected filters are studied for segmenting sheet- and thread-like cracks in images of shale rock. A volume formed from a stack of 2-D X-ray images is processed using 3-D attributes. The shape-preserving property ...

Erik R. Urbach; Marina Pervukhina; Leanne Bischof

2011-07-01T23:59:59.000Z

122

Digital radiographic systems detect boiler tube cracks  

SciTech Connect

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

123

Final report on PCRV thermal cylinder axial tendon failures  

SciTech Connect

The post-test examination of the failed tendons from the PCRV thermal cylinder experiment has been concluded. Failures in the wires are attributed to stress-corrosion cracking. The cause of tendon failures has not been unequivocably established, but they may have been due to nitrates in the duct. The wires employed in the manufacture of the tendons will crack in less than 72 hr in a 0.2 M solution of ammonium nitrate at 70$sup 0$C. The quality of the wires is poor, and surface cracks were detected. These could have acted as concentrating sites for both stress and the deleterious contaminants. It is believed that the factors that led to the failures in the thermal cylinder experiment were unique. An improper formulation of the epoxy resin did not provide the tendon anchor plate seal that was desired; indeed, the improper formulation is responsible for the high level of nitrogen in the ducts of the failed tendons. (auth)

Canonico, D.A.; Griess, J.C.; Robinson, G.C.

1976-01-01T23:59:59.000Z

124

Thermal fatigue evaluation of solder alloys. Final report  

SciTech Connect

An evaluation was made of the relative thermal fatigue resistance of 29 solder alloys. A number of these alloys were found to be less susceptible to thermal fatigue cracking in encapsulated printed wiring board applications than the commonly used tin-lead eutectic (63Sn-37Pb). Three alloys, 95Sn-5Ag, 96.5Sn-3.5Ag, and 95Sn-5Sb offered the greatest resistance to thermal fatigue. The selection of the encapsulation materials was confirmed to be a significant factor in thermal fatigue of solder joints, regardless of the solder alloy used.

Jarboe, D.M.

1980-02-01T23:59:59.000Z

125

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

126

SCREENING TESTS FOR IMPROVED METHANE CRACKING MATERIALS  

DOE Green Energy (OSTI)

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

Klein, J; Jeffrey Holder, J

2007-07-16T23:59:59.000Z

127

Circumferential cracking of steam generator tubes  

SciTech Connect

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

Karwoski, K.J.

1997-04-01T23:59:59.000Z

128

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

129

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

130

Hydrogen Induced Cracking of Drip Shield  

DOE Green Energy (OSTI)

One potential failure mechanism for titanium and its alloys under repository conditions is via the absorption of atomic hydrogen in the metal crystal lattice. The resulting decreased ductility and fracture toughness may lead to brittle mechanical fracture called hydrogen-induced cracking (HIC) or hydrogen embrittlement. For the current design of the engineered barrier without backfill, HIC may be a problem since the titanium drip shield can be galvanically coupled to rock bolts (or wire mesh), which may fall onto the drip shield, thereby creating conditions for hydrogen production by electrochemical reaction. The purpose of this scientific analysis and modeling activity is to evaluate whether the drip shield will fail by HIC or not under repository conditions within 10,000 years of emplacement. This Analysis and Model Report (AMR) addresses features, events, and processes related to hydrogen induced cracking of the drip shield. REV 00 of this AMR served as a feed to ''Waste Package Degradation Process Model Report'' and was developed in accordance with the activity section ''Hydrogen Induced Cracking of Drip Shield'' of the development plan entitled ''Analysis and Model Reports to Support Waste Package PMR'' (CRWMS M&O 1999a). This AMR, prepared according to ''Technical Work Plan for: Waste Package Materials Data Analyses and Modeling'' (BSC 2002), is to feed the License Application.

G. De

2003-02-24T23:59:59.000Z

131

Methane cracking over a bituminous coal char  

Science Conference Proceedings (OSTI)

Methane cracking over a bed of Chinese bituminous coal char was studied using a fixed-bed reactor at atmospheric pressure and temperatures between 1073 and 1223 K. Methane conversion over the fresh char increased with increasing temperature to 90% at 1223 K. Hydrogen was the only gas-phase product that was detected during the experimentation. The char was shown to exert a significant catalytic effect on methane cracking by comparing results from experiments with the raw char and demineralised char as well as from blank experiments using quartz. It was further shown that the ash was not the source of the catalytic effect of the char. However, both methane conversion and hydrogen yield decreased with increasing reaction time, irrespective of other experimental conditions, indicating that the char rapidly became deactivated following the exposure to methane. It was speculated that the deposition of carbon from methane cracking was responsible for this deactivation, which is supported by scanning electron microscopy (SEM) image analysis. It was demonstrated that the catalytic activity of the deactivated char can be partially recovered by burning off the carbon deposits with an oxidizing gas mixture containing 0.46% oxygen. 10 refs., 11 figs., 1 tab.

Zhi-qiang Sun; Jin-hu Wu; Mohammad Haghighi; John Bromly; Esther Ng; Hui Ling Wee; Yang Wang; Dong-ke Zhang [Chinese Academy of Sciences, Taiyuan (China). Institute of Coal Chemistry

2007-06-15T23:59:59.000Z

132

Crack tip plasticity in single crystal UO2: Atomistic simulations  

SciTech Connect

The fracture behavior of single crystal uranium dioxide is studied using molecular dynamics simulations at room temperature. Initially, an elliptical notch is created on either {111} or {110} planes, and tensile loading is applied normal to the crack planes. For cracks on both planes, shielding of crack tips by plastic deformation is observed, and crack extension occurs for crack on {111} planes only. Two plastic processes, dislocation emission and phase transformation are identified at crack tips. The dislocations have a Burgers vector of ?110?/2, and glide on {100} planes. Two metastable phases, the so-called Rutile and Scrutinyite phases, are identified during the phase transformation, and their relative stability is confirmed by separate density- functional-theory calculations. Examination of stress concentration near crack tips reveals that dislocation emission is not an effective shielding mechanism. The formation of new phases may effectively shield the crack provided all phase interfaces formed near the crack tips are coherent, as in the case of cracks residing on {110} planes.

Yongfeng Zhang; Paul C. Millett; Michael Tonks; Bulent Biner; Xiang-Yang Liu; David A. Andersson

2012-11-01T23:59:59.000Z

133

Role of crack tip shielding in the initiation and growth of long and small fatigue cracks in composite microstructures  

Science Conference Proceedings (OSTI)

The role of crack tip shielding in retarding the initiation and growth of fatigue cracks has been examined in metallic composite microstructures (consisting of hard and soft phases), with the objective of achieving maximum resistance to fatigue. Specifically, duplex ferritic-martensitic structures have been developed in AISI 1008 and 1015 mild steels to promote shielding without loss in strength. The shielding is developed primarily from crack deflection and resultant crack closure, such that unusually high long crack propagation resistance is obtained. It is found that the fatigue threshold ..delta..K/sub TH/ in AISI 1008 can be increased by more than 100 pct to over 20 MPa ..sqrt..m, without sacrifice in strength, representing the highest ambient temperature threshold reported for a metallic alloy to date. Similar but smaller increases are found in AISI 1015. The effect of the dual-phase microstructures on crack initiation and small crack (10 to 1000 ..mu..m) growth, however, is markedly different, characteristic of behavior influenced by the mutual competition of intrinsic and extrinsic (shielding) ''toughening'' mechanisms. Accordingly, the composite microstructures which appear to show the highest resistance to the growth of long cracks, show the lowest resistance to crack initiation and small crack growth. In general, dual-phase steels are found to display remarkable fatigue properties, with fatigue limits as high as 58 pct of the tensile strengths and fatigue thresholds in the range of 13 to 20 MPa..sqrt..m.

Shang, J.K.; Tzou, J.L.; Ritchie, R.O. (Materials and Chemical Sciences Div., Lawrence Berkeley Lab., and Dept. of Materials Science and Mineral Engineering, Univ. of California, Berkeley, CA (US))

1987-09-01T23:59:59.000Z

134

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

DOE Green Energy (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

135

Thermal fatigue behavior of US and Russian grades of beryllium  

Science Conference Proceedings (OSTI)

A novel technique has been used to test the relative low cycle thermal fatigue resistance of different grades of US and Russian beryllium which is proposed as plasma facing armor for fusion reactor first wall, limiter, and divertor components. The 30 KW electron beam test system at Sandia National Laboratories was used to sweep the beam spot along one direction at 1 Hz. This produces a localized temperature ``spike`` of 750{degrees}C for each pass of the beam. Large thermal stress in excess of the yield strength are generated due to very high spot heat flux, 250 MW/m{sup 2}. Cyclic plastic strains on the order of 0.6% produced visible cracking on the heated surface in less than 3000 cycles. An in-vacuo fiber optic borescope was used to visually inspect the beryllium surfaces for crack initiation. Grades of US beryllium tested included: S-65C, S-65H, S-200F, S-300F-H, Sr-200, I-400, extruded high purity. HIP`d sperical powder, porous beryllium (94% and 98% dense), Be/30% BeO, Be/60% BeO, and TiBe{sub 12}. Russian grades included: TGP-56, TShGT, DShG-200, and TShG-56. Both the number of cycles to crack initiation, and the depth of crack propagation, were measured. The most fatigue resistant grades were S-65C, DShG-200, TShGT, and TShG-56. Rolled sheet Be(SR-200) showed excellent crack propagation resistance in the plane of rolling, despite early formation of delamination cracks. Only one sample showed no evidence of surface melting, Extruded (T). Metallographic and chemical analyses are provided. Good agreement was found between the measured depth of cracks and a 2-D elastic-plastic finite element stress analysis.

Watson, R.D.; Youchison, D.L. [Sandia National Labs., Albuquerque, NM (United States); Dombrowski, D.E. [Brush Wellman, Inc., Cleveland, OH (United States); Guiniatouline, R.N. [Efremov Institute, St. Petersburg (USSR); Kupriynov, I.B. [Russian Inst. of Inorganic Materials, Moscow (USSR)

1996-02-01T23:59:59.000Z

136

Hydrogen induced crack growth in Grade-12 titanium  

DOE Green Energy (OSTI)

Internal hydrogen induced crack growth rates were measured in Grade-12 titanium which is a candidate material for high-level nuclear waste containers. As-received and hydrogen charged samples (5 ppM to 330 ppM hydrogen) were used for slow crack growth measurements at constant loads using a Krak Gauge. The testing temperature ranged from room temperature to 148/sup 0/C. The crack growth kinetics under low to moderate loads are linear, but this linear rate is interrupted by discrete fast crack jump segments with parabolic or cubic type kinetics. These fast jump segments are thought to be associated with the passage of the crack front through the alpha-beta interface phase or with the initial loading sequence. By measuring striation spacings on the fracture surface, most crack growth rates observed are found to be in stage II. The striations are considered to be associated with hydride fracture. The crack path is either transgranular in the alpha phase or interfacial in the alpha phase adjacent to the beta phase. For transgranular growth, crack growth rates are constant and slower than those for interfacial growth which is associated with fast crack growth through a high hydrogen concentration region. Most stage II crack growth rates depend slightly on the stress intensity suggesting the contribution of plastic tearing process to stage II kinetics. The activation energies for crack growth are much lower than the activation energy of hydrogen diffusion through the alpha phase, implying that hydrogen is transported along dislocations, grain boundaries or interfaces. When the temperature is increased, the crack velocity first reaches a maximum and then decreases at higher temperatures. These temperature effects come from lower hydrogen concentration trapped at dislocations or from slower hydride nucleation kinetics, both at higher temperatures.

Ahn, T.M.; Lee, K.S.

1984-01-01T23:59:59.000Z

137

Relationships Between Stress Corrosion Cracking Tests and Utility ...  

Science Conference Proceedings (OSTI)

Aug 1, 1999 ... Several utility steam generator and stress corrosion cracking ... Superheated steam and neutral solution environments are found to be...

138

Influence of Different Cooling Structure on Surface Crack of HSLA ...  

Science Conference Proceedings (OSTI)

Presentation Title, Influence of Different Cooling Structure on Surface Crack of .... of Si3N4-SiC Heat Absorption Ceramic Material Used for Tower Type Solar...

139

Basic Aspects of Superalloy Design for Crack Growth Resistance  

Science Conference Proceedings (OSTI)

theories for fatigue and creep crack growth resistance that are particularly ... devices as the nuclear reactors and in such strategic and expensive vehicles.

140

Fatigue Property-Microstructure Relationships and Crack Growth  

Science Conference Proceedings (OSTI)

Feb 28, 2011 ... Effect of Microstructure on Fatigue Behavior of Two Pipeline Steels: .... to a transition crack length (LEFM applicable) is approximated using...

Note: This page contains sample records for the topic "thermal cracking visbreaking" 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

In-vitro Evaluation of Stress Corrosion Cracking of Biomedical ...  

Science Conference Proceedings (OSTI)

In this study, the susceptibility to stress corrosion cracking of biodegradable and aluminium-free magnesium alloys, WZ21 and WE43, was investigated using...

142

Corrosion Inhibition of Stress Corrosion Cracking and Localized ...  

Science Conference Proceedings (OSTI)

Abstract Scope, Stress corrosion cracking of 7050 aluminum alloys in the turbo expander industry can cause expensive catastrophic failures, especially for turbo

143

Strain Rate Sensitivity of Alloy 718 Stress Corrosion Cracking  

Science Conference Proceedings (OSTI)

Stress corrosion cracking (SCC) tests were conducted in 36O'C pressurized- water-reactor. (PWR) primary water using. Alloy 718 heat-treated to produce.

144

Stress Corrosion Cracking of Aluminium-Free Magnesium Alloys in ...  

Science Conference Proceedings (OSTI)

Presentation Title, Stress Corrosion Cracking of Aluminium-Free Magnesium Alloys in a Simulated Human Body Fluid. Author(s), Lokesh Choudhary, R. K. Singh...

145

Environmentally Assisted Cracking of Alloy 7050-T7451 Exposed to ...  

Science Conference Proceedings (OSTI)

Under cyclic loading notched specimens failed by transgranular stress corrosion cracking. Striations were observed on the cleavage-like facets. The number of...

146

Stress Corrosion Crack Initiation of Alloy 690 in Subcritical and ...  

Science Conference Proceedings (OSTI)

Abstract Scope, The objective of this study is to investigate the structure and chemistry of corrosion and stress corrosion crack initiation in Alloy 690. To avoid

147

grain boundary oxidation and stress corrosion cracking in nickel ...  

Science Conference Proceedings (OSTI)

Accelerated stress corrosion cracking tests and exposures were conducted on alloy 600, Ni-9Fe, and Ni-9Fe-5Cr (LCr) in constant extension rate mode in...

148

Model for the Superimposed Effects of Stress-Corrosion Cracking ...  

Science Conference Proceedings (OSTI)

Symposium, Fatigue and Corrosion Damage in Metallic Materials: Fundamentals, ... and a stress-corrosion cracking mode acting at high stress intensity in NaCl.

149

Stress Corrosion Cracking Threshold of Ti 6-4 Extrusions  

Science Conference Proceedings (OSTI)

Ti 6Al-4V extrusions with standard chemistry and extra low interstitial are evaluated for their stress corrosion cracking resistance. Also examined is the affect of...

150

A Study on the Stress Corrosion Cracking Mechanism of Carbon ...  

Science Conference Proceedings (OSTI)

Abstract Scope, Carbon steel is susceptible to stress corrosion cracking (SCC) in fuel grade ethanol (FGE). The research results obtained thus far have found...

151

Stress Corrosion Cracking Initiation of Austenitic Alloys in ...  

Science Conference Proceedings (OSTI)

Presentation Title, Stress Corrosion Cracking Initiation of Austenitic Alloys in Supercritical Water. Author(s), Guoping Cao, Vahid Firouzdor, Todd Allen. On-

152

Galvanic Corrosion and Stress Corrosion Cracking of Steel and ...  

Science Conference Proceedings (OSTI)

No aluminum bolt AW 7075 failed in magnesium due to stress corrosion cracking (SCC). Even aluminum bolts in T6 condition can be used for automotive...

153

Orientation Effects and Influence of Delta Phase on Fatigue Crack ...  

Science Conference Proceedings (OSTI)

including a hold time at maximum load lead to increased crack propagation rates when compared ... 720C ;' 8 hours .! controlled cooling rate at 50C per hour.

154

Stress Corrosion Cracking of Stabilized Austenitic Stainless Steels ...  

Science Conference Proceedings (OSTI)

Aug 1, 1999 ... Stress Corrosion Cracking of Stabilized Austenitic Stainless Steels in Various Types of Nuclear Power Plants by M.O. Speidel and R.

155

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

Open Energy Info (EERE)

P wave anisotropy, stress, and crack distribution at Coso geothermal field, California Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: P wave...

156

Failure Analysis of a Cracked Thermite Welded Rail Section  

Science Conference Proceedings (OSTI)

Brittle fracture followed the fatigue crack propagation causing complete separation of the rail. Although the excess material was thought to reinforce the rails it...

157

High-Temperature Stress Relaxation Cracking and Stress Rupture ...  

Science Conference Proceedings (OSTI)

An incident occurred that resulted in the cracking of gasifier internals, bulging and stress rupture of the shell and the escape of hot syngas, causing a fire.

158

Corrosion Fatigue and Crack Propagation of Different Austenitic ...  

Science Conference Proceedings (OSTI)

A FIB Study of the Resistance of Grain Boundaries to Short Fatigue Crack Propagation in Three-Dimensions in High Strength Al Alloys A Non-Linear Damage...

159

Effect of Interstitial Content on High Temperature Fatigue Crack ...  

Science Conference Proceedings (OSTI)

instance; resulted in fatigue crack propagation (FCP)' programs like ESDADTA(2) and ENSIP(3). Fatigue resistance of nickel base superalloys is affected by...

160

Fatigue and Fatigue Crack Propagation Behaviors of High ...  

Science Conference Proceedings (OSTI)

The S-N fatigue and fatigue crack propagation (FCP) behaviors of high ... The mechanisms associated with the improved fatigue resistance for the high...

Note: This page contains sample records for the topic "thermal cracking visbreaking" 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.


161

Intergranular Liquid Formation, Distribution, and Cracking in the ...  

Science Conference Proceedings (OSTI)

zone adjacent to the fusion zone. These intergranular cracks form when liquid ...... 718, and A286 in Light Water Reactor. Environments",. J. Mater. Eng., 2, pp.

162

Stress corrosion cracking of zirconium in nitric acid  

Science Conference Proceedings (OSTI)

The susceptibility of zirconium and its common alloys to stress corrosion cracking (SCC) in nitric acid was investigated by slow strain-rate and constant deflection techniques. Cracking occurred at 25/sup 0/C over a wide range of acid concentrations and electrochemical potentials. The crack velocity increased slightly with increasing temperature. The failure mode was transgranular and the morphology was similar to SCC failures of zirconium alloys in other environments. The fracture was very orientation-dependent suggesting that it occurs on a single crystallographic plane in the material. The results of the study are not consistent with a hydrogen mechanism for cracking.

Beavers, J.A.; Griess, J.C.; Boyd, W.K.

1980-01-01T23:59:59.000Z

163

One-Dimensional Cold Rolling Effects on Stress Corrosion Crack ...  

Science Conference Proceedings (OSTI)

A Microstructural Investigation on the Effect of Cold Work on Environmentally .... Stress Corrosion Cracking Behavior near the Fusion Boundary of Dissimilar...

164

Solidification Cracking Study of High Chromium Nickel-Base Filler ...  

Science Conference Proceedings (OSTI)

... and rank the relative cracking susceptibility of these filler metal specifications. ... Surface Processing of Ag /TiO2 Nanowire Membranes for Solar Photovoltaic...

165

Research and Evaluation of Low Temperature Crack Propagation of ...  

Science Conference Proceedings (OSTI)

NRC/EPRI Welding Residual Stress Validation Program (Phase III) On the Microstructure of Alloy 600 SCC Cracks Observed by TEM on PWR SG Pulled Tubes...

166

DPQ Event Cracked Bushing Leads to Transformer Bank Failure  

Science Conference Proceedings (OSTI)

As part of EPRI's distribution power quality (DPQ) project this power quality (PQ) case study investigates cracked bushing recorded by PQ monitors that led to tranformer bank failure.

2003-12-31T23:59:59.000Z

167

Ranking the Susceptibility to Hydrogen-assisted Cracking in Super ...  

Science Conference Proceedings (OSTI)

Thus, SDSS welds are exposed to hydrogen charging to under CP. There have been reported hydrogen assisted cracking (HAC) failures in SDSS welds during...

168

Hydrogen Induced Cracking Susceptibility of Titanium Alloys in ...  

Science Conference Proceedings (OSTI)

May 16, 2007 ... This report evaluates hydrogen-induced cracking (HIC) susceptibility of titanium alloys in environments anticipated in the Yucca Mountain...

169

Ductile Crack Investigation in Multicomponent Materials  

Science Conference Proceedings (OSTI)

At this stage of the research Authors proposed two scale numerical model. ... Optimization of Thermal Cycle for Rails with Respect to the Wear Resistance.

170

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

Science Conference Proceedings (OSTI)

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

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

1997-07-01T23:59:59.000Z

171

Short-Crack Response of Alloy 182 Weld Metal Undergoing Stress Corrosion Cracking in High-Temperature PWR Primary Water  

Science Conference Proceedings (OSTI)

Mechanistic investigations of environmentally assisted cracking (EAC), to date, have focused more on propagation relative to initiation. At the same time, components spend most of their life in the initiation and "short-crack" growth regimes. Prior exploratory work conducted at General Electric Global Research Center (GE GRC) showed that stainless steels, Alloy 600, and Alloy 182 weld metal exhibit lower average growth rates when the cracks are very short or small (1050 m). In those tests, the transition...

2008-10-31T23:59:59.000Z

172

Materials Reliability Program: Thermal Fatigue Monitoring Guidelines (MRP-32, Revision 1)  

Science Conference Proceedings (OSTI)

This report provides thermal fatigue monitoring guidelines for attached piping systems in which there might be high potential for thermal fatigue cracking. The Materials Reliability Program (MRP) has published guidance under the Nuclear Energy Institute (NEI) 03-08 materials initiative for addressing potential thermal fatigue cycling in non-isolable reactor coolant system branch lines. This guidance calls for monitoring, inspection, and/or fatigue analysis of susceptible lines.

2011-06-16T23:59:59.000Z

173

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

174

Evaluation of Circumferential Cracking on Supercritical Boiler Waterwalls  

Science Conference Proceedings (OSTI)

Circumferential cracking of the fireside surfaces of supercritical waterwalls remains a problem for many coal-fired boilers. Two parallel test programs at Pennsylvania Power and Light's (PPL) Brunner Island Unit 3 attempted to correlate operating conditions with the development and propagation of circumferential cracks.

2008-03-31T23:59:59.000Z

175

Micro-crack Damage Evolution of Fracturing Rock Chaotic Characteristics  

Science Conference Proceedings (OSTI)

Chaotic theory and bifurcation of modern nonlinear science were used to study the evolution of micro-cracks under the hydraulic fracturing of the rock mass characteristics, the tensor damage variable which described the chao evolution of micro-cracks ... Keywords: chaos theory, bifurcation theory, damage evolution

Zhaowan Chun; Wang Tingting

2010-06-01T23:59:59.000Z

176

WATER PERMEABILITY OF CRACKED CEMENTITIOUS MICHAEL LEPECH & VICTOR C. LI  

E-Print Network (OSTI)

with inherently tight crack widths, typically less than 80 micron, even when strained up to 5% in uniaxial tension to undergo large deformations while maintaining load capacity. Of interest to this study are the tight crack mixture. Mixing proportions of both materials are shown in Table 1. The sand used in ECC had an average

Lepech, Michael D.

177

Fatigue-crack propagation behavior of Inconel 718  

DOE Green Energy (OSTI)

The techniques of linear-elastic fracture mechanics were used to characterize the effect of several variables (temperature, environment, cyclic frequency, stress ratio, and heat-treatment variations) upon the fatigue-crack growth behavior of Inconel 718 base metal and weldments. Relevant crack growth data on this alloy from other laboratories is also presented. (33 fig, 39 references) (auth)

James, L.A.

1975-09-01T23:59:59.000Z

178

Fatigue Crack Closure and Corrosion Fatigue in Al 7075 Alloy Using ...  

Science Conference Proceedings (OSTI)

Traditional methods to quantify crack closure load, such as load-displacement curves, are not very accurate. In this study, the degree of crack closure through...

179

A Study on Fatigue-Crack-Deformation Behavior Following a Single ...  

Science Conference Proceedings (OSTI)

Apr 27, 2009 ... Width. Using this method, the respective crackopening load (COL) at various crack-growth stages can be determined ?om the curve of the...

180

Induction Heating Stress Improvement Effectiveness on Crack Growth in Operating Plants (BWRVIP-61)  

Science Conference Proceedings (OSTI)

New reports of intergranular stress corrosion cracking prompted this review of factors that could influence the performance of the pipe cracking remedy known as induction heating stress improvement.

1999-01-27T23:59:59.000Z

Note: This page contains sample records for the topic "thermal cracking visbreaking" 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

Assessment of Crack in Corrosion Defects in Natural Gas Transmission Pipelines.  

E-Print Network (OSTI)

??Pipelines are one of the safest forms of transportation for oil and gas. However, pipelines may experience some defects, such as cracks, corrosion and cracks (more)

Hosseini, Seyed Aliakbar

2010-01-01T23:59:59.000Z

182

Atmospheric Crude Oil Distillation Operable Capacity  

Gasoline and Diesel Fuel Update (EIA)

(Barrels per Calendar Day) (Barrels per Calendar Day) Data Series: Total Number of Operable Refineries Number of Operating Refineries Number of Idle Refineries Atmospheric Crude Oil Distillation Operable Capacity (B/CD) Atmospheric Crude Oil Distillation Operating Capacity (B/CD) Atmospheric Crude Oil Distillation Idle Capacity (B/CD) Atmospheric Crude Oil Distillation Operable Capacity (B/SD) Atmospheric Crude Oil Distillation Operating Capacity (B/SD) Atmospheric Crude Oil Distillation Idle Capacity (B/SD) Vacuum Distillation Downstream Charge Capacity (B/SD) Thermal Cracking Downstream Charge Capacity (B/SD) Thermal Cracking Total Coking Downstream Charge Capacity (B/SD) Thermal Cracking Delayed Coking Downstream Charge Capacity (B/SD Thermal Cracking Fluid Coking Downstream Charge Capacity (B/SD) Thermal Cracking Visbreaking Downstream Charge Capacity (B/SD) Thermal Cracking Other/Gas Oil Charge Capacity (B/SD) Catalytic Cracking Fresh Feed Charge Capacity (B/SD) Catalytic Cracking Recycle Charge Capacity (B/SD) Catalytic Hydro-Cracking Charge Capacity (B/SD) Catalytic Hydro-Cracking Distillate Charge Capacity (B/SD) Catalytic Hydro-Cracking Gas Oil Charge Capacity (B/SD) Catalytic Hydro-Cracking Residual Charge Capacity (B/SD) Catalytic Reforming Charge Capacity (B/SD) Catalytic Reforming Low Pressure Charge Capacity (B/SD) Catalytic Reforming High Pressure Charge Capacity (B/SD) Catalytic Hydrotreating/Desulfurization Charge Capacity (B/SD) Catalytic Hydrotreating Naphtha/Reformer Feed Charge Cap (B/SD) Catalytic Hydrotreating Gasoline Charge Capacity (B/SD) Catalytic Hydrotreating Heavy Gas Oil Charge Capacity (B/SD) Catalytic Hydrotreating Distillate Charge Capacity (B/SD) Catalytic Hydrotreating Kerosene/Jet Fuel Charge Capacity (B/SD) Catalytic Hydrotreating Diesel Fuel Charge Capacity (B/SD) Catalytic Hydrotreating Other Distillate Charge Capacity (B/SD) Catalytic Hydrotreating Residual/Other Charge Capacity (B/SD) Catalytic Hydrotreating Residual Charge Capacity (B/SD) Catalytic Hydrotreating Other Oils Charge Capacity (B/SD) Fuels Solvent Deasphalting Charge Capacity (B/SD) Catalytic Reforming Downstream Charge Capacity (B/CD) Total Coking Downstream Charge Capacity (B/CD) Catalytic Cracking Fresh Feed Downstream Charge Capacity (B/CD) Catalytic Hydro-Cracking Downstream Charge Capacity (B/CD) Period:

183

Total Number of Operable Refineries  

U.S. Energy Information Administration (EIA) Indexed Site

Data Series: Total Number of Operable Refineries Number of Operating Refineries Number of Idle Refineries Atmospheric Crude Oil Distillation Operable Capacity (B/CD) Atmospheric Crude Oil Distillation Operating Capacity (B/CD) Atmospheric Crude Oil Distillation Idle Capacity (B/CD) Atmospheric Crude Oil Distillation Operable Capacity (B/SD) Atmospheric Crude Oil Distillation Operating Capacity (B/SD) Atmospheric Crude Oil Distillation Idle Capacity (B/SD) Vacuum Distillation Downstream Charge Capacity (B/SD) Thermal Cracking Downstream Charge Capacity (B/SD) Thermal Cracking Total Coking Downstream Charge Capacity (B/SD) Thermal Cracking Delayed Coking Downstream Charge Capacity (B/SD Thermal Cracking Fluid Coking Downstream Charge Capacity (B/SD) Thermal Cracking Visbreaking Downstream Charge Capacity (B/SD) Thermal Cracking Other/Gas Oil Charge Capacity (B/SD) Catalytic Cracking Fresh Feed Charge Capacity (B/SD) Catalytic Cracking Recycle Charge Capacity (B/SD) Catalytic Hydro-Cracking Charge Capacity (B/SD) Catalytic Hydro-Cracking Distillate Charge Capacity (B/SD) Catalytic Hydro-Cracking Gas Oil Charge Capacity (B/SD) Catalytic Hydro-Cracking Residual Charge Capacity (B/SD) Catalytic Reforming Charge Capacity (B/SD) Catalytic Reforming Low Pressure Charge Capacity (B/SD) Catalytic Reforming High Pressure Charge Capacity (B/SD) Catalytic Hydrotreating/Desulfurization Charge Capacity (B/SD) Catalytic Hydrotreating Naphtha/Reformer Feed Charge Cap (B/SD) Catalytic Hydrotreating Gasoline Charge Capacity (B/SD) Catalytic Hydrotreating Heavy Gas Oil Charge Capacity (B/SD) Catalytic Hydrotreating Distillate Charge Capacity (B/SD) Catalytic Hydrotreating Kerosene/Jet Fuel Charge Capacity (B/SD) Catalytic Hydrotreating Diesel Fuel Charge Capacity (B/SD) Catalytic Hydrotreating Other Distillate Charge Capacity (B/SD) Catalytic Hydrotreating Residual/Other Charge Capacity (B/SD) Catalytic Hydrotreating Residual Charge Capacity (B/SD) Catalytic Hydrotreating Other Oils Charge Capacity (B/SD) Fuels Solvent Deasphalting Charge Capacity (B/SD) Catalytic Reforming Downstream Charge Capacity (B/CD) Total Coking Downstream Charge Capacity (B/CD) Catalytic Cracking Fresh Feed Downstream Charge Capacity (B/CD) Catalytic Hydro-Cracking Downstream Charge Capacity (B/CD) Period:

184

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

SciTech Connect

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

185

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

DOE Green Energy (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

186

Cracking in liquid petroleum gas Horton spheres  

Science Conference Proceedings (OSTI)

A gas processing plant on the western coast of India produces sweet gas after processing sour natural gas. Liquid petroleum gas (LPG) is recovered from the sweet gas. The LPG, containing a H{sub 2}S concentration of 10 ppm to 20 ppm, is stored in Horton spheres, each 17 m in diameter with a capacity of {minus}27 C to 55 C. Horton spheres for containing liquid petroleum gas (LPG) were fabricated on-site using prestressed plates of high-strength carbon steel (CS) SA 537 Class-1 with post-weld heat treatment. High-residual tensile stresses and hydrogen absorption from H{sub 2}S present in LPG could be the cause of cracking at weld and heat-affected zone interfaces at high hardness locations. Recommendations are given for inspection and use of lower-strength CS and improved welding procedures.

Trivedi, D.K. Gupta, S.C. [Oil and Natural Gas Corp., Surat (India). Hazari Gas Processing Complex

1997-07-01T23:59:59.000Z

187

THE NON-CONSTANT CTOD/CTOA IN CRACK PROPAGATION  

SciTech Connect

Unlike the common belief that crack propagation behavior can be predicted successfully by employing fracture criteria based on a constant crack tip opening displacement or angle (CTOD/CTOA), this paper shows that the initially non-constant portion of the CTOD/CTOA plays an essential role in predicting the fracture load for a growing crack. Three- and two-dimensional finite element analyses indicate that a severe underestimate of the experimental load vs. crack extension curve would occur if a constant CTOD/CTOA criterion is used. However, the use of a simplified, bilinear CTOD/CTOA criterion including its non-constant portion will closely duplicate the test data. Furthermore, as a result of using the experimental data from J-integral test with various crack length to specimen width ratios (a/W), it is demonstrated that the CTOD/CTOA is crack tip constraint dependent. The initially higher values of the CTOD/CTOA are in fact a natural consequence of crack growth process which is refl ected by the J-resistance curve and its slope (tearing modulus).

LAM, POH-SANG

2004-07-19T23:59:59.000Z

188

Analysis of Alloy 600 and X-750 stress corrosion cracks  

Science Conference Proceedings (OSTI)

A few months ago, KAPL evidence supported the view that Primary or Pure Water Stress Corrosion Cracking (PWSCC) of Alloy 600 results from a hydrogen mechanism. Figure 1 shows an Analytical Electron Microscope (AEM) analysis of a stress corrosion crack (SCC) crack in an A600 split tube U-bend specimen exposed to primary water at 338{degree}C (640{degrees}F) for 462 days. The features which appear to confirm a hydrogen mechanism are: (1) A very narrow (< 200 {angstrom}) crack with a sharp tip, nearly free of deposits. (2) No evidence of severe plastic deformation in the region immediately ahead of the crack tip. (3) A line of small voids preceding the main crack tip, of which the largest is about 5 x 10{sup {minus}6} cm in length. Shen and Shewmon proposed that PWSCC of Alloy 600 occurs due to small microvoids ahead of a main crack tip. The hypothesis is that such voids result from pockets of methane gas formed by the reaction of atomic hydrogen with carbon in the base metal. The voids are about 10 x 10{sup {minus}6} cm diameter, approximately a factor of 2 larger than the largest voids.

Thompson, C.D.; Lewis, N.; Krasodomski, H.

1993-06-01T23:59:59.000Z

189

Improved load ratio method for predicting crack length  

SciTech Connect

The elastic compliance from unloading/reloading sequences in a load-displacement record estimates well crack length in elastic-plastic fracture toughness tests of compact tension [C(T)] and bending type specimens. The need for partial unloading of the specimen makes it difficult to run the test under static loading and impossible under either dynamic loading or very high temperatures. Furthermore, fracture toughness testing in which crack length is determined from elastic compliance requires high precision testing equipment and highly skilled technicians. As a result, such tests are confined usually to research laboratories and seldom used under production settings. To eliminate these problems, an improved load ratio method of predicting crack length is proposed that utilizes only the recorded load versus load-line displacement curve (or load versus crack-mouth-opening displacement curve) without unloading/reloading sequences. As a result, the instrumentation is much simpler than in the elastic compliance or potential drop methods. If only a monotonic load-displacement record is to be measured the fracture toughness test becomes almost as simple to perform as a tension test. The method described here improves in three ways the ``original load ratio method`` proposed by Hu et al. First, a blunting term is added to the crack length before maximum load. Second, a strain hardening correction is included after maximum load. And, third, the initial crack length and the physical (final) crack length measured at the end of the test serve to anchor the predicted crack lengths, forcing agreement between predicted and measured values. The method predicts crack extension with excellent accuracy in specimens fabricated from A302, A508, and A533B piping and pressure vessel steels, A588 and A572 structural steels, and HY-80 ship steel.

Chen, X.; Albrecht, P. [Univ. of Maryland, College Park, MD (United States). Inst. for Systems Research; Wright, W. [Federal Highway Administration, McLean, VA (United States). Turner-Fairbank Highway Research Center; Joyce, J.A. [Naval Academy, Annapolis, MD (United States). Mechanical Engineering Dept.

1995-04-01T23:59:59.000Z

190

Hydrogen-Induced Cracking of the Drip Shield  

DOE Green Energy (OSTI)

Hydrogen-induced cracking is characterized by the decreased ductility and fracture toughness of a material due to the absorption of atomic hydrogen in the metal crystal lattice. Corrosion is the source of hydrogen generation. For the current design of the engineered barrier without backfill, hydrogen-induced cracking may be a concern because the titanium drip shield can be galvanically coupled to rock bolts (or wire mesh), which may fall onto the drip shield, thereby creating conditions for hydrogen production by electrochemical reaction. The purpose of this report is to analyze whether the drip shield will fail by hydrogen-induced cracking under repository conditions within 10,000 years after emplacement. Hydrogen-induced cracking is a scenario of premature failure of the drip shield. This report develops a realistic model to assess the form of hydrogen-induced cracking degradation of the drip shield under the hydrogen-induced cracking. The scope of this work covers the evaluation of hydrogen absorbed due to general corrosion and galvanic coupling to less noble metals (e.g., Stainless Steel Type 316 and carbon steels) under the repository conditions during the 10,000-year regulatory period after emplacement and whether the absorbed hydrogen content will exceed the critical hydrogen concentration value, above which the hydrogen-induced cracking is assumed to occur. This report also provides the basis for excluding the features, events, and processes (FEPs) related to hydrogen-induced cracking of the drip shield with particular emphasis on FEP 2.1.03.04.OB, hydride cracking of drip shields (DTN: M00407SEPFEPLA.000 [DIRS 170760]). This report is prepared according to ''Technical Work Plan (TWP) for: Regulatory Integration Modeling and Analysis of the Waste Form and Waste Package'' (BSC 2004 [DIRS 169944]).

F. Hua

2004-09-07T23:59:59.000Z

191

Examination of cracked turbine discs from nuclear power plants  

SciTech Connect

Investigations were performed on a cracked turbine disc from the Cooper Nuclear Power Station (BWR), and on two failed turbine discs from the Yankee-Rowe Nuclear Power Station (PWR). The Yankee-Rowe discs were subjected to SEM/EDAX, uniaxial tension tests, hardness testing, notch sensitivity tests, and environmental notched tensile tests. The results of this investigation support the model whereby the cracks initiated at startup of the turbine, probably from H/sub 2/S produced by hydrolysis of MoS/sub 2/, and grew at a rate consistent with published data for propagation of cracks in pure steam.

Czajkowski, C.J.; Weeks, J.R.

1983-03-01T23:59:59.000Z

192

Shale oil cracking. 2. Effect on oil composition  

DOE Green Energy (OSTI)

Results from spectroscopic investigations are presented that demonstrate the effect of oil cracking on shale oil composition. Techniques used include infrared spectroscopy, capillary column gas chromatography/mass spectroscopy and /sup 13/C nuclear magnetic resonance. We show that cracking causes an increase in aromatic and alkene content of the oil. We compare our results for oils prepared in the laboratory with oils prepared in the TOSCO-II semi-works and in modified and true-in-situ combustion retorts. We demonstrate that the napthalene/2-methyl-naphthalene ratio is a good indicator of cracking conditions in an oil shale retort.

Burnham, A.K.; Sanborn, R.H.; Crawford, R.W.; Newton, J.C.; Happe, J.A.

1980-08-01T23:59:59.000Z

193

Evaluation of Cracks in ABB HK Arc Chutes  

Science Conference Proceedings (OSTI)

The nuclear power industry has a number of medium voltage (5 Kv-15 Kv) ABB HK air-magnetic circuit breakers with cracks in various places on the ceramic liner plate and cold-molded asbestos portions of the arc chutes. These cracks may or may not be cosmetic. This "jump gap crack" issue has been discussed in several ABB circuit breaker users group meetings. Five utilities (Brunswick, Seabrook, TVA, Duke, and Vogtle) have previously expressed interest in this issue. The present ABB Quality Assurance Proced...

2005-05-03T23:59:59.000Z

194

Strategies for planar crack propagation based on the concept of material forces  

Science Conference Proceedings (OSTI)

This paper presents a computational framework for the simulation of planar crack growth (including kinking) driven by "material forces". An evolution law for the crack tip position is formulated, which is shown to give rise to different propagation strategies ... Keywords: Configurational forces, Crack curving, Crack propagation

Jim Brouzoulis; Fredrik Larsson; Kenneth Runesson

2011-03-01T23:59:59.000Z

195

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, and migration from condensation of atmospheric moisture. The general corrosion rate of steels under insulation is predictable (within a broad scatter band) on the basis of temperature and oxygen content. This relationship is presented graphically based on plant case histories. Rainwater, washwater and the insulation itself are compared as potential sources of chloride to promote external SCC of stainless steels. Preventative measures will be discussed.

McIntyre, D. R.

1984-01-01T23:59:59.000Z

196

Temperature dependence of the intrinsic small fatigue crack growth behavior in Ni-base superalloys based on measurement of crack closure  

Science Conference Proceedings (OSTI)

The effect of temperature on the small fatigue crack growth behavior of a single crystal and directionally solidified Ni-base superalloys was investigated at temperatures between 873 to 1,123 K by measuring the crack closure. The results were also compared with those of the physically long crack. It was found that the propagation resistance and the fatigue threshold of the long cracks increased with temperature in all the materials. The long crack growth rates at three temperatures were approximately represented by an unique curve, after taking account of crack closure level and elastic modulus. In contrast, the small crack growth resistance decreased with temperature even when the crack closure phenomenon was taken into consideration. Furthermore, the small fatigue cracks exhibited considerably higher growth rates than the long cracks at a given effective stress intensity factor range and also grew under effective stress intensity factor ranges below the long crack threshold. The factors responsible for the lack of similitude in propagation rates between small and long cracks were also discussed, based on these observations and the chemical analysis near the crack tip using the electron probe microanalyzer.

Okazaki, M.; Yamada, H. [Nagaoka Univ. of Technology (Japan). Dept. of Mechanical Engineering; Nohmi, S. [Kawasaki Heavy Industries Co. Ltd., Akashi (Japan)

1996-04-01T23:59:59.000Z

197

Nucleation and growth of cracks in vitreous-bonded aluminum oxide at elevated temperatures  

Science Conference Proceedings (OSTI)

The nucleation and growth of cracks was studied at elevated temperatures on a grade of vitreous-bonded aluminium oxide that contained approx. =8 vol% glass at the grain boundaries. Cracks were observed to nucleate within the vitreous phase, close to the tensile surface of the flexural test specimens used in these experiments. Crack nucleation occurred at a strain of approx. =0.08% to 0.12% which corresponded to a crack nucleation time of approx. =35% of the time to failure by creep rupture. Once nucleated, cracks propagated along grain boundaries, as long as the stress for crack propagation was maintained. The crack velocity for cracks that were nucleated by the creep process was found to be linearly proportional to the apparent stress intensity factor, whereas for cracks that were nucleated by indentation, the crack velocity was proportional to the fourth power of the apparent stress intensity factor.

Jakus, K.; Wiederhorn, S.M.; Hockey, B.J.

1986-10-01T23:59:59.000Z

198

Irradiation-Induced Stress Corrosion Cracking of Austenitic Stainless  

NLE Websites -- All DOE Office Websites (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

199

Environmentally Assisted Cracking of Ni-Base Alloys [Corrosion and  

NLE Websites -- All DOE Office Websites (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

200

Crack coalescence in rock-like material under cycling loading  

E-Print Network (OSTI)

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

Ko, Tae Young, 1973-

2005-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "thermal cracking visbreaking" 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

Evaluation of Stress Corrosion Cracking Susceptibility of Drill Pipe ...  

Science Conference Proceedings (OSTI)

G-105 and S-135 grades of drill pipe steels have been used to study the effect of temperature and solution chemistry on the stress corrosion cracking behavior of...

202

SLAC National Accelerator Laboratory - SLAC Research Cracks Puzzle...  

NLE Websites -- All DOE Office Websites (Extended Search)

Press Release Archive SLAC Research Cracks Puzzle of Enzyme Critical to Food Supply November 17, 2011 Menlo Park, Calif. - If we could make plant food from nitrogen the way nature...

203

3D Characterization and Modeling of Fatigue Cracks  

Science Conference Proceedings (OSTI)

The HEDM and CT are performed with high energy x-rays at the Advanced Photon Source (APS). One set of LSHR specimens has small cracks on the order of...

204

Cracked shaft detection and diagnostics: A literature review  

E-Print Network (OSTI)

ABSTRACTCracks in shafts have long been identified as factors limiting the safe and reliable operation of turbomachines. They can sometimes result in catastrophic failure of equipment (rotor bursts) and, more often, in costly process upsets, repairs and premature scrapping and replacement of equipment. Cracked shafts still pose a significant and real threat to equipment in spite of the great advances made in the areas of metallurgy, manufacturing and design. In the past two decades, much research and many resources have gone into developing various on-line and off-line diagnostic techniques to effectively detect cracks before they cause serious damage. Because of the enormous amount of ongoing research in this area (more than 500 technical papers have been published in English alone in the past 30 years), there is a real need to periodically condense and summarize the information. This paper reviews literature on cracked shaft detection and diagnostics published after 1990.

Giridhar Sabnavis; R. Gordon Kirk; Mary Kasarda; Dane Quinn; Giridhar Sabnavis; R. Gordon Kirk; Mary Kasarda; Dane Quinn

2004-01-01T23:59:59.000Z

205

Effect of Oxygen Potential on Crack Growth in Alloy 617  

Science Conference Proceedings (OSTI)

Static crack growth rate increases from 4 x 10-9 m/sec to 4 x 10-8 m/sec when the oxygen concentration decreases from .001 to .0000001 atm. Proceedings...

206

Process to minimize cracking of pyrolytic carbon coatings  

DOE Patents (OSTI)

Carbon-coated microspheroids useful as fuels in nuclear reactors are produced with a low percentage of cracked coatings and are imparted increased strength and mechanical stability characteristics by annealing immediately after the carbon coating processes.

Lackey, Jr., Walter J. (Oak Ridge, TN); Sease, John D. (Knoxville, TN)

1978-01-01T23:59:59.000Z

207

Thermal Properties  

Science Conference Proceedings (OSTI)

Table 12   Thermal conductivities of polymers and other materials...40,000 2.8 Aluminum 24,000 1.7 Steel 5000 0.35 Granite 350 0.02 Crown glass (75 wt% silica) 90 0.006 Source: Ref 4...

208

BWRVIP-196: BWR Vessel and Internals Project, Assessment of Mixing Tee Thermal Fatigue Susceptibility in BWR Plants  

Science Conference Proceedings (OSTI)

In 1998, a French pressurized water reactor (PWR) plant experienced leakage due to thermal fatigue from piping immediately downstream of a residual heat removal (RHR) heat exchanger. EPRI report 1013305, Materials Reliability Program: Assessment of RHR Mixing Tee Thermal Fatigue in PWR Plants (MRP-192), December 2006, was prepared so that owners of PWR plants could determine if their RHR piping systems might be susceptible to similar thermal fatigue cracking and if additional inspection should be recomme...

2008-09-23T23:59:59.000Z

209

Reliability Centered Lifetime Prediction of Environmentally Assisted Cracking  

Science Conference Proceedings (OSTI)

This report describes the results of joint research sponsored by EPRI in cooperation with Tohoku University and a number of Japanese organizations to address the issue of environmentally assisted cracking (EAC) in boiling water reactors (BWRs) and pressurized water reactors (PWRs). The term EAC includes intergranular stress corrosion cracking and corrosion fatigue. The goal of this project was to develop a fundamental understanding of processes controlling EAC of stainless steels and nickel-base alloys i...

2003-09-02T23:59:59.000Z

210

Crack reconstruction using a level-set strategy  

Science Conference Proceedings (OSTI)

We present a level-set based technique to recover key characteristics of a defect or crack (e.g. location, length and shape) in a two-dimensional material from boundary electrical measurements. The key feature of this work is to extend the usual level-set ... Keywords: 02.30.Zz, 41.20.Cv, 42.30.Wb, Crack reconstruction, Electrical impedance tomography, Level-sets

Diego lvarez; Oliver Dorn; Natalia Irishina; Miguel Moscoso

2009-09-01T23:59:59.000Z

211

Uptake swelling and thermal expansion of CFRP tendons  

E-Print Network (OSTI)

research. Changes in the concrete cover do not have much of an influence on the maximum hoop stress generated. However, this should be treated with caution since the analysis in Figure 11 only considers elastic behaviour up to first cracking. The concrete... composites. Journal of Composite Materials, 1978, 12, No. 2, 153168. 15. TOMPKINS S. S. Thermal expansion of selected graphite- reinforced polyimide-, epoxy- and glass-matrix composites. International Journal of Thermophysics, 1987, 8, No. 1, 119132. 16...

Scott, P.; Lees, Janet M.

2009-08-01T23:59:59.000Z

212

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

SciTech Connect

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

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

2011-06-15T23:59:59.000Z

213

AQUIFER THERMAL ENERGY STORAGE  

E-Print Network (OSTI)

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

Tsang, C.-F.

2011-01-01T23:59:59.000Z

214

AQUIFER THERMAL ENERGY STORAGE  

E-Print Network (OSTI)

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

Tsang, C.-F.

2011-01-01T23:59:59.000Z

215

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

216

Materials Reliability Program: Lessons Learned from PWR Thermal Fatigue Management Training (MRP-83)  

Science Conference Proceedings (OSTI)

In January 2001, The EPRI Materials Reliability Program (MRP) issued an Interim Guideline (MRP-24) for the management of thermal fatigue in non-isolable piping attached to reactor coolant piping in pressurized water reactor (PWR) plants (EPRI report 1000701). To assist utility personnel in understanding the potential for thermal fatigue in this piping, the MRP also conducted plant-specific workshops at plant sites. These workshops offered training on fatigue and fatigue cracking in non-isolable piping, a...

2002-12-05T23:59:59.000Z

217

Laser ultrasonic furnace tube coke monitor. Quarterly technical progress report No. 1, May 1--August 1, 1998  

Science Conference Proceedings (OSTI)

The overall aim of the project is to demonstrate the performance and practical use of a laser ultrasonic probe for measuring the thickness of coke deposits located within the high temperature tubes of a thermal cracking furnace. This aim will be met by constructing an optical probe that will be tested using simulated coke deposits that are positioned inside of a bench-scale furnace. Successful development of the optical coke detector will provide industry with the only available method for on-line measurement of coke deposits. The optical coke detector will have numerous uses in the refining and petrochemical sectors including monitoring of visbreakers, hydrotreaters, delayed coking units, vacuum tower heaters, and various other heavy oil heating applications where coke formation is a problem. The coke detector will particularly benefit the olefins industry where high temperature thermal crackers are used to produce ethylene, propylene, butylene and other important olefin intermediates. The ethylene industry requires development of an on-line method for gauging the thickness of coke deposits in cracking furnaces because the current lack of detailed knowledge of coke deposition profiles introduces the single greatest uncertainty in the simulation and control of modern cracking furnaces. The laser ultrasonic coke detector will provide operators with valuable new information allowing them to better optimize the decoking turnaround schedule and therefore maximize production capacity.

NONE

1998-08-15T23:59:59.000Z

218

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

SciTech Connect

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

219

Crack Surface Roughness in Three-Dimensional Random Fuse Networks  

SciTech Connect

Using large system sizes with extensive statistical sampling, we analyze the scaling properties of crack roughness and damage profiles in the three-dimensional random fuse model. The analysis of damage profiles indicates that damage accumulates in a diffusive manner up to the peak load, and localization sets in abruptly at the peak load starting from a uniform damage landscape. The global crack width scales as $W \\sim L^{0.5}$ and is consistent with the scaling of localization length $\\xi \\sim L^{0.5}$ used in the data collapse of damage profiles in the post-peak regime. This consistency between the global crack roughness exponent and the post-peak damage profile localization length supports the idea that the post-peak damage profile is predominantly due to the localization produced by the catastrophic failure, which at the same time results in the formation of the final crack. Finally, the crack width distributions can be collapsed for different system sizes and follow a log-normal distribution.

Nukala, Phani K [ORNL; Zapperi, Stefano [University of La Sapienza, Rome; Simunovic, Srdjan [ORNL

2006-01-01T23:59:59.000Z

220

Thermal Shock-resistant Cement  

SciTech Connect

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 cements 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

Note: This page contains sample records for the topic "thermal cracking visbreaking" 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

Low cycle thermal fatigue testing of beryllium grades for ITER plasma facing components  

Science Conference Proceedings (OSTI)

A novel technique has been used to test the relative low cycle thermal fatigue resistance of different grades of US and Russian beryllium, which is proposed as plasma facing armor for fusion reactor first wall, limiter, and divertor components. The 30 kW electron beam test system at Sandia National Laboratories was used to sweep the beam spot along one direction at 1 Hz. This produces a localized temperature ``spike`` of 750{degree}C for each pass of the beam. Large thermal stresses in excess of the yield strength are generated due to very high spot heat flux, 250 MW/m{sup 2}. Cyclic plastic strains on the order of 0.6% produced visible cracking on the heated surface in less than 3000 cycles. An in-vacuo fiber optic borescope was used to visually inspect the beryllium surfaces for crack initiation. Grades of US beryllium tested included: S-65C, S- 65H, S-200F, S-200F-H, SR-200, I-400, extruded high purity, HIP`d spherical powder, porous beryllium (94% and 98% dense), Be/30% BeO, Be/60% BeO, and TiBe{sub 12}. Russian grades included: TGP-56, TShGT, DShG-200, and TShG-56. Both the number of cycles to crack initiation, and the depth of crack propagation, were measured. The most fatigue resistant grades were S-65C, DShG-200, TShGT, and TShG-56. Rolled sheet Be (SR-200) showed excellent crack propagation resistance in the plane of rolling, despite early formation of delamination cracks. Only one sample showed no evidence of surface melting, Extruded (T). Metallographic and chemical analyses are provided. Good agreement was found between the measured depth of cracks and a 2-D elastic-plastic finite element stress analysis.

Watson, R.D.; Youchison, D.L. [Sandia National Labs., Livermore, CA (United States); Dombrowski, D.E. [Brush Wellman, Inc., Cleveland, OH (United States); Guiniatouline, R.N. [Efremov Institute, (Russia); Kupriynov, I.B. [Russian Institute of Inorganic Materials (Russia)

1996-02-01T23:59:59.000Z

222

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

Science Conference Proceedings (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 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

223

Angle of crack propagation for a vertical hydraulic fracture  

DOE Green Energy (OSTI)

Using the strain-energy-density-factor (S) theory, the positive fracture angle +theta/sub o/ (the initial fracture angle of crack propagation) of a near-vertical crack is predicted by using the opening- and sliding-mode stress-intensity factors in the presence of the overburden pressure, the least in situ horizontal principal stress, and the borehole fluid pressure. The crack spreads in the positive theta/sub o/ direction (counter-clockwise) in the plane for which S is a minimum, S/sub min/. It was verified that S/sub min/ is greater than or equal to S/sub c/. The quantity S/sub c/ is defined as the critical value of S, and remains essentially constant. Of interest is the numerical example for calculating fracture angle and the critical uniform borehole fluid pressure required to initiate fracture at such an angle for the present LASL Dry Hot Rock Geothermal Energy Program. (auth)

Sarda, J.P.; Hsu, Y.C.

1975-12-01T23:59:59.000Z

224

Cracking a Cold Case and Enduring Mystery | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

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

225

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

226

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

227

Cracking Condition of Cohesionless Porous Materials in Drying Processes  

E-Print Network (OSTI)

The invasion of air into porous systems in drying processes is often localized in soft materials, such as colloidal suspensions and granular pastes, and it typically develops in the form of cracks before ordinary drying begins. To investigate such processes, we construct an invasion percolation model on a deformable lattice for cohesionless elastic systems, and with this model we derive the condition under which cracking occurs. A Griffith-like condition characterized by a dimensionless parameter is proposed, and its validity is checked numerically. This condition indicates that the ease with which cracking occurs increases as the particles composing the material become smaller, as the rigidity of the system increases, and as the degree of heterogeneity characterizing the drying processes decreases.

So Kitsunezaki

2013-01-15T23:59:59.000Z

228

Stress corrosion cracking of candidate waste container materials  

SciTech Connect

Six alloys have been selected as candidate container materials for the storage of high-level nuclear waste at the proposed Yucca Mountain site in Nevada. These materials are Type 304L stainless steel (SS), Type 316L SS, Incology 825, P-deoxidized Cu, Cu-30%Ni, and Cu-7% Al. The present program has been initiated to determine whether any of these materials can survive for 300 years in the site environment without developing through-wall stress corrosion cracks, and to assess the relative resistance of these materials to stress corrosion cracking (SCC). A series of slow-strain-rate tests (SSRTs) in simulated Well J-13 water which is representative of the groundwater present at the Yucca Mountain site has been completed, and crack-growth-rate (CGR) tests are also being conducted under the same environmental conditions. 13 refs., 60 figs., 22 tabs.

Maiya, P.S.; Soppet, W.K.; Park, J.Y.; Kassner, T.F.; Shack, W.J.; Diercks, D.R.

1990-11-01T23:59:59.000Z

229

Dynamic crack initiation toughness : experiments and peridynamic modeling.  

SciTech Connect

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

Foster, John T.

2009-10-01T23:59:59.000Z

230

Weld solidification cracking in 304 to 204L stainless steel  

Science Conference Proceedings (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

231

Weld solidification cracking in 304 to 304L stainless steel  

Science Conference Proceedings (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

232

Crack Growth in Solid Oxide Fuel Cell Materials: From Discrete to Continuum Damage Modeling  

Science Conference Proceedings (OSTI)

This paper addresses the cracking problem of glass and ceramic materials used in solid oxide fuel cells (SOFCs). Analyses of an internal crack and of an interface crack between dissimilar materials were conducted using a modified boundary layer modeling approach. In this approach, fracture is allowed to occur in a small process window situated at an initial crack tip. Elastic displacement crack-tip fields are prescribed as remote boundary conditions. Crack propagation was first modeled discretely. Next, a continuum damage mechanics (CDM) model for brittle materials was developed to capture damage and crack growth in the process window. In particular, the damage model was applied to a glass-ceramic material that had been developed in-house for sealing purposes. Discrete and continuum damage solutions were then compared. Finally, the CDM model was used to determine the crack propagation direction as a function of a mode mixity measure.

Nguyen, Ba Nghiep; Koeppel, Brian J.; Ahzi, Said; Khaleel, Mohammad A.; Singh, Prabhakar

2006-04-01T23:59:59.000Z

233

Thermal conductivity of thermal-battery insulations  

DOE Green Energy (OSTI)

The thermal conductivities of a variety of insulating materials used in thermal batteries were measured in atmospheres of argon and helium using several techniques. (Helium was used to simulate the hydrogen atmosphere that results when a Li(Si)/FeS{sub 2} thermal battery ages.) The guarded-hot-plate method was used with the Min-K insulation because of its extremely low thermal conductivity. For comparison purposes, the thermal conductivity of the Min-K insulating board was also measured using the hot-probe method. The thermal-comparator method was used for the rigid Fiberfrax board and Fiberfrax paper. The thermal conductivity of the paper was measured under several levels of compression to simulate the conditions of the insulating wrap used on the stack in a thermal battery. The results of preliminary thermal-characterization tests with several silica aerogel materials are also presented.

Guidotti, R.A.; Moss, M.

1995-08-01T23:59:59.000Z

234

Laboratory And Field Investigations To Address Erosion, Volume Change And Desiccation Cracking Of Compost Amended Expansive Subsoils.  

E-Print Network (OSTI)

??Puppala, Anand Desiccations cracks are formed during drying process of fine grained cohesive soils in summer and these cracks often appear on unpaved subgrades due (more)

Intharasombat, Napat

2007-01-01T23:59:59.000Z

235

Status Report on Studies of Recovery Boiler Composite Floor Tube Cracking  

DOE Green Energy (OSTI)

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

236

Influence of p-method finite element parameters on predictions of crack front geometry  

Science Conference Proceedings (OSTI)

The effect of various p-method finite element model parameters on the prediction of planar crack front geometry in three dimensional structures is evaluated. An automatic crack growth method was developed using the commercial software StressCheck coupled ... Keywords: ?, Corner crack, Crack front, Finite element, Mesh, Stress intensity factor, a, b, b/a, c, ctrat, ipr, m, mrat, p-method, trans

Diane Wowk, Kyle Gamble, Ross Underhill

2013-10-01T23:59:59.000Z

237

Effect of Specimen Size on the Crack Growth Rate Behavior of Irradiated Type 304 Stainless Steel  

Science Conference Proceedings (OSTI)

BackgroundCracks in actual plant components are mainly under plane strain. In order to generate relevant crack growth rate data in the laboratory, specimens where most of the crack front is under plane strain should be used. Since the ASTM E399 size criterion for linear elastic plane-strain fracture toughness is probably conservative, it seems appropriate to also apply it to SCC tests. However, in stress corrosion crack growth rate (CGR) tests on austenitic stainless ...

2012-12-21T23:59:59.000Z

238

Early Development Of Stress Corrosion Cracks At The Grain Scale: Incomplete Random Tessellation Model  

E-Print Network (OSTI)

Early Development Of Stress Corrosion Cracks At The Grain Scale: Incomplete Random Tessellation is needed to quantify those effects more accurately. 1 INTRODUCTION Intergranular stress corrosion cracking to the dependence of microscopic stress fields at crack tips on the random orientation of neighboring grains

Cizelj, Leon

239

Age-based preventive maintenance for passive components submitted to stress corrosion cracking  

Science Conference Proceedings (OSTI)

This paper deals with an age-based preventive maintenance for critical systems or structures subject to a gradual degradation phenomenon such as stress corrosion cracking. We analyze a system subjected to different cracks. A crack can be only detected ... Keywords: Age-based maintenance, Counting processes, Gamma process, Non-homogeneous Poisson process, SCC models

I. T. Castro; Anne Barros; Antoine Grall

2011-07-01T23:59:59.000Z

240

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

E-Print Network (OSTI)

on slow crack growth and stress corrosion processes [Wiederhorn, 1966; Anderson and Grew, 1977; Atkinson for independent controls of the confining pressure, the axial stress, and pore pressure. We produced cracks, to our knowledge, none con- sidered crack evolution under compressive stress. Some of this work explored

Fortin, Jérôme

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241

How Tough is Human Cortical Bone? In-Situ Measurements on Realistically Short Cracks  

SciTech Connect

Bone is more difficult to break than to split. Although this is well known, and many studies exist on the behavior of long cracks in bone, there is a need for data on the orientation-dependent crack-growth resistance behavior of human cortical bone which accurately assesses its toughness at appropriate size-scales. Here we use in-situ mechanical testing in the scanning electron microscope and x-ray computed tomography to examine how physiologically-pertinent short (<600 mu m) cracks propagate in both the transverse and longitudinal orientations in cortical bone, using both crack-deflection/twist mechanics and nonlinear-elastic fracture mechanics to determine crack-resistance curves. We find that after only 500 mu m of cracking, the driving force for crack propagation was more than five times higher in the transverse (breaking) direction than in the longitudinal (splitting) direction due to major crack deflections/twists principally at cement sheathes. Indeed, our results show that the true transverse toughness of cortical bone is far higher than previously reported. However, the toughness in the longitudinal orientation, where cracks tend to follow the cement lines, is quite low at these small crack sizes; it is only when cracks become several millimeters in length that bridging mechanisms can develop leading to the (larger-crack) toughnesses generally quoted for bone.

Ritchie, Robert O; Koester, K. J.; Ager III, J. W.; Ritchie, R.O.

2008-05-10T23:59:59.000Z

242

Uplift Pressures in Cracks in Concrete Gravity Dams--An Experimental Study: Volume 8  

Science Conference Proceedings (OSTI)

Uplift pressure distribution in cracks in concrete dams is affected by a combination of several factors, such as crack properties, drain dimensions, and the type of flow in the crack. This study shows that most uplift pressure distributions can be controlled using a vertical drain system with diameters from two to four inches and spacing of about ten feet.

1992-12-20T23:59:59.000Z

243

Coarsening of the Sn-Pb Solder Microstructure in Constitutive Model-Based Predictions of Solder Joint Thermal Mechanical Fatigue  

SciTech Connect

Thermal mechanical fatigue (TMF) is an important damage mechanism for solder joints exposed to cyclic temperature environments. Predicting the service reliability of solder joints exposed to such conditions requires two knowledge bases: first, the extent of fatigue damage incurred by the solder microstructure leading up to fatigue crack initiation, must be quantified in both time and space domains. Secondly, fatigue crack initiation and growth must be predicted since this metric determines, explicitly, the loss of solder joint functionality as it pertains to its mechanical fastening as well as electrical continuity roles. This paper will describe recent progress in a research effort to establish a microstructurally-based, constitutive model that predicts TMF deformation to 63Sn-37Pb solder in electronic solder joints up to the crack initiation step. The model is implemented using a finite element setting; therefore, the effects of both global and local thermal expansion mismatch conditions in the joint that would arise from temperature cycling.

Vianco, P.T.; Burchett, S.N.; Neilsen, M.K.; Rejent, J.A.; Frear, D.R.

1999-04-12T23:59:59.000Z

244

A computational study of the time dependent crack growth process  

SciTech Connect

Universal studies of creep crack growth for (1) constant load and (2) variable load cases are presented. Results of the constant load cases is compared to experiment. The behavior of displacements and integral creep for fracture parameters are discussed for both load cases. The need for using a constitutive law which can handle cyclic creep is discussed.

Brust, F.W.; Krishnaswamy, P.

1992-01-01T23:59:59.000Z

245

Ductile Fracture Handbook, Volume 1: Circumferential Throughwall Cracks  

Science Conference Proceedings (OSTI)

Over the past 10 years, the focus of fracture research related to nuclear power plants has shifted from brittle fractures to fractures of steels used for piping and vessels. This handbook developed by EPRI and Novetech Corporation is the first single-source document containing formulas for evaluating throughwall cracks in these tough ductile steels.

1989-07-01T23:59:59.000Z

246

Method of making crack-free zirconium hydride  

DOE Patents (OSTI)

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

Sullivan, Richard W. (Denver, CO)

1980-01-01T23:59:59.000Z

247

Fatigue crack growth estimation by relevance vector machine  

Science Conference Proceedings (OSTI)

The investigation of damage propagation mechanisms on a selected safety-critical component or structure requires the quantification of its remaining useful life (RUL) to verify until when it can continue performing the required function. In this work, ... Keywords: Bayesian techniques, Fatigue crack growth, Prognostics, Relevance vector machine, Residual useful life, Support vector machine

Enrico Zio; Francesco Di Maio

2012-09-01T23:59:59.000Z

248

Solvent control of crack dynamics in a reversible hydrogel  

E-Print Network (OSTI)

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

Tristan Baumberger; Christiane Caroli; David Martina

2006-05-16T23:59:59.000Z

249

Catalytic cracking. (Latest citations from the Compendex database). Published Search  

Science Conference Proceedings (OSTI)

The bibliography contains citations concerning applications of catalytic cracking processes in fluidized bed systems, moving beds, refineries, vacuum distillations, and reformers. Design aspects, modeling, control systems, and operating procedures are also discussed. (Contains a minimum of 149 citations and includes a subject term index and title list.)

Not Available

1993-07-01T23:59:59.000Z

250

Incipient Crack Detection in Composite Wind Turbine Blades  

DOE Green Energy (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

251

Seasonal thermal energy storage  

DOE Green Energy (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

252

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

Science Conference Proceedings (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

253

The nature of fire-cracked rock: new insights from ethnoarchaeological and laboratory experiments  

E-Print Network (OSTI)

Fire-cracked rock (FCR) is the archaeological by-product of the systemic use of hot rocks for cooking and heating purposes. As a record of various cooking and heating facilities, FCR has substantial potential for addressing research questions on past settlement and subsistence systems. To be able to address these questions requires reliable methods that can identify or infer how a given FCR was used. A series of ethnoarchaeological replication experiments are conducted in order to improve the understanding of the geothennodynamics of FCR production. FCR from two experimental data sets are cut to expose flat surfaces that are inspected for thermal-weathering characteristics under low-power magnification. Analytical results indicate that rock structure and the length of heat application have the most control over thermal weathering. The five most important rock structure characteristics are (1) strength of the bond between grains/crystals, (2) degree of porosity, (3) grain/crystal mineralogy, (4) presence of discontinuities, and (5) grain size; thin section analysis can identify these characteristics for any rock sample. The length of heat application varies dependent on the type of cooking or heating facility, for instance, a typical earth oven remains hot for a longer duration than a typical stone-boil facility; multiple uses of a rock in a facility also increases the sum total of heat application. In broad terms, experimental tests indicate igneous rock types withstand thermal weathering better than metamorphic or sedimentary rock types. Ethnoarchaeological results are applied to six archaeological FCR features, and provide new insights on the use-history of five of the features. Microscopic observations of archaeological FCR also all for the re-evaluation of the current model which explains the occurrence of various FCR shape types within features.

Jackson, Michael A

1998-01-01T23:59:59.000Z

254

How Tough is Human Cortical Bone? In-Situ Measurements on Realistically Short Cracks  

Science Conference Proceedings (OSTI)

Bone is more difficult to break than to split. Although this is well known, and many studies exist on the behavior of long cracks in bone, there is a need for data on the orientation-dependent crack-growth resistance behavior of human cortical bone which accurately assesses its toughness at appropriate size-scales. Here we use in-situ mechanical testing in the scanning electron microscope and x-ray computed tomography to examine how physiologically-pertinent short (propagate in both the transverse and longitudinal orientations in cortical bone, using both crack-deflection/twist mechanics and nonlinear-elastic fracture mechanics to determine crack-resistance curves. We find that after only 500 mu m of cracking, the driving force for crack propagation was more than five times higher in the transverse (breaking) direction than in the longitudinal (splitting) direction due to major crack deflections/twists principally at cement sheathes. Indeed, our results show that the true transverse toughness of cortical bone is far higher than previously reported. However, the toughness in the longitudinal orientation, where cracks tend to follow the cement lines, is quite low at these small crack sizes; it is only when cracks become several millimeters in length that bridging mechanisms can develop leading to the (larger-crack) toughnesses generally quoted for bone.

Ritchie, Robert O; Koester, K. J.; Ager III, J. W.; Ritchie, R.O.

2008-05-10T23:59:59.000Z

255

Integrating Broad-Band High-Fidelity Acoustic Emission Sensors and Array Processing to Study Drying Shrinkage Cracking in Concrete  

E-Print Network (OSTI)

, cracks can create stress concentrations which can cause further cracking at loads which are well under energy released from the formation of a crack is converted into stress waves which in turn produce Shrinkage Cracking in Concrete Gregory C. McLaskeya,1 , Steven D. Glasera , Christian U. Grosseb

Glaser, Steven D.

256

Stress corrosion cracking of candidate waste container materials; Final report  

Science Conference Proceedings (OSTI)

Six alloys have been selected as candidate container materials for the storage of high-level nuclear waste at the proposed Yucca mountain site in Nevada. These materials are Type 304L stainless steel (SS). Type 316L SS, Incoloy 825, phosphorus-deoxidized Cu, Cu-30%Ni, and Cu-7%Al. The present program has been initiated to determine whether any of these materials can survive for 300 years in the site environment without developing through-wall stress corrosion cracks. and to assess the relative resistance of these materials to stress corrosion cracking (SCC)- A series of slow-strain-rate tests (SSRTs) and fracture-mechanics crack-growth-rate (CGR) tests was performed at 93{degree}C and 1 atm of pressure in simulated J-13 well water. This water is representative, prior to the widespread availability of unsaturated-zone water, of the groundwater present at the Yucca Mountain site. Slow-strain-rate tests were conducted on 6.35-mm-diameter cylindrical specimens at strain rates of 10-{sup {minus}7} and 10{sup {minus}8} s{sup {minus}1} under crevice and noncrevice conditions. All tests were interrupted after nominal elongation strain of 1--4%. Scanning electron microscopy revealed some crack initiation in virtually all the materials, as well as weldments made from these materials. A stress- or strain-ratio cracking index ranks these materials, in order of increasing resistance to SCC, as follows: Type 304 SS < Type 316L SS < Incoloy 825 < Cu-30%Ni < Cu and Cu-7%Al. Fracture-mechanics CGR tests were conducted on 25.4-mm-thick compact tension specimens of Types 304L and 316L stainless steel (SS) and Incoloy 825. Crack-growth rates were measured under various load conditions: load ratios M of 0.5--1.0, frequencies of 10{sup {minus}3}-1 Hz, rise nines of 1--1000s, and peak stress intensities of 25--40 MPa{center_dot}m {sup l/2}.

Park, J.Y.; Maiya, P.S.; Soppet, W.K.; Diercks, D.R.; Shack, W.J.; Kassner, T.F. [Argonne National Lab., IL (United States)

1992-06-01T23:59:59.000Z

257

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

Science Conference Proceedings (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 650C 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

258

"Cracking-the-whip" effect stretches driven polymers  

E-Print Network (OSTI)

Cracking the whip accelerates the tail of a chain to hit the air loudly and clearly. We proved that the similar acceleration effect causes coil deformation of driven chain-like polymers. We first preformed Monte Carlo simulations of a single driven polymer coil to demonstrate its deformation in company with faster or slower deviations of velocities. We then performed parallel Brownian Dynamics simulations to demonstrate that the coil deformation can be caused by the so-called "cracking-the-whip" effect due to non-synchronous biased Brownian motions of monomers inherited in Monte Carlo simulations. Since such non-synchronous motions represent random perturbations in the environmentally dependent potential energy landscape or mobility, reflecting heterogeneous dynamics of polymers in the liquid phase, our observations bring new insights into the non-linear dynamics of driven chain-like polymers.

Juan Li; Wenbing Hu

2013-10-31T23:59:59.000Z

259

Environmentally assisted cracking of light-water reactor materials  

SciTech Connect

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

260

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

Note: This page contains sample records for the topic "thermal cracking visbreaking" 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

Gas Turbine Rotor Life: General Electric FA Disc Cracking  

Science Conference Proceedings (OSTI)

This report covers the integrated results of the investigation into the occurrence of cooling slot and other rim cracking found in GE 7FA and 9FA gas turbine first and second stage rotor discs. Sections of the report address dimensional characterization, rim temperature measurement, metallurgical results, analytical methods, evaluation of mitigation approaches, and damage tolerance. Structural stress analysis assessed the effectiveness of the blend-polish-peen slot modification and a redesigned ...

2010-12-08T23:59:59.000Z

262

Stress relief cracking in creep resisting low alloy ferritic steels.  

E-Print Network (OSTI)

The Problem of Stress Relief Cracking in Low Alloy Steels During the welding of a ferritic steel, the HAZ adjacent to the weld transforms to austenite, the grains close to the fusion zone attaining particularly high tempel'ature and undergoing considerable... growth. At the same time, carbides tend to dissolve, dissolution being more complete in the coarse 14 grained region because it attains a higher temperature. The HAZ is cooled rapidly by the cold parent metal and, as a result, re- precipitation...

Tait, Robert Andrew

1976-10-26T23:59:59.000Z

263

Evaluation of Fundamental Linkage Among Stress Corrosion Cracking (SCC) Phenomena  

Science Conference Proceedings (OSTI)

Many in-core components of stainless steels in light water reactors (LWRs) are susceptible to a degradation process known as irradiation assisted stress corrosion cracking (IASCC). This report describes the results of environmental testing on irradiated Type 304 stainless steel in boiling water reactor (BWR) and pressurized water reactor (PWR) environments to assess their susceptibility to IASCC. The work was sponsored by the Cooperative IASCC Research (CIR I) Program, an international research effort ma...

2002-10-23T23:59:59.000Z

264

Comparing Methods of Estimating Crack Volume in Shrink-Swell Soils  

E-Print Network (OSTI)

Predicting soil crack formation and closure in high shrink-swell soils is crucial for modeling water movement and solute transport. However, soil cracking, as it occurs in natural conditions, is not well understood. The objectives of this research are to 1) compare shrinking and swelling of two Vertisols with different mineralogy and 2) compare two methods for estimating soil crack volume. The first soil monitored, Ships Clay (Very-fine, mixed, thermic Chromic Hapluderts) has mixed mineralogy and is located in Snook, TX. The second soil monitored is a Burleson Clay (Fine, smectitic, thermic Udic Haplusterts), which has smectitic mineralogy and is located 1 mile southwest of the Ships site. During two drying events, vertical subsidence and cracking were measured on both soils. Vertical subsidence was measured at three locations in each soil with rods fixed at four depths. Rod movement was converted to soil crack volume by assuming equi-dimensional shrinkage. A second method for estimating crack volume used direct measurements of cracks in the field. This second method was time consuming and the accuracy is unknown. A neutron moisture meter access tube was installed to measure soil moisture at each subsidence location. A total of 20 levling and moisture measurements were completed and 10 hand measurements of cracking were made. At the completion of the study, full characterization of each measurement location was performed, including COLE measurements. These COLE measurements were used as a third method of estimating crack volume in relation to soil moisture. Total crack volume will be compared at both sites to show the differences in the drying and cracking patterns. Crack volume as a function of moisture will be used to show how soil cracking and moisture relate. The two methods of estimating crack volume will be compared to see where possible cracking was measured with subsidence but not seen visually. The results showed the leveling-predicted crack volume was ten times that of the hand measured crack volume but followed the same temporal trend. The leveling-predicted crack volume is the most accurate of the three methods. COLE was also shown to be a good predictor a soils shrink-swell potential.

Rivera, Leonardo D.

2011-08-04T23:59:59.000Z

265

Computer Simulation of Intergranular Stress Corrosion Cracking via Hydrogen Embrittlement  

DOE Green Energy (OSTI)

Computer simulation has been applied to the investigation of intergranular stress corrosion cracking in Ni-based alloys based on a hydrogen embrittlement mechanism. The simulation employs computational modules that address (a) transport and reactions of aqueous species giving rise to hydrogen generation at the liquid-metal interface, (b) solid state transport of hydrogen via intergranular and transgranular diffusion pathways, and (c) fracture due to the embrittlement of metallic bonds by hydrogen. A key focus of the computational model development has been the role of materials microstructure (precipitate particles and grain boundaries) on hydrogen transport and embrittlement. Simulation results reveal that intergranular fracture is enhanced as grain boundaries are weakened and that microstructures with grains elongated perpendicular to the stress axis are more susceptible to cracking. The presence of intergranular precipitates may be expected to either enhance or impede cracking depending on the relative distribution of hydrogen between the grain boundaries and the precipitate-matrix interfaces. Calculations of hydrogen outgassing and in gassing demonstrate a strong effect of charging method on the fracture behavior.

Smith, R.W.

2000-04-01T23:59:59.000Z

266

SAES ST 909 PILOT SCALE METHANE CRACKING TESTS  

DOE Green Energy (OSTI)

Pilot scale (500 gram) SAES St 909 methane cracking tests were conducted to determine material performance for tritium process applications. Tests that ran up to 1400 hours have been performed at 700 C, 202.7 kPa (1520 torr) with a 30 sccm feed of methane, with various impurities, in a 20 vol% hydrogen, balance helium, stream. A 2.5 vol% methane feed was reduced below 30 ppm for 631 hours. A feed of 1.1 vol% methane plus 1.4 vol% carbon dioxide was reduced below 30 ppm for 513 hours. The amount of carbon dioxide gettered by St 909 can be equated to an equivalent amount of methane gettered to estimate a reduced bed life for methane cracking. The effect of 0.4 vol % and 2.1 vol% nitrogen in the feed reduced the time to exceed 30 ppm methane to 362 and 45 hours, respectively, but the nitrogen equivalence to reduced methane gettering capacity was found to be dependent on the nitrogen feed composition. Decreased hydrogen concentrations increased methane getter rates while a drop of 30 C in one bed zone increased methane emissions by over a factor of 30. The impact of gettered nitrogen can be somewhat minimized if the nitrogen feed to the bed has been stopped and sufficient time given to recover the methane cracking rate.

Klein, J; Henry Sessions, H

2007-07-02T23:59:59.000Z

267

Materials Reliability Program: Evaluation of Potential for Low Temperature Crack Propagation in Reactor Pressure Vessel Outlet Nozzl e Dissimilar Metal Butt Welds by Stress and Fracture Mechanics Analyses (MRP-247)  

Science Conference Proceedings (OSTI)

Low Temperature Crack Propagation is a form of hydrogen embrittlement that can cause, under specific environmental conditions in laboratory tests, severe degradation of the fracture resistance of nickel-base alloys X-750 and 690, and weld metals 82/182 and 52/152. While no operating plant has exhibited evidence of LTCP, the hydrogen levels and temperature conditions necessary for LTCP to occur are present during some PWR shutdowns. This report evaluates the potential for the thermal stresses generated du...

2008-12-22T23:59:59.000Z

268

PowerPoint Presentation  

National Nuclear Security Administration (NNSA)

y x Main crack surface Dislocation loops Crack initiation point Crack branching (BLJ + thermal motion) Crack embryo 3D view of surface particles Developed crack Crack development...

269

Fatigue Crack Propagation from Notched Specimens of 304 SS in elevated Temperature Aqueous Environment  

DOE Green Energy (OSTI)

Fatigue crack propagation (FCP) rates for 304 stainless steel (304SS) were determined in 24 degree C and 288 degree C air and 288 degree C water using double-edged notch (DEN) specimens of 304 stainless steel (304 SS). Test performed at matched loading conditions in air and water at 288 degree C with 20-6- cc h[sub]2/kg h[sub]2O provided a direct comparison of the relative crack growth rates in air and water over a wide range of crack growth rates. The DEN crack extension ranged from short cracks (0.03-0.25 mm) to long cracks up to 4.06 mm, which are consistent with conventional deep crack tests. Crack growth rates of 304 SS in water were about 12 times the air rate. This 12X environmental enhancement persisted to crack extensions up to 4.06 mm, far outside the range associated with short crack effects. The large environmental degradation for 304 SS crack growth is consistent with the strong reduction of fatigue life in high hydrogen water. Further, very similar environmental effects w ere reported in fatigue crack growth tests in hydrogen water chemistry (HWC). Most literature data in high hydrogen water show only a mild environmental effect for 304 SS, of order 2.5 times air or less, but the tests were predominantly performed at high cyclic stress intensity or equivalently, high air rates. The environmental effect in low oxygen environments at low stress intensity depends strongly on both the stress ratio, R, and the load rise time, T[sub]r, as recently reported for austenitic stainless steel in BWR water. Fractography was performed for both tests in air and water. At 288 degree C in water, the fracture surfaces were crisply faceted with a crystallographic appearance, and showed striations under high magnification. The cleavage-like facets on the fracture surfaces suggest that hydrogen embrittlement is the primary cause of accelerated cracking.

Wire, G. L.; Mills, W. J.

2002-08-01T23:59:59.000Z

270

HEATS: Thermal Energy Storage  

SciTech Connect

HEATS Project: The 15 projects that make up ARPA-Es 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

271

On the micromechanisms of fatigue-crack propagation in aluminum- lithium alloys: Sheet vs. plate material  

Science Conference Proceedings (OSTI)

Micromechanisms influencing the propagation of long (>10 mm) fatigue cracks in aluminum-lithium alloys are examined by specifically comparing crack-growth kinetics in a peak-aged Al-Li-Cu-Zr alloy 2090, processed as 1.6-mm thin (T83) sheet and 12.7-mm thick (T81) plate. It is found that in general crack-growth rates are significantly faster in the sheet material at equivalent stress-intensity levels, due to differences in the role of crack-tip shielding, resulting from crack deflection and consequent crack closure from wedging of fracture-surface asperities. Microstructurally, such differences are related to variations in the degree of recrystallization, grain structure and deformation texture in the two wrought-product forms. 14 refs., 4 figs.

Rao Venkateswara, K.T.; Ritchie, R.O. (Lawrence Berkeley Lab., CA (United States) California Univ., Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering); Bucci, R.J. (Aluminum Co. of America, Alcoa Center, PA (United States). Alcoa Labs.)

1989-12-01T23:59:59.000Z

272

Cessation of environmentally-assisted cracking in a low-alloy steel: Experimental results  

SciTech Connect

The presence of dissolved metallurgical sulfides in pressure vessel and piping steels has been linked to Environmentally-Assisted Cracking (EAC), a phenomenon observed in laboratory tests that results in fatigue crack growth rates as high as 100 times that in air. Previous experimental and analytical work based on diffusion as the mass transport process has shown that surface cracks that are initially clean of sulfides will not initiate EAC in most applications. This is because the average crack tip velocity would not be sufficiently high to expose enough metallurgical sulfides per unit time and produce the sulfide concentration required for EAC. However, there is a potential concern for the case of a relatively large embedded crack breaking through to the wetted surface. Such a crack would not be initially clean of sulfides, and EAC could initiate. This paper presents the results of a series of experiments conducted on two heats of an EAC susceptible, high-sulfur, low-alloy steel in 243{degrees}C low-oxygen water to further study the phenomenon of EAC persistence at low crack tip velocities. A load cycle profile that incorporated a significant load dwell period at minimum load was used. In one experiment, the fatigue cycling history was such that relatively high crack tip velocities at the start of the experiment produced a persistent case of EAC even when crack tip velocities were later reduced to levels below the EAC initiation velocity. The other series of experiments used initial crack tip velocities that were much lower and probably more realistic. Air precracking of the compact tension specimens produced an initial inventory of undissolved sulfides on the crack flanks that directly simulates the array of sulfides expected from the breakthrough of an embedded crack. In all cases, results showed EAC ceased after several hundred hours of cycling.

Li, Y.Y.

1997-01-01T23:59:59.000Z

273

LARGE NUMBERS OF UNDETECTED CRACKS IN THE WORLDS PWRS  

E-Print Network (OSTI)

Documents of the Davis-Besse incident reveal a strong possibility that there are large numbers of undetected cracks in the worlds pressurized water reactors, particularly in the US. This suspicion has been confirmed by the discovery of an additional crack at Davis-Besse itself. (568.5402) NIRS/WISE Amsterdam The cracks are nothing new: they were first discovered in Bugey-3,

unknown authors

2002-01-01T23:59:59.000Z

274

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

Science Conference Proceedings (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

275

Thermal and Electrical Transport in Oxide Heterostructures  

E-Print Network (OSTI)

of thermal conductivity . . . . . . . . . . . . . . . .4.4 Thermal transport in2.3.2 Thermal transport . . . . . . . . . . . . . . . .

Ravichandran, Jayakanth

2011-01-01T23:59:59.000Z

276

Elevated-Temperature Creep-Fatigue Crack-Growth Behavior of ...  

Science Conference Proceedings (OSTI)

the nickel-base HAYNES R-41, HAYNES 230 and HASTELLOY. X superalloys at temperatures ... The crack-growth tests for R-41 alloy were conducted using a.

277

An introduction to crack spreads - Today in Energy - U.S ...  

U.S. Energy Information Administration (EIA)

Crack spreads are differences between wholesale petroleum product prices and crude oil prices. These spreads are often used to estimate refining margi ...

278

A model of crack based on dislocations in smectic A liquid crystals  

E-Print Network (OSTI)

A plastic crack model for smectic A liquid crystals under longitudinal shear is suggested. The solution of screw dislocation in smectic A is the key in which the correct result is just obtained by overcoming a longstanding puzzle [19]. We further use the dislocation pile-up principle and the singular integral equation method, construct the solution of the crack in the phase. From the solution we can determine the size of the plastic zone at the crack tip and the crack tip opening (tearing) displacement, which are parameters being relevant to the local stability/instability of materials. The results may be useful in developing soft-matter mechanics.

Tian You Fan

2012-10-30T23:59:59.000Z

279

Cyclic Deformation and Fatigue Cracking Mechanisms of F.C.C. ...  

Science Conference Proceedings (OSTI)

Fatigue Crack Tip Mechanics Following a Tensile Overload Fatigue Weak-Link Density and Strength Distribution in High Strength Al Wrought and Cast Alloys.

280

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

Science Conference Proceedings (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

Note: This page contains sample records for the topic "thermal cracking visbreaking" 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

Manufacturing of Crack-Free Hastelloy-X Components by Selective ...  

Science Conference Proceedings (OSTI)

Lubricants in Deposition and Machining of Wire and Arc Additive Manufactured Structures Manufacturing of Crack-Free Hastelloy-X Components by Selective...

282

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

283

Thermal Management of Solar Cells  

E-Print Network (OSTI)

phonon transmission and interface thermal conductance acrossF. Miao, et al. , "Superior Thermal Conductivity of Single-Advanced Materials for Thermal Management of Electronic

Saadah, Mohammed Ahmed

2013-01-01T23:59:59.000Z

284

Thermal Spray Coatings  

Science Conference Proceedings (OSTI)

Table 35   Thermal spray coatings used for hardfacing applications...piston ring (internal combustion);

285

Plasma-Thermal Synthesis  

INLs Plasma-Thermal Synthesis process improves the conversion process for natural gas into liquid hydrocarbon fuels.

286

Ocean Thermal Energy Conversion  

Energy.gov (U.S. Department of Energy (DOE))

A process called ocean thermal energy conversion (OTEC) uses the heat energy stored in the Earth's oceans to generate electricity.

287

Nanocomposite Thermal Spray Coatings.  

Science Conference Proceedings (OSTI)

Long-Term Surface Restoration Effect Introduced by Advanced Lubricant Additive Nanocomposite Thermal Spray Coatings. New Hardfacing Overlay Claddings...

288

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

289

Stress Corrosion Cracking Behavior of Cast Stainless Steels  

SciTech Connect

Casting of austenitic stainless steels offers the possibility of directly producing large and/or relatively complex structures, such as the first wall shield modules or the diverter cassette for the ITER fusion reactor. Casting offers major cost savings when compared to fabrication via welding of quarter modules machined from large forgings. However, the strength properties of such cast components are typically considered inferior to those of conventionally forged and annealed components. To improve and validate cast stainless steel as a substitute for wrought stainless steel, a development and testing program was initiated, utilizing nitrogen and manganese additions to promote improved performance. This paper focuses on the response of the first set of developmental alloys to neutron-irradiation and susceptibility to stress corrosion cracking. These cast materials may also have applications for different components in light water reactors. Results showed that all steels exhibited irradiation-induced hardening and a corresponding drop in ductility, as expected, although there is still considerable ductility in the irradiated samples. The cast steels all exhibited reduced hardening in comparison to a wrought reference steels, which may be related to a larger grain size. Higher nitrogen contents did not negatively influence irradiation performance. Regarding stress corrosion cracking susceptibility, the large difference in grain size limits the comparison between wrought and cast materials, and inclusions in a reference and archive cast alloy tests complicate analysis of these samples. Results suggest that the irradiated archive heat was more susceptible to cracking than the modified alloys, which may be related to the more complex microstructure. Further, the results suggest that the modified cast steel is at least as SCC resistant as wrought 316LN. The beneficial effect of nitrogen on the mechanical properties of the alloys remains after irradiation and is not detrimental to SCC resistance.

Teysseyre, Sebastien [University of Michigan; Busby, Jeremy T [ORNL; Was, Gary [University of Michigan

2009-01-01T23:59:59.000Z

290

Physics-Based Stress Corrosion Cracking Component Reliability  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

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

291

Temperature and environmentally assisted cracking in low alloy steel  

Science Conference Proceedings (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 15 ppb.

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

1995-04-01T23:59:59.000Z

292

Building Energy Software Tools Directory: Thermal Comfort  

NLE Websites -- All DOE Office Websites (Extended Search)

Thermal Comfort Thermal Comfort logo. Provides a user-friendly interface for calculating thermal comfort parameters and making thermal comfort predictions using several thermal...

293

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

294

Micromechanisms of monotonic and cyclic subcritical crack growth in advanced high-melting-point low-ductility intermetallics. Annual report No. 1, 15 Apr 90-14 Apr 91  

Science Conference Proceedings (OSTI)

The next generation of high-performance jet engines will require markedly stiffer materials, operating at higher stress levels and capable of withstanding temperatures of up to 1650 C. Prime candidates for such applications include ordered intermetallics, ceramics and composites based on metal, intermetallic and ceramic or carbon matrices, all of which are currently of limited use due to their low ductility and fracture properties. Moreover, there is a lack of fundamental understanding on the micromechanisms influencing crack growth in these materials, particularly intermetallics. Accordingly, the present study is aimed at exploring the potential of intermetallic alloys and their composites as advanced structural materials by identifying the critical factors influencing the crack-propagation resistance under monotonic and cyclic loads. Attention is focused on the Nb{sub 3}Al and TiAl intermetallic systems. In both cases, the principal mechanism of toughening is to impede crack advance from crack bridging by ductile second phase particles. Reactive sintering and vacuum hot pressing techniques are successful is processing Nb{sub 3}Al intermetallics and duplex Nb/Nb{sub 3}Al microstructure with a stringy niobium phase can be achieved through thermal treatments. Characterization of mechanical properties will commence in the second year.

Rao, K.T.; Murugesh, L.; DeJonghe, L.C.

1991-05-01T23:59:59.000Z

295

Residual stresses and stress corrosion cracking in pipe fittings  

Science Conference Proceedings (OSTI)

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

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

1994-06-01T23:59:59.000Z

296

Review of industry efforts to manage pressurized water reactor feedwater nozzle, piping, and feedring cracking and wall thinning  

Science Conference Proceedings (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

297

Influence of Radiolysis and Hydrogen Embrittlement on the In-Service Cracking of PWR Internal Structures  

Science Conference Proceedings (OSTI)

Irradiation-assisted stress corrosion cracking (IASCC) of austenitic stainless steel components exposed to a high neutron flux in light water reactors is becoming an increasing concern for nuclear power plant owners. This study investigates the interaction between hydrogen in the metal and the water environment that may exacerbate the cracking process in PWRs.

1999-11-10T23:59:59.000Z

298

On saturation-strip model of a permeable crack in a piezoelectric ceramic  

E-Print Network (OSTI)

, h0, in the analysis of electrical and mechanical fields in the vicinity of a permeable crack tip under both mechanical as well electrical loads. Both local and global energy release rates. This permeable saturation crack model reveals that there exists a possible leaky mode for electrical field, which

Li, Shaofan

299

Apparatus and method for prevention of cracking in welded brittle alloys  

DOE Patents (OSTI)

An apparatus and method for reducing cracking in a heated material as the material cools. The apparatus includes a variable frequency electric signal generator that is coupled to a transducer. The transducer produces a variable frequency acoustic signal in response to the variable frequency electric signal, which is applied to the heated material to reduce cracking as the material cools.

Kronberg, James W. (Aiken, SC); Younkins, Robert M. (New Ellenton, SC)

2000-01-01T23:59:59.000Z

300

Delamination of a sensitized commercial AlMg alloy during fatigue crack growth  

E-Print Network (OSTI)

as sensitization to corrosion and stress corrosion cracking [1,3,4,8], with exposure to tem- peratures between 50,9­12]. The presence and growth of b-phase have been shown to severely degrade the corrosion resistance and stressDelamination of a sensitized commercial Al­Mg alloy during fatigue crack growth J.K. Brosi and J

Rollins, Andrew M.

Note: This page contains sample records for the topic "thermal cracking visbreaking" 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

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

E-Print Network (OSTI)

the free energy, and thus the energy barrier, via numerous competing mech- anisms like stress corrosion speed of crack growth with increasing G; a weak stress- sensitive regime II follows where transportAverage crack front velocity during subcritical fracture propagation in a heterogeneous medium

Ampuero, Jean Paul

302

Prediction of Environmental Crack Growth in Nuclear Power Plant Components: Volumes 1-3  

Science Conference Proceedings (OSTI)

In-service assessment of crack growth rates plays a crucial role in decisions involving component integrity and life. The research presented in this three-volume report examines many important aspects of the crack tip damage processes in aqueous environments, providing an improved scientific basis for life prediction technology development.

1993-11-04T23:59:59.000Z

303

Fatigue Crack Growth Characteristics of Thin Sheet Titanium Alloy Ti 6-2-2-2-2  

Science Conference Proceedings (OSTI)

Fatigue crack growth rates of Ti 6-2-2-2-2 as a function of stress ratio, temperature (24 or 177 degrees C), tensile orientation and environment (laboratory air or ultrahigh vacuum) are presented. Fatigue crack growth rates of Ti 6-2-2-2-2 are also compared ...

Smith Stephen W.; Piascik Robert S.

2001-03-01T23:59:59.000Z

304

Behavior of Stress Corrosion Cracking for Type 316L Stainless Steel ...  

Science Conference Proceedings (OSTI)

Crack Growth Rates of Irradiated Commercial Stainless Steels in BWR and PWR ... Detailed Root Cause Analysis of SG Tube ODSCC Indications within the Tube Sheets of NPP Biblis Unit A .... Radiation Damage in Fe-C-Met Model Alloys ... Stress Corrosion Cracking Behavior near the Fusion Boundary of Dissimilar Weld

305

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

306

Vickers microindentation toughness of a sintered SiC in the median-crack regime  

SciTech Connect

The Vickers microindentation method for the determination of the fracture toughness of ceramics was investigated in the median crack regime for a sintered alpha SiC. The results are compared with fracture toughness measurements by conventional fracture mechanics technique and also with the reported indentation toughness for the low-load Palmqvist crack regime. Indentation toughnesses in the median crack regime vary widely depending on the choice of the specific equation which is applied. The indentation toughnesses are also load (crack length) dependent. A decreasing R-curve trend results, in contradiction to the flat R-curve that has been observed with conventional fracture mechanics techniques. It is concluded that the Vickers microindentation method is not a reliable technique for the determination of the fracture toughness of ceramics in the median crack regime.

Ghosh, Asish; Kobayashi, A.S. (Washington Univ., Seattle, WA (United States). Coll. of Engineering); Li, Zhuang (Argonne National Lab., IL (United States)); Henager, C.H. Jr. (Pacific Northwest Lab., Richland, WA (United States)); Bradt, R.C. (Nevada Univ., Reno, NV (United States). Mackay School of Mines)

1991-01-01T23:59:59.000Z

307

BWRVIP-99-A: BWR Vessel and Internals Project, Crack Growth Rates in Irradiated Stainless Steels in BWR Internal Components  

Science Conference Proceedings (OSTI)

The BWR Vessel and Internals Project (BWRVIP) has developed methodologies to evaluate crack growth in internal components of stainless steel and nickel-base alloys in the BWR vessel. One BWRVIP reportBWRVIP-14developed an approach to evaluate crack growth by intergranular stress corrosion cracking in austenitic stainless steel core shrouds exposed to a limited amount of neutron irradiation. Subsequently another reportBWRVIP-99was prepared to provide a crack growth methodology applicable to irradiated...

2008-11-24T23:59:59.000Z

308

Assessing the potential and limitations of heavy oil upgrading by electron beam irradiation  

E-Print Network (OSTI)

Radiation technology can economically overcome principal problems of heavy oil processing arising from heavy oilâ??s unfavorable physical and chemical properties. This technology promises to increase considerably yields of valuable and environmentally satisfying products of thermal cracking; to simplify complexity of refinery configuration; and to reduce energy expenses of thermal cracking. Objectives of the present study are: â? Evaluate heavy oil viscosities with respect to absorbed dose and effect of different solvents on the viscosity of irradiated crude oil by comparing selected physical properties of irradiated samples to a non-irradiated control group; â? Investigate effect of e-beam radiation on the yields of light fractions comparing yields of radiation-thermal cracking to yields of conventional thermal cracking. The viscosity was used as an indicator of the change in the molecular structure of hydrocarbons upon irradiation. We found that the irradiation of pure oil leads to the increase of the molecular weight calculated from the Riazi-Daubert correlation. Thus, irradiation up to 10 kGy resulted in a 1.64% increase in the molecular weight, 20 kGy â?? 4.35% and 30 kGy â?? 3.28%. It was found that if irradiated oil was stored for 17 days, its viscosity increased by 14% on average. The irradiation of samples with added organic solvent in the following weight percentages 10, 5, 2.5wt.% resulted in the increase in the viscosity by 3.3, 3.6 and 14.5%, respectively. The irradiation of the sample with added distilled water also resulted in an increase in the viscosity. This increase mainly happened because the thermal component was absent in the activation energy and hydrogen, produced from radiolysis of solvent and water molecules in mixture with crude oil, and was not consumed by hydrocarbon molecules and no reduction in molecular size occurred. Implementation of radiation to the thermal cracking increased yields of light fractions by 35wt.% on average compared to the process where no radiation was present. The last chapter of this thesis discusses a profitability of installation the hypothetical radiation-thermal visbreaking unit. The calculation of profitability was performed by a rate of return on investment (ROI) method. It showed that implementation of radiation-thermal processing resulted in an increase of ROI from 16 to 60%.

Zhussupov, Daniyar

2006-12-01T23:59:59.000Z

309

Catalytic thermal barrier coatings  

Science Conference Proceedings (OSTI)

A catalyst element (30) for high temperature applications such as a gas turbine engine. The catalyst element includes a metal substrate such as a tube (32) having a layer of ceramic thermal barrier coating material (34) disposed on the substrate for thermally insulating the metal substrate from a high temperature fuel/air mixture. The ceramic thermal barrier coating material is formed of a crystal structure populated with base elements but with selected sites of the crystal structure being populated by substitute ions selected to allow the ceramic thermal barrier coating material to catalytically react the fuel-air mixture at a higher rate than would the base compound without the ionic substitutions. Precious metal crystallites may be disposed within the crystal structure to allow the ceramic thermal barrier coating material to catalytically react the fuel-air mixture at a lower light-off temperature than would the ceramic thermal barrier coating material without the precious metal crystallites.

Kulkarni, Anand A. (Orlando, FL); Campbell, Christian X. (Orlando, FL); Subramanian, Ramesh (Oviedo, FL)

2009-06-02T23:59:59.000Z

310

Extent of surface regions near corner points of notched cracked bodies subjected to mode-I loading  

Science Conference Proceedings (OSTI)

In the present paper, the extent of surface regions in cracked bodies subjected to mode-I loading was examined, which is important for a proper definition of finite element meshes. Different specimen geometries with and without lateral notches, representative ... Keywords: Crack shape evolution, Extent of surface region, Fatigue crack growth, Finite element method, Stress triaxiality

R. Branco; F. V. Antunes; L. C. H. Ricardo; J. D. Costa

2012-03-01T23:59:59.000Z

311

Applying neural networks, genetic algorithms and fuzzy logic for the identification of cracks in shafts by using coupled response measurements  

Science Conference Proceedings (OSTI)

This paper considers the dynamic behavior of a shaft with two transverse cracks characterized by three measures: position, depth and relative angle. Both cracks are considered to lie along arbitrary angular positions with respect to the longitudinal ... Keywords: Coupling, Crack identification, Genetic algorithms, Neural networks, Shaft

K. M. Saridakis; A. C. Chasalevris; C. A. Papadopoulos; A. J. Dentsoras

2008-06-01T23:59:59.000Z

312

Thermally Conductive Graphite Foam  

oriented graphite planes, similar to high performance carbon fibers, which have been estimated to exhibit a thermal conductivity greater than 1700 ...

313

Thermal Barrier Coatings  

NLE Websites -- All DOE Office Websites (Extended Search)

Thermal Barrier Coatings Opportunity The Department of Energy's National Energy Technology Laboratory (NETL) is seeking licensing partners interested in implementing United States...

314

Variable pressure thermal insulating jacket  

DOE Patents (OSTI)

A device for controlled insulation of a thermal device. The device includes a thermal jacket with a closed volume able to be evacuated to form an insulating jacket around the thermal source. A getter material is in communcation with the closed volume of the thermal jacket. The getter material can absorb and desorb a control gas to control gas pressure in the volume of the thermal jacket to control thermal conductivity in the thermal jacket.

Nelson, Paul A. (Wheaton, IL); Malecha, Richard F. (Naperville, IL); Chilenskas, Albert A. (Chicago, IL)

1994-01-01T23:59:59.000Z

315

Variable pressure thermal insulating jacket  

DOE Patents (OSTI)

A device for controlled insulation of a thermal device is disclosed. The device includes a thermal jacket with a closed volume able to be evacuated to form an insulating jacket around the thermal source. A getter material is in communication with the closed volume of the thermal jacket. The getter material can absorb and desorb a control gas to control gas pressure in the volume of the thermal jacket to control thermal conductivity in the thermal jacket. 10 figs.

Nelson, P.A.; Malecha, R.F.; Chilenskas, A.A.

1994-09-20T23:59:59.000Z

316

EMAT based inspection of natural gas pipelines for SSC cracks  

NLE Websites -- All DOE Office Websites (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,

317

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

E-Print Network (OSTI)

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

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

2012-09-16T23:59:59.000Z

318

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

E-Print Network (OSTI)

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

Tsoy, L A; Komarov, A G; Tsoy, A N

2012-01-01T23:59:59.000Z

319

CRACK GROWTH ANALYSIS OF SOLID OXIDE FUEL CELL ELECTROLYTES  

DOE Green Energy (OSTI)

Defects and Flaws control the structural and functional property of ceramics. In determining the reliability and lifetime of ceramics structures it is very important to quantify the crack growth behavior of the ceramics. In addition, because of the high variability of the strength and the relatively low toughness of ceramics, a statistical design approach is necessary. The statistical nature of the strength of ceramics is currently well recognized, and is usually accounted for by utilizing Weibull or similar statistical distributions. Design tools such as CARES using a combination of strength measurements, stress analysis, and statistics are available and reasonably well developed. These design codes also incorporate material data such as elastic constants as well as flaw distributions and time-dependent properties. The fast fracture reliability for ceramics is often different from their time-dependent reliability. Further confounding the design complexity, the time-dependent reliability varies with the environment/temperature/stress combination. Therefore, it becomes important to be able to accurately determine the behavior of ceramics under simulated application conditions to provide a better prediction of the lifetime and reliability for a given component. In the present study, Yttria stabilized Zirconia (YSZ) of 9.6 mol% Yttria composition was procured in the form of tubes of length 100 mm. The composition is of interest as tubular electrolytes for Solid Oxide Fuel Cells. Rings cut from the tubes were characterized for microstructure, phase stability, mechanical strength (Weibull modulus) and fracture mechanisms. The strength at operating condition of SOFCs (1000 C) decreased to 95 MPa as compared to room temperature strength of 230 MPa. However, the Weibull modulus remains relatively unchanged. Slow crack growth (SCG) parameter, n = 17 evaluated at room temperature in air was representative of well studied brittle materials. Based on the results, further work was planned to evaluate the strength degradation, modulus and failure in more representative environment of the SOFCs.

S. Bandopadhyay; N. Nagabhushana

2003-10-01T23:59:59.000Z

320

Effect of PCC Joint Skew on Reflective Cracking in HMA Overlays  

E-Print Network (OSTI)

Reflective cracking is a relatively premature distress that occurs in HMA materials overlaying cracked and jointed underlying pavements. The high concentration of stresses and strains in the vicinity of the discontinuity of the old pavement causes the cracks to reflect into the newly placed HMA overlay. While it is a common practice to use skewed transverse joints in rigid pavements to improve the latter's performance, the impact of such a practice on the cracking of a potential HMA overlay has not been examined so far. In this context, this study investigates the effect of using skewed transverse joints in rigid pavements on reflective cracking development in the HMA overlay. Advanced three-dimensional Finite Element models including viscoelastic material properties for the HMA overlay, 3D beam modeling of dowel bars, non-uniform tire-pavement contact stresses, friction interfaces, and infinite boundary elements were constructed for both normal and skewed transverse joints using ABAQUS v-6.11. The potential for reflective cracking was monitored through the fracture mechanics J-integral parameter. Results obtained show, among other things, that the practice of skewing transverse joints increases the potential for reflective cracking development in the asphalt concrete overlay.

Ziad G. Ghauch

2011-10-14T23:59:59.000Z

Note: This page contains sample records for the topic "thermal cracking visbreaking" 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

Crack Formation in the Presence of an Electric Field in Droplets of Laponite Gel  

E-Print Network (OSTI)

When a colloidal gel dries through evaporation, cracks are usually formed, which often reveal underlying processes at work during desiccation. Desiccating colloid droplets of few hundred $\\mu l$ size show interesting effects of pattern formation and cracking which makes this an active subject of current research. Since aqueous gels of clay are known to be strongly affected by an electric field, one may expect crack patterns to exhibit a field effect. In the present study we allow droplets of laponite gel to dry under a radial electric field. This gives rise to highly reproducible patterns of cracks, which depend on the strength, direction and time of exposure to the electric field. For a continuously applied DC voltage, cracks always appear on dissipation of a certain constant amount of energy. If the field is switched off before cracks appear, the observed results are shown to obey a number of empirical scaling relations, which enable us to predict the time of appearance and the number of cracks under specified conditions.

Tajkera Khatun; Tapati Dutta; Sujata Tarafdar

2013-08-14T23:59:59.000Z

322

Thermal protection apparatus  

DOE Patents (OSTI)

An apparatus which thermally protects sensitive components in tools used in a geothermal borehole. The apparatus comprises a Dewar within a housing. The Dewar contains heat pipes such as brass heat pipes for thermally conducting heat from heat sensitive components to a heat sink such as ice.

Bennett, Gloria A. (Los Alamos, NM); Elder, Michael G. (Los Alamos, NM); Kemme, Joseph E. (Albuquerque, NM)

1985-01-01T23:59:59.000Z

323

Thermal protection apparatus  

DOE Patents (OSTI)

The disclosure is directed to an apparatus for thermally protecting sensitive components in tools used in a geothermal borehole. The apparatus comprises a Dewar within a housing. The Dewar contains heat pipes such as brass heat pipes for thermally conducting heat from heat sensitive components such as electronics to a heat sink such as ice.

Bennett, G.A.; Elder, M.G.; Kemme, J.E.

1984-03-20T23:59:59.000Z

324

Thermal masses in leptogenesis  

E-Print Network (OSTI)

We investigate the validity of using thermal masses in the kinematics of final states in the decay rate of heavy neutrinos in leptogenesis calculations. We find that using thermal masses this way is a reasonable approximation, but corrections arise through quantum statistical distribution functions and leptonic quasiparticles.

Kiessig, Clemens P

2009-01-01T23:59:59.000Z

325

Crack growth rates of nickel alloy welds in a PWR environment.  

Science Conference Proceedings (OSTI)

In light water reactors (LWRs), vessel internal components made of nickel-base alloys are susceptible to environmentally assisted cracking. A better understanding of the causes and mechanisms of this cracking may permit less conservative estimates of damage accumulation and requirements on inspection intervals. A program is being conducted at Argonne National Laboratory to evaluate the resistance of Ni alloys and their welds to environmentally assisted cracking in simulated LWR coolant environments. This report presents crack growth rate (CGR) results for Alloy 182 shielded-metal-arc weld metal in a simulated pressurized water reactor (PWR) environment at 320 C. Crack growth tests were conducted on 1-T compact tension specimens with different weld orientations from both double-J and deep-groove welds. The results indicate little or no environmental enhancement of fatigue CGRs of Alloy 182 weld metal in the PWR environment. The CGRs of Alloy 182 in the PWR environment are a factor of {approx}5 higher than those of Alloy 600 in air under the same loading conditions. The stress corrosion cracking for the Alloy 182 weld is close to the average behavior of Alloy 600 in the PWR environment. The weld orientation was found to have a profound effect on the magnitude of crack growth: cracking was found to propagate faster along the dendrites than across them. The existing CGR data for Ni-alloy weld metals have been compiled and evaluated to establish the effects of key material, loading, and environmental parameters on CGRs in PWR environments. The results from the present study are compared with the existing CGR data for Ni-alloy welds to determine the relative susceptibility of the specific Ni-alloy weld to environmentally enhanced cracking.

Alexandreanu, B.; Chopra, O. K.; Shack, W. J.; Energy Technology

2006-05-31T23:59:59.000Z

326

Thermal treatment wall  

DOE Patents (OSTI)

A thermal treatment wall emplaced to perform in-situ destruction of contaminants in groundwater. Thermal destruction of specific contaminants occurs by hydrous pyrolysis/oxidation at temperatures achievable by existing thermal remediation techniques (electrical heating or steam injection) in the presence of oxygen or soil mineral oxidants, such as MnO.sub.2. The thermal treatment wall can be installed in a variety of configurations depending on the specific objectives, and can be used for groundwater cleanup, wherein in-situ destruction of contaminants is carried out rather than extracting contaminated fluids to the surface, where they are to be cleaned. In addition, the thermal treatment wall can be used for both plume interdiction and near-wellhead in-situ groundwater treatment. Thus, this technique can be utilized for a variety of groundwater contamination problems.

Aines, Roger D. (Livermore, CA); Newmark, Robin L. (Livermore, CA); Knauss, Kevin G. (Livermore, CA)

2000-01-01T23:59:59.000Z

327

Solar thermal aircraft  

DOE Patents (OSTI)

A solar thermal powered aircraft powered by heat energy from the sun. A heat engine, such as a Stirling engine, is carried by the aircraft body for producing power for a propulsion mechanism, such as a propeller. The heat engine has a thermal battery in thermal contact with it so that heat is supplied from the thermal battery. A solar concentrator, such as reflective parabolic trough, is movably connected to an optically transparent section of the aircraft body for receiving and concentrating solar energy from within the aircraft. Concentrated solar energy is collected by a heat collection and transport conduit, and heat transported to the thermal battery. A solar tracker includes a heliostat for determining optimal alignment with the sun, and a drive motor actuating the solar concentrator into optimal alignment with the sun based on a determination by the heliostat.

Bennett, Charles L. (Livermore, CA)

2007-09-18T23:59:59.000Z

328

Thermally-related safety issues associated with thermal batteries.  

DOE Green Energy (OSTI)

Thermal batteries can experience thermal runaway under certain usage conditions. This can lead to safety issues for personnel and cause damage to associated test equipment if the battery thermally self destructs. This report discusses a number of thermal and design related issues that can lead to catastrophic destruction of thermal batteries under certain conditions. Contributing factors are identified and mitigating actions are presented to minimize or prevent undesirable thermal runaway.

Guidotti, Ronald Armand

2006-06-01T23:59:59.000Z

329

Efficient thermal management for multiprocessor systems  

E-Print Network (OSTI)

2.2.4 Thermal Modeling . . . . . . . .63 Table 4.3: Thermal Hot Spots . . . . . . . . . . . . . .Performance-Efficient Thermal Management . . . . . . . . . .

Co?kun, Ay?e K?v?lc?m

2009-01-01T23:59:59.000Z

330

Damage Evolution in Thermal Barrier Coatings with Thermal Cycling  

Science Conference Proceedings (OSTI)

Abstract Scope, Thermal barrier coatings typically fail on cooling after prolonged thermal cycling by the growth of sub-critical interface separations. Observations...

331

Multilayer thermal barrier coating systems  

DOE Patents (OSTI)

The present invention generally describes multilayer thermal barrier coating systems and methods of making the multilayer thermal barrier coating systems. The thermal barrier coating systems comprise a first ceramic layer, a second ceramic layer, a thermally grown oxide layer, a metallic bond coating layer and a substrate. The thermal barrier coating systems have improved high temperature thermal and chemical stability for use in gas turbine applications.

Vance, Steven J. (Orlando, FL); Goedjen, John G. (Oviedo, FL); Sabol, Stephen M. (Orlando, FL); Sloan, Kelly M. (Longwood, FL)

2000-01-01T23:59:59.000Z

332

Cooling thermal storage  

Science Conference Proceedings (OSTI)

This article gives some overall guidelines for successful operation of cooling thermal storage installations. Electric utilities use rates and other incentives to encourage thermal storage, which not only reduces their system peaks but also transfers a portion of their load from expensive daytime inefficient peaking plants to less expensive nighttime base load high efficiency coal and nuclear plants. There are hundreds of thermal storage installations around the country. Some of these are very successful; others have failed to achieve all of their predicted benefits because application considerations were not properly addressed.

Gatley, D.P.

1987-04-01T23:59:59.000Z

333

Solar Thermal Conversion  

DOE Green Energy (OSTI)

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

Kreith, F.; Meyer, R. T.

1982-11-01T23:59:59.000Z

334

Thermal insulations using vacuum panels  

DOE Patents (OSTI)

Thermal insulation vacuum panels are formed of an inner core of compressed low thermal conductivity powders enclosed by a ceramic/glass envelope evaluated to a low pressure.

Glicksman, Leon R. (Lynnfield, MA); Burke, Melissa S. (Pittsburgh, PA)

1991-07-16T23:59:59.000Z

335

Ocean Thermal | Open Energy Information  

Open Energy Info (EERE)

Community Login | Sign Up Search Page Edit History Facebook icon Twitter icon Ocean Thermal Jump to: navigation, search TODO: Add description List of Ocean Thermal Incentives...

336

Comparison of Thermal Insulation Materials.  

E-Print Network (OSTI)

??This thesis is about comparing of different thermal insulation materials of different manufactures. In our days there are a lot of different thermal insulation materials (more)

Chaykovskiy, German

2010-01-01T23:59:59.000Z

337

Integral identities for a semi-infinite interfacial crack in 2D and 3D elasticity  

E-Print Network (OSTI)

The paper is concerned with the problem of a semi-infinite crack at the interface between two dissimilar elastic half-spaces, loaded by a general asymmetrical system of forces distributed along the crack faces. On the basis of the weight function approach and the fundamental reciprocal identity (Betti formula), we formulate the elasticity problem in terms of singular integral equations relating the applied loading and the resulting crack opening. Such formulation is fundamental in the theory of elasticity and extensively used to solve several problems in linear elastic fracture mechanics (for instance various classic crack problems in homogeneous and heterogeneous media). This formulation is also crucial in important recent multiphysics applications, where the elastic problem is coupled with other concurrent physical phenomena. A paradigmatic example is hydraulic fracturing, where the elasticity equations are coupled with fluid dynamics.

Andrea Piccolroaz; Gennady Mishuris

2011-10-17T23:59:59.000Z

338

Integral identities for a semi-infinite interfacial crack in 2D and 3D elasticity  

E-Print Network (OSTI)

The paper is concerned with the problem of a semi-infinite crack at the interface between two dissimilar elastic half-spaces, loaded by a general asymmetrical system of forces distributed along the crack faces. On the basis of the weight function approach and the fundamental reciprocal identity (Betti formula), we formulate the elasticity problem in terms of singular integral equations relating the applied loading and the resulting crack opening. Such formulation is fundamental in the theory of elasticity and extensively used to solve several problems in linear elastic fracture mechanics (for instance various classic crack problems in homogeneous and heterogeneous media). This formulation is also crucial in important recent multiphysics applications, where the elastic problem is coupled with other concurrent physical phenomena. A paradigmatic example is hydraulic fracturing, where the elasticity equations are coupled with fluid dynamics.

Piccolroaz, Andrea

2011-01-01T23:59:59.000Z

339

P wave anisotropy, stress, and crack distribution at Coso geothermal field,  

Open Energy Info (EERE)

wave anisotropy, stress, and crack distribution at Coso geothermal field, wave anisotropy, stress, and crack distribution at Coso geothermal field, California Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: P wave anisotropy, stress, and crack distribution at Coso geothermal field, California Details Activities (1) Areas (1) Regions (0) Abstract: A new inversion method for P wave anisotropy (Wu and Lees, 1999a) has been applied to high-precision, microseismic traveltime data collected at Coso geothermal region, California. Direction-dependent P wave velocity and thus its perturbation, are represented by a symmetric positive definite matrix A instead of a scalar. The resulting anisotropy distribution is used to estimate variations in crack density, stress distribution and permeability within the producing geothermal field. A circular dome-like

340

An Overview of Stress Cracking of Pipeline Steels in Near-neutral ...  

Science Conference Proceedings (OSTI)

Abstract Scope, Stress cracking of pipeline steels in near-neutral pH has remained a virile integrity risk for oil and gas pipelines. Although it was termed as stress...

Note: This page contains sample records for the topic "thermal cracking visbreaking" 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

Influence of Cerium on Stress Corrosion Cracking in AZ91D  

Science Conference Proceedings (OSTI)

This paper considers the effect of cerium additions on the stress corrosion cracking in the Mg-Al-Zn alloy AZ91D. The two dominant phases in the AZ91D...

342

Stress intensity magnification factors for fully circumferential cracks in valve bodies (thick cylinders)  

SciTech Connect

The stress intensity solutions presented herein were obtained using an energy method in conjunction with a two-dimensional finite element program in order to explicitly account for curvature effect for fully circumferential cracks. The magnification factors for a specific crack depth were calculated by successively loading the crack surface by a uniform, linear, quadratic, and a cubic loading distribution. The magnification factors can be used to calculate the stress intensity factors by superposition method. The functions for each load condition in terms of radius to thickness ratio (R/t) and a fractional distance in terms of crack depth to thickness ratio (a/t) were developed. The validity of these functions is R/t = 1.5 to 10.0 and for 0.0125 {le} a/t {le} 0.8125. The functions agree to within 1% of the finite elements solutions for most magnification factors.

Toor, P.M.

1998-11-01T23:59:59.000Z

343

Remarks on the energy release rate for an antiplane moving crack in couple stress elasticity  

E-Print Network (OSTI)

This paper is concerned with the steady-state propagation of an antiplane semi-infinite crack in couple stress elastic materials. A distributed loading applied at the crack faces and moving with the same velocity of the crack tip is considered, and the influence of the loading profile variations and microstructural effects on the dynamic energy release rate is investigated. The behaviour of both energy release rate and maximum total shear stress when the crack tip speed approaches the critical speed (either that of the shear waves or that of the Rayleigh waves) is studied. The limit case corresponding to vanishing characteristic scale lengths is addressed both numerically and analytically by means of a comparison with classical elasticity results.

L. Morini; A. Piccolroaz; G. Mishuris

2013-11-21T23:59:59.000Z

344

Interpretation of warm prestress-induced fracture toughness based on crack-tip constraint  

SciTech Connect

This study explores the possibility of using J-Q-related crack-tip constraint concepts to provide a basis for both the interpretation of warm prestress (WPS)-induced fracture toughness and their transferability to structural applications. A finite-element boundary-layer formulation based on small-scale yielding (SSY), remote mode I K-dominant assumptions is adopted. Effects of WPS-induced crack-tip constraint are quantified in terms of deviation in either the opening-mode or the mean stress component of the WPS crack-tip fields relative to the reference K-dominant SSY state associated with monotonic-loading conditions. Over the range of WPS load-paths considered the WPS-induced crack-tip constraint closely resembles a spatially varying hydrostatic stress field. Interpretation and transferability of WPS fracture toughness under SSY conditions are specified in terms of the unload and reload ratio.

Shum, D.K.M.

1993-06-01T23:59:59.000Z

345

SLAC National Accelerator Laboratory - BaBar Data Hint at Cracks...  

NLE Websites -- All DOE Office Websites (Extended Search)

Press Release Archive BaBar Data Hint at Cracks in the Standard Model June 18, 2012 Menlo Park, Calif. - Recently analyzed data from the BaBar experiment may suggest possible flaws...

346

Studies on the disbonding initiation of interfacial cracks.  

SciTech Connect

With the continuing trend of decreasing feature sizes in flip-chip assemblies, the reliability tolerance to interfacial flaws is also decreasing. Small-scale disbonds will become more of a concern, pointing to the need for a better understanding of the initiation stage of interfacial delamination. With most accepted adhesion metric methodologies tailored to predict failure under the prior existence of a disbond, the study of the initiation phenomenon is open to development and standardization of new testing procedures. Traditional fracture mechanics approaches are not suitable, as the mathematics assume failure to originate at a disbond or crack tip. Disbond initiation is believed to first occur at free edges and corners, which act as high stress concentration sites and exhibit singular stresses similar to a crack tip, though less severe in intensity. As such, a 'fracture mechanics-like' approach may be employed which defines a material parameter--a critical stress intensity factor (K{sub c})--that can be used to predict when initiation of a disbond at an interface will occur. The factors affecting the adhesion of underfill/polyimide interfaces relevant to flip-chip assemblies were investigated in this study. The study consisted of two distinct parts: a comparison of the initiation and propagation phenomena and a comparison of the relationship between sub-critical and critical initiation of interfacial failure. The initiation of underfill interfacial failure was studied by characterizing failure at a free-edge with a critical stress intensity factor. In comparison with the interfacial fracture toughness testing, it was shown that a good correlation exists between the initiation and propagation of interfacial failures. Such a correlation justifies the continuing use of fracture mechanics to predict the reliability of flip-chip packages. The second aspect of the research involved fatigue testing of tensile butt joint specimens to determine lifetimes at sub-critical load levels. The results display an interfacial strength ranking similar to that observed during monotonic testing. The fatigue results indicate that monotonic fracture mechanics testing may be an adequate screening tool to help predict cyclic underfill failure; however lifetime data is required to predict reliability.

McAdams, Brian J. (Lehigh University, Bethlehem, PA); Pearson, Raymond A. (Lehigh University, Bethlehem, PA)

2005-08-01T23:59:59.000Z

347

Root Causes of Circumferential Cracking in Waterwalls of Supercritical Units: State-of-Knowledge  

Science Conference Proceedings (OSTI)

Circumferential cracking on the waterwalls has again become a significant problem for many supercritical units, especially with the implementation of low-NOx systems. Damage typically consists of multiple, parallel cracks perpendicular to the longitudinal axis of the tube and to the direction of maximum tensile stress. There can be numerous potential causes, and the choice of the appropriate control strategy will depend on identifying the underlying cause(s) for a particular outbreak of damage. This repo...

2008-02-08T23:59:59.000Z

348

Stress Corrosion Cracking Initiation Model for Stainless Steel and Nickel Alloys  

Science Conference Proceedings (OSTI)

This report provides a quantitative framework or model of general applicability in an engineering evaluation of stress corrosion cracking (SCC) initiation, including initial short crack growth, which accounts for the varied effects of cold work (CW) on SCC susceptibility. The microstructural impact of CW is accounted for through the materials strength and strain-hardening response. CW generally acts as an accelerant in SCC. Both the surface-layer-limited cold work and the through-thickness condition nee...

2009-11-20T23:59:59.000Z

349

Program on Technology Innovation: A Mechanistic Basis for Irradiation Assisted Stress Corrosion Cracking  

Science Conference Proceedings (OSTI)

Irradiation-assisted stress corrosion cracking (IASCC) refers to intergranular stress corrosion cracking that is accelerated under the action of irradiation in light water reactor core components. It is referred to as assisted because irradiation enhances, or accelerates, the IGSCC process over the non-irradiated state. IASCC has been a problem in the nuclear industry for the last 40 years and continues to occur due to a lack of understanding of its underlying mechanism. It is the single most important...

2009-09-08T23:59:59.000Z

350

Repair and Replacement Applications Center: Stress Corrosion Cracking in Closed Cooling Water Systems  

Science Conference Proceedings (OSTI)

The results of a recent EPRI project "Stress Corrosion Cracking in PWR and BWR Closed Cooling Water Systems," (EPRI Report 1009721, October 2004) indicated that approximately 10 of 143 light water reactor (LWR) plants surveyed had through-wall leaks in carbon steel piping in their closed cooling water (CCW) systems. The root cause of this leakage was intergranular stress corrosion cracking. Since there has not been extensive non-destructive testing in these systems, it is likely that the incidence rate o...

2006-09-28T23:59:59.000Z

351

Development of an LP Rotor Rim-Attachment Cracking Life Assessment Code (LPRimLife)  

Science Conference Proceedings (OSTI)

Most of the domestic turbine fleet has reached the 50,000-hour range of service operation. Unfortunately, above this level of operational hours, a number of turbines have begun to experience low-pressure (LP) rim-attachment cracking. A computer code developed by EPRI, LPRimLife, provides utilities with a methodology for assessing the remaining life of LP rim attachments with known or suspected cracking.

1999-12-07T23:59:59.000Z

352

Understanding the Interaction Between Localized Deformation in Materials and Environmentally Assisted Cracking  

Science Conference Proceedings (OSTI)

This report sets out to develop an understanding of the interaction between localized mechanical deformation in reactor structural materials (such as nickel-base alloys, austenitic stainless steels, or carbon and low-alloy steels) and their susceptibility to degradation by environmentally assisted cracking (EAC) after long-term exposure to light water reactor coolant. The main emphasis is on stress corrosion cracking (SCC), with and without the influence of irradiation, in the pressurized water reactor (...

2005-12-19T23:59:59.000Z

353

Stress Corrosion Cracking Resistance of Weld Metals 182, 72, and 308L  

Science Conference Proceedings (OSTI)

Intergranular stress corrosion cracking (IGSCC) has occurred in alloy 182 weld metal in operating BWRs. This study compares the propagation behavior of IGSCC for nickel-base weld metal, alloy 182, with two other weld metals: type 308L stainless steel and a high-chromium nickel-base BWR candidate, alloy 72. Results indicate that weld metal 72 is more stress corrosion crack (SCC) resistant than either weld metals 182 or type 308L.

1992-08-01T23:59:59.000Z

354

Development of a Thin Film Sensor for Detecting Initiation of Stress Corrosion Cracks in Stainless Steels  

Science Conference Proceedings (OSTI)

The study of initiation of intergranular stress corrosion cracking (IGSCC) has been hindered by lack of techniques to detect small cracks ranging in depth from sub-micron to several microns. The present investigation's main objective is to develop a thin film sample suitable for detecting and studying initiation of IGSCC in sensitized austenitic stainless steel. Two approaches are being investigated to produce thin films of stainless steel: pulse laser deposition (PLD) of ultrathin films (20-150 nm) usin...

2002-12-11T23:59:59.000Z

355

Program on Technology Innovation: Development of Thin-Film Sensors to Detect Stress Corrosion Crack Initiation  

Science Conference Proceedings (OSTI)

A great amount of effort has been expended measuring stress corrosion crack (SCC) growth rates and investigating the mechanisms of SCC propagation. By contrast, relatively little effort has been devoted to studies of SCC initiation. The small amount of work on SCC initiation is due, in part, to the difficulty in investigating this phase of cracking. The main objective of the present investigation is to develop a thin-film sensor suitable for detecting and studying the initiation of intergranular stress c...

2005-12-02T23:59:59.000Z

356

Assessment of Nondestructive Evaluation Methods and Analytical Procedures for Thick-Section Component Cracking  

Science Conference Proceedings (OSTI)

A significant concern for owners and operators, damage in the form of cracking in thick-section components (valves, casings, headers, and so on) in fossil fuelfired boilers continues to be observed. With increased cyclic duty and the fast startups associated with combined-cycle plants, such damage will remain a prevalent industry problem. Specifically, the concerns for continued operation of cracked thick-section components arise from the uncertainties associated with the nondestructive ...

2013-08-21T23:59:59.000Z

357

Integrability vs Quantum Thermalization  

E-Print Network (OSTI)

Non-integrability is often taken as a prerequisite for quantum thermalization. Still, a generally accepted definition of quantum integrability is lacking. With the basis in the driven Rabi model we discuss this careless usage of the term "integrability" in connection to quantum thermalization. The model would be classified as non-integrable according to the most commonly used definitions, for example, the only preserved quantity is the total energy. Despite this fact, a thorough analysis conjectures that the system will not thermalize. Thus, our findings suggest first of all (i) that care should be paid when linking non-integrability with thermalization, and secondly (ii) that the standardly used definitions for quantum integrability are unsatisfactory.

Jonas Larson

2013-04-12T23:59:59.000Z

358

Contact thermal lithography  

E-Print Network (OSTI)

Contact thermal lithography is a method for fabricating microscale patterns using heat transfer. In contrast to photolithography, where the minimum achievable feature size is proportional to the wavelength of light used ...

Schmidt, Aaron Jerome, 1979-

2004-01-01T23:59:59.000Z

359

Properties of Thermal Glueballs  

E-Print Network (OSTI)

We study the properties of the 0++ glueball at finite temperature using SU(3) quenched lattice QCD. We find a significant thermal effects near T_c. We perform the \\chi^2 fit analyses adopting two Ansaetze for the spectral function, i.e., the conventional narrow-peak Ansatz and an advanced Breit-Wigner Ansatz. The latter is an extension of the former, taking account of the appearance of the thermal width at T>0. We also perform the MEM analysis. These analyses indicate that the thermal effect on the glueball is a significant thermal-width broadening \\Gamma(T_c) \\sim 300 MeV together with a modest reduction in the peak center \\Delta\\omega_0(T_c) \\sim 100 MeV.

Noriyoshi Ishii; Hideo Suganuma

2003-12-27T23:59:59.000Z

360

Thermal springs of Wyoming  

SciTech Connect

This bulletin attempts, first, to provide a comprehensive inventory of the thermal springs of Wyoming; second, to explore the geologic and hydrologic factors producing these springs; and, third, to analyze the springs collectively as an indicator of the geothermal resources of the state. A general discussion of the state's geology and the mechanisms of thermal spring production, along with a brief comparison of Wyoming's springs with worldwide thermal features are included. A discussion of geothermal energy resources, a guide for visitors, and an analysis of the flora of Wyoming's springs follow the spring inventory. The listing and analysis of Wyoming's thermal springs are arranged alphabetically by county. Tabulated data are given on elevation, ownership, access, water temperature, and flow rate. Each spring system is described and its history, general characteristics and uses, geology, hydrology, and chemistry are discussed. (MHR)

Breckenridge, R.M.; Hinckley, B.S.

1978-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "thermal cracking visbreaking" 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

Thermal springs of Wyoming  

DOE Green Energy (OSTI)

This bulletin attempts, first, to provide a comprehensive inventory of the thermal springs of Wyoming; second, to explore the geologic and hydrologic factors producing these springs; and, third, to analyze the springs collectively as an indicator of the geothermal resources of the state. A general discussion of the state's geology and the mechanisms of thermal spring production, along with a brief comparison of Wyoming's springs with worldwide thermal features are included. A discussion of geothermal energy resources, a guide for visitors, and an analysis of the flora of Wyoming's springs follow the spring inventory. The listing and analysis of Wyoming's thermal springs are arranged alphabetically by county. Tabulated data are given on elevation, ownership, access, water temperature, and flow rate. Each spring system is described and its history, general characteristics and uses, geology, hydrology, and chemistry are discussed. (MHR)

Breckenridge, R.M.; Hinckley, B.S.

1978-01-01T23:59:59.000Z

362

Solar Thermal Manufacturing Activities  

Reports and Publications (EIA)

This report, Solar Thermal Collector Manufacturing Activities, providesan overview and tables with historical data spanning 2000-2009. These tables willcorrespond to similar tables to be presented in the Renewable Energy Annual 2009 andare numbered accordingly.

Michele Simmons

2010-12-01T23:59:59.000Z

363

Effects of hydrogen on electropotential monitoring of stress corrosion crack growth  

DOE Green Energy (OSTI)

Electropotential monitoring (EPM) has a crack growth measurement resolution that is an order of magnitude greater than methods that rely on crack mouth opening displacement. However, two phenomena have been identified that compromise the accuracy of the EPM technique. Coolant hydrogen concentrations above those needed to chemically reduce nickel oxide to metallic nickel cause EPM to underestimate the true crack length. The metallic nickel provides an electrical conduction path at contact points across the irregular crack surface thereby lowering the EPM potential. The coolant hydrogen concentration at which this reduction occurs is temperature dependent and correlates with an abrupt decrease in the rate of SCC crack growth. It was also found that EPM can indicate large crack growth when none actually exists. At temperatures > 315 C (600 F) the electrical resistivity of mill annealed Alloy 600 increased by as much as 5% in a period of weeks or months. Each 1% increase in resistivity results in a bias in the EPM indicated cracklength of about 0.2 mm (0.008 inches). Smaller changes in the electrical resistivity of other alloys have been measured which rank as EN52> X-750> 304SS> nickel. It has been shown that these resistivity changes occur during exposure to high temperature water or inert gas. Strategies to minimize the effects of these two phenomena on EPM measurement are discussed.

Thompson, C.D.; Carey, D.M.; Perazzo, N.L.

1997-08-01T23:59:59.000Z

364

Predicting runaway reaction in a solid explosive containing a single crack  

Science Conference Proceedings (OSTI)

Mechanically damaged high explosive (HE) undergoing defiagration has recently been shown capable of generating combustion pressures and flame speeds dramatically in excess of those observed in undamaged HE. Flame penetration of HE cracks large enough to support the reaction zone serves to increase the burning surface area and the rate of gas production. Cracks confine the product gas, elevating the local pressure and reducing the reaction zone thickness such that the flame can enter smaller-width cracks. As the reaction zone decreases sufficiently to enter the smallest cracks, the flame surface area will grow appreciably, rapidly pressurizing the cracks. This runaway of pressure and burning area, termed combustion bootstrapping, can dramatically accelerate the combustion mode and in the most extreme cases may result in deflagration-to-detonation transition [3, 4]. The current study is intended to help predict the conditions required for the onset of reaction runaway in a narrow slot in HE. We review experiments [5] where flames were observed to propagate though a narrow slot (intended to simulate a well-formed crack) in high explosive at velocities up to 10 km/s, reaching pressures in excess of 1 kbar. Pressurization of the slot due to gas-dynamic choking is then used to predict the onset of runaway reaction. This model agrees with experimental pressure measurements of observed reaction runaway in slots.

Jackson, Scott I [Los Alamos National Laboratory; Hill, Larry G [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

365

Fatigue-crack propagation in aluminum-lithium alloys processed by power and ingot metallurgy  

Science Conference Proceedings (OSTI)

Fatigue-crack propagation behavior in powder-metallurgy (P/M) aluminum-lithium alloys, namely, mechanically-alloyed (MA) Al-4.0Mg-1.5Li-1.1C-0.80{sub 2} (Inco 905-XL) and rapid-solidification-processed (RSP) Al-2.6Li-1.0Cu-0.5Mg-0.5Zr (Allied 644-B) extrusions, has been studied, and results compared with data on an equivalent ingot-metallurgy (I/M) Al-Li alloy, 2090-T81 plate. Fatigue-crack growth resistance of the RSP Al-Li alloy is found to be comparable to the I/M Al-Li alloy; in contrast, crack velocities in MA 905-XL extrusions are nearly three orders of magnitude faster. Growth-rate response in both P/M Al-Li alloys, however, is high anisotropic. Results are interpreted in terms of the microstructural influence of strengthening mechanism, slip mode, grain morphology and texture on the development of crack-tip shielding from crack-path deflection and crack closure. 14 refs., 7 figs., 2 tabs.

Venkateswara Rao, K.T.; Ritchie, R.O. (Lawrence Berkeley Lab., CA (United States)); Kim, N.J. (Pohang Inst. of Science and Technology (Korea, Republic of)); Pizzo, P.P. (San Jose State Univ., CA (United States))

1990-04-01T23:59:59.000Z

366

Texas Thermal Comfort Report  

NLE Websites -- All DOE Office Websites (Extended Search)

thermal comfort thermal comfort Too often, the systems in our houses are both physically and intellectually inaccessible. In the SNAP House, HVAC components are integrated into the overall structure, and act as an experiential threshold between public and private spaces. They are located in a central, structural chase that supports the clerestory and gives the systems a functional presence within the interior. Each individual component is contained within a single chase

367

Photovoltaic-thermal collectors  

DOE Patents (OSTI)

A photovoltaic-thermal solar cell including a semiconductor body having antireflective top and bottom surfaces and coated on each said surface with a patterned electrode covering less than 10% of the surface area. A thermal-absorbing surface is spaced apart from the bottom surface of the semiconductor and a heat-exchange fluid is passed between the bottom surface and the heat-absorbing surface.

Cox, III, Charles H. (Carlisle, MA)

1984-04-24T23:59:59.000Z

368

Thermal Energy Storage  

Science Conference Proceedings (OSTI)

This Technology Brief provides an update on the current state of cool thermal energy storage systems (TES) for end-use applications. Because of its ability to shape energy use, TES is strategic technology that allows end-users to reduce their energy costs while simultaneously providing benefits for electric utilities through persistent peak demand reduction and peak shifting. In addition to discussing the concepts of thermal energy storage, the Brief discusses the current state of TES technologies and dr...

2008-12-16T23:59:59.000Z

369

Methodology for extracting local constants from petroleum cracking flows  

DOE Patents (OSTI)

A methodology provides for the extraction of local chemical kinetic model constants for use in a reacting flow computational fluid dynamics (CFD) computer code with chemical kinetic computations to optimize the operating conditions or design of the system, including retrofit design improvements to existing systems. The coupled CFD and kinetic computer code are used in combination with data obtained from a matrix of experimental tests to extract the kinetic constants. Local fluid dynamic effects are implicitly included in the extracted local kinetic constants for each particular application system to which the methodology is applied. The extracted local kinetic model constants work well over a fairly broad range of operating conditions for specific and complex reaction sets in specific and complex reactor systems. While disclosed in terms of use in a Fluid Catalytic Cracking (FCC) riser, the inventive methodology has application in virtually any reaction set to extract constants for any particular application and reaction set formulation. The methodology includes the step of: (1) selecting the test data sets for various conditions; (2) establishing the general trend of the parametric effect on the measured product yields; (3) calculating product yields for the selected test conditions using coupled computational fluid dynamics and chemical kinetics; (4) adjusting the local kinetic constants to match calculated product yields with experimental data; and (5) validating the determined set of local kinetic constants by comparing the calculated results with experimental data from additional test runs at different operating conditions.

Chang, Shen-Lin (Woodridge, IL); Lottes, Steven A. (Naperville, IL); Zhou, Chenn Q. (Munster, IN)

2000-01-01T23:59:59.000Z

370

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

Science Conference Proceedings (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

371

Thermal Performance Engineer's Handbook: Introduction to Thermal Performance  

Science Conference Proceedings (OSTI)

The two-volume Thermal Performance Engineer Handbook will assist thermal performance engineers in identifying and investigating the cause of megawatt (MWe) losses as well as in proposing new ways to increase MWe output. Volume 1 contains a thermal performance primer to provide a brief review of thermodynamic principles involved in the stream power plant thermal cycle. The primer also contains brief descriptions of the equipment and systems in the cycle that can be sources of thermal losses. Also in Volum...

1998-04-01T23:59:59.000Z

372

Thermal Management of Solar Cells  

E-Print Network (OSTI)

UNIVERSITY OF CALIFORNIA RIVERSIDE Thermal Management ofUniversity of California, Riverside Acknowledgments First, I

Saadah, Mohammed Ahmed

2013-01-01T23:59:59.000Z

373

Multilayer Nanoscale Thermal Barrier Coatings  

Science Conference Proceedings (OSTI)

Advanced high-efficiency gas turbines require thermal barrier coatings (TBCs) with low thermal conductivity and excellent thermal-cycling resistance. The multilayer TBC developed in this project has a thermal conductivity about half that of conventional TBCs and also rejects up to 70 percent of incoming radiant energy.

1999-05-26T23:59:59.000Z

374

Carbon fiber composite characterization in adverse thermal environments.  

Science Conference Proceedings (OSTI)

The behavior of carbon fiber aircraft composites was studied in adverse thermal environments. The effects of resin composition and fiber orientation were measured in two test configurations: 102 by 127 millimeter (mm) test coupons were irradiated at approximately 22.5 kW/m{sup 2} to measure thermal response, and 102 by 254 mm test coupons were irradiated at approximately 30.7 kW/m{sup 2} to characterize piloted flame spread in the vertically upward direction. Carbon-fiber composite materials with epoxy and bismaleimide resins, and uni-directional and woven fiber orientations, were tested. Bismaleimide samples produced less smoke, and were more resistant to flame spread, as expected for high temperature thermoset resins with characteristically lower heat release rates. All materials lost approximately 20-25% of their mass regardless of resin type, fiber orientation, or test configuration. Woven fiber composites displayed localized smoke jetting whereas uni-directional composites developed cracks parallel to the fibers from which smoke and flames emanated. Swelling and delamination were observed with volumetric expansion on the order of 100% to 200%. The purpose of this work was to provide validation data for SNL's foundational thermal and combustion modeling capabilities.

Gomez-Vasquez, Sylvia; Brown, Alexander L.; Hubbard, Joshua A.; Ramirez, Ciro J.; Dodd, Amanda B.

2011-05-01T23:59:59.000Z

375

MacroscoMacroscopic Cracking Determination in LaBS Glasspic Cracking Determination in LaBS Glass  

SciTech Connect

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

Marra, James

2005-08-01T23:59:59.000Z

376

The effects of prolonged thermal exposure on the fracture and fatigue behavior of aluminum-lithium alloy 8090  

Science Conference Proceedings (OSTI)

Aluminum-lithium alloys are currently being considered for applications at moderately elevated temperatures; accordingly, a study has been made on the effects of prolonged (100 and 1,000 hours overaging) thermal exposure at 149 C and 260 C on the mechanical properties of a peak-aged Al-Li-Cu-Mg-Zr alloy 8090-T8771. In the as-received T8771 temper, the alloy exhibits an excellent combination of strength ([approximately]500 MPa) and toughness (35 MPa[radical]m) with moderate tensile elongation (4 pct). Overaging at 149 C results in a [approximately]50 pct reduction in ductility and toughness, primarily associated with the growth of equilibrium phases along grain/subgrain boundaries, resulting in formation of solute-depleted precipitate-free zones and coarsening of matrix [delta][prime] and S precipitates; strength levels and fatigue-crack growth rates, however, remain largely unchanged. Thermal exposures at 260 C, conversely, lead to dramatic reductions in strength (by [approximately]50 to 80 pct), toughness (by [approximately]30 pct) and fatigue-crack propagation resistance; crack-growth rates at all [Delta]K levels above [approximately]5 MPa[radical]m are 2 to 3 orders of magnitude faster. Microstructurally, this was associated with complete dissolution of [delta][prime], severe coarsening of S and T[sub 2] precipitates in the matrix, and formation of equilibrium Cu and Mg-rich intermetallic phases in the matrix and along grain boundaries. The resulting lack of planar-slip deformation and low yield strength of 8090 following overaging exposures at 260 C increase the cumulative crack-tip damage per cycle and reduce the tendency for crack-path deflection, thereby accelerating fatigue-crack growth rates. Despite this degradation in properties, the 8090-T8771 alloy has better strength retention and generally superior fatigue-crack growth properties compared to similarly overaged Al-Li-Cu-Zr 2090 and Al-Cu-Zn-Mg 7,150 alloys.

Venkateswara Rao, K.T.; Ritchie, R.O. (Univ. of California, Berkeley, CA (United States)); McNulty, J.C. (Univ. of California, Santa Barbara (United States). Materials Dept.)

1993-10-01T23:59:59.000Z

377

Article for thermal energy storage  

DOE Patents (OSTI)

A thermal energy storage composition is provided which is in the form of a gel. The composition includes a phase change material and silica particles, where the phase change material may comprise a linear alkyl hydrocarbon, water/urea, or water. The thermal energy storage composition has a high thermal conductivity, high thermal energy storage, and may be used in a variety of applications such as in thermal shipping containers and gel packs.

Salyer, Ival O. (Dayton, OH)

2000-06-27T23:59:59.000Z

378

Solar-thermal technology  

DOE Green Energy (OSTI)

Solar-thermal technology converts sunlight into thermal energy. It stands alongside other solar technologies including solar-electric and photovoltaic technologies, both of which convert sunlight into electricity. Photovoltaic technology converts by direct conversion, and solar-electric converts by using sunlight`s thermal energy in thermodynamic power cycles. The numerous up-and-running solar energy systems prove solar-thermal technology works. But when is it cost-effective, and how can HVAC engineers and facility owners quickly identify cost-effective applications? This article addresses these questions by guiding the reader through the basics of solar-thermal technology. The first section provides an overview of today`s technology including discussions of collectors and typical systems. The next section presents an easy method for identifying potentially cost-effective applications. This section also identifies sources for obtaining more information on the technology--collector ratings and performance, solar manufacturers, and solar design and analysis tools. The article discusses only those collectors and systems that are most often used. Many others are on the market--the article does not, by omission, mean to infer that one is better than the other.

Bennett, C. [Sandia National Labs., Albuquerque, NM (United States)

1995-09-01T23:59:59.000Z

379

Welding and Repair Technology Center: Evaluation of High-Chromium Nickel-Base Welding Alloys, Resistance to Solidification Cracking - Update  

Science Conference Proceedings (OSTI)

One of the challenges faced by nuclear power industry engineers and managers responsible for making welding and repair decisions is selection of weld metals that have adequate resistance to stress corrosion cracking (SCC) with acceptable resistance to other forms of cracking. Continued testing and evaluation of new and enhanced high-chromium nickel-base filler metals is important to understanding the influence of slight composition changes on sensitivity to known cracking mechanisms and general ...

2013-08-14T23:59:59.000Z

380

Resistance of Alloy 600 and Alloy 690 Tubing to Stress Corrosion Cracking in Environments With and Without Lead  

Science Conference Proceedings (OSTI)

Recent examinations of degraded steam generator tubes pulled from several plants suggest possible lead (Pb) involvement in intergranular attack/stress corrosion cracking (IGA/SCC). EPRI sponsored this research program to determine the factors influencing lead stress corrosion cracking (PbSCC) in Alloy 600 and Alloy 690 steam generator tubes. The most severe cracking condition occurred at the open circuit corrosion potential, contrary to previous testing results. A film rupture/anodic dissolution model, w...

2004-06-07T23:59:59.000Z

Note: This page contains sample records for the topic "thermal cracking visbreaking" 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

Summary of Analytical Electron Microscopy Observation of Intergranular Attack and Stress Corrosion Cracks in Alloy 600 Steam Generator Tubing  

Science Conference Proceedings (OSTI)

High-resolution analytical transmission electron microscopy (ATEM) can identify structures and compositions of corrosion products in attacked boundaries, cracks, and crack tips to help assess impurities that promote intergranular degradation. ATEM analyses has recently been performed on samples from Watts Bar 1 and Diablo Canyon 2 steam generator (SG) tubing and has revealed that lead (Pb) was involved in intergranular stress corrosion cracking (IGSCC). These new results in combination with previous resu...

2005-04-29T23:59:59.000Z

382

The effect of water flow rate upon the environmentally-assisted cracking response of a low-alloy steel  

SciTech Connect

Effect of water flow rate on the environmentally-assisted cracking (EAC) response of a high-sulfur ferritic steel was studied at 243C. In contrast to earlier studies with compact-type specimens, this study employed relatively large tight semi-elliptical surface cracks tested under generally linear-elastic conditions. Flow velocities parallel to the crack as low as 1.68 {minus} 1.84 m/s were effective in mitigating EAC.

James, L.A.; Wire, G.L. [Westinghouse Electric Corp., West Mifflin, PA (United States). Bettis Atomic Power Lab.; Cullen, W.H. [Materials Engineering Associates, Lanham, MD (United States)

1994-09-01T23:59:59.000Z

383

Thermal insulated glazing unit  

SciTech Connect

An improved insulated glazing unit is provided which can attain about R5 to about R10 thermal performance at the center of the glass while having dimensions about the same as those of a conventional double glazed insulated glazing unit. An outer glazing and inner glazing are sealed to a spacer to form a gas impermeable space. One or more rigid, non-structural glazings are attached to the inside of the spacer to divide the space between the inner and outer glazings to provide insulating gaps between glazings of from about 0.20 inches to about 0.40 inches. One or more glazing surfaces facing each thermal gap are coated with a low emissivity coating. Finally, the thermal gaps are filled with a low conductance gas such as krypton gas.

Selkowitz, Stephen E. (Piedmont, CA); Arasteh, Dariush K. (Oakland, CA); Hartmann, John L. (Seattle, WA)

1991-01-01T23:59:59.000Z

384

THERMAL NEUTRON BACKSCATTER IMAGING.  

DOE Green Energy (OSTI)

Objects of various shapes, with some appreciable hydrogen content, were exposed to fast neutrons from a pulsed D-T generator, resulting in a partially-moderated spectrum of backscattered neutrons. The thermal component of the backscatter was used to form images of the objects by means of a coded aperture thermal neutron imaging system. Timing signals from the neutron generator were used to gate the detection system so as to record only events consistent with thermal neutrons traveling the distance between the target and the detector. It was shown that this time-of-flight method provided a significant improvement in image contrast compared to counting all events detected by the position-sensitive {sup 3}He proportional chamber used in the imager. The technique may have application in the detection and shape-determination of land mines, particularly non-metallic types.

VANIER,P.; FORMAN,L.; HUNTER,S.; HARRIS,E.; SMITH,G.

2004-10-16T23:59:59.000Z

385

Thermal insulated glazing unit  

DOE Patents (OSTI)

An improved insulated glazing unit is provided which can attain about R5 to about R10 thermal performance at the center of the glass while having dimensions about the same as those of a conventional double glazed insulated glazing unit. An outer glazing and inner glazing are sealed to a spacer to form a gas impermeable space. One or more rigid, non-structural glazings are attached to the inside of the spacer to divide the space between the inner and outer glazings to provide insulating gaps between glazings of from about 0.20 inches to about 0.40 inches. One or more glazing surfaces facing each thermal gap are coated with a low emissivity coating. Finally, the thermal gaps are filled with a low conductance gas such as krypton gas. 2 figs.

Selkowitz, S.E.; Arasteh, D.K.; Hartmann, J.L.

1988-04-05T23:59:59.000Z

386

Environmentally assisted cracking of nickel anode substrates in Li/SOCl{sub 2} cells: An engineering approach  

DOE Green Energy (OSTI)

Intergranular environmentally assisted cracking (EAC) of Ni anode substrates is likely to occur in a large proportion of Li/SOCl{sub 2} cells, but it is not generally detected because in the majority of cases it does not lead to catatrophic failure. However, EAC could become a problem for applications requiring continuous power with high reliability for 10--15 years. In the present work, we determine why simple galvanic couple constant-strain tests do not produce cracking, and introduce a constant strain test that does produce cracking. Objective of this investigation is to determine the stress threshold for cracking as a function of Ni composition and microstructure.

Cieslak, W.R.; Weigand, D.E.; Buchheit, R.G.

1993-06-01T23:59:59.000Z

387

Hydrodesulfurization of Fluid Catalytic Cracking Decant Oils for the Production of Low-sulfur Needle Coke Feedstocks.  

E-Print Network (OSTI)

??Needle coke, produced by the delayed coking of fluid catalytic cracking decant oils, is the primary filler used in the production of graphite electrodes. The (more)

Wincek, Ronald

2013-01-01T23:59:59.000Z

388

Thermal energy storage material  

DOE Patents (OSTI)

A thermal energy storage material which is stable at atmospheric temperature and pressure and has a melting point higher than 32.degree.F. is prepared by dissolving a specific class of clathrate forming compounds, such as tetra n-propyl or tetra n-butyl ammonium fluoride, in water to form a substantially solid clathrate. The resultant thermal energy storage material is capable of absorbing heat from or releasing heat to a given region as it transforms between solid and liquid states in response to temperature changes in the region above and below its melting point.

Leifer, Leslie (Hancock, MI)

1976-01-01T23:59:59.000Z

389

Thermal test options  

SciTech Connect

Shipping containers for radioactive materials must be qualified to meet a thermal accident environment specified in regulations, such at Title 10, Code of Federal Regulations, Part 71. Aimed primarily at the shipping container design, this report discusses the thermal testing options available for meeting the regulatory requirements, and states the advantages and disadvantages of each approach. The principal options considered are testing with radiant heat, furnaces, and open pool fires. The report also identifies some of the facilities available and current contacts. Finally, the report makes some recommendations on the appropriate use of these different testing methods.

Koski, J.A.; Keltner, N.R.; Sobolik, K.B.

1993-02-01T23:59:59.000Z

390

Thermal ignition combustion system  

DOE Patents (OSTI)

The thermal ignition combustion system comprises means for providing walls defining an ignition chamber, the walls being made of a material having a thermal conductivity greater than 20 W/m C and a specific heat greater than 480 J/kg C with the ignition chamber being in constant communication with the main combustion chamber, means for maintaining the temperature of the walls above a threshold temperature capable of causing ignition of a fuel, and means for conducting fuel to the ignition chamber. 8 figs.

Kamo, R.; Kakwani, R.M.; Valdmanis, E.; Woods, M.E.

1988-04-19T23:59:59.000Z

391

Thermal Insulation Systems  

E-Print Network (OSTI)

Thermal insulation systems are receiving a high degree of attention in view of increasing energy cost. Industrial, commercial and residential energy users are all well aware of energy cost increases and great emphasis is being directed to energy cost reduction programs. One of the best places to start with energy conservation is to employ proper insulation systems. This article discusses the significant properties of thermal insulation materials primarily for industrial application. Some of the information is applicable to commercial and residential insulation. Only hot service conditions will be covered.

Stanley, T. F.

1982-01-01T23:59:59.000Z

392

Simulation and Experiment of Thermal Fatigue in the CPV Die Attach: Preprint  

DOE Green Energy (OSTI)

FEM simulation and accelerated thermal cycling have been performed for the CPV die attach. Trends in fatigue damage accumulation and equivalent test time are explored and found to be most sensitive to temperature ramp rate. Die attach crack growth is measured through cycling and found to be in excellent agreement with simulations of the inelastic strain energy accumulated. Simulations of an entire year of weather data provides for the relative ranking of fatigue damage between four cites as well as their equivalent accelerated test time.

Bosco, N.; Silverman, T.; Kurtz, S.

2012-05-01T23:59:59.000Z

393

R-curve and subcritical crack growth behavior at elevated temperatures in coarse grain alumina  

SciTech Connect

The effect of temperature and subcritical crack growth on the R-curve of a 99.5% purity coarse grained alumina was studied using chevron-notched, short-bar specimens. Constant loading rate tests were used to measure toughness as a function of crack length and static load tests were used to measure subcritical crack growth as a function of time. It was found that the intrinsic toughness decreased monotonically from 20 to 1200 C while the bridging contribution to the R-curve remained relatively constant over this temperature range. The constant load tests at 700, 1000 and 1200 C showed that substantial subcritical crack growth occurs under static loading. Using the subcritical crack growth parameters derived from these static load tests, the effect of loading rate on R-curve measurement was predicted and compared to experiment. The predicted decrease in the magnitude of the R-curve with a decrease in over five orders of magnitude in loading rate was relatively small compared to experimental scatter.

Webb, J.E.; Jakus, K.; Ritter, J.E. [Univ. of Massachusetts, Amherst, MA (United States). Dept. of Mechanical Engineering

1996-06-01T23:59:59.000Z

394

Cracking of simulated oil refinery off-gas over a coal char, petroleum coke, and quartz  

Science Conference Proceedings (OSTI)

The cracking of oil refinery off-gas, simulated with a gas mixture containing methane (51%), ethylene (21.4%), ethane (21.1%), and propane (6.5%), over a coal char, petroleum coke, and quartz, respectively, has been studied in a fixed bed reactor. The experiments were performed at temperatures between 850 and 1000{sup o}C and at atmospheric pressure. The results show that the conversions of all species considered increased with increasing temperature. Ethane and propane completely decomposed over all three bed materials in the temperature range investigated. However, the higher initial conversion rates of methane and ethylene cracking at all temperatures were observed only over the coal char and not on the petroleum coke and quartz, indicating a significant catalytic effect of the coal char on methane and ethylene cracking. Methane and ethylene conversions decreased with reaction time due to deactivation of the coal char by carbon deposition on the char surface and, in the later stage of a cracking experiment, became negative, suggesting that methane and ethylene had been formed during the cracking of ethane and propane. 16 refs., 13 figs., 2 tabs.

Yuan Zhang; Jin-hu Wu; Dong-ke Zhang [Chinese Academy of Sciences, Taiyuan (China). Institute of Coal Chemistry

2008-03-15T23:59:59.000Z

395

Acoustic Emission and Guided Wave Monitoring of Fatigue Crack Growth on a Full Pipe Specimen  

Science Conference Proceedings (OSTI)

Continuous on-line monitoring of active and passive systems, structures and components in nuclear power plants will be critical to extending the lifetimes of nuclear power plants in the US beyond 60 years. Acoustic emission and guided ultrasonic waves are two tools for continuously monitoring passive systems, structures and components within nuclear power plants and are the focus of this study. These tools are used to monitor fatigue damage induced in a SA 312 TP304 stainless steel pipe specimen. The results of acoustic emission monitoring indicate that crack propagation signals were not directly detected. However, acoustic emission monitoring exposed crack formation prior to visual confirmation through the detection of signals caused by crack closure friction. The results of guided ultrasonic wave monitoring indicate that this technology is sensitive to the presence and size of cracks. The sensitivity and complexity of GUW signals is observed to vary with respect to signal frequency and path traveled by the guided ultrasonic wave relative to the crack orientation.

Meyer, Ryan M.; Cumblidge, Stephen E.; Ramuhalli, Pradeep; Watson, Bruce E.; Doctor, Steven R.; Bond, Leonard J.

2011-05-06T23:59:59.000Z

396

Solar thermal financing guidebook  

DOE Green Energy (OSTI)

This guidebook contains information on alternative financing methods that could be used to develop solar thermal systems. The financing arrangements discussed include several lease alternatives, joint venture financing, R and D partnerships, industrial revenue bonds, and ordinary sales. In many situations, alternative financing arrangements can significantly enhance the economic attractiveness of solar thermal investments by providing a means to efficiently allocate elements of risk, return on investment, required capital investment, and tax benefits. A net present value approach is an appropriate method that can be used to investigate the economic attractiveness of alternative financing methods. Although other methods are applicable, the net present value approach has advantages of accounting for the time value of money, yielding a single valued solution to the financial analysis, focusing attention on the opportunity cost of capital, and being a commonly understood concept that is relatively simple to apply. A personal computer model for quickly assessing the present value of investments in solar thermal plants with alternative financing methods is presented in this guidebook. General types of financing arrangements that may be desirable for an individual can be chosen based on an assessment of his goals in investing in solar thermal systems and knowledge of the individual's tax situation. Once general financing arrangements have been selected, a screening analysis can quickly determine if the solar investment is worthy of detailed study.

Williams, T.A.; Cole, R.J.; Brown, D.R.; Dirks, J.A.; Edelhertz, H.; Holmlund, I.; Malhotra, S.; Smith, S.A.; Sommers, P.; Willke, T.L.

1983-05-01T23:59:59.000Z

397

Thermal Reactor Safety  

Science Conference Proceedings (OSTI)

Information is presented concerning fire risk and protection; transient thermal-hydraulic analysis and experiments; class 9 accidents and containment; diagnostics and in-service inspection; risk and cost comparison of alternative electric energy sources; fuel behavior and experiments on core cooling in LOCAs; reactor event reporting analysis; equipment qualification; post facts analysis of the TMI-2 accident; and computational methods.

Not Available

1980-06-01T23:59:59.000Z

398

Thermal barrier coating  

SciTech Connect

A thermal barrier coating for hot gas path components of a combustion turbine based on a zirconia-scandia system. A layer of zirconium scandate having the hexagonal Zr.sub.3 Sc.sub.4 O.sub.12 structure is formed directly on a superalloy substrate or on a bond coat formed on the substrate.

Bowker, Jeffrey Charles (Gibsonia, PA); Sabol, Stephen M. (Orlando, FL); Goedjen, John G. (Oviedo, FL)

2001-01-01T23:59:59.000Z

399

Cylindrical thermal contact conductance  

E-Print Network (OSTI)

Thermal contact conductance is highly important in a wide variety of applications, from the cooling of electronic chips to the thermal management of spacecraft. The demand for increased efficiency means that components need to withstand higher temperatures and heat transfer rates. Many situations call for contact heat transfer through nominally cylindrical interfaces, yet relatively few studies of contact conductance through cylindrical interfaces have been undertaken. This study presents a review of the experimental and theoretical investigations of the heat transfer characteristics of composite cylinders, presenting data available in open literature in comparison with relevant correlations. The present investigation presents a study of the thermal contact conductance of cylindrical interfaces. The experimental investigation of sixteen different material combinations offers an opportunity to develop predictive correlations of the contact conductance, in conjunction with an analysis of the interface pressure as a function of the thermal state of the individual cylindrical shells. Experimental results of the present study are compared with previously published conductance data and conductance models.

Ayers, George Harold

2003-08-01T23:59:59.000Z

400

The thermal conductivity of rock under hydrothermal conditions: measurements and applications  

SciTech Connect

The thermal conductivities of most major rock-forming minerals vary with both temperature and confining pressure, leading to substantial changes in the thermal properties of some rocks at the high temperatures characteristic of geothermal systems. In areas with large geothermal gradients, the successful use of near-surface heat flow measurements to predict temperatures at depth depends upon accurate corrections for varying thermal conductivity. Previous measurements of the thermal conductivity of dry rock samples as a function of temperature were inadequate for porous rocks and susceptible to thermal cracking effects in nonporous rocks. We have developed an instrument for measuring the thermal conductivity of water-saturated rocks at temperatures from 20 to 350 C and confining pressures up to 100 MPa. A transient line-source of heat is applied through a needle probe centered within the rock sample, which in turn is enclosed within a heated pressure vessel with independent controls on pore and confining pressure. Application of this technique to samples of Franciscan graywacke from The Geysers reveals a significant change in thermal conductivity with temperature. At reservoir-equivalent temperatures of 250 C, the conductivity of the graywacke decreases by approximately 25% relative to the room temperature value. Where heat flow is constant with depth within the caprock overlying the reservoir, this reduction in conductivity with temperature leads to a corresponding increase in the geothermal gradient. Consequently, reservoir temperature are encountered at depths significantly shallower than those predicted by assuming a constant temperature gradient with depth. We have derived general equations for estimating the thermal conductivity of most metamorphic and igneous rocks and some sedimentary rocks at elevated temperature from knowledge of the room temperature thermal conductivity. Application of these equations to geothermal exploration should improve estimates of subsurface temperatures derived from heat flow measurements.

Williams, Colin F.; Sass, John H.

1996-01-24T23:59:59.000Z

Note: This page contains sample records for the topic "thermal cracking visbreaking" 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

Preliminary requirements for thermal storage subsystems in solar thermal applications  

DOE Green Energy (OSTI)

Methodologies for the analysis of value and comparing thermal storage concepts are presented. Value is a measure of worth and is determined by the cost of conventional fuel systems. Value data for thermal storage in large solar thermal electric power applications are presented. Thermal storage concepts must be compared when all are performing the same mission. A method for doing that analysis, called the ranking index, is derived. Necessary data to use the methodology are included.

Copeland, R.J.

1980-04-01T23:59:59.000Z

402

Supercomputers Crack Sixty-Trillionth Binary Digit of Pi-Squared |  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Supercomputers Crack Sixty-Trillionth Binary Digit of Pi-Squared Supercomputers Crack Sixty-Trillionth Binary Digit of Pi-Squared Supercomputers Crack Sixty-Trillionth Binary Digit of Pi-Squared April 28, 2011 - 11:28am Addthis David H. Bailey | Photo Courtesy of Lawrence Berkely National Lab David H. Bailey | Photo Courtesy of Lawrence Berkely National Lab Linda Vu What are the key facts? Australian researchers have found the sixty-trillionth binary digit of Pi-squared. The calculation would have taken a single computer processor unit (CPU) 1,500 years to calculate, but it took just a few months on IBM's "BlueGene/P" supercomputer, which is designed to run continuously at one quadrillion calculations per second. Pi is one of the most mysterious numbers in mathematics and can never be expressed as a finite decimal number -- humanity will never have

403

Diffraction coefficients of a semi-infinite planar crack embedded in a transversely-isotropic space  

E-Print Network (OSTI)

We have considered a semi-infinite crack embedded in a transversely isotropic medium and studied two special cases, one, in which the axis of symmetry is normal to the crack face and the wave incidence is arbitrary and another, in which the axis lies in the crack plane normal to the edge and the incident wave vector is also normal to the edge. The problem is of interest in Non-Destructive Evaluation, because austenitic steels that are found in claddings and other welds in the nuclear reactors are often modeled as transversely isotropic. In both of cases, we have expressed the scattered field in a closed form and computed the corresponding diffraction coefficients.

A. Gautesen; V. Zernov; L. Fradkin

2008-02-04T23:59:59.000Z

404

A Review of Stress Corrosion Cracking/Fatigue Modeling for Light Water  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

A Review of Stress Corrosion Cracking/Fatigue Modeling for Light A Review of Stress Corrosion Cracking/Fatigue Modeling for Light Water Reactor Cooling System Components A Review of Stress Corrosion Cracking/Fatigue Modeling for Light Water Reactor Cooling System Components In the United States currently there are approximately 104 operating light water reactors. Of these, 69 are pressurized water reactors (PWRs) and 35 are boiling water reactors (BWRs). In 2007, the 104 light-water reactors (LWRs) in the United States generated approximately 100 GWe, equivalent to 20% of total US electricity production. Most of the US reactors were built before 1970 and the initial design lives of most of the reactors are 40 years. It is expected that by 2030, even those reactors that have received 20-year life extension license from the US Nuclear Regulatory Commission

405

Physics-Based Stress Corrosion Cracking Component Reliability Model cast in  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Physics-Based Stress Corrosion Cracking Component Reliability Model Physics-Based Stress Corrosion Cracking Component Reliability Model cast in an R7-Compatible Cumulative Damage Framework Physics-Based Stress Corrosion Cracking Component Reliability Model cast in an R7-Compatible Cumulative Damage Framework The Risk-Informed Safety Margin Characterization (RISMC) pathway is a set of activities defined under the U.S. Department of Energy Light Water Reactor Sustainability Program. The overarching objective of RISMC is to support plant life-extension decision-making by providing a state-of-knowledge characterization of safety margins in key systems, structures, and components (SSCs). The methodology emerging from the RISMC pathway is not a conventional probabilistic risk assessment (PRA)-based one; rather, it relies on a reactor systems simulation framework in which

406

Physics-Based Stress Corrosion Cracking Component Reliability Model cast in  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Physics-Based Stress Corrosion Cracking Component Reliability Model Physics-Based Stress Corrosion Cracking Component Reliability Model cast in an R7-Compatible Cumulative Damage Framework Physics-Based Stress Corrosion Cracking Component Reliability Model cast in an R7-Compatible Cumulative Damage Framework The Risk-Informed Safety Margin Characterization (RISMC) pathway is a set of activities defined under the U.S. Department of Energy Light Water Reactor Sustainability Program. The overarching objective of RISMC is to support plant life-extension decision-making by providing a state-of-knowledge characterization of safety margins in key systems, structures, and components (SSCs). The methodology emerging from the RISMC pathway is not a conventional probabilistic risk assessment (PRA)-based one; rather, it relies on a reactor systems simulation framework in which

407

Cracking Molecular Structures with Bright Lights - and a Few Good Eggs |  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Cracking Molecular Structures with Bright Lights - and a Few Good Cracking Molecular Structures with Bright Lights - and a Few Good Eggs Cracking Molecular Structures with Bright Lights - and a Few Good Eggs June 22, 2012 - 11:04am Addthis This rendering shows a lysozyme structural model against its X-ray diffraction pattern from SLAC’s Linac Coherent Light Source (LCLS), a powerful X-ray laser facility. Researchers have achieved high-resolution images of these simple biomolecules using advanced crystallography at LCLS. | Photo by Anton Barty/DESY This rendering shows a lysozyme structural model against its X-ray diffraction pattern from SLAC's Linac Coherent Light Source (LCLS), a powerful X-ray laser facility. Researchers have achieved high-resolution images of these simple biomolecules using advanced crystallography at LCLS.

408

A STUDY OF CORROSION AND STRESS CORROSION CRACKING OF CARBON STEEL NUCLEAR WASTE STORAGE TANKS  

SciTech Connect

The Hanford reservation Tank Farms in Washington State has 177 underground storage tanks that contain approximately 50 million gallons of liquid legacy radioactive waste from cold war plutonium production. These tanks will continue to store waste until it is treated and disposed. These nuclear wastes were converted to highly alkaline pH wastes to protect the carbon steel storage tanks from corrosion. However, the carbon steel is still susceptible to localized corrosion and stress corrosion cracking. The waste chemistry varies from tank to tank, and contains various combinations of hydroxide, nitrate, nitrite, chloride, carbonate, aluminate and other species. The effect of each of these species and any synergistic effects on localized corrosion and stress corrosion cracking of carbon steel have been investigated with electrochemical polarization, slow strain rate, and crack growth rate testing. The effect of solution chemistry, pH, temperature and applied potential are all considered and their role in the corrosion behavior will be discussed.

BOOMER, K.D.

2007-08-21T23:59:59.000Z

409

Method for cracking hydrocarbon compositions using a submerged reactive plasma system  

DOE Patents (OSTI)

A method for cracking a liquid hydrocarbon composition (e.g. crude oil) to produce a cracked hydrocarbon product. A liquid hydrocarbon composition is initially provided. An electrical arc is generated directly within the hydrocarbon composition so that the arc is entirely submerged in the composition. Arc generation is preferably accomplished using a primary and secondary electrode each having a first end submerged in the composition. The first ends of the electrodes are separated from each other to form a gap therebetween. An electrical potential is then applied to the electrodes to generate the arc within the gap. A reactive gas is thereafter delivered to the arc which forms a bubble around the arc. Gas delivery may be accomplished by providing a passageway through each electrode and delivering the gas through the passageways. The arc and gas cooperate to produce a plasma which efficiently cracks the hydrocarbon composition.

Kong, Peter C. (Idaho Falls, ID)

1997-01-01T23:59:59.000Z

410

Method for cracking hydrocarbon compositions using a submerged reactive plasma system  

DOE Patents (OSTI)

A method is described for cracking a liquid hydrocarbon composition (e.g. crude oil) to produce a cracked hydrocarbon product. A liquid hydrocarbon composition is initially provided. An electrical arc is generated directly within the hydrocarbon composition so that the arc is entirely submerged in the composition. Arc generation is preferably accomplished using a primary and secondary electrode each having a first end submerged in the composition. The first ends of the electrodes are separated from each other to form a gap there between. An electrical potential is then applied to the electrodes to generate the arc within the gap. A reactive gas is thereafter delivered to the arc which forms a bubble around the arc. Gas delivery may be accomplished by providing a passageway through each electrode and delivering the gas through the passageways. The arc and gas cooperate to produce a plasma which efficiently cracks the hydrocarbon composition. 6 figs.

Kong, P.C.

1997-05-06T23:59:59.000Z

411

Method and apparatus for detecting external cracks from within a metal tube  

DOE Patents (OSTI)

A method and tool using a continuous electromagnetic wave from a transverse magnetic-dipole source with a coaxial electric-dipole receiver is described for the detection of external sidewall cracks and other anomalies in boiler tubes and other enclosures. The invention utilizes the concept of radar backscatter rather than eddy-currents or ultrasound, which are sometimes used in prior art crack-detection methods. A numerical study of the distribution of the fields shows that the direct transmission from the source to the receiver is reduced from that in free space. Further, if the diameter of the receiver dipole is made sufficiently small, it should be possible to detect cracks with a scattering loss of up to -40 dB in thin-walled boiler tubes.

Caffey, Thurlow W. H. (Albuquerque, NM)

2001-08-07T23:59:59.000Z

412

Evaluation of cracking in the 241-AZ tank farm ventilation line at the Hanford Site  

Science Conference Proceedings (OSTI)

In the period from April to October of 1988, a series of welding operations on the outside of the AZ Tank Farm ventilation line piping at the Hanford Site produced unexpected and repeated cracking of the austenitic stainless steel base metal and of a seam weld in the pipe. The ventilation line is fabricated from type 304L stainless steel pipe of 24 inch diameter and 0.25 inch wall thickness. The pipe was wrapped in polyethylene bubble wrap and buried approximately 12 feet below grade. Except for the time period between 1980 and 1987, impressed current cathodic protection has been applied to the pipe since its installation in 1974. The paper describes the history of the cracking of the pipe, the probable cracking mechanisms, and the recommended future action for repair/replacement of the pipe.

ANANTATMULA, R.P.

1999-10-20T23:59:59.000Z

413

Steam Generator Management Program: Thermal-Hydraulic and Flow-Induced Vibration Analyses of a Representative Model F Steam Generato r  

Science Conference Proceedings (OSTI)

During the Fall 2006 refueling outage of Vogtle 1, circumferential outside-diameter stress corrosion cracking (ODSCC) indications were observed in Model F steam generator tubes on the hot leg near the top of the tubesheet at low-row number, high-column number tubes. Additional ODSCC indications were observed in the same region during the Spring 2008 outage. All tubes with cracklike indications were plugged and stabilized. This report summarizes the comprehensive thermal-hydraulic and flow-induced vibrati...

2009-06-25T23:59:59.000Z

414

A computational study of ethane cracking in cluster models of zeolite H-ZSM-5.  

DOE Green Energy (OSTI)

Protolytic cracking of ethane by zeolites has been studied using quantum-chemical techniques and a cluster model of the zeolite Broensted acid site. Previous computational studies have utilized small cluster models and have not accounted for the long-range effects of the zeolite lattice. These studies have found reaction barriers for cracking which are significantly higher than experimental values. In this work we used a larger zeolite cluster model containing five tetrahedral (Si, Al) atoms (denoted 5T) and searched for stationary points along one possible reaction path for cracking at the HF/6-31 G(d) level of theory. This path involves a multi-step cracking reaction, in which the proton is first transferred from the acid site to the adsorbed ethane molecule to form an ion-pair equilibrium complex. Subsequently the proton attacks the C-C bond to complete the cracking process. The activation barrier for cracking was calculated, including corrections for (i) vibrational energies at the experimental reaction temperature of 773 K; (ii) electron correlation and an extended basis set at the B3LYP/6-311+G(3df,2p) level; and (iii) the influence of the surrounding zeolite lattice in H-ZSM-5. The barrier we obtain, 53 {+-} 5 kcal/mol, is significantly smaller than previous theoretical results and is in good agreement with typical experimental values for small hydrocarbons. Work is currently in progress to extend this study by carrying out geometry optimization of these complexes using the B3LYP method of density functional theory.

Zygmunt, S. A.

1998-08-21T23:59:59.000Z

415

National Solar Thermal Test Facility  

SciTech Connect

This is a brief report about a Sandia National Laboratory facility which can provide high-thermal flux for simulation of nuclear thermal flash, measurements of the effects of aerodynamic heating on radar transmission, etc

Cameron, C.P.

1989-12-31T23:59:59.000Z

416

AQUIFER THERMAL ENERGY STORAGE-A SURVEY  

E-Print Network (OSTI)

High temperature underground thermal energy storage, inProceedings, Thermal Energy Storage in Aquifers Workshop:underground thermal energy storage, in ATES newsletter:

Tsang, Chin Fu

2012-01-01T23:59:59.000Z

417

Thermal Transport in Graphene Multilayers and Nanoribbons  

E-Print Network (OSTI)

1 CHAPTER 2 Thermal transport atvalues of graphenes thermal conductivity and different1 Thermal conductivity : metals and non - metallic

Subrina, Samia

2011-01-01T23:59:59.000Z

418

Modeling thermal comfort in stratified environments  

E-Print Network (OSTI)

Arens E. , and Wang D. 2004. "Thermal sensation and comfortin transient non-uniform thermal environments", European7730, 1994, Moderate Thermal Environments Determination of

Zhang, H.; Huizenga, C.; Arens, Edward A; Yu, T.

2005-01-01T23:59:59.000Z

419

Thermal Conduction in Graphene and Graphene Multilayers  

E-Print Network (OSTI)

1 1.2 Thermal transport atxv Introduction xii 1.1 Thermal conductivity and65 4.13 Thermal conductivity of graphene as a function of

Ghosh, Suchismita

2009-01-01T23:59:59.000Z

420

Indoor Thermal Comfort, an Evolutionary Biology Perspective  

E-Print Network (OSTI)

ASHRAE Standard 55-2004: Thermal environmental conditionsA behavioural approach to thermal comfort assessment inBerger, X. , 1998. Human thermal comfort at Nimes in summer

Stoops, John L.

2006-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "thermal cracking visbreaking" 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

AQUIFER THERMAL ENERGY STORAGE-A SURVEY  

E-Print Network (OSTI)

1978, High temperature underground thermal energy storage,in Proceedings, Thermal Energy Storage in Aquifers Workshop:High temperature underground thermal energy storage, in ATES

Tsang, Chin Fu

2012-01-01T23:59:59.000Z

422

THERMAL ENERGY STORAGE IN AQUIFERS WORKSHOP  

E-Print Network (OSTI)

B. Quale. Seasonal storage of thermal energy in water in theand J. Schwarz, Survey of Thermal Energy Storage in AquifersSecond Annual Thermal Energy Storage Contractors'

Authors, Various

2011-01-01T23:59:59.000Z

423

Year/PAD District Distillation Crude Oil Atmospheric Distillation  

U.S. Energy Information Administration (EIA) Indexed Site

Distillation Crude Oil Atmospheric Distillation Vacuum Cracking Thermal Catalytic Cracking Fresh Recycled Catalytic Hydro- Cracking Catalytic Reforming Desulfurization...

424

Effects of neutron irradiation on fatigue and creep-fatigue crack propagation in type 316 stainless steel at 649 degree C produced no significant effect on the crack propagation rate when compared with unirradiated steel tested at 649 degree C  

Science Conference Proceedings (OSTI)

The fatigue and creep-fatigue crack propagation performance of Type 316 stainless steel has been investigated following fast neutron (n) irradiation. The purpose was to evaluate the effects of neutron fluence and temperature on the crack propagation resistance and failure mode of the steel. Results are presented from fatigue tests of the annealed steel that were irradiated at 649 degree C Scanning electron microscope examination of the fracture surfaces of the tested specimens revealed that the failure mode of the specimens which exhibited increased crack propagation rates was primarily intergranular while a transgranular mode was observed for specimens with lower crack propagation rates. The results point toward a synergistic relationship between thermomechanical history, precipitate formation, and hold time effects as the responsible mechanism for the crack propagation performance.

Michel, D.J.; Smith, H.H.

1981-01-01T23:59:59.000Z

425

Imprinting the memory into paste and its visualization as crack patterns in drying process  

E-Print Network (OSTI)

In the drying process of paste, we can imprint into the paste the order how it should be broken in the future. That is, if we vibrate the paste before it is dried, it remembers the direction of the initial external vibration, and the morphology of resultant crack patterns is determined solely by the memory of the direction. The morphological phase diagram of crack patterns and the rheological measurement of the paste show that this memory effect is induced by the plasticity of paste.

Akio Nakahara; Yousuke Matsuo

2005-01-19T23:59:59.000Z

426

THERMAL INSULATION MATERIALS TEST METHOD ...  

Science Conference Proceedings (OSTI)

... _____ 01/W01 CAN/CGSB-51.2-M88 Thermal Insulation, Calcium Silicate, for Piping, Machinery and Boilers _____ ...

2012-05-22T23:59:59.000Z

427

Liquid metal thermal electric converter  

DOE Patents (OSTI)

A liquid metal thermal electric converter which converts heat energy to electrical energy. The design of the liquid metal thermal electric converter incorporates a unique configuration which directs the metal fluid pressure to the outside of the tube which results in the structural loads in the tube to be compressive. A liquid metal thermal electric converter refluxing boiler with series connection of tubes and a multiple cell liquid metal thermal electric converter are also provided.

Abbin, Joseph P. (Albuquerque, NM); Andraka, Charles E. (Albuquerque, NM); Lukens, Laurance L. (Albuquerque, NM); Moreno, James B. (Albuquerque, NM)

1989-01-01T23:59:59.000Z

428

NVLAP Thermal Insulation Materials LAP  

Science Conference Proceedings (OSTI)

... for thermal insulation materials. The final report for Round 31 was released in February 2010. Proficiency testing is on hold ...

2013-07-18T23:59:59.000Z

429

Prediction of Failure Due to Thermal Aging, Corrosion and Environmental Fracture in Amorphous and Titanium Alloys  

DOE Green Energy (OSTI)

DARPA is exploring a number of advanced materials for military applications, including amorphous metals and titanium-based alloys. Equipment made from these materials can undergo degradation due to thermal aging, uniform corrosion, pitting, crevice corrosion, denting, stress corrosion cracking, corrosion fatigue, hydrogen induced cracking and microbial influenced corrosion. Amorphous alloys have exceptional resistance to corrosion, due in part to the absence of grain boundaries, but can undergo crystallization and other phase instabilities during heating and welding. Titanium alloys are extremely corrosion resistant due to the formation of a tenacious passive film of titanium oxide, but is prone to hydrogen absorption in crevices, and hydrogen induced cracking after hydrogen absorption. Accurate predictions of equipment reliability, necessary for strategic planning, requires integrated models that account for all relevant modes of attack, and that can make probabilistic predictions. Once developed, model parameters must be determined experimentally, and the validity of models must be established through careful laboratory and field tests. Such validation testing requires state-of-the-art surface analytical techniques, as well as electrochemical and fracture mechanics tests. The interaction between those processes that perturb the local environment on a surface and those that alter metallurgical condition must be integrated in predictive models. The material and environment come together to drive various modes of corrosive attack (Figure 1). Models must be supported through comprehensive materials testing capabilities. Such capabilities are available at LLNL and include: the Long Term Corrosion Test Facility (LTCTF) where large numbers of standard samples can be exposed to realistic test media at several temperature levels; a reverse DC machine that can be used to monitor the propagation of stress corrosion cracking (SCC) in situ; and banks of potentiostats with temperature controlled cells for potentiostatic and potentiodynamic testing (Figure 2).

Farmer, J C

2003-04-15T23:59:59.000Z

430

Growth of geologic fractures into large-strain populations: review of nomenclature, subcritical crack growth, and some implications  

E-Print Network (OSTI)

. An array of initially mixed-mode (I±II) cracks will evolve under remote tensile least principal stress±network evolution. An increase in the stress corrosion index promotes joint clustering and signi®cant changes crack growth, and some implications for rock engineering R.A. Schultz* Geomechanics-Rock Fracture Group

431

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

E-Print Network (OSTI)

stress corrosion, diffusion, dissolution, and plasticity [1,5]. Several experimental empirical relations results in an increase in the speed of crack growth. A weak stress-sensitive regime follows wherePHYSICAL REVIEW E 84, 036104 (2011) Average crack-front velocity during subcritical fracture

Schmittbuhl, Jean

432

ENERGY CHANGES IN STRESSED BODIES DUE TO VOID AND CRACK J. R. Rice** and D. C. Drucker***  

E-Print Network (OSTI)

, and the mechanical aspects of stress corrosion cracking are discussed. INTRODUCTION A comparison is made firstENERGY CHANGES IN STRESSED BODIES DUE TO VOID AND CRACK GROWTH* J. R. Rice** and D. C. Drucker materials, and for the mechanical aspects of stress corrosion. The authors acknowledge with thei~ respective

433

Effect of Oxygen on the Crack Growth Behavior of V-4Cr-4Ti at 600C  

SciTech Connect

Exploratory experiments were performed to evaluate the effect of oxygen on the crack growth response of V-4Cr-4Ti at 600C under constant load. Tests were run in gettered argon, argon containing 2000 ppm oxygen, and laboratory air using fatigue pre-cracked compact tension specimens. Crack growth was measured primarily by post-test fracture surface examination, but also by in-test compliance measurements. Crack growth rates measured in air and gettered argon were about 2-3x10-3 mm/h at a stress intensity factor of about 40 MPavm. The crack growth rate in argon with 2000 ppm oxygen was about 7x10-2 mm/h at the same stress intensity level. The crack growth rates were very sensitive to the stress intensity factor. Over a limited range of stress intensity values the crack growth rate in argon plus 2000 ppm oxygen appears to be power-law dependent on stress intensity with an exponent of about 8.9. The fracture mode in air and gettered argon was transgranular cleavage with 20 to 30% intergranular fracture. In the oxygenated argon environment crack growth occurred predominantly by transgranular cleavage.

Kurtz, Richard J.

2000-09-01T23:59:59.000Z

434

Some mechanistic observations on the crack growth characteristics of pressure vessel and piping steels in PWR environment  

SciTech Connect

The fatigue crack growth behavior of A533B and A508 pressure vessel steel and AISI Types 304 and 316 steels used in reactor coolant piping have been studied in a pressurized water reactor environment at 288/sup 0/C (550/sup 0/F). The influence of stress ratio (P/sub min//P/sub max/), frequency, ramp times, specimen orientation and material microstructures were included in the study. While none of the materials showed evidence of static crack growth in the environment, the ferritic steels did show an enhanced fatigue crack growth rate at test frequencies of five cycles per minute and lower. Based on fractographic examinations the enhanced growth rate is not the result of environmentally induced intergranular or cleavage modes of crack propagation. Instead, striation spacing measurements were found to agree with the macroscopic crack growth rate, demonstrating a time dependent environmental interaction which introduces a frequency dependent enhancement of the mechanically developed striations. Crack growth experiments using hold times have confirmed the absence of any superimposed contribution of static crack growth components. Fatigue crack growth tests were conducted in an environment of Hydrogen Sulfide gas to establish the contribution of hydrogen embrittlement and will also be described.

Bamford, W.H.; Moon, D.M.

1979-01-01T23:59:59.000Z

435

Acoustic wave propagation in cracked porous rocks and application to interpreting acoustic log data in tight formations  

Science Conference Proceedings (OSTI)

Rocks in earth's crust usually contain both pores and cracks. Typical examples include tight sandstone and shale rocks that have low porosity but contain abundant microcracks. By extending the classic Biot's poroelastic wavetheory to include the effects of cracks

Xiaoming Tang; Xuelian Chen

2012-01-01T23:59:59.000Z

436

Finite element analysis of grain-matrix micro-cracking in shale within the context of a multiscale modeling  

E-Print Network (OSTI)

, hydrofracturing, or oil shale production. Current macro- scale and multiscale models do not account simultaneouslyFinite element analysis of grain-matrix micro-cracking in shale within the context of a multiscale-cracking in shale at grain-matrix inter- faces, assuming constituents are composed of quart silt grains

Regueiro, Richard A.

437

An extended finite element method for hydraulic fracture propagation in deformable porous media with the cohesive crack model  

Science Conference Proceedings (OSTI)

In this paper, a fully coupled numerical model is developed for the modeling of the hydraulic fracture propagation in porous media using the extended finite element method in conjunction with the cohesive crack model. The governing equations, which account ... Keywords: Cohesive crack propagation, Fluid flow, Fracturing porous media, Fully coupled model, Hydraulic fracturing, XFEM

T. Mohammadnejad, A. R. Khoei

2013-10-01T23:59:59.000Z

438

Holographic Thermal Helicity  

E-Print Network (OSTI)

We study the thermal helicity, defined in arXiv:1211.3850, of a conformal field theory with anomalies in the context of AdS$_{2n+1}$/CFT$_{2n}$. To do so, we consider large charged rotating AdS black holes in the Einstein-Maxwell-Chern-Simons theory with a negative cosmological constant using fluid/gravity expansion. We compute the anomaly-induced current and stress tensor of the dual CFT in leading order of the fluid/gravity derivative expansion and show their agreement with the field theoretical replacement rule for the thermal helicity. Such replacement rule is reflected in the bulk by new replacement rules obeyed by the Hall currents around the black hole.

Tatsuo Azeyanagi; R. Loganayagam; Gim Seng Ng; Maria J. Rodriguez

2013-11-12T23:59:59.000Z

439

Reactor Thermal-Hydraulics  

NLE Websites -- All DOE Office Websites (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

440

Thermally stable diamond brazing  

DOE Patents (OSTI)

A cutting element and a method for forming a cutting element is described and shown. The cutting element includes a substrate, a TSP diamond layer, a metal interlayer between the substrate and the diamond layer, and a braze joint securing the diamond layer to the substrate. The thickness of the metal interlayer is determined according to a formula. The formula takes into account the thickness and modulus of elasticity of the metal interlayer and the thickness of the TSP diamond. This prevents the use of a too thin or too thick metal interlayer. A metal interlayer that is too thin is not capable of absorbing enough energy to prevent the TSP diamond from fracturing. A metal interlayer that is too thick may allow the TSP diamond to fracture by reason of bending stress. A coating may be provided between the TSP diamond layer and the metal interlayer. This coating serves as a thermal barrier and to control residual thermal stress.

Radtke, Robert P. (Kingwood, TX)

2009-02-10T23:59:59.000Z

Note: This page contains sample records for the topic "thermal cracking visbreaking" 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

Thermal spallation drilling  

DOE Green Energy (OSTI)

Thermal spallation drilling is an underdeveloped process with great potential for reducing the costs of drilling holes and mining shafts and tunnels in most very hard rocks. Industry has used this process to drill blast holes for emplacing explosives and to quarry granite. Some theoretical work has been performed, and many signs point to a great future for this process. The Los Alamos National Laboratory has studied the theory of the spallation process and is conducting experiments to prove out the system and to adapt it for use with a conventional rotary rig. This report describes work that has been accomplished at the Laboratory on the development of thermal spallation drilling and some work that is projected for the future on the system. 3 references, 3 figures.

Williams, R.E.

1985-01-01T23:59:59.000Z

442

Solar thermal power  

DOE Green Energy (OSTI)

Solar thermal power is produced by three types of concentrating systems, which utilize parabolic troughs, dishes, and heliostats as the solar concentrators. These systems are at various levels of development and commercialization in the United States and in Europe. The U.S. Industry is currently developing these systems for export at the end of this century and at the beginning of the next one for remote power, village electrification, and grid-connected power. U.S. utilities are not forecasting to need power generation capacity until the middle of the first decade of the 21{sup st} century. At that time, solar thermal electric power systems should be cost competitive with conventional power generation in some unique U.S. markets. In this paper, the authors describe the current status of the development of trough electric, dish/engine, and power tower solar generation systems. 46 refs., 20 figs., 8 tabs.

Mancini, T.R.; Kolb, G.J.; Prairie, M.R. [Sandia National Labs., Albuquerque, NM (United States)

1997-12-31T23:59:59.000Z

443

Thermal Stabilization Blend Plan  

SciTech Connect

This Blend Plan documents the feed material items that are stored in 2736-2 vaults, the 2736-ZB 638 cage, the 192C vault, and the 225 vault that will be processed through the thermal stabilization furnaces. The purpose of thermal stabilization is to heat the material to 1000 degrees Celsius to drive off all water and leave the plutonium and/or uranium as oxides. The stabilized material will be sampled to determine the Loss On Ignition (LOI) or percent water. The stabilized material must meet water content or LOI of less than 0.5% to be acceptable for storage under DOE-STD-3013-99 specifications. Out of specification material will be recycled through the furnaces until the water or LOI limits are met.

RISENMAY, H.R.

2000-05-02T23:59:59.000Z

444

Initiation and stable crack growth behavior of API X70 steel at low temperatures (25C [>=] T [>=] [minus]95C)  

SciTech Connect

Small-scale tests employing single edge notch bend (SENB) specimens of API X70 pipeline steel were conducted to assess the initiation and stable growth behavior of this material at test temperatures between 25C and [minus]95C. Material resistance curves were generated based on various proposed J-integral and crack tip opening displacement (CTOD) relationships and criteria for defining crack initiation and stable growth. DC potential drop crack growth monitoring was employed to provide crack propagation data for development of the resistance curves. The temperature dependence of crack initiation and stable growth properties of this material are quantified and presented. Verification of the temperature independence of the normalized J or CTOD tearing modulus is also provided.

Romilly, D.P. (Univ. of British Columbia, Vancouver, B.C. (Canada). Dept. of Mechanical Engineering)

1993-07-01T23:59:59.000Z

445

Characterization of Effective Built-in Curling and Concrete Pavement Cracking on the Palmdale Test Sections  

E-Print Network (OSTI)

temperature, solar radiation, and weather phenomena. Resultsolar radiation, base/subbase thermal conductivity and temperature, weather

Rao, Shreenath; Roesler, Jeffery R.

2005-01-01T23:59:59.000Z

446

Concentrating Solar Thermal Technology  

Science Conference Proceedings (OSTI)

After nearly 20 years of commercial dormancy, concentrating solar thermal (CST) power development and investment activity is heating up globally. Encouraged by volatile energy prices, carbon markets, and renewable-friendly policies, an increasing number of established companies, newcomers, utilities, and government agencies are planning to deploy CST systems to tap the technologies' improving conversion efficiencies and low-cost electricity production potential. This renewable energy technology perspecti...

2009-03-27T23:59:59.000Z

447

THERMAL NEUTRONIC REACTOR  

DOE Patents (OSTI)

A novel thermal reactor was designed in which a first reflector formed from a high atomic weight, nonmoderating material is disposed immediately adjacent to the reactor core. A second reflector composed of a moderating material is disposed outwardly of the first reflector. The advantage of this novel reflector arrangement is that the first reflector provides a high slow neutron flux in the second reflector, where irradiation experiments may be conducted with a small effect on reactor reactivity.

Spinrad, B.I.

1960-01-12T23:59:59.000Z

448

Thermal reactor safety  

SciTech Connect

Information is presented concerning new trends in licensing; seismic considerations and system structural behavior; TMI-2 risk assessment and thermal hydraulics; statistical assessment of potential accidents and verification of computational methods; issues with respect to improved safety; human factors in nuclear power plant operation; diagnostics and activities in support of recovery; LOCA transient analysis; unresolved safety issues and other safety considerations; and fission product transport.

1980-06-01T23:59:59.000Z

449

Thermally actuated thermionic switch  

DOE Patents (OSTI)

A thermally actuated thermionic switch which responds to an increase of temperature by changing from a high impedance to a low impedance at a predictable temperature set point. The switch has a bistable operation mode switching only on temperature increases. The thermionic material may be a metal which is liquid at the desired operation temperature and held in matrix in a graphite block reservoir, and which changes state (ionizes, for example) so as to be electrically conductive at a desired temperature.

Barrus, D.M.; Shires, C.D.

1982-09-30T23:59:59.000Z

450

Mobile Window Thermal Test  

NLE Websites -- All DOE Office Websites (Extended Search)

Mobile Window Thermal Test (MoWiTT) Facility Mobile Window Thermal Test (MoWiTT) Facility winter.jpg (469135 bytes) The window has come a long way since the days when it was a single pane of glass in a wood frame. Low-emissivity windows were designed to help buildings retain some of the energy that would have leaked out of less efficient windows. Designing efficient window-and-frame systems is one strategy for reducing the energy use of buildings. But the net energy flowing through a window is a combination of temperature- driven thermal flows and transmission of incident solar energy, both of which vary with time. U-factor and solar heat gain coefficient (SHGC), the window properties that control these flows, depend partly on ambient conditions. Window energy flows can affect how much energy a building uses, depending on when the window flows are available to help meet other energy demands within the building, and when they are adverse, adding to building energy use. This leads to a second strategy for reducing building energy use: using the beneficial solar gain available through a window, either for winter heating or for daylighting, while minimizing adverse flows.

451

MECHANISTIC UNDERSTANDING OF CAUSTIC CRACKING OF CARBON STEELS  

SciTech Connect

Liquid waste generated by the PUREX process for separation of nuclear materials is concentrated and stored in Type IV single-shell carbon steel tanks at the Savannah River Site (SRS). The Type IV tanks for this waste do not have cooling coils and have not undergone heat treatment to stress-relieve the tanks. After the waste is concentrated by evaporation, it becomes very alkaline and can cause stress corrosion cracking (SCC) and pitting corrosion of the tank materials. SRS has experienced leakage from non-stress-relieved waste tanks constructed of A285 carbon steel and pitting of A212 carbon steel tanks in the vapor space. An investigation of tank materials has been undertaken at SRS to develop a basic understanding of caustic SCC of A285 and A212 grade carbon steels exposed to aqueous solutions, primarily containing sodium hydroxide (NaOH), sodium nitrate (NaNO{sub 3}), and sodium nitrite (NaNO{sub 2}) at temperatures relevant to the operating conditions of both the F and H area plants. This report presents the results of this corrosion testing program. Electrochemical tests were designed using unstressed coupons in a simulated tank environment. The purpose of this testing was to determine the corrosion susceptibility of the tank materials as a function of chemical concentration, pH, and temperature. A285 and A516 (simulates A212 carbon steel) coupons were used to investigate differences in the corrosion of these carbon steels. Electrochemical testing included measurement of the corrosion potential and polarization resistance as well as cyclic potentiodynamic polarization (CPP) testing of coupons. From the CPP experiments, corrosion characteristics were determined including: corrosion potential (E{sub corr}), pitting or breakdown potential (E{sub pit}), and repassivation potential (E{sub prot}). CPP results showed no indications of localized corrosion, such as pitting, and all samples showed the formation of a stable passive layer as evidenced by the positive hysteresis during the scan. Analysis of the CPP data was performed to compare the corrosion susceptibility of the samples under different environmental conditions. Test results indicated that the most important factors affecting corrosion of the steel are the solution temperature, hydroxide concentration, and the material used in constructing the tanks. Variables that did not significantly affect the corrosion susceptibility of the steel were the nitrate or nitrite concentration and the atmosphere in the tank. The passivation current of the coupons increased exponentially with temperature. Longer-term studies of the passivation current are suggested based on results from the literature for iron in highly caustic environments. Polarization resistance studies showed a significant increase in corrosion rate at 125 C and 12 M hydroxide concentration when compared with tests at lower temperatures and lower hydroxide concentrations. Within the temperature and pH range of these tests, iron oxide, Fe{sub 3}O{sub 4}, becomes unstable and could account for the increased corrosion susceptibility. The applicability of these conditions should be confirmed and detailed surface studies should be conducted to determine the corrosion resistance of A285 and A516 carbon steels under these conditions. Surface science studies should also be conducted to determine the role of the carbon steel composition in preventing corrosion under these conditions.

Garcia-Diaz, B.; Roy, A.

2009-10-19T23:59:59.000Z

452

Syngas Production from Propane Using Atmospheric Non-thermal Plasma  

E-Print Network (OSTI)

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

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

2009-01-01T23:59:59.000Z

453

CALIFORNIA SOLAR INITIATIVE-THERMAL PROGRAMHANDBOOK  

E-Print Network (OSTI)

CALIFORNIA SOLAR INITIATIVE-THERMAL PROGRAMHANDBOOK CALIFORNIA PUBLIC UTILITIES California Solar Initiative Thermal Program Handbook i 1. Introduction to CSI-Thermal Program...........................................................................................................................11 #12;Table of Contents California Solar Initiative Thermal Program Handbook ii 2.5 Surface

454

Hydrogen permeation and related stress corrosion cracking (SCC) can limit the use of metals and alloys in aqueous environments. The interactions between hydrogen and the  

E-Print Network (OSTI)

Background Hydrogen permeation and related stress corrosion cracking (SCC) can limit the use in the microstructure initiate the events leading to a crack. Various methods like the post-heat treatment, alloying. These methods however, do not reduce the hydrogen entry below the threshold level that is safe of cracking

Popov, Branko N.

455

EFFECT OF HEAT TREATMENT ON THERMAL PROPERTIES OF PITCH-BASED AND PAN-BASED CARBON-CARBON COMPOSITES  

Science Conference Proceedings (OSTI)

Thermal properties of two directional (2D) pitch-based carbon fiber with charred resin and three directional (3D) PAN-based carbon fiber with CVI carbon matrix C/C composite were investigated for non-heat treated (NHT) and heat treated (HT) materials through the thickness (z-direction). Heat treatment was performed at 1800, 2100 and 2400 oC for 1-hr in inert argon atmosphere. Thermal diffusivity, heat capacity and bulk density were measured to calculate thermal conductivity. Thermal diffusivity and conductivity was the highest for 3D C/C heat treated at maximum temperature with non-heat treated one exhibiting the lowest one. Similarly, 2D C/C heat treated at maximum temperature exhibited the highest thermal diffusivity and thermal conductivity. Polarized light microscopy (PLM) images of HTT C/C show a progressive improvement in microstructure when compared to NHT C/C. However, HTT 2D and 3D C/C composites exhibited extensive shrinkage of charred resin and CVI carbon matrix, respectively, from fibers resulting in intra and inter-bundles cracking when compared to NHT one. Raman spectroscopy and XRD results of NHT and HTT C/C indicated increased ordering of structure. A progressive improvement in thermal properties was observed with increased heat treatment temperatures.

Iqbal, Sardar S. [Southern Illinois University; Dinwiddie, Ralph Barton [ORNL; Porter, Wallace D [ORNL; Lance, Michael J [ORNL; Fillip, Peter [Southern Illinois University

2011-01-01T23:59:59.000Z

456

Thermal and non-thermal energies in solar flares  

E-Print Network (OSTI)

The energy of the thermal flare plasma and the kinetic energy of the non-thermal electrons in 14 hard X-ray peaks from 9 medium-sized solar flares have been determined from RHESSI observations. The emissions have been carefully separated in the spectrum. The turnover or cutoff in the low-energy distribution of electrons has been studied by simulation and fitting, yielding a reliable lower limit to the non-thermal energy. It remains the largest contribution to the error budget. Other effects, such as albedo, non-uniform target ionization, hot target, and cross-sections on the spectrum have been studied. The errors of the thermal energy are about equally as large. They are due to the estimate of the flare volume, the assumption of the filling factor, and energy losses. Within a flare, the non-thermal/thermal ratio increases with accumulation time, as expected from loss of thermal energy due to radiative cooling or heat conduction. Our analysis suggests that the thermal and non-thermal energies are of the same magnitude. This surprising result may be interpreted by an efficient conversion of non-thermal energy to hot flare plasma.

Pascal Saint-Hilaire; Arnold O. Benz

2005-03-03T23:59:59.000Z

457

A New Method To Predict Fatigue Crack Growth Life for the Armored Hull  

Science Conference Proceedings (OSTI)

Based on theories of dynamics of multi-body systems and linear elastic fracture mechanics, by using virtual prototyping technique, the model of tracked vehicle is established, and stress spectrums of the armored hulls weak points are tested by ... Keywords: Virtual Prototyping, Virtual Test, Fatigue Crack Grow, Simulation

Wang Hongyan; Yang Tao; Shang Qigang

2010-11-01T23:59:59.000Z

458

Program on Technology Innovation: Prediction and Evaluation of Environmentally Assisted Cracking in LWR Structural Materials  

Science Conference Proceedings (OSTI)

This report describes the final results of Phase III of a three-year joint research program sponsored by EPRI in collaboration with Fracture & Reliability Research Institute (FRRI) at Tohoku University, Japanese utilities, vendors, and international organizations. The program addressed environmentally assisted cracking (EAC) of light water reactor (LWR) structural materials in pressurized water reactor (PWR) and boiling water reactor (BWR) environments.

2007-11-20T23:59:59.000Z

459

Program on Technology Innovation: Prediction and Evaluation of Environmentally Assisted Cracking in LWR Structural Materials  

Science Conference Proceedings (OSTI)

This report describes the interim results of Phase III of a joint research program sponsored by EPRI in collaboration with the Fracture Reliability Research Institute (FRRI) at Tohoku University, Japanese utilities, vendors, and international organizations to address environmentally assisted cracking (EAC) of LWR structural materials.

2005-11-30T23:59:59.000Z

460

Overlapping double etch technique for evaluation of metallic alloys to stress corrosion cracking  

DOE Patents (OSTI)

A double overlapping etch zone technique for evaluation of the resistance of metallic alloys to stress corrosion cracking. The technique involves evaluating the metallic alloy along the line of demarcation between an overlapping double etch zone and single etch zone formed on the metallic alloy surface.

Steeves, Arthur F. (Schenectady, NY); Stewart, James C. (Loudonville, NY)

1981-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "thermal cracking visbreaking" 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.


461

Overlapping double etch technique for evaluation of metallic alloys to stress corrosion cracking  

DOE Patents (OSTI)

A double overlapping etch zone technique for evaluation of the resistance of metallic alloys to stress corrosion cracking is described. The technique involves evaluating the metallic alloy along the line of demarcation between an overlapping double etch zone and single etch zone formed on the metallic alloy surface.

Not Available

1980-05-28T23:59:59.000Z

462

Dispersion of elastic moduli in a porous-cracked rock: Theoretical predictions for squirt-flow  

E-Print Network (OSTI)

. Attenuation and dispersion of compressional waves in fluid-filled porous rocks with partial gas saturationDispersion of elastic moduli in a porous-cracked rock: Theoretical predictions for squirt-flow M Available online xxxx Keywords: Frequency dispersion Rock properties Bimodal porosity Effective medium

Fortin, Jérôme

463

A Parametric Study of the Lead-Induced Stress Corrosion Cracking of Alloy 690  

Science Conference Proceedings (OSTI)

Alloy 690 steam generator tubing, which has been the material of choice for replacement steam generators, is susceptible to lead-induced stress corrosion cracking (PbSCC) in alkaline environments. No obvious correlation was found between processing parameters or material characteristics and PbSCC susceptibility.

1999-04-22T23:59:59.000Z

464

Technical note: Filling trim cracks on GPU-rendered solid models  

Science Conference Proceedings (OSTI)

We present an algorithm for improving the rendering appearance of CAD models with trimmed freeform surfaces when evaluated on graphics processing units (GPUs). Rendering on client GPUs allows mechanical CAD to embrace cloud computing by storing a single ... Keywords: Cracks, GPU rendering, Geometric modeling, Trimmed surfaces

Sushrut Pavanaskar; Sara Mcmains

2013-02-01T23:59:59.000Z

465

Crack growth behavior of encapsulation processed SiC-PMMA particulate composites  

Science Conference Proceedings (OSTI)

The effect of processing on the fatigue crack propagation and fracture toughness of ceramic-polymer composites was investigated. A new process for composite production was developed with homogeneous particle distribution and low residual stress levels in mind. PMMA was uniformly distributed by encapsulating the SiC substrate by means of precipitation polymerization. The encapsulation processed powders were then compacted at temperatures above T{sub g} to form the composite. The encapsulation process was optimized by varying the initial concentrations of the reactants until homogeneous nucleation was suppressed. The coatings were found to be continuous at the SiC-PMMA interface, with particle agglomeration occurring between coated particles. Polymer loadings equivalent to 30 vol % SiC were achieved. Composites of several particle size ranges were tested under cyclic fatigue and static loading conditions. Fatigue growth rates and fracture toughness data display a trend of increasing crack growth resistance with increasing particle size, with encapsulation processed composites outperforming conventionally cast composites in both cyclic fatigue and fracture resistance. The largest K{sub Ic} value was found to be 2.95 MPa(m){sup 1/2}, a factor of 3 increase over un-reinforced PMMA. The roles of crack deflection, shielding, bridging, and pinning in enhancing toughness were discussed in light of crack profile fracture surface details. 65 refs., 30 figs., 2 tabs.

Sheu, C.H.

1990-05-01T23:59:59.000Z

466

Catalytic cracking. (Latest citations from the NTIS Bibliographic database). Published Search  

SciTech Connect

The bibliography contains citations concerning applications of catalytic cracking in fluidized beds, moving beds, refineries, vacuum distillation, and reformers. Design criteria, models, controls, and operating procedures are also discussed. (Contains 250 citations and includes a subject term index and title list.)

Not Available

1993-09-01T23:59:59.000Z

467

Catalytic cracking. (Latest citations from the NTIS data base). Published Search  

SciTech Connect

The bibliography contains citations concerning applications of catalytic cracking in fluidized beds, moving beds, refineries, vacuum distillation, and reformers. Design criteria, models, controls, and operating procedures are also discussed. (Contains 250 citations and includes a subject term index and title list.)

Not Available

1992-05-01T23:59:59.000Z

468

Catalytic cracking. (Latest citations from the NTIS bibliographic database). Published Search  

Science Conference Proceedings (OSTI)

The bibliography contains citations concerning applications of catalytic cracking in fluidized beds, moving beds, refineries, vacuum distillation, and reformers. Design criteria, models, controls, and operating procedures are also discussed. (Contains 250 citations and includes a subject term index and title list.)

Not Available

1994-02-01T23:59:59.000Z

469

Effect of Blast Design on Crack Response C.H. Dowding  

E-Print Network (OSTI)

to determine those with the best correlation. Variations in the ground motion and air pressure wave (air blast Conference Siebert and Dowding (2000) described development of the autonomous crack measurement (ACM) system). These theses are available online at www.iti.northwestern.edu/research/current/acm. This article describes

470

Understanding crack versus cavitation in pressure-sensitive adhesives: the role of kinetics  

E-Print Network (OSTI)

We perform traction experiments on viscous liquids highly confined between parallel plates, a geometry known as the probe-tack test in the adhesion community. Direct observation during the experiment coupled to force measurement shows the existence of several mechanisms for releasing the stress. Bubble nucleation and instantaneous growth had been observed in a previous work. Upon increasing further the traction velocity or the viscosity, the bubble growth is progressively delayed. At high velocities, cracks at the interface between the plate and the liquid appear before the bubbles have grown to their full size. Bubbles and cracks are thus observed concomitantly. At even higher velocities, cracks develop fully so early that the bubbles are not even visible. We present a theoretical model that describes these regimes, using a Maxwell fluid as a model for the actual fluid, a highly viscous silicon oil. We present the resulting phase diagramme for the different force peak regimes. The predictions are compatible with the data. Our results show that in addition to cavitation, interfacial cracks are encountered in a probe-tack traction test with viscoelastic, \\emph{liquid} materials and not solely with viscoelastic solids like adhesives.

Jrmie Teisseire; F. Nallet; P. Fabre; Cyprien Gay

2006-09-18T23:59:59.000Z

471

Modeling the cracking process of rocks from continuity to discontinuity using a cellular automaton  

Science Conference Proceedings (OSTI)

A rock discontinuous cellular automaton (RDCA) was developed for modeling rock fracturing processes from continuous to discontinuous deformation under mechanical loading. RDCA is an integration of the following basic concepts: (1) representation of heterogeneity ... Keywords: Cracking process, Discontinuity, Elasto-plastic cellular automaton, Level set, Partition of unity, Rock discontinuous cellular automaton

Peng-Zhi Pan; Fei Yan; Xia-Ting Feng

2012-05-01T23:59:59.000Z

472

THE INFLUENCE OF THE GRAIN STRUCTURE SIZE ON MICROSTRUCTURALLY SHORT CRACKS  

E-Print Network (OSTI)

tensor 0 yield stress () Taylor's resolved shear stress AISI American Iron and Steel Institute CTOD Crack in this paper are typical for the AISI 316L austenitic stainless steel, which is extensively used in nuclear industry (e.g. pipes) and has also been selected for a number of components of the International

Cizelj, Leon

473

Investigation of Potential Concrete Tie Rail Seat Deterioration Mechanisms: Cavitation Erosion and Hydraulic Pressure Cracking  

E-Print Network (OSTI)

Investigation of Potential Concrete Tie Rail Seat Deterioration Mechanisms: Cavitation Erosion and Hydraulic Pressure Cracking 10-2411 Transportation Research Board 89th Annual Meeting Submitted: November 15-2411 1 ABSTRACT Rail seat deterioration (RSD) is the most critical problem with concrete tie performance

Barkan, Christopher P.L.

474

Program on Technology Innovation: Prediction and Evaluation of Environmentally Assisted Cracking in LWR Structural Materials  

Science Conference Proceedings (OSTI)

This report describes the interim results of PEACE-E, a Five-year extension of the joint research program sponsored by EPRI in collaboration with the Fracture Reliability Research Institute (FRRI) at Tohoku University, Japanese utilities, vendors, and international organizations. The program addressed environmentally assisted cracking (EAC) of light water reactor structural materials in PWR and BWR environments.

2008-11-24T23:59:59.000Z

475

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

SciTech Connect

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

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

1996-12-01T23:59:59.000Z

476

Thermal transient anemometer  

DOE Patents (OSTI)

A thermal transient anemometer is disclosed having a thermocouple probe which is utilized to measure the change in temperature over a period of time to provide a measure of fluid flow velocity. The thermocouple probe is located in the fluid flow path and pulsed to heat or cool the probe. The cooling of the heated probe or the heating of the cooled probe from the fluid flow over a period of time is measured to determine the fluid flow velocity. The probe is desired to be locally heated near the tip to increase the efficiency of devices incorporating the probe. 12 figs.

Bailey, J.L.; Vresk, J.

1989-07-18T23:59:59.000Z

477

Thermal indicator for wells  

DOE Patents (OSTI)

Minute durable plate-like thermal indicators are employed for precision measuring static and dynamic temperatures of well drilling fluids. The indicators are small enough and sufficiently durable to be circulated in the well with drilling fluids during the drilling operation. The indicators include a heat resistant indicating layer, a coacting meltable solid component and a retainer body which serves to unitize each indicator and which may carry permanent indicator identifying indicia. The indicators are recovered from the drilling fluid at ground level by known techniques.

Gaven, Jr., Joseph V. (Oakton, VA); Bak, Chan S. (Newbury Park, CA)

1983-01-01T23:59:59.000Z

478

Multispectral thermal imaging  

SciTech Connect

Many remote sensing applications rely on imaging spectrometry. Here the authors use imaging spectrometry for thermal and multispectral signatures measured from a satellite platform enhanced with a combination of accurate calibrations and on-board data for correcting atmospheric distortions. The approach is supported by physics-based end-to-end modeling and analysis, which permits a cost-effective balance between various hardware and software aspects. The goal is to develop and demonstrate advanced technologies and analysis tools toward meeting the needs of the customer; at the same time, the attributes of this system can address other applications in such areas as environmental change, agriculture, and volcanology.

Weber, P.G.; Bender, S.C.; Borel, C.C.; Clodius, W.B.; Smith, B.W. [Los Alamos National Lab., NM (United States). Space and Remote Sensing Sciences Group; Garrett, A.; Pendergast, M.M. [Westinghouse Savannah River Corp., Aiken, SC (United States). Savannah River Technology Center; Kay, R.R. [Sandia National Lab., Albuquerque, NM (United States). Monitoring Systems and Technology Center

1998-12-01T23:59:59.000Z

479

Manipulation of Thermal Phonons  

E-Print Network (OSTI)

Developing materials that can conduct electricity easily, but block the motion of phonons is necessary in the applications of thermoelectric devices, which can generate electricity from temperature differences. In converse, a key requirement as chips get faster is to obtain better ways to dissipate heat. Controlling heat transfer in these crystalline materials devices such as silicon is important. The heat is actually the motion or vibration of atoms known as phonons. Finding ways to manipulate the behavior of phonons is crucial for both energy applications and the cooling of integrated circuits. A novel class of artificially periodic structured materials phononic crystals might make manipulation of thermal phonons possible. In many fields of physical sciences and engineering, acoustic wave propagation in solids attracts many researchers. Wave propagation phenomena can be analyzed by mathematically solving the acoustic wave equation. However, wave propagation in inhomogeneous media with various geometric structures is too complex to find an exact solution. Hence, the Finite Difference Time Domain method is developed to investigate these complicated problems. In this work, the Finite-Difference Time-Domain formula is derived from acoustic wave equations based on the Taylors expansion. The numerical dispersion and stability problems are analyzed. In addition, the convergence conditions of numerical acoustic wave are stated. Based on the periodicity of phononic crystal, the Blochs theorem is applied to fulfill the periodic boundary condition of the FDTD method. Then a wide-band input signal is used to excite various acoustic waves with different frequencies. In the beginning of the calculation process, the wave vector is chosen and fixed. By means of recording the displacement field and taking the Fourier transformation, we can obtain the eigenmodes from the resonance peaks of the spectrum and draw the dispersion relation curve of acoustic waves. With the large investment in silicon nanofabrication techniques, this makes tungsten/silicon phononic crystal a particularly attractive platform for manipulating thermal phonons. Phononic crystal makes use of the fundamental properties of waves to create band gap over which there can be no propagation of acoustic waves in the crystal. This crystal can be applied to deterministically manipulate the phonon dispersion curve affected by different crystal structures and to modify the phonon thermal conductivity accordingly. We can expect this unique metamaterial is a promising route to creating unprecedented thermal properties for highly-efficient energy harvesting and thermoelectric cooling.

Hsu, Chung-Hao

2013-05-01T23:59:59.000Z

480

Thermal Stabilization Blend Plan  

SciTech Connect

The Blend Plan was written to identify items stored outside of the 213 MBA that will be moved into the MBA for thermal stabilization processing. Product quality oxide items stored in our vaults are found in Appendix A. A table is included in Appendix A which details the isotopic values for the oxide items and calculates the amount of material of any specific run that can be placed in a product can and maintain the 15 watt limit to meet storage vault specifications. This Revision of the Blend Plan adds items of lesser dose rate to lower the exposure of the workers until additional shielding can be added to the gloveboxes.

RISENMAY, H.R.

2000-04-20T23:59:59.000Z

Note: This page contains sample records for the topic "thermal cracking visbreaking" 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.


481

Advanced solar thermal technology  

SciTech Connect

The application of dish solar collectors to industrial process heat (IPH) has been reviewed. IPH represents a market for displacement of fossil fuels (10 quads/y). A 10% market penetration would indicate a substantial market for solar thermal systems. Apparently, parabolic dish systems can produce IPH at a lower cost than that of troughs or compound parabolic concentrators, even though dish fabrication costs per unit area are more expensive. Successful tests of point-focusing collectors indicate that these systems can meet the energy requirements for process heat applications. Continued efforts in concentrator and transport technology development are needed. 7 figures.

Leibowitz, L.P.; Hanseth, E.; Liu, T.M.

1982-06-01T23:59:59.000Z

482

Hard thermal effective action in QCD through the thermal operator  

E-Print Network (OSTI)

Through the application of the thermal operator to the zero temperature retarded Green's functions, we derive in a simple way the well known hard thermal effective action in QCD. By relating these functions to forward scattering amplitudes for on-shell particles, this derivation also clarifies the origin of important properties of the hard thermal effective action, such as the manifest Lorentz and gauge invariance of its integrand.

Ashok Das; J. Frenkel

2007-03-08T23:59:59.000Z

483

2 Technology Description: Solar Thermal Parabolic Trough Solar Thermal  

E-Print Network (OSTI)

Parabolic troughs track sun, concentrate incident light onto a centralized, tubular receiver that runs length of each trough Thermal fluid circulates through all receivers in solar field Thermal fluid brought to one or more centralized power production facilities Heat transferred to a steam cycle, drives a steam turbine to generate power Cooled thermal fluid is then recirculated th through h solar fi field ld Wet cooling is common, dry cooling possible

Timothy J. Skone; Risks Of Implementation

2012-01-01T23:59:59.000Z

484

Influence of microstructure on stress corrosion cracking of mild steel in synthetic caustic-nitrate nuclear waste solution  

DOE Green Energy (OSTI)

The influence of alloy microstructure on stress corrosion cracking of mild steel in caustic-nitrate synthetic nuclear waste solutions was studied. An evaluation was made of the effect of heat treatment on a representative material (ASTM A 516 Grade 70) used in the construction of high activity radioactive waste storage tanks at Savannah River Plant. Several different microstructures were tested for susceptibility to stress corrosion cracking. Precracked fracture specimens loaded in either constant load or constant crack opening displacement were exposed to a variety of caustic-nitrate and nitrate solutions. Results were correlated with the mechanical and corrosion properties of the microstructures. Crack velocity and crack arrest stress intensity were found to be related to the yield strength of the steel microstructures. Fractographic evidence indicated pH depletion and corrosive crack tip chemistry conditions even in highly caustic solutions. Experimental results were compatible with crack growth by a strain- assisted anodic dissolution mechanism; however, hydrogen embrittlement also was considered possible. (auth)

Sarafian, P.G.

1975-12-01T23:59:59.000Z

485

Thermal and Structural Equilibrium Studies of Organic Thermal ...  

Science Conference Proceedings (OSTI)

These organic materials undergo a solid-solid state phase transition before melting which will store large amounts of thermal energy. The binary system of...

486

Electric Vehicle Battery Thermal Issues and Thermal Management Techniques (Presentation)  

SciTech Connect

This presentation examines the issues concerning thermal management in electric drive vehicles and management techniques for improving the life of a Li-ion battery in an EDV.

Rugh, J. P.; Pesaran, A.; Smith, K.

2013-07-01T23:59:59.000Z

487

THERMALLY DRIVEN ATMOSPHERIC ESCAPE  

Science Conference Proceedings (OSTI)

Accurately determining the escape rate from a planet's atmosphere is critical for determining its evolution. A large amount of Cassini data is now available for Titan's upper atmosphere and a wealth of data is expected within the next decade on escape from Pluto, Mars, and extra-solar planets. Escape can be driven by upward thermal conduction of energy deposited well below the exobase, as well as by nonthermal processes produced by energy deposited in the exobase region. Recent applications of a model for escape driven by upward thermal conduction, called the slow hydrodynamic escape model, have resulted in surprisingly large loss rates for the atmosphere of Titan, Saturn's largest moon. Based on a molecular kinetic simulation of the exobase region, these rates appear to be orders of magnitude too large. Therefore, the slow hydrodynamic model is evaluated here. It is shown that such a model cannot give a reliable description of the atmospheric temperature profile unless it is coupled to a molecular kinetic description of the exobase region. Therefore, the present escape rates for Titan and Pluto must be re-evaluated using the atmospheric model described here.

Johnson, Robert E., E-mail: rej@virginia.ed [Engineering Physics, Thornton Hall B102, University of Virginia, Charlottesville, VA 22902 (United States); Physics Department, New York University, New York, NY 10003 (United States)

2010-06-20T23:59:59.000Z

488