Sample records for fatigue design curves

  1. FATIGUE DESIGN CURVES FOR

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power AdministrationField8,Dist. Category UC-l 1,EnergyExploringGamma-ray2As atoActFATIGUE DESIGN

  2. Application of NUREG/CR-5999 interim fatigue curves to selected nuclear power plant components

    SciTech Connect (OSTI)

    Ware, A.G.; Morton, D.K.; Nitzel, M.E. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

    1995-03-01T23:59:59.000Z

    Recent test data indicate that the effects of the light water reactor (LWR) environment could significantly reduce the fatigue resistance of materials used in the reactor coolant pressure boundary components of operating nuclear power plants. Argonne National Laboratory has developed interim fatigue curves based on test data simulating LWR conditions, and published them in NUREG/CR-5999. In order to assess the significance of these interim fatigue curves, fatigue evaluations of a sample of the components in the reactor coolant pressure boundary of LWRs were performed. The sample consists of components from facilities designed by each of the four U.S. nuclear steam supply system vendors. For each facility, six locations were studied, including two locations on the reactor pressure vessel. In addition, there are older vintage plants where components of the reactor coolant pressure boundary were designed to codes that did not require an explicit fatigue analysis of the components. In order to assess the fatigue resistance of the older vintage plants, an evaluation was also conducted on selected components of three of these plants. This report discusses the insights gained from the application of the interim fatigue curves to components of seven operating nuclear power plants.

  3. Fatigue threshold R-curves for predicting reliability of ceramics under cyclic loading

    E-Print Network [OSTI]

    Ritchie, Robert

    Fatigue threshold R-curves for predicting reliability of ceramics under cyclic loading J.J. Kruzic for the prediction of reliability in bridging ceramics under cyclic loading conditions based on a fatigue threshold R-curve threshold R-curve may express this crack-size dependence, analogous to the traditional fracture toughness R-curve

  4. MECH 491 Mechanical Engineering Design I -Project Description Project Topic: A corrosion fatigue experiment setup design

    E-Print Network [OSTI]

    Muradoglu, Metin

    Topic: A deformation setup design for testing of small scale metallic materials Project DescriptionProject 1 MECH 491 ­ Mechanical Engineering Design I - Project Description Project Topic: A corrosion fatigue experiment setup design Project Description: It is required for the students to design

  5. Design and fabrication of a bending rotation fatigue test rig for in situ electrochemical analysis during fatigue testing of NiTi shape memory alloy wires

    SciTech Connect (OSTI)

    Neelakantan, Lakshman [Ruhr-Universitaet Bochum, Institute for Materials, 44801 Bochum (Germany); Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, 600 036 Chennai (India); Zglinski, Jenni Kristin; Eggeler, Gunther [Ruhr-Universitaet Bochum, Institute for Materials, 44801 Bochum (Germany); Frotscher, Matthias [Ruhr-Universitaet Bochum, Institute for Materials, 44801 Bochum (Germany); CORTRONIK GmbH, 18119 Rostock-Warnemuende (Germany)

    2013-03-15T23:59:59.000Z

    The current investigation proposes a novel method for simultaneous assessment of the electrochemical and structural fatigue properties of nickel-titanium shape memory alloy (NiTi SMA) wires. The design and layout of an in situ electrochemical cell in a custom-made bending rotation fatigue (BRF) test rig is presented. This newly designed test rig allows performing a wide spectrum of experiments for studying the influence of fatigue on corrosion and vice versa. This can be achieved by performing ex situ and/or in situ measurements. The versatility of the combined electrochemical/mechanical test rig is demonstrated by studying the electrochemical behavior of NiTi SMA wires in 0.9% NaCl electrolyte under load. The ex situ measurements allow addressing various issues, for example, the influence of pre-fatigue on the localized corrosion resistance, or the influence of hydrogen on fatigue life. Ex situ experiments showed that a pre-fatigued wire is more susceptible to localized corrosion. The synergetic effect can be concluded from the polarization studies and specifically from an in situ study of the open circuit potential (OCP) transients, which sensitively react to the elementary repassivation events related to the local failure of the oxide layer. It can also be used as an indicator for identifying the onset of the fatigue failure.

  6. Presented at 1999 EWEC Effects of Materials Parameters and Design Details on the Fatigue of

    E-Print Network [OSTI]

    of Composite Materials for Wind Turbine Blades John F. Mandell and Herbert J. Sutherland* Daniel D. SamborskyPresented at 1999 EWEC Effects of Materials Parameters and Design Details on the Fatigue Wind Energy Technology Dept. Dept. of Chemical Engineering Sandia National Laboratories Montana State

  7. Update and Improve Subsection NH –– Alternative Simplified Creep-Fatigue Design Methods

    SciTech Connect (OSTI)

    Tai Asayama

    2009-10-26T23:59:59.000Z

    This report described the results of investigation on Task 10 of DOE/ASME Materials NGNP/Generation IV Project based on a contract between ASME Standards Technology, LLC (ASME ST-LLC) and Japan Atomic Energy Agency (JAEA). Task 10 is to Update and Improve Subsection NH -- Alternative Simplified Creep-Fatigue Design Methods. Five newly proposed promising creep-fatigue evaluation methods were investigated. Those are (1) modified ductility exhaustion method, (2) strain range separation method, (3) approach for pressure vessel application, (4) hybrid method of time fraction and ductility exhaustion, and (5) simplified model test approach. The outlines of those methods are presented first, and predictability of experimental results of these methods is demonstrated using the creep-fatigue data collected in previous Tasks 3 and 5. All the methods (except the simplified model test approach which is not ready for application) predicted experimental results fairly accurately. On the other hand, predicted creep-fatigue life in long-term regions showed considerable differences among the methodologies. These differences come from the concepts each method is based on. All the new methods investigated in this report have advantages over the currently employed time fraction rule and offer technical insights that should be thought much of in the improvement of creep-fatigue evaluation procedures. The main points of the modified ductility exhaustion method, the strain range separation method, the approach for pressure vessel application and the hybrid method can be reflected in the improvement of the current time fraction rule. The simplified mode test approach would offer a whole new advantage including robustness and simplicity which are definitely attractive but this approach is yet to be validated for implementation at this point. Therefore, this report recommends the following two steps as a course of improvement of NH based on newly proposed creep-fatigue evaluation methodologies. The first step is to modify the current approach by incorporating the partial advantages the new method offer, and the second step is to replace the current method by the simplified test approach when it has become technically mature enough. The recommendations are basically in line with the work scope of the Task Force on Creep-Fatigue of the Subgroup on Elevated Temperature Design of the Standards Committee of the ASME Boiler and Pressure Vessel Committee Section III.

  8. GUIDELINES FOR DESIGN AND SAFE HANDLING OF CURVED I-SHAPED STEEL GIRDERS

    E-Print Network [OSTI]

    Texas at Austin, University of

    0-5574-P1 GUIDELINES FOR DESIGN AND SAFE HANDLING OF CURVED I-SHAPED STEEL GIRDERS Authors: Jason FOR DESIGN AND SAFE HANDLING OF CURVED I-SHAPED STEEL GIRDERS PURPOSE: The purpose of this set of guidelines-sixth #12;2 (Eq. 6.10.2.2-2). However, TxDOT's Preferred Practices for Steel Bridge Design, Fabrication

  9. Design computing of complex-curved geometry using digital fabrication methods

    E-Print Network [OSTI]

    Griffith, Kenfield A. (Kenfield Allistair)

    2006-01-01T23:59:59.000Z

    The production of design information for digital fabrication is presented in this thesis. This thesis outlines the research of generating information for physical construction as architectural models of complex curved walls ...

  10. Relationship between design speed and operating speed at horizontal curves on suburban arterials

    E-Print Network [OSTI]

    Shamburger, Carl Brian

    1995-01-01T23:59:59.000Z

    RELATIONSHIP BETWEEN DESIGN SPEED AND OPERATING SPEED AT HORIZONTAL CURVES ON SUBURBAN ARTERIALS A Thesis by CARL BRIAN SHAMBURGER Submitted to the OIIice of Graduate Studies of Texas A&M University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE December 1995 Major Subject: Civil Engineering RELATIONSHIP BETWEEN DESIGN SPEED AND OPERATING SPEED AT HORIZONTAL CURVES ON SUBURBAN ARTERIALS A Thesis by CARL BRIAN SHAMBURGER Submitted to Texas A&M University...

  11. EDIC RESEARCH PROPOSAL 1 Performative Curve Network Design

    E-Print Network [OSTI]

    piece by rapid-prototyping techniques such as 3D printing, architectural dimensions call for a more or energy consumption. Index Terms--architectural geometry, performative design, rationalization, paneling

  12. Road Materials and Pavements Design. Volume X No X/2009, pages 1 to 16 Pavement Design for Curved Road Sections

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Road Materials and Pavements Design. Volume X ­ No X/2009, pages 1 to 16 Pavement Design for Curved pavements Christophe Petit* -- Malick Diakhaté* -- Anne Millien* -- Annabelle Phelipot-Mardelé* -- Bertrand@eurovia.com ABSTRACT. This paper focuses on damage processes other than the main one observed and studied in pavement

  13. The impact of modern headlamps on the design of sag vertical curves

    E-Print Network [OSTI]

    Gogula, Madhuri

    2006-08-16T23:59:59.000Z

    &M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved by: Chair of Committee, H. Gene Hawkins Committee Members, Dominique Lord Rodger J. Koppa Paul J. Carlson Head of Department... was recognized and used in the design of the Pennsylvania Turnpike. The review of literature revealed that the Pennsylvania Turnpike used the first design charts (documented in 1940) to provide sight distance on sag curves (44). These design charts used a...

  14. Ris-R-1374(EN) Design of a 21 m Blade with Ris-A1

    E-Print Network [OSTI]

    , power curve and fatigue loads were derived on basis of the measurements. Most of the design criteria as the wind turbine with LM 21.0P blades but at the same time a 15% decrease in blade fatigue loads. However National Laboratory, made the power curve analysis. · Peter Fuglsang, Risø National Laboratory, responsible

  15. A Scan-based Attack on Elliptic Curve Cryptosystems in presence of Industrial Design-for-Testability Structures

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    A Scan-based Attack on Elliptic Curve Cryptosystems in presence of Industrial Design-based attack on hardware implementations of Elliptic Curve Cryptosystems (ECC). Several up-to-date Design aspects of the proposed scan-based attack are described, namely timing and leakage analysis that allows

  16. An evaluation of alternative horizontal curve design approaches for rural two-lane highways

    E-Print Network [OSTI]

    Voigt, Anthony Paul

    1995-01-01T23:59:59.000Z

    (8), and Fink (9). The significance of these relationships was evaluated to determine if present values used in design of superelevation and side friction should be reevaluated. Results of the analysis were used to evaluate alternative methods... of these relafionships. Anderson (8) and Fink (9), respectively, conducted safety analyses using a data base that included roadways from three regions of the United States. This data base included rural roadways in Texas, Washington, and New York. Several curve...

  17. Fatigue-crack growth correlations for design and analysis of stainless steel components

    SciTech Connect (OSTI)

    James, L.A.

    1981-10-01T23:59:59.000Z

    A relatively large collection of fatigue-crack growth results for annealed Types 304 and 316 stainless steels over a wide range of temperature was processed and analyzed in a consistent way. Only data that satisfied the criteria of ASTM E647-82 was retained and used in the statistical treatments that followed. Linear least-squares regression equations and 95% confidence intervals were fitted through the results for each material/temperature set. The regression results (and their associated limits of validity) provide useful equations for the analysis of structural components. Overlap (or the lack of overlap) of the confidence intervals was employed as a criterion as to whether the results for Types 304 and 316 should be separated into discrete sets, and on this basis it was concluded that the two alloys should be treated separately. 38 references, 16 figures, 1 table.

  18. Design, build and test of an axial flow hydrokinetic turbine with fatigue analysis

    E-Print Network [OSTI]

    Ketcham, Jerod W

    2010-01-01T23:59:59.000Z

    OpenProp is an open source propeller and turbine design and analysis code that has been in development since 2007 by MIT graduate students under the supervision of Professor Richard Kimball. In order to test the performance ...

  19. Projection of fractures in ships for the evaluation of fatigue resistant designs

    E-Print Network [OSTI]

    Hadjiyiannis, Nicholas

    2009-01-01T23:59:59.000Z

    Cracks in ships have been of great concern to the maritime industry for a very long time. The problem is controlled by improving design, minimizing operating stresses and through regular inspections and repairs. The big ...

  20. Comparison of fatigue analysis approaches for predicting fatigue lives of hot-mix asphalt concrete (HMAC) mixtures

    E-Print Network [OSTI]

    Walubita, Lubinda F.

    2006-08-16T23:59:59.000Z

    Hot-mix asphalt concrete (HMAC) mixture fatigue characterization constitutes a fundamental component of HMAC pavement structural design and analysis to ensure adequate field fatigue performance. HMAC is a heterogeneous complex composite material...

  1. A Fatigue Approach to Wind Turbine Control

    E-Print Network [OSTI]

    A Fatigue Approach to Wind Turbine Control Keld Hammerum Kongens Lyngby 2006 #12;Technical to the turbulent nature of wind, the structural components of a wind turbine are exposed to highly varying loads. Therefore, fatigue damage is a major consideration when designing wind turbines. The control scheme applied

  2. Multiaxial fatigue models for short glass fiber reinforced polyamide. Part II: Fatigue life estimation.

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    -as-moulded (DAM). Post-processing the cyclic response in steady-state allows the comparison of several fatigue to design those components against fatigue failure has become a serious issue during the last years, when giving the best correlation with the number of cycles to failure. The relationship

  3. Development of Yield and Tensile Strength Design Curves for Alloy 617

    SciTech Connect (OSTI)

    Nancy Lybeck; T. -L. Sham

    2013-10-01T23:59:59.000Z

    The U.S. Department of Energy Very High Temperature Reactor Program is acquiring data in preparation for developing an Alloy 617 Code Case for inclusion in the nuclear section of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code. A draft code case was previously developed, but effort was suspended before acceptance by ASME. As part of the draft code case effort, a database was compiled of yield and tensile strength data from tests performed in air. Yield strength and tensile strength at temperature are used to set time independent allowable stress for construction materials in B&PV Code, Section III, Subsection NH. The yield and tensile strength data used for the draft code case has been augmented with additional data generated by Idaho National Laboratory and Oak Ridge National Laboratory in the U.S. and CEA in France. The standard ASME Section II procedure for generating yield and tensile strength at temperature is presented, along with alternate methods that accommodate the change in temperature trends seen at high temperatures, resulting in a more consistent design margin over the temperature range of interest.

  4. On the Fatigue Analysis of Wind Turbines

    SciTech Connect (OSTI)

    Sutherland, Herbert J.

    1999-06-01T23:59:59.000Z

    Modern wind turbines are fatigue critical machines that are typically used to produce electrical power from the wind. Operational experiences with these large rotating machines indicated that their components (primarily blades and blade joints) were failing at unexpectedly high rates, which led the wind turbine community to develop fatigue analysis capabilities for wind turbines. Our ability to analyze the fatigue behavior of wind turbine components has matured to the point that the prediction of service lifetime is becoming an essential part of the design process. In this review paper, I summarize the technology and describe the ''best practices'' for the fatigue analysis of a wind turbine component. The paper focuses on U.S. technology, but cites European references that provide important insights into the fatigue analysis of wind turbines.

  5. Collect Available Creep-Fatigue Data and Study Existing Creep-Fatigue Evaluation Procedures for Grade 91 and Hastelloy XR

    SciTech Connect (OSTI)

    Tai Asayama; Yukio Tachibana

    2007-09-30T23:59:59.000Z

    This report describes the results of investigation on Task 5 of DOE/ASME Materials Project based on a contract between ASME Standards Technology, LLC (ASME ST-LLC) and Japan Atomic Energy Agency (JAEA). Task 5 is to collect available creep-fatigue data and study existing creep-fatigue evaluation procedures for Grade 91 steel and Hastelloy XR. Part I of this report is devoted to Grade 91 steel. Existing creep-fatigue data were collected (Appendix A) and analyzed from the viewpoints of establishing a creep-fatigue procedure for VHTR design. A fair amount of creep-fatigue data has been obtained and creep-fatigue phenomena have been clarified to develop design standards mainly for fast breeder reactors. Following this, existing creep-fatigue procedures were studied and it was clarified that the creep-fatigue evaluation procedure of the ASME-NH has a lot of conservatisms and they were analyzed in detail from the viewpoints of the evaluation of creep damage of material. Based on the above studies, suggestions to improve the ASME-NH procedure along with necessary research and development items were presented. Part II of this report is devoted to Hastelloy XR. Existing creep-fatigue data used for development of the high temperature structural design guideline for High Temperature Gas-cooled Reactor (HTGR) were collected. Creep-fatigue evaluation procedure in the design guideline and its application to design of the intermediate heat exchanger (IHX) for High Temperature Engineering Test Reactor (HTTR) was described. Finally, some necessary research and development items in relation to creep-fatigue evaluation for Gen IV and VHTR reactors were presented.

  6. Learning Curve

    Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

    1997-03-28T23:59:59.000Z

    It is a fundamental human characteristic that a person engaged in a repetitive task will improve his performance over time. If data are gathered on this phenomenon, a curve representing a decrease in effort per unit for repetitive operations can be developed. This phenomenon is real and has a specific application in cost analysis, cost estimating, or profitability studies related to the examination of future costs and confidence levels in an analysis. This chapter discusses the development and application of the learning curve.

  7. Drag amplification and fatigue damage in vortex-induced vibrations

    E-Print Network [OSTI]

    Jhingran, Vikas Gopal

    2008-01-01T23:59:59.000Z

    Fatigue damage and drag force amplification due to Vortex-Induced-Vibrations (VIV) continue to cause significant problems in the design of structures which operate in ocean current environments. These problems are magnified ...

  8. Flow Duration Curve Load Duration Curve

    E-Print Network [OSTI]

    #12;Flow Duration Curve Load Duration Curve #12;1. Develop Flow Duration Curve 2. Estimate load given flow and concentration data--select appropriate conversion factors 3. Develop Load Duration Curve 4. Plot observed data with Load Duration Curve #12;What are they? How do you make one? #12;Describes

  9. Flow Duration Curve Load Duration Curve

    E-Print Network [OSTI]

    Flow Duration Curve Load Duration Curve 1. Develop Flow Duration Curve 2. Estimate load given flow and concentration data--select appropriate conversion factors 3. Develop Load Duration Curve 4. Plot observed data with Load Duration Curve What are they? How do you make one? Describes the percent of time a flow rate

  10. Curved Space or Curved Vacuum?

    E-Print Network [OSTI]

    Eric V. Linder

    2005-10-11T23:59:59.000Z

    While the simple picture of a spatially flat, matter plus cosmological constant universe fits current observation of the accelerated expansion, strong consideration has also been given to models with dynamical vacuum energy. We examine the tradeoff of ``curving'' the vacuum but retaining spatial flatness, vs. curving space but retaining the cosmological constant. These different breakdowns in the simple picture could readily be distinguished by combined high accuracy supernovae and cosmic microwave background distance measurements. If we allow the uneasy situation of both breakdowns, the curvature can still be measured to 1%, but at the price of degrading estimation of the equation of state time variation by 60% or more, unless additional information (such as weak lensing data or a tight matter density prior) is included.

  11. Every curve is a Teichmuller curve

    E-Print Network [OSTI]

    Ellenberg, Jordan S

    2009-01-01T23:59:59.000Z

    We prove that every algebraic curve X defined over the algebraic closure of the rationals is birational over the complex numbers to a Teichmuller curve.

  12. A Summary of the Fatigue Properties of Wind Turbine Materials

    SciTech Connect (OSTI)

    SUTHERLAND, HERBERT J.

    1999-10-07T23:59:59.000Z

    Modern wind turbines are fatigue critical machines that are typically used to produce electrical power from the wind. The materials used to construct these machines are subjected to a unique loading spectrum that contains several orders of magnitude more cycles than other fatigue critical structures, e.g., an airplane. To facilitate fatigue designs, a large database of material properties has been generated over the past several years that is specialized to materials typically used in wind turbines. In this paper, I review these fatigue data. Major sections are devoted to the properties developed for wood, metals (primarily aluminum) and fiberglass. Special emphasis is placed on the fiberglass discussion because this material is current the material of choice for wind turbine blades. The paper focuses on the data developed in the U.S., but cites European references that provide important insights.

  13. Standard test method for creep-fatigue testing

    E-Print Network [OSTI]

    American Society for Testing and Materials. Philadelphia

    2009-01-01T23:59:59.000Z

    1.1 This test method covers the determination of mechanical properties pertaining to creep-fatigue deformation or crack formation in nominally homogeneous materials, or both by the use of test specimens subjected to uniaxial forces under isothermal conditions. It concerns fatigue testing at strain rates or with cycles involving sufficiently long hold times to be responsible for the cyclic deformation response and cycles to crack formation to be affected by creep (and oxidation). It is intended as a test method for fatigue testing performed in support of such activities as materials research and development, mechanical design, process and quality control, product performance, and failure analysis. The cyclic conditions responsible for creep-fatigue deformation and cracking vary with material and with temperature for a given material. 1.2 The use of this test method is limited to specimens and does not cover testing of full-scale components, structures, or consumer products. 1.3 This test method is primarily ...

  14. Predicting the fatigue life of asphalt concrete overlay systems

    E-Print Network [OSTI]

    Germann, Frederick P

    1979-01-01T23:59:59.000Z

    ON CRACK GROWTH IN VISCOELASTIC MATERIALS C'HAPTER V - STATE OF THE ART Effect of Mix Variables on Fatigue and Cracking Resistance in Asphalt Concrete Pavements . Field Performance of Asphalt Overlays with Fabric Summary CHAPTER VI ? MATERIALS... LIFE OF AN ASPHALT OVERLAY CHAPTER X - CONCLUSIONS AND RECOMMENDATIONS REFERENCES APPENDIX A. CRACK TIP STRESS ANALYSIS APPENDIX B. CONSTRUCTION OF THE MASTER RESILIENT MODULUS AND MASTER CREEP COMPLIANCE CURVES APPENDIX C. CRACK GROWTH RATES, da...

  15. Application of bi-linear loglog SN model to strain-controlled fatigue data of aluminum alloys and its effect on life predictions

    E-Print Network [OSTI]

    Fatemi, Ali

    Application of bi-linear log­log S­N model to strain-controlled fatigue data of aluminum alloys­log model is applied to stress amplitude versus fatigue life data of 14 aluminum alloys. It is shown-life curves are discussed. Life predictions of aluminum alloys based on linear and bi-linear models are also

  16. A NON-ISOTHERMAL FATIGUE CRACK GROWTH LAW FOR THE A356-T7 ALUMINUM ALLOY

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 A NON-ISOTHERMAL FATIGUE CRACK GROWTH LAW FOR THE A356-T7 ALUMINUM ALLOY E. Merhy 1,2,3* , L rate, Damage tolerant design, Life time prediction, A356 cast alloy ABSTRACT Fatigue crack growth period in cylinder heads of A356-T7 casting alloy has been found to constitute an important part

  17. Reversal bending fatigue testing

    SciTech Connect (OSTI)

    Wang, Jy-An John; Wang, Hong; Tan, Ting

    2014-10-21T23:59:59.000Z

    Embodiments for apparatuses for testing reversal bending fatigue in an elongated beam are disclosed. Embodiments are configured to be coupled to first and second end portions of the beam and to apply a bending moment to the beam and create a pure bending condition in an intermediate portion of the beam. Embodiments are further configured to cyclically alternate the direction of the bending moment applied to the beam such that the intermediate portion of the beam cyclically bends in opposite directions in a pure bending condition.

  18. 1 INTRODUCTION Flexural fatigue is one of the main failure modes in asphalt mixtures and flexible pavement

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    pavement structures. This means good prediction of a pavement's fatigue life will help to develop and im- prove pavement design procedures. Fatigue resistance and stiffness are two required parameters for pavement design necessary to dimension the pavement structure (layer thickness). European standards (EN

  19. Ris-R-1168 (EN) Fatigue damage development

    E-Print Network [OSTI]

    blades for wind turbines, for instance, hybrid designs with glass/carbon fibre reinforced plastics/carbon fibre hybrid laminates Olivia Redon Materials Research Department Risø National Laboratory, Roskilde are under consideration as the blades are getting larger than 30-40 metres. The tensile fatigue behaviour

  20. Static and fatigue testing of full-scale fuselage panels fabricated using a Therm-X(R) process

    SciTech Connect (OSTI)

    Dinicola, A.J.; Kassapoglou, C.; Chou, J.C.

    1992-09-01T23:59:59.000Z

    Large, curved, integrally stiffened composite panels representative of an aircraft fuselage structure were fabricated using a Therm-X process, an alternative concept to conventional two-sided hard tooling and contour vacuum bagging. Panels subsequently were tested under pure shear loading in both static and fatigue regimes to assess the adequacy of the manufacturing process, the effectiveness of damage tolerant design features co-cured with the structure, and the accuracy of finite element and closed-form predictions of postbuckling capability and failure load. Test results indicated the process yielded panels of high quality and increased damage tolerance through suppression of common failure modes such as skin-stiffener separation and frame-stiffener corner failure. Finite element analyses generally produced good predictions of postbuckled shape, and a global-local modelling technique yielded failure load predictions that were within 7% of the experimental mean.

  1. PREDICTORS OF POST-STROKE FATIGUE

    E-Print Network [OSTI]

    Tseng, Benjamin Yichen

    2009-01-29T23:59:59.000Z

    .3.4 Fatigue Classifications 10 1.4 Fatigue Scales 12 1.4.1 Previous Fatigue Scales 12 1.4.2 Measuring Chronic Fatigue 14 1.4.3 Measuring Exertion Fatigue 16 1.5 Post-Stroke Fatigue 18 1.6 Contributing Factors to PSF 21 1.6....1 Overview of Potential Factors 21 1.6.2 Aerobic Fitness 22 1.6.3 Physical Impairment 23 1.6.4 Depression 26 vii 1.6.5 Lesion Characteristics 28 1.6.6 Sleep Disorders 30 1.6.7 Medication Side Effects 31 1...

  2. Peridynamic model for fatigue cracking.

    SciTech Connect (OSTI)

    Silling, Stewart A.; Abe Askari (Boeing)

    2014-10-01T23:59:59.000Z

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

  3. Effect of fiber fabric orientation on the monotonic and fatigue behavior of a continuous fiber ceramic composite

    SciTech Connect (OSTI)

    Chawla, N.; Liaw, P.K. [Tennessee Univ., Knoxville, TN (United States). Dept. of Materials Science and Engineering; Lara-Curzio, E.; Lowden, R.A.; Ferber, M.K. [Oak Ridge National Lab., TN (United States)

    1994-09-01T23:59:59.000Z

    The monotonic fast fracture and fatigue behavior of a Nextel{trademark} 312 reinforced SiC matrix composite was investigated. Effect of fabric orientation with respect to the loading axis on the monotonic and fatigue behavior of the composite was examined. Two geometries were investigated: transverse, where fiber fabric is perpendicular to loading direction; and edge-on where the fabric is parallel to the loading axis. The edge-on geometry showed higher flexure strengths than the transverse orientation. The different deformation mechanisms between the edge-on and transverse orientations were due to strong in-plane shearing of the fiber fabric and weak interlaminar shear of the plies, respectively. In cyclic fatigue, stress versus cycles (S-N) curves showed high fatigue endurance limits in both orientations, although the transverse orientation survived more cycles than the edge-on orientation at stresses slightly above the endurance limit.

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

    E-Print Network [OSTI]

    American Society for Testing and Materials. Philadelphia

    2010-01-01T23:59:59.000Z

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

  5. Fatigue of extracted lead zirconate titanate multilayer actuators under unipolar high field electric cycling

    SciTech Connect (OSTI)

    Wang, Hong [ORNL; Lee, Sung Min [ORNL; Wang, James L [ORNL; Lin, Hua-Tay [ORNL

    2014-01-01T23:59:59.000Z

    Testing of large prototype lead zirconate titanate (PZT) stacks presents substantial technical challenges to electronic testing systems, so an alternative approach that uses subunits extracted from prototypes has been pursued. Extracted 10-layer and 20-layer plate specimens were subjected to an electric cycle test under an electric field of 3.0/0.0 kV/mm, 100 Hz to 10^8 cycles. The effects of measurement field level and stack size (number of PZT layers) on the fatigue responses of piezoelectric and dielectric coefficients were observed. On-line monitoring permitted examination of the fatigue response of the PZT stacks. The fatigue rate (based on on-line monitoring) and the fatigue index (based on the conductance spectrum from impedance measurement or small signal measurement) were developed to quantify the fatigue status of the PZT stacks. The controlling fatigue mechanism was analyzed against the fatigue observations. The data presented can serve as input to design optimization of PZT stacks and to operation optimization in critical applications such as piezoelectric fuel injectors in heavy-duty diesel engines.

  6. FRACTURE MECHANICS APPROACH TO ESTIMATE FATIGUE LIVES OF WELDED LAP-SHEAR SPECIMENS

    SciTech Connect (OSTI)

    Lam, P.; Michigan, J.

    2014-04-25T23:59:59.000Z

    A full range of stress intensity factor solutions for a kinked crack is developed as a function of weld width and the sheet thickness. When used with the associated main crack solutions (global stress intensity factors) in terms of the applied load and specimen geometry, the fatigue lives can be estimated for the laser-welded lap-shear specimens. The estimations are in good agreement with the experimental data. A classical solution for an infinitesimal kink is also employed in the approach. However, the life predictions tend to overestimate the actual fatigue lives. The traditional life estimations with the structural stress along with the experimental stress-fatigue life data (S-N curve) are also provided. In this case, the estimations only agree with the experimental data under higher load conditions.

  7. Stress intensity factors and fatigue growth of a surface crack in a drill pipe during rotary drilling operation

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Stress intensity factors and fatigue growth of a surface crack in a drill pipe during rotary drilling operation Ngoc Ha Daoa, , Hedi Sellamia aMines ParisTech, 35 rue Saint-Honoré, 77305 Fontainebleau cedex, France Abstract Drill pipe in a curved section of the drilled well is considered as a rotating

  8. Pairings on hyperelliptic curves

    E-Print Network [OSTI]

    Balakrishnan, Jennifer; Chisholm, Sarah; Eisentraeger, Kirsten; Stange, Katherine; Teske, Edlyn

    2009-01-01T23:59:59.000Z

    We assemble and reorganize the recent work in the area of hyperelliptic pairings: We survey the research on constructing hyperelliptic curves suitable for pairing-based cryptography. We also showcase the hyperelliptic pairings proposed to date, and develop a unifying framework. We discuss the techniques used to optimize the pairing computation on hyperelliptic curves, and present many directions for further research.

  9. Simultaneous confidence bands in curve prediction applied to load curves

    E-Print Network [OSTI]

    Boyer, Edmond

    Simultaneous confidence bands in curve prediction applied to load curves J.M. Aza¨is1, S. Bercu2, J, load curve. 1 Introduction In curve prediction, one is generally interested in deriving simultaneous this technique in the numerical context of load curve pre- diction: power producers like EDF, the electrical

  10. Seismic fragility curves for reinforced concrete A Dissertation Submitted in Partial Fulfilment of the Requirements

    E-Print Network [OSTI]

    Seismic fragility curves for reinforced concrete buildings A Dissertation Submitted in Partial dissertation entitled "Seismic fragility curves for reinforced concrete frame and wall- frame buildings. Buildings designed for seismic loading, and buildings designed only for gravity loads, are considered

  11. Auto/Steel Partnership: Fatigue of AHSS Strain Rate Characterization...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Fatigue of AHSS Strain Rate Characterization AutoSteel Partnership: Fatigue of AHSS Strain Rate Characterization 2009 DOE Hydrogen Program and Vehicle Technologies Program Annual...

  12. Crude oil supply curves

    E-Print Network [OSTI]

    Adelman, Morris Albert

    1998-01-01T23:59:59.000Z

    Short-run cost curves shift over time as depletion counters increasing knowledge. Under competition, a rightward (leftward) shift indicates lower (higher) cost and greater (lesser) productivity. A simple coefficient captures ...

  13. Prediction of the Creep-Fatigue Lifetime of Alloy 617: An Application of Non-destructive Evaluation and Information Integration

    SciTech Connect (OSTI)

    Vivek Agarwal; Richard Wright; Timothy Roney

    2014-08-01T23:59:59.000Z

    A relatively simple method using the nominal constant average stress information and the creep rupture model is developed to predict the creep-fatigue lifetime of Alloy 617, in terms of time to rupture. The nominal constant average stress is computed using the stress relaxation curve. The predicted time to rupture can be converted to number of cycles to failure using the strain range, the strain rate during each cycle, and the hold time information. The predicted creep-fatigue lifetime is validated against the experimental measurements of the creep-fatigue lifetime collected using conventional laboratory creep-fatigue tests. High temperature creep-fatigue tests of Alloy 617 were conducted in air at 950°C with a tensile hold period of up to 1800s in a cycle at total strain ranges of 0.3% and 0.6%. It was observed that the proposed method is conservative in that the predicted lifetime is less than the experimentally determined values. The approach would be relevant to calculate the remaining useful life to a component like a steam generator that might fail by the creep-fatigue mechanism.

  14. Human Muscle Fatigue Model in Dynamic Motions

    E-Print Network [OSTI]

    Boyer, Edmond

    into account. In this paper, each human joint is assumed to be controlled by two muscle groups to generate on motor units pattern. They demonstrated the relationship among muscle activation, fatigue and recovery fatigue trend in static working posture (elbow = 90 , shoulder = 30 ), but in dynamic working situation

  15. : runout specimen max : maximum fatigue stress

    E-Print Network [OSTI]

    High Performance Fibre Reinforced Concrete (UHPFRC) layer to concrete bridge deck slab was conceived was drawn without runout specimens .) Figure 6 Fatigue fracture surface of (a) UHPFRC, (b) steel rebar (a influenced by fibre distribution and orientation. Fatigue fracture surface of UHPFRC is similar

  16. DOE/MSU composite material fatigue database: Test methods, materials, and analysis

    SciTech Connect (OSTI)

    Mandell, J.F.; Samborsky, D.D. [Montana State Univ., Bozeman, MT (United States). Dept. of Chemical Engineering

    1997-12-01T23:59:59.000Z

    This report presents a detailed analysis of the results from fatigue studies of wind turbine blade composite materials carried out at Montana State University (MSU) over the last seven years. It is intended to be used in conjunction with the DOE/MSU composite Materials Fatigue Database. The fatigue testing of composite materials requires the adaptation of standard test methods to the particular composite structure of concern. The stranded fabric E-glass reinforcement used by many blade manufacturers has required the development of several test modifications to obtain valid test data for materials with particular reinforcement details, over the required range of tensile and compressive loadings. Additionally, a novel testing approach to high frequency (100 Hz) testing for high cycle fatigue using minicoupons has been developed and validated. The database for standard coupon tests now includes over 4,100 data points for over 110 materials systems. The report analyzes the database for trends and transitions in static and fatigue behavior with various materials parameters. Parameters explored are reinforcement fabric architecture, fiber content, content of fibers oriented in the load direction, matrix material, and loading parameters (tension, compression, and reversed loading). Significant transitions from good fatigue resistance to poor fatigue resistance are evident in the range of materials currently used in many blades. A preliminary evaluation of knockdowns for selected structural details is also presented. The high frequency database provides a significant set of data for various loading conditions in the longitudinal and transverse directions of unidirectional composites out to 10{sup 8} cycles. The results are expressed in stress and strain based Goodman Diagrams suitable for design. A discussion is provided to guide the user of the database in its application to blade design.

  17. Modeling Thermal Fatigue in CPV Cell Assemblies (Presentation)

    SciTech Connect (OSTI)

    Bosco, N.; Panchagade, D.; Kurtz, S.

    2011-02-01T23:59:59.000Z

    This presentation outlines the modeling of thermal fatigue in concentrating photovoltaic (CPV) assemblies.

  18. Accelerating Fatigue Testing for Cu Ribbon Interconnects (Presentation)

    SciTech Connect (OSTI)

    Bosco, N.; Silverman, T.; Wohlgemuth , J.; Kurtz, S.; Inoue, M.; Sakurai, K.; Shioda, T.; Zenkoh, H.; Miyashita, M.; Tadanori, T.; Suzuki, S.

    2013-05-01T23:59:59.000Z

    This presentation describes fatigue experiments and discusses dynamic mechanical loading for Cu ribbon interconnects.

  19. Solder fatigue reduction in point focus photovoltaic concentrator modules

    SciTech Connect (OSTI)

    Hund, T.D.; Burchett, S.N.

    1991-01-01T23:59:59.000Z

    Solder fatigue tests have been conducted on point focus photovoltaic concentration cell assemblies to identify a baseline fatigue life and to quantify the fatigue life improvements that result using a copper-molybdenum-copper low-expansion insert between the solar cell and copper heat spreader. Solder microstructural changes and fatigue crack growth were identified using cross sections and ultrasonic scans of the fatigue solder joints. The Coffin-Manson and Total Strain fatigue models for low-cycle fatigue were evaluated for use in fatigue life predictions. Since both of these models require strain calculations, two strain calculation methods were compared: hand-calculated shear strain and a finite element method shear strain. At present, the available theoretical models for low-cycle solder fatigue are limited in their ability to predict failure; consequently, extensive thermal cycling is continuing to define the fatigue life for point focus photovoltaic cell assemblies. 9 refs., 9 figs., 2 tabs.

  20. Substrate Creep on The Fatigue Life of A Model Dental Multilayer Structure

    SciTech Connect (OSTI)

    Zhou, J; Huang, M; Niu, X; soboyejo, W

    2006-10-09T23:59:59.000Z

    In this paper, we investigated the effects of substrate creep on the fatigue behavior of a model dental multilayer structure, in which a top glass layer was bonded to a polycarbonate substrate through a dental adhesive. The top glass layers were ground using 120 grit or 600 grit sand papers before bonding to create different sub-surface crack sizes and morphologies. The multilayer structures were tested under cyclic Hertzian contact loading to study crack growth and obtain fatigue life curves. The experiment results showed that the fatigue lives of the multilayer structures were impaired by increasing crack sizes in the sub-surfaces. They were also significantly reduced by the substrate creep when tested at relatively low load levels i.e. P{sub m} < 60 N (Pm is the maximum magnitude of cyclic load). But at relatively high load levels i.e. P{sub m} > 65 N, slow crack growth (SCG) was the major failure mechanisms. A modeling study was then carried out to explore the possible failure mechanisms over a range of load levels. It is found that fatigue life at relatively low load levels can be better estimated by considering the substrate creep effect (SCE).

  1. A study of fatigue in drill collars

    E-Print Network [OSTI]

    Fowler, Joe Robert

    1969-01-01T23:59:59.000Z

    A STUDY OF FATIGUE IN DRILL COLLARS A Thesis by Joe Robert Feeler Approved as to style and content by: Chairman of Committee Head of Department Member /n/X~l~~ Member Member January 1969 ABSTRACT A Study of Fatigue in Drill Collars.... (January, 1969) Joe R. Fowler, B. S. , Texas A&M University; Directed by: Dr. P. D. Neiner Fatigue failures of drill collar connectors are presently cost- ing the major oil companies enormous sums of money in ruined equipment and lost time...

  2. Extinction curves in AGN

    E-Print Network [OSTI]

    B. Czerny

    2006-12-16T23:59:59.000Z

    The presence of the dust in the circumnuclear region strongly affects our view of the nucleus itself. The effect is strong in type 2 objects but weaker effect is likely to be present in type 1 objects as well. In these objects a correction to the observed optical/UV spectrum must be done in order to recover the intrinsic spectrum of a nucleus. The approach based on the extinction curve is convenient for that purpose so significant effort has been recently done in order to determine the extinction curve for the circumnuclear material. It seems clear that the circumnuclear dust is different from the average properties of the dust in the Interstellar Medium in our galaxy: the well known 2175 A feature is weak or absent in AGN nuclear dust, and the extinction curve at shorter wavelength does not seem to be rising as steeply. The circumnuclear dust is therefore more similar to SMC dust, or more likely, to the dust in very dense molecular clouds in our Galaxy. However, the exact shape of the extinction curve in the far UV is still a matter of debate, and various effects are difficult to disentangle.

  3. Solution to the problem of the poor cyclic fatigue resistance of bulk metallic glasses

    E-Print Network [OSTI]

    Ritchie, Robert

    length scales of 2 m, i.e., to less than the critical crack size for failure. Confinement of the damage of magnitude, making these ``designed'' composites as resistant to fatigue dam- age as high-strength steels failure can ensue along a single shear plane with essentially zero macroscopic ductility (6, 7

  4. Fatigue Enhancement of Category E' Detailsin Steel Bridge Girders Using CFRP Materials

    E-Print Network [OSTI]

    Kaan, Benjamin Nicolaas

    2008-01-01T23:59:59.000Z

    is reduced, resulting in an increased fatigue life of the detail. The CFRP overlays were also designed to be tough enough to resist internal crack growth and delamination due to shear stress from applied loads. Development of the CFRP overlay elements...

  5. An analysis of muscle fatigue due to complex tasks and its relation to the strain index

    E-Print Network [OSTI]

    Stephens, John-Paul

    2009-06-02T23:59:59.000Z

    The Strain Index was originally designed to analyze mono-task jobs. An experiment using a grip dynamometer was used to simulate six multiple task jobs to study the effect of complex tasks on localized muscle fatigue and to evaluate six different...

  6. Modelling the role of non metallic inclusions on the anisotropic fatigue behaviour of forged steel

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    reported as being 35% for 42CrMo4 steel [1] and 15% for a duplex stainless steel [2]. To design a forged steel E. Pessard* , F. Morel, A. Morel, D. Bellett LAMPA (EA1427) Arts et Métiers ParisTech Angers 2, Bd. This study aims at describing the high cycle fatigue response of a forged bainitic steel. This material

  7. AIAA-2003-0692 NEW FATIGUE DATA FOR W IND TURBINE BLADE M ATERIALS

    E-Print Network [OSTI]

    1 AIAA-2003-0692 NEW FATIGUE DATA FOR W IND TURBINE BLADE M ATERIALS John F. Mandell, Daniel D to the wind turbine industry in several areas: (a) very high cycle S-N data; (b) refined Goodman Diagram; (c the expected cycle range for turbines. While the data cannot be used directly in design due to the specialized

  8. Damage and fatigue Continuum damage mechanics modeling

    E-Print Network [OSTI]

    -CLÉS : endommagement, fatigue, métaux, béton, élastomères, roche REGC ­ 10/2006. Geomechanics in energy production, pages 849 to 877 #12;850 REGC ­ 10/2006. Geomechanics in energy production 1. Introduction Continuum

  9. Contact fatigue : life prediction and palliatives

    E-Print Network [OSTI]

    Conner, Brett P. (Brett Page), 1975-

    2002-01-01T23:59:59.000Z

    Fretting fatigue is defined as damage resulting from small magnitude (0.5-50 microns) displacement between contacting bodies where at least one of the bodies has an applied bulk stress. The applicability and limits of a ...

  10. Sensitivity of Solder Joint Fatigue to Sources of Variation in Advanced Vehicular Power Electronics Cooling

    SciTech Connect (OSTI)

    Vlahinos, A.; O'Keefe, M.

    2010-06-01T23:59:59.000Z

    This paper demonstrates a methodology for taking variation into account in thermal and fatigue analyses of the die attach for an inverter of an electric traction drive vehicle. This method can be used to understand how variation and mission profile affect parameters of interest in a design. Three parameters are varied to represent manufacturing, material, and loading variation: solder joint voiding, aluminum nitride substrate thermal conductivity, and heat generation at the integrated gate bipolar transistor. The influence of these parameters on temperature and solder fatigue life is presented. The heat generation loading variation shows the largest influence on the results for the assumptions used in this problem setup.

  11. Connecting curves for dynamical systems

    E-Print Network [OSTI]

    R. Gilmore; Jean-Marc Ginoux; Timothy Jones; C. Letellier; U. S. Freitas

    2010-03-08T23:59:59.000Z

    We introduce one dimensional sets to help describe and constrain the integral curves of an $n$ dimensional dynamical system. These curves provide more information about the system than the zero-dimensional sets (fixed points) do. In fact, these curves pass through the fixed points. Connecting curves are introduced using two different but equivalent definitions, one from dynamical systems theory, the other from differential geometry. We describe how to compute these curves and illustrate their properties by showing the connecting curves for a number of dynamical systems.

  12. Fatigue crack propagation in a quasi one-dimensional elasto-plastic model

    E-Print Network [OSTI]

    Tomás M. Guozden; Eduardo A. Jagla

    2012-06-27T23:59:59.000Z

    Fatigue crack advance induced by the application of cyclic quasistatic loads is investigated both numerically and analytically using a lattice spring model. The system has a quasi-one-dimensional geometry, and consists in two symmetrical chains that are pulled apart, thus breaking springs which connect them, and producing the advance of a crack. Quasistatic crack advance occurs as a consequence of the plasticity included in the springs which form the chains, and that implies a history dependent stress-strain curve for each spring. The continuous limit of the model allows a detailed analytical treatment that gives physical insight of the propagation mechanism. This simple model captures key features that cause well known phenomenology in fatigue crack propagation, in particular a Paris-like law of crack advance under cyclic loading, and the overload retardation effect.

  13. Fatigue failure in thin-film polysilicon is due to subcriticalcracking within the oxide layer

    SciTech Connect (OSTI)

    Alsem, D.H.; Muhlstein, C.L.; Stach, E.A.; Ritchie, R.O.

    2005-01-11T23:59:59.000Z

    It has been established that microelectromechanical systems (MEMS) created from polycrystalline silicon thin-films are subject to cyclic fatigue. Prior work by the authors has suggested that although bulk silicon is not susceptible to fatigue failure in ambient air, fatigue in micron-scale silicon is a result of a ''reaction-layer'' process, whereby high stresses induce a thickening of the post-release oxide at stress concentrations such as notches, which subsequently undergoes moisture-assisted cracking. However, there exists some controversy regarding the post-release oxide thickness of the samples used in the prior study. In this Letter, we present data from devices from a more recent fabrication run that confirm our prior observations. Additionally, new data from tests in high vacuum show that these devices do not fatigue when oxidation and moisture are suppressed. Each of these observations lends credence to the '''reaction-layer'' mechanism. Recent advances in the design of microelectromechanical systems (MEMS) have increased the demand for more reliable microscale structures. Although silicon is an effective and widely used structural material at the microscale, it is very brittle. Consequently, reliability is a limiting factor for commercial and defense applications. Since the surface to volume ratio of these structural films is very large, classical models for failure modes in bulk materials cannot always be applied. For example, whereas bulk silicon is immune to cyclic fatigue failure thin micron-scale structural films of silicon appear to be highly susceptible. It is clear that at these size scales, surface effects may become dominant in controlling mechanical properties. The main reliability issues for MEMS are stiction, fatigue and wear. Fatigue is important in cases where devices are subjected to a large number of loading cycles with amplitudes below their (single-cycle) fracture stress, which may arise due to vibrations intentionally induced in the structure (i.e. a resonator) or those which arise from the service environment. While the reliability of MEMS has received extensive attention, the physical mechanisms responsible for these failure modes have yet to be conclusively determined. This is particularly true for fatigue, where the mechanisms have been subject to intense debate. Recently we have proposed that the fatigue of micron-scale polysilicon is associated with stress-induced surface oxide thickening and moisture-assisted subcritical cracking in the amorphous SiO{sub 2} oxide layer (''reaction-layer'' fatigue). The mechanism of oxide thickening is as yet unknown, but is likely related to some form of stress-assisted diffusion. Allameh et al. suggest a complementary mechanism involving stress-assisted oxide thickening, caused by dissolution of the surface oxide which forms deep grooves that are sites for crack initiation. Kahn et al. have criticized these mechanisms and proposed that, instead, fatigue is caused by subcritical cracking due to contacting surface asperities in the compressive part of the cycle. To the authors' knowledge, there is no direct experimental observation of such asperity contact. Also, their model cannot explain why micron-scale silicon, and not bulk silicon, is susceptible to fatigue. Moreover, Kahn et al. do not acknowledge the role of stress-induced oxide thickening, which has been observed directly using TEM and indirectly using atomic-force microscope measurements by several investigators, and have questioned whether the materials utilized by Muhlstein et al. and Allameh et al. were representative due to the relatively thick oxide scales. Accordingly, the goal of the present research is to seek a definitive understanding of the physical mechanisms responsible for fatigue in polysilicon structural thin-films. Our approach is to combine on-chip testing methods with electron microscopy by fatiguing thin-film samples and observing them, in an unthinned condition, using high-voltage transmission electron microscopy (HVTEM). Two principal results are found from this work: (1

  14. Fatigue properties of die cast zinc alloys for automotive lock applications

    SciTech Connect (OSTI)

    Schrems, Karol K.; Dogan, Omer N.; Goodwin, F.E. (International Lead and Zinc Research Organization, Research Triangle, NC)

    2004-06-01T23:59:59.000Z

    During the 1970’s many automotive lock systems were converted from zinc die casting alloys to engineering plastics for reasons of weight and cost. Recent increases in requirements for precision and security have caused automotive and other lock designers to reconsider zinc alloy die-castings for these applications. To enable this, there is a need for mechanical property data comparable to that of the plastics materials used in these applications. In this work, rotary bending fatigue tests were performed on Alloys 3, 5, ZA-8 and AcuZinc 5 using an R.R. Moore fatigue machine. Testing was performed at 30 Hz and was stopped at 1x107 cycles. The fatigue limit results were compared to data reported in the literature for higher number of cycles and faster rotations.

  15. Rolling Contact Fatigue of Ceramics

    SciTech Connect (OSTI)

    Wereszczak, Andrew A [ORNL; Wang, W. [Bournemouth University, Bournemouth, United Kingdom; Wang, Y. [Bournemouth University, Bournemouth, United Kingdom; Hadfield, M. [Bournemouth University, Bournemouth, United Kingdom; Kanematsu, W. [National Institute of Advanced Industrial Science and Technology, Japan; Kirkland, Timothy Philip [ORNL; Jadaan, Osama M. [University of Wisconsin, Platteville

    2006-09-01T23:59:59.000Z

    High hardness, low coefficient of thermal expansion and high temperature capability are properties also suited to rolling element materials. Silicon nitride (Si{sub 3}N{sub 4}) has been found to have a good combination of properties suitable for these applications. However, much is still not known about rolling contact fatigue (RCF) behavior, which is fundamental information to assess the lifetime of the material. Additionally, there are several test techniques that are employed internationally whose measured RCF performances are often irreconcilable. Due to the lack of such information, some concern for the reliability of ceramic bearings still remains. This report surveys a variety of topics pertaining to RCF. Surface defects (cracks) in Si{sub 3}N{sub 4} and their propagation during RCF are discussed. Five methods to measure RCF are then briefly overviewed. Spalling, delamination, and rolling contact wear are discussed. Lastly, methods to destructively (e.g., C-sphere flexure strength testing) and non-destructively identify potential RCF-limiting flaws in Si{sub 3}N{sub 4} balls are described.

  16. Characterization of Fatigue Cracking and Healing of Asphalt Mixtures

    E-Print Network [OSTI]

    Luo, Xue

    2012-07-16T23:59:59.000Z

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

  17. Fatigue behavior of alpha-zirconium phosphate/epoxy nanocomposites

    E-Print Network [OSTI]

    Varadharajan, Balaji R.

    2006-04-12T23:59:59.000Z

    Fatigue crack growth in ±-Zirconium phosphate/epoxy nanocomposites was investigated. A new fatigue testing technique was implemented for miniature samples. Two different methods ?strength of materials and Rayleigh-Ritz - were used in determining...

  18. Reversible Bending Fatigue Testing on Zry-4 Surrogate Rods

    SciTech Connect (OSTI)

    Wang, Jy-An John [ORNL; Wang, Hong [ORNL; Bevard, Bruce Balkcom [ORNL; Howard, Rob L [ORNL

    2014-01-01T23:59:59.000Z

    Testing high-burnup spent nuclear fuel (SNF) presents many challenges in areas such as specimen preparation, specimen installation, mechanical loading, load control, measurements, data acquisition, and specimen disposal because these tasks are complicated by the radioactivity of the test specimens. Research and comparison studies conducted at Oak Ridge National Laboratory (ORNL) resulted in a new concept in 2010 for a U-frame testing setup on which to perform hot-cell reversible bending fatigue testing. Subsequently, the three-dimensional finite element analysis and the engineering design of components were completed. In 2013 the ORNL team finalized the upgrade of the U-frame testing setup and the integration of the U-frame setup into a Bose dual linear motor test bench to develop a cyclic integrated reversible-bending fatigue tester (CIRFT). A final check was conducted on the CIRFT test system in August 2013, and the CIRFT was installed in the hot cell in September 2013 to evaluate both the static and dynamic mechanical response of SNF rods under simulated loads. The fatigue responses of Zircaloy-4 (Zry-4) cladding and the role of pellet pellet and pellet clad interactions are critical to SNF vibration integrity, but such data are not available due to the unavailability of an effective testing system. While the deployment of the developed CIRFT test system in a hot cell will provide the opportunity to generate the data, the use of a surrogate rod has proven quite effective in identifying the underlying deformation mechanism of an SNF composite rod under an equivalent loading condition. This paper presents the experimental results of using surrogate rods under CIRFT reversible cyclic loading. Specifically, monotonic and cyclic bending tests were conducted on surrogate rods made of a Zry-4 tube and alumina pellet inserts, both with and without an epoxy bond.

  19. Microstructural heterogeneities and fatigue anisotropy of forged steels

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    procedure are compared to results from self-heating fatigue tests. For specimens orientated at 0 relative of the fatigue strength with the self-heating method has been observed to be correct. For specimens orientated and the fatigue strength drops significantly. For this case, it appears that the self-heating method has

  20. Sparkr Blade Test Centre Fatigue tests of wind turbine blades

    E-Print Network [OSTI]

    Sparkær Blade Test Centre Fatigue tests of wind turbine blades Flapwise fatigue tests of 3 blades wind load. By turning and oscillating the blade in the horzontal direction, an R-ratio of ­1 running at the Sparkær Centre Blade Test Facilities. Fatigue blade tests are performed in order

  1. Fatigue of Wind Blade Laminates:Fatigue of Wind Blade Laminates: Effects of Resin and Fabric Structure

    E-Print Network [OSTI]

    Fatigue of Wind Blade Laminates:Fatigue of Wind Blade Laminates: Effects of Resin and Fabric University MCARE 2012 #12;Outline · Overview of MSU Fatigue Program on Wind Blade MaterialsWind Blade Wind Blade Component Materials Acknowledgements: Sandia National Laboratories/DOE (Joshua Paquette

  2. STORAGE-YIELD CURVES WITH INFLOWS FROM A DIVERSION PIERLUIGI CLAPS

    E-Print Network [OSTI]

    Poggi, Davide

    1 STORAGE-YIELD CURVES WITH INFLOWS FROM A DIVERSION CHANNEL PIERLUIGI CLAPS DIFA, Università della Probabilistic analytical methods for building storage-yield curves provide reliable preliminary design condition of storage-yield curves of reservoirs when additional inflows from a diversion channel are available

  3. Langevin Equation on Fractal Curves

    E-Print Network [OSTI]

    Seema Satin; A. D. Gangal

    2014-04-28T23:59:59.000Z

    We analyse a random motion of a particle on a fractal curve, using Langevin approach. This involves defining a new velocity in terms of mass of the fractal curve, as defined in recent work. The geometry of the fractal curve, hence plays an important role in this analysis. A Langevin equation with a particular noise model is thus proposed and solved using techniques of the newly developed $F^\\alpha$-Calculus .

  4. Quantum curves and topological recursion

    E-Print Network [OSTI]

    Paul Norbury

    2015-02-16T23:59:59.000Z

    This is a survey article describing the relationship between quantum curves and topological recursion. A quantum curve is a Schr\\"odinger operator-like noncommutative analogue of a plane curve which encodes (quantum) enumerative invariants in a new and interesting way. The Schr\\"odinger operator annihilates a wave function which can be constructed using the WKB method, and conjecturally constructed in a rather different way via topological recursion.

  5. CREEP AND CREEP-FATIGUE OF ALLOY 617 WELDMENTS

    SciTech Connect (OSTI)

    Wright, Jill; Carroll, Laura; Wright, Richard

    2014-08-01T23:59:59.000Z

    The Very High Temperature Reactor (VHTR) Intermediate Heat Exchanger (IHX) may be joined to piping or other components by welding. Creep-fatigue deformation is expected to be a predominant failure mechanism of the IHX1 and thus weldments used in its fabrication will experience varying cyclic stresses interrupted by periods of elevated temperature deformation. These periods of elevated temperature deformation are greatly influenced by a materials’ creep behavior. The nickel-base solid solution strengthened alloy, Alloy 617, is the primary material candidate for a VHTR-type IHX, and it is expected that Alloy 617 filler metal will be used for welds. Alloy 617 is not yet been integrated into Section III of the Boiler and Pressure Vessel Code, however, nuclear component design with Alloy 617 requires ASME (American Society of Mechanical Engineers) Code qualification. The Code will dictate design for welded construction through significant performance reductions. Despite the similar compositions of the weldment and base material, significantly different microstructures and mechanical properties are inevitable. Experience of nickel alloy welds in structural applications suggests that most high temperature failures occur at the weldments or in the heat-affected zone. Reliably guarding against this type of failure is particularly challenging at high temperatures due to the variations in the inelastic response of the constituent parts of the weldment (i.e., weld metal, heat-affected zone, and base metal) [ref]. This work focuses on the creep-fatigue behavior of nickel-based weldments, a need noted during the development of the draft Alloy 617 ASME Code Case. An understanding of Alloy 617 weldments when subjected to this important deformation mode will enable determination of the appropriate design parameters associated with their use. Specifically, the three main areas emphasized are the performance reduction due to a weld discontinuity in terms of the reduced number of the cycles to failure and whether a saturation in reduced cycle life with increased hold times is observed, the microstructural stability over long cycle times, and finally, the location of the generated weldment data on a creep-fatigue damage diagram (D-diagram).

  6. Optimal Railroad Rail Grinding for Fatigue Mitigation

    E-Print Network [OSTI]

    Tangtragulwong, Potchara

    2012-02-14T23:59:59.000Z

    This dissertation aims to study the benefit of rail grinding on service life of railroad rails, focusing on failures due to rolling contact fatigue (RCF) at the rail head. Assuming a tangent rail with one-point contact at the running surface, a...

  7. Actuation Fatigue of Shape Memory Alloys

    E-Print Network [OSTI]

    Calhoun, Christopher

    2012-07-16T23:59:59.000Z

    A testing method was developed to cycle quickly and repeatably Ni60Ti40 (wt. %) SMA specimens through temperature-induced transformation while under constant stress until failure. Previous works have shown fatigue cracks to initiate in or around Ni3...

  8. Quantifying the Thermal Fatigue of CPV Modules

    SciTech Connect (OSTI)

    Bosco, N.; Kurtz, S.

    2011-02-01T23:59:59.000Z

    A method is presented to quantify thermal fatigue in the CPV die-attach from meteorological data. A comparative; study between cities demonstrates a significant difference in the accumulated damage. These differences are most; sensitive to the number of larger (?T) thermal cycles experienced for a location. High frequency data (<1/min) may; be required to most accurately employ this method.

  9. Random Curves by Conformal Welding

    E-Print Network [OSTI]

    K. Astala; P. Jones; A. Kupiainen; E. Saksman

    2009-12-17T23:59:59.000Z

    We construct a conformally invariant random family of closed curves in the plane by welding of random homeomorphisms of the unit circle given in terms of the exponential of Gaussian Free Field. We conjecture that our curves are locally related to SLE$(\\kappa)$ for $\\kappa<4$.

  10. Random Curves by Conformal Welding

    E-Print Network [OSTI]

    Astala, K; Kupiainen, A; Saksman, E

    2009-01-01T23:59:59.000Z

    We construct a conformally invariant random family of closed curves in the plane by welding of random homeomorphisms of the unit circle given in terms of the exponential of Gaussian Free Field. We conjecture that our curves are locally related to SLE$(\\kappa)$ for $\\kappa<4$.

  11. Fourier duality of quantum curves

    E-Print Network [OSTI]

    Luu, Martin

    2015-01-01T23:59:59.000Z

    There are two different ways to deform a quantum curve along the flows of the KP hierarchy. We clarify the relation between the two KP orbits: In the framework of suitable connections attached to the quantum curve they are related by a local Fourier duality. As an application we give a conceptual proof of duality results in 2D quantum gravity.

  12. Progress Report on Alloy 617 Isochronous Stress-Strain Curves

    SciTech Connect (OSTI)

    Jill K. Wright; Richard N. Wright; Nancy J. Lybeck

    2014-03-01T23:59:59.000Z

    Isochronous stress-strain curves for Alloy 617 up to a temperature of 1000°C will be required to qualify the material for elevated temperature design in Section III, Division 1, Subsection NH of the ASME Boiler and Pressure Vessel Code. Several potential methods for developing these curves are reviewed in this report. It is shown that in general power-law creep is the rate controlling deformation mechanism for a wide range of alloy heats, test temperatures and stresses. Measurement of the strain rate sensitivity of Alloy 617 indicates that the material is highly strain rate sensitive in the tensile deformation range above about 750°C. This suggests that the concept of a hot tensile curve as a bounding case on the isochronous stress-strain diagrams is problematic. The impact of strain rate on the hot tensile curves is examined and it is concluded that incorporating such a curve is only meaningful if a single tensile strain rate (typically the ASTM standard rate of 0.5%/min) is arbitrarily defined. Current experimentally determined creep data are compared to isochronous stress-strain curves proposed previously by the German programs in the 1980s and by the 1990 draft ASME Code Case. Variability in how well the experimental data are represented by the proposed design curves that suggests further analysis is necessary prior to completing a new draft Code Case.

  13. Driver mental workload requirements on horizontal curves based on occluded vision test measurements

    E-Print Network [OSTI]

    Shafer, Mark Anthony

    1994-01-01T23:59:59.000Z

    This thesis documents an evaluation of driver mental workload requirements on horizontal curves based on occluded vision test measurements. Driver workload is an important concept in the design of highway systems. A successful highway design...

  14. Advanced Tools For Characterizing HMA Fatigue Resistance

    E-Print Network [OSTI]

    Lawrence, James Jefferies

    2011-02-22T23:59:59.000Z

    5 RDT* Test Data??????????????????????... 44 6 DPSE Integration Bands. Adapted from Luo et al. (20)???????. 51 7 RDT* Data Import Correlations????????????????.. 88 8 TxDOT Type C Master Gradation Bands (% Passing by Weight or Volume) (21... with the Calibrated Mechanistic Surface Energy (CMSE) and Revised CMSE (CMSE*) methods. Data analysis procedures for fatigue tests associated with these methods will be included and discussed. Microsoft Excel macro?s developed for the analysis of the data obtained...

  15. Parabolic curves in Lie groups

    SciTech Connect (OSTI)

    Pauley, Michael [School of Mathematics and Statistics, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009 (Australia)

    2010-05-15T23:59:59.000Z

    To interpolate a sequence of points in Euclidean space, parabolic splines can be used. These are curves which are piecewise quadratic. To interpolate between points in a (semi-)Riemannian manifold, we could look for curves such that the second covariant derivative of the velocity is zero. We call such curves Jupp and Kent quadratics or JK-quadratics because they are a special case of the cubic curves advocated by Jupp and Kent. When the manifold is a Lie group with bi-invariant metric, we can relate JK-quadratics to null Lie quadratics which arise from another interpolation problem. We solve JK-quadratics in the Lie groups SO(3) and SO(1,2) and in the sphere and hyperbolic plane, by relating them to the differential equation for a quantum harmonic oscillator00.

  16. Use of CFRP Overlays to Repair Fatigue Damage in Steel Bridge Girders and Components

    E-Print Network [OSTI]

    Gangel, Regan Elisabeth

    2012-05-31T23:59:59.000Z

    Fatigue damage in steel girder bridges built prior to the mid-1980s is common due to distortion-induced fatigue. Different repair techniques have been developed and implemented to retrofit bridges of this era with existing fatigue damage...

  17. assisted fatigue crack: Topics by E-print Network

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

    an ongoing French project financially Boyer, Edmond 270 PREDICTING FATIGUE DURING ELECTRICALLY STIMULATED NON-ISOMETRIC CONTRACTIONS Biology and Medicine Websites Summary:...

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

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

    CONTRACTIONS Biology and Medicine Websites Summary: PREDICTING FATIGUE DURING ELECTRICALLY STIMULATED NON- ISOMETRIC CONTRACTIONS M. SUSAN MARION, Ph were to: (1) develop a...

  19. Residual Stresses for Structural Analysis and Fatigue Life Prediction...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Stresses for Structural Analysis and Fatigue Life Prediction in Vehicle Components: Success stories from the High Temperature Materials Laboratory (HTML) User Program Residual...

  20. Fatigue and Creep-Fatigue Deformation of an Ultra-Fine Precipitate Strengthened Advanced Austenitic Alloy

    SciTech Connect (OSTI)

    M.C. Carroll; L.J. Carroll

    2012-10-01T23:59:59.000Z

    An advanced austenitic alloy, HT-UPS (high-temperature ultrafine-precipitation-strengthened), has been identified as an ideal candidate material for the structural components of fast reactors and energy-conversion systems. HT-UPS alloys demonstrate improved creep resistance relative to 316 stainless steel (SS) through additions of Ti and Nb, which precipitate to form a widespread dispersion of stable nanoscale metallic carbide (MC) particles in the austenitic matrix. The low-cycle fatigue and creep-fatigue behavior of an HT-UPS alloy have been investigated at 650 °C and a 1.0% total strain, with an R-ratio of -1 and hold times at peak tensile strain as long as 150 min. The cyclic deformation response of HT-UPS is directly compared to that of standard 316 SS. The measured values for total cycles to failure are similar, despite differences in peak stress profiles and in qualitative observations of the deformed microstructures. Crack propagation is primarily transgranular in fatigue and creep-fatigue of both alloys at the investigated conditions. Internal grain boundary damage in the form of fine cracks resulting from the tensile hold is present for hold times of 60 min and longer, and substantially more internal cracks are quantifiable in 316 SS than in HT-UPS. The dislocation substructures observed in the deformed material differ significantly; an equiaxed cellular structure is observed in 316 SS, whereas in HT-UPS the microstructure takes the form of widespread and relatively homogenous tangles of dislocations pinned by the nanoscale MC precipitates. The significant effect of the fine distribution of precipitates on observed fatigue and creep-fatigue response is described in three distinct behavioral regions as it evolves with continued cycling.

  1. Wind turbine blade fatigue tests: lessons learned and application to SHM system development

    SciTech Connect (OSTI)

    Taylor, Stuart G. [Los Alamos National Laboratory; Farinholt, Kevin M. [Los Alamos National Laboratory; Jeong, Hyomi [Chonbuk National University, Korea; Jang, JaeKyung [Chonbuk National University, Korea; Park, Gyu Hae [Los Alamos National Laboratory; Todd, Michael D. [Los Alamos National Laboratory; Farrar, Charles R. [Los Alamos National Laboratory; Ammerman, Curtt N. [Los Alamos National Laboratory

    2012-06-28T23:59:59.000Z

    This paper presents experimental results of several structural health monitoring (SHM) methods applied to a 9-meter CX-100 wind turbine blade that underwent fatigue loading. The blade was instrumented with piezoelectric transducers, accelerometers, acoustic emission sensors, and foil strain gauges. It underwent harmonic excitation at its first natural frequency using a hydraulically actuated resonant excitation system. The blade was initially excited at 25% of its design load, and then with steadily increasing loads until it failed. Various data were collected between and during fatigue loading sessions. The data were measured over multiple frequency ranges using a variety of acquisition equipment, including off-the-shelf systems and specially designed hardware developed by the authors. Modal response, diffuse wave-field transfer functions, and ultrasonic guided wave methods were applied to assess the condition of the wind turbine blade. The piezoelectric sensors themselves were also monitored using a sensor diagnostics procedure. This paper summarizes experimental procedures and results, focusing particularly on fatigue crack detection, and concludes with considerations for implementing such damage identification systems, which will be used as a guideline for future SHM system development for operating wind turbine blades.

  2. Incorporating Experience Curves in Appliance Standards Analysis

    E-Print Network [OSTI]

    Desroches, Louis-Benoit

    2012-01-01T23:59:59.000Z

    experience curves for wind farms. Energy Policy 33, 133-150.curves for wind power. Energy Policy 30, 1181- Jakob, M. ,

  3. Corrosion fatigue in nitrocarburized quenched and tempered steels

    SciTech Connect (OSTI)

    Karim Khani, M.; Dengel, D. [Technical Univ. of Berlin (Germany). Dept. of Materials Technology

    1996-05-01T23:59:59.000Z

    In order to investigate the fatigue strength and fracture mechanism of salt bath nitrocarburized steels, specimens of the steels SAE 4135 and SAE 4140, in a quenched and tempered state, and additionally in a salt bath nitrocarburized and oxidizing cooled state as well as in a polished (after the oxidizing cooling) and renewed oxidized state, were subjected to comparative rotating bending fatigue tests in inert oil and 5 pct NaCl solution. In addition, some of the quenched and tempered specimens of SAE 4135 material were provided with an approximately 50-{mu}m-thick electroless Ni-P layer, in order to compare corrosion fatigue behavior between the Ni-P layer and the nitride layers. Long-life corrosion fatigue tests of SAE 4135 material were carried out under small stresses in the long-life range up to 10{sup 8} cycles with a test frequency of 100 Hz. Fatigue tests of SAE 4140 material were carried out in the range of finite life (low-cycle range) with a test frequency of 13 Hz. The results show that the 5 pct NaCl environment drastically reduced fatigue life, but nitrocarburizing plus oxidation treatment was found to improve the corrosion fatigue life over that of untreated and Ni-P coated specimens. The role of inclusions in initiating fatigue cracks was investigated. It was found that under corrosion fatigue conditions, the fatigue cracks started at cavities along the interfaces of MnS inclusions and matrix in the case of quenched and tempered specimens. The nitrocarburized specimens, however, showed a superposition of pitting corrosion and corrosion fatigue in which pores and nonmetallic inclusions in the compound layer play a predominant role concerning the formation of pits in the substrate.

  4. STRUCTURAL HEALTH MONITORING SOLUTIONS FOR POWER PLANTS Benoit Jouan, Jurgen Rudolph, Steffen Bergholz

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    but also in the context of conventional power plants and renewables such as wind power plants. Consequently of the fatigue analysis process: new design fatigue curves, consideration of environmental fatigue (EAF : Structural Health Monitoring, Fatigue Monitoring, Ageing Management, Power Plants, AREVA Fatigue Concept (AFC

  5. SANDIA CONTRACTORS REPORT FATIGUE OF COMPOSITE MATERIALS AND

    E-Print Network [OSTI]

    SANDIA CONTRACTORS REPORT FATIGUE OF COMPOSITE MATERIALS AND SUBSTRUCTURES FOR WIND TURBINE BLADES Abstract ThisreportpresentsthemajorfindingsoftheMontanaStateUniversityCompositeMaterialsFatigue Program from 1997 to 2001, and is intended to be used in conjunction with the DOE/MSU Composite Materials

  6. Dynamics and Fatigue Damage of Wind Turbine Rotors

    E-Print Network [OSTI]

    6 3 RiS0-Rr512 Dynamics and Fatigue Damage of Wind Turbine Rotors during Steady Operation Peter OF WIND TURBINE ROTORS DURING STEADY OPERATION Peter Hauge Madsen, Sten Frandsen, William E. Holley-carrying capacity of a wind turbine rotor with respect to short-term strength and material fatigue are presented

  7. Fatigue Testing of 9 m Carbon Fiber Wind Turbine Research Blades

    SciTech Connect (OSTI)

    Paquette, J.; van Dam, J.; Hughes, S.; Johnson, J.

    2008-01-01T23:59:59.000Z

    Fatigue testing was conducted on Carbon Experimental and Twist-Bend Experimental (CX-100 and TX-100) 9-m wind turbine research blades. The CX-100 blade was designed to investigate the use of a carbon spar cap to reduce weight and increase stiffness while being incorporated using conventional manufacturing techniques. The TX-100 blade used carbon in the outboard portion of the skin to produce twist-bend coupling to passively alleviate aerodynamic loads. In the fatigue tests, the CX-100 blade was loaded by a single hydraulic cylinder while the TX-100 blade was loaded via a hydraulically-actuated resonant loading system called the Universal Resonant Exciter. The blades were outfitted with approximately 30 strain gages as well as displacement and load sensors. Both blades survived to cycle counts sufficient to demonstrate a 20-year operational life. The CX-100 blade failed at approximately 1.6 million cycles because of a buckle and crack that formed and grew just outboard of max-chord. The TX-100 blade failed because of a crack that grew from the termination point of the spar cap at the midspan of the blade. This paper covers the results of the fatigue tests.

  8. A PROBABILISTIC TWO-SCALE MODEL FOR HIGH CYCLE FATIGUE LIFE PREDICTIONS

    E-Print Network [OSTI]

    volumes of a dual-phase steel. Keywords Fatigue limits; Weibull model; Microplasticity; Thermomechanics. 1

  9. NEW BAINITIC STEELS BY DESIGN Displacive Phase Transformations and their Appli-

    E-Print Network [OSTI]

    Cambridge, University of

    are the days when industry could simply make a whole matrix of alloys, test them, and then hope for the best Stress corrosion Slow corrosion & cracking Creep strength High temperature service Creep ductility Safe design Creep­fatigue Fatigue at creep temperatures Elastic modulus Deflection, stored energy Thermal

  10. Optical conductivity of curved graphene

    E-Print Network [OSTI]

    A. J. Chaves; T. Frederico; O. Oliveira; W. de Paula; M. C. Santos

    2014-05-01T23:59:59.000Z

    We compute the optical conductivity for an out-of-plane deformation in graphene using an approach based on solutions of the Dirac equation in curved space. Different examples of periodic deformations along one direction translates into an enhancement of the optical conductivity peaks in the region of the far and mid infrared frequencies for periodicities $\\sim100\\,$nm. The width and position of the peaks can be changed by dialling the parameters of the deformation profiles. The enhancement of the optical conductivity is due to intraband transitions and the translational invariance breaking in the geometrically deformed background. Furthemore, we derive an analytical solution of the Dirac equation in a curved space for a general deformation along one spatial direction. For this class of geometries, it is shown that curvature induces an extra phase in the electron wave function, which can also be explored to produce interference devices of the Aharonov-Bohm type.

  11. Thermomechanics of damage and fatigue by a phase field model

    E-Print Network [OSTI]

    Giovambattista Amendola; Mauro Fabrizio

    2014-10-26T23:59:59.000Z

    In the paper we present an isothermal model for describing damage and fatigue by the use of the Ginzburg-Landau (G-L) equation. Fatigue produces progressive damage, which is related with a variation of the internal structure of the material. The G-L equation studies the evolution of the order parameter, which describes the constitutive arrangement of the system and, in this framework, the evolution of damage. The thermodynamic coherence of the model is proved. In the last part of the work, we extend the results of the paper to a non-isothermal system, where fatigue contains thermal effects, which increase the damage of materials.

  12. Life prediction for bridged fatigue cracks

    SciTech Connect (OSTI)

    Cox, B.N.

    1994-08-01T23:59:59.000Z

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

  13. Harmonic algebraic curves and noncrossing partitions

    E-Print Network [OSTI]

    Martin, Jeremy L.; Savitt, David; Singer, Ted

    2007-02-01T23:59:59.000Z

    Motivated by Gauss’s first proof of the fundamental Theorem of Algebra, we study the topology of harmonic algebraic curves. By the maximum principle, a harmonic curve has no bounded components; its topology is determined by the combinatorial data...

  14. additional thermal fatigue: Topics by E-print Network

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

    Heikkinen, Samuli; Wuensch, Walter 2010-01-01 9 Prediction of Thermal Fatigue in Tooling for Die-casting Copper via Finite Element Analysis CiteSeer Summary: Abstract. Recent...

  15. The biological versus psychological basis of fatigue in depression

    E-Print Network [OSTI]

    Coscio, Stacey Aileen

    1993-01-01T23:59:59.000Z

    The objective of this study was to attempt to determine if the symptom of fatigue represents a metabolically induced or a perceived component in depressed individuals. Dietary intake patterns were analyzed for 20 depressed individuals to identify...

  16. Fatigue Enhancement of a Carbon Fiber Reinforced Nanocomposite

    E-Print Network [OSTI]

    Wilkerson, Justin W.

    2008-08-19T23:59:59.000Z

    The primary objective of the present investigation is to study the fatigue characteristics of a woven carbon fiber reinforced polymer which has been modified with either amine or fluorine functionalized carbon nanotubes on the fiber-matrix interface...

  17. Grain size effects on the fatigue response of nanocrystalline materials

    E-Print Network [OSTI]

    Hanlon, Timothy, 1977-

    2004-01-01T23:59:59.000Z

    The resistance of metals and alloys to fatigue crack initiation and propagation is known to be influenced significantly by grain size. Based on a wealth of experimental results obtained from microcrystalline metals, where ...

  18. A centurial history of technological change and learning curves or pulverized coal-fired utility boilers

    E-Print Network [OSTI]

    Yeh, Sonia; Rubin, Edward S

    2007-01-01T23:59:59.000Z

    cost of U.S. fossil–steam power plants from 1981 to 1997curve: the case of steam-electric power plant design andpower plant; Learning-by-doing; Technological change; Steam

  19. Explicit Coleman integration for hyperelliptic curves

    E-Print Network [OSTI]

    Balakrishnan, Jennifer S; Kedlaya, Kiran S

    2010-01-01T23:59:59.000Z

    Coleman's theory of p-adic integration figures prominently in several number-theoretic applications, such as finding torsion and rational points on curves, and computing p-adic regulators in K-theory (including p-adic heights on elliptic curves). We describe an algorithm for computing Coleman integrals on hyperelliptic curves, and its implementation in Sage.

  20. Multipath Curved Planar Reformation of the Peripheral

    E-Print Network [OSTI]

    Multipath Curved Planar Reformation of the Peripheral Arterial Tree in CT Angiography1 Justus that cause artifacts in multipath curved planar reformations (MPCPRs) of the peripheral arterial tree in 10-oblique multiplanar reformations perpendicular to the ves- sel centerline (10), and curved planar reformations

  1. JAEA Fatigue Analysis of EBR-II Duplex Tubing

    SciTech Connect (OSTI)

    J. H. Jackson; D. L. Porter; W. R. Lloyd

    2009-07-01T23:59:59.000Z

    This work addresses questions brought up concerning the mechanisms associated with fatigue crack growth retardation and/or arrest within the nickel bond layer in duplex 2¼ Cr-1Mo steel superheater tubes. Previous work performed at the Idaho National Laboratory (INL) indicated that the nickel bond layer did not function as a crack arrestor during fatigue crack propagation with the exception of one, isolated case involving an exceptionally low fatigue load and a high temperature (400 0C) environment. Since it is atypical for a fatigue crack to propagate from a relatively soft material (the nickel bond layer) to a harder material (the 2¼ Cr-1Mo steel) there has been speculation that the nickel bond layer was hardened in service. Additionally, there are questions surrounding the nature of the fatigue crack propagation within the nickel bond layer; specifically with regard to the presence of voids seen on micrographs of the bond layer and oxidation within the steel along the edge of the nickel bond layer. There is uncertainty as to the effect of these voids and/or oxide barriers with respect to potential fatigue crack arrest.

  2. Gravitational-wave sensitivity curves

    E-Print Network [OSTI]

    Moore, C. J.; Cole, R. H.; Berry, C. P. L.

    2014-12-08T23:59:59.000Z

    the detectability of a given source (see figure A1). An additional advantage of this convention is that the values on the strain axis for the detector curve hn(f) have a simple physical interpretation: they correspond to the root-mean- square noise in a bandwidth f... , such as cryogenic cooling. The Einstein Telescope (ET) is an ambitious proposal to construct an underground third- generation detector. Its location would provide shielding from seismic noise, allowing it to observe frequencies of ?(10 10 )Hz4 . We use...

  3. Does the Environmental Kuznets Curve Describe How Individual Countries Behave?

    E-Print Network [OSTI]

    Deacon, Robert; Norman, Catherine S

    2004-01-01T23:59:59.000Z

    for an Environmental Kuznets Curve. ” Review of EconomicsFactoring the Environmental Kuznets Curve: Evidence fromand Development: Is There a Kuznets Curve for Air Pollution

  4. Is the environmental Kuznets curve an empirical regularity?

    E-Print Network [OSTI]

    Deacon, Robert; Norman, Catherine S

    2004-01-01T23:59:59.000Z

    the Environmental Kuznets Curve: Turning a Black Box into aand Development: Is There a Kuznets Curve for Air Pollutionon the Environmental Kuznets Curve? ” Environment and

  5. Dislocation substructure in fatigued duplex stainless steel

    SciTech Connect (OSTI)

    Polak, J. (Ecole Centrale de Lille, Villeneuve d'Ascq (France). Lab. de Mecanique de Lille Inst. of Physical Metallurgy, Brno (Czechoslovakia). Academy of Sciences); Degallaix, S. (Ecole Centrale de Lille, Villeneuve d'Ascq (France). Lab. de Mecanique de Lille); Kruml, T. (Inst. of Physical Metallurgy, Brno (Czechoslovakia). Academy of Sciences)

    1993-12-15T23:59:59.000Z

    Cyclic plastic straining of crystalline materials results in the formation of specific dislocation structures. Considerable progress in mapping and understanding internal dislocation structures has been achieved by studying single crystal behavior: however, most structural materials have a polycrystalline structure and investigations of polycrystals in comparison to single crystal behavior of simple metals prove to be very useful in understanding more complex materials. There are some classes of materials, however, with complicated structure which do not have a direct equivalent in single crystalline form. Moreover, the specific dimensions and shapes of individual crystallites play an important role both in the cyclic stress-strain response of these materials and in the formation of their interior structure in cyclic straining. Austenitic-ferritic duplex stainless steel, which is a kind of a natural composite, is a material of this type. The widespread interest in the application of duplex steels is caused by approximately doubled mechanical properties and equal corrosion properties, when compared with classical austenitic stainless steels. Fatigue resistance of these steels as well as the surface damage evolution in cyclic straining have been studied; however, much less is known about the internal substructure development in cyclic straining. In this study the dislocation arrangement in ferritic and austenitic grains of the austenitic-ferritic duplex steel alloyed with nitrogen and cyclically strained with two strain amplitudes, is reported and compared to the dislocation arrangement found in single and polycrystals of austenitic and ferritic materials of a similar composition and with the surface relief produced in cyclic plastic straining.

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

    E-Print Network [OSTI]

    Nagy, Peter B.

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

  7. Study of the Fatigue Life of Steel Catenary Risers in Interaction with the Seabed

    E-Print Network [OSTI]

    Nakhaee, Ali

    2011-02-22T23:59:59.000Z

    The fatigue life of a Steel Catenary Riser (SCR) near its touch-down zone is substantially affected by its interaction with the seabed. Hence, accurate estimate of its fatigue life requires the understanding and realistic modeling of the interaction...

  8. A Model to Predict Work-Related Fatigue Based on Hours of Work

    E-Print Network [OSTI]

    A Model to Predict Work-Related Fatigue Based on Hours of Work Gregory D. Roach, Adam Fletcher, and Drew Dawson ROACH GD, FLETCHER A, DAWSON D. A model to predict work- related fatigue based on hours

  9. Fatigue performance and cyclic softening of F82H, a ferritic martensic steel

    SciTech Connect (OSTI)

    Stubbins, J.F. [Univ. of Illinois, Urbana, IL (United States); Gelles, D.S. [Pacific Northwest National Laboratory, Richland, WA (United States)

    1996-04-01T23:59:59.000Z

    The room temperature fatigue performance of F82H has been examined. The fatigue life was determined in a series of strain-controlled tests where the stress level was monitored as a function of the number of accrued cycles. Fatigue lives in the range of 10{sup 3} to 10{sup 6} cycles to failure were examined. The fatigue performance was found to be controlled primarily by the elastic strain range over most of the range of fatigue lives examined. Only at low fatigue lives did the plastic strain range contribute to the response. However, when the significant plastic strain did contribute, the material showed a tendency to cyclically soften. That is the load carrying capability of the material degrades with accumulated fatigue cycles. The overall fatigue performance of the F82H alloy was found to be similiar to other advanced martensitic steels, but lower than more common low alloy steels which possess lower yield strengths.

  10. Design, prototyping and preliminary testing of an elastic-powered climbing exoskeleton

    E-Print Network [OSTI]

    Briner, Hazel (Hazel Linn)

    2011-01-01T23:59:59.000Z

    Human powered elastic mechanisms can be used to reduce work requirements of muscles, by storing and releasing energy to more evenly distribute work load. An exoskeleton was designed to delay human fatigue during rock ...

  11. Development of load and resistance factor design for FRP strengthening of reinforced concrete structures

    E-Print Network [OSTI]

    Atadero, Rebecca Anne

    2006-01-01T23:59:59.000Z

    Design for FRP Strengthening of Reinforced Concrete. In 7 thFRP) Reinforcement for Concrete Structure; Shield, C.K. ,G.C. Fatigue Performance of Concrete Beams Strengthened with

  12. UV Light Curves of Thermonuclear Supernovae

    E-Print Network [OSTI]

    S. I. Blinnikov; E. I. Sorokina

    2000-03-17T23:59:59.000Z

    Ultraviolet light curves are calculated for several thermonuclear supernova models using a multifrequency radiation hydrodynamic code. It is found that Chandrasekhar-mass models produce very similar light curves both for detonation and deflagration. Sub-Chandrasekhar-mass models essentially differ from ``normal'' Chandrasekhar ones regarding behaviour of their UV fluxes. Differences in absolute brightness and in shape of light curves of thermonuclear supernovae could be detectable up to 300 Mpc with modern UV space telescopes.

  13. Learning Curve - DOE Directives, Delegations, and Requirements

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

    This chapter discusses the development and application of the learning curve. g4301-1chp21.pdf -- PDF Document, 28 KB Writer: John Makepeace Subjects: Administration Management...

  14. Canonical correlation of shipping forward curves

    E-Print Network [OSTI]

    Hadjiyiannis, Nicholas

    2010-01-01T23:59:59.000Z

    The behavior and interrelations between the main shipping forward curves are analyzed using multivariate statistics after removing the volatility distortions dictated by the Samuelson hypothesis. Principal Components ...

  15. Effects of Glass Fabric and Laminate Construction on the Fatigue of Resin Infused Blade Materials

    E-Print Network [OSTI]

    Effects of Glass Fabric and Laminate Construction on the Fatigue of Resin Infused Blade Materials. Introduction Wind turbine blades experience very high numbers of fatigue cycles varying between tension and wind conditions. The fatigue of composite laminates appropriate for wind turbine blades has been

  16. A continuum damage modelling of quasi-static fatigue strength of plain concrete

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    A continuum damage modelling of quasi-static fatigue strength of plain concrete S. H. Maia,b , F of concrete. The approach is based on the framework of continuum damage mechanics where the fatigue model fatigue tests have been performed on a concrete the formulation of which is close to the one used

  17. Effects of stretching and cycling on the fatigue behavior of polymer-supported Ag thin films

    E-Print Network [OSTI]

    Effects of stretching and cycling on the fatigue behavior of polymer-supported Ag thin films Gi March 2013 Keywords: Fatigue Thin films Fatigue crack initiation Intergranular failure Ductile fracture on characterizing the mechanical behavior of thin metal films and have observed that metals in thin-film form can

  18. A Joint-level Model of Fatigue for the Postural Control of Virtual Humans

    E-Print Network [OSTI]

    Rodríguez, Inmaculada

    A Joint-level Model of Fatigue for the Postural Control of Virtual Humans Inmaculada Rodríguezb , e. Keywords: human body simulation, posture control, fatigue, computer animation. 1 Introduction Achieving specifically with humans should produce realistic animation in all the sense of the word, including fatigue

  19. Final Report on In-Reactor Creep-Fatigue Deformation Behaviour of a

    E-Print Network [OSTI]

    , in-reactor creep- fatigue tests have been performed at strain amplitudes of 0.25 and 0 temperatures of 326K and 323K. For comparison purposes corresponding out-of-reactor creep-fatigue tests were.2 Test module and irradiation rig 6 2.3 In-reactor creep-fatigue tests 7 2.4 Out-of-reactor creep

  20. Sex Differences in Long Bone Fatigue Using a Rat Model Luisa D. Moreno,1

    E-Print Network [OSTI]

    Waldman, Stephen D.

    response to fatigue, we also determined the creep that occurred during the fatigue test. From the creep progress (Fig. 1). Caler and Carter32 studied cortical bone creep behavior during fatigue testing. When adaptation. From these results, we hypothesized that creep was the underlying mechanism that accounted

  1. Prediction of the Fatigue Life of Cast Steel Containing Shrinkage Porosity

    E-Print Network [OSTI]

    Beckermann, Christoph

    Prediction of the Fatigue Life of Cast Steel Containing Shrinkage Porosity RICHARD A. HARDIN and CHRISTOPH BECKERMANN A simulation methodology for predicting the fatigue life of cast steel components model is developed to reduce the dependence of the fatigue life predictions on the numerical mesh chosen

  2. Fatigue Testing of Abrasive Water Jet Cut Titanium

    SciTech Connect (OSTI)

    Hovanski, Yuri; Dahl, Michael E.; Williford, Ralph E.

    2009-06-08T23:59:59.000Z

    Battelle Memorial Institute as part of its U.S. Department of Energy (USDOE) Contract No. DE-AC05-76RL01830 to operate the Pacific Northwest National Laboratory (PNNL) provides technology assistance to qualifying small businesses in association with a Technology Assistance Program (TAP). Qualifying companies are eligible to receive a set quantity of labor associated with specific technical assistance. Having applied for a TAP agreement to assist with fatigue characterization of Abrasive Water Jet (AWJ) cut titanium specimens, the OMAX Corporation was awarded TAP agreement 09-02. This program was specified to cover dynamic testing and analysis of fatigue specimens cut from titanium alloy Ti-6%Al-4%V via AWJ technologies. In association with the TAP agreement, a best effort agreement was made to characterize fatigue specimens based on test conditions supplied by OMAX.

  3. Reliability analysis of fatigue sensitive joints in FPSO

    SciTech Connect (OSTI)

    Kaminski, M.L. [Nevesbu, The Hague (Netherlands); Krekel, M. [Bluewater, Hoofddorp (Netherlands)

    1995-12-31T23:59:59.000Z

    This paper contains a general description and the results of a reliability analysis made for fatigue sensitive joints in an FPSO. The main aim of the analysis was to demonstrate that the inspection program, which was specified based on the IMO resolution, will guarantee an acceptable probability level of fatigue and fracture failure during 20 years of service of the unit. Three approaches have been followed: the SN-approach and the fracture mechanics approach with and without allowance for fracture. The planned inspection program has been taken into account in the third approach. The stress assessment has been based on the spectral analysis corrected for the intermittent wetting effect. A short description of the deterministic analyses which preceded the reliability analysis has been included. It has been demonstrated in the paper that the probability of fatigue and fracture failure in an inspected structure can be assessed and judged by use of the reliability analysis.

  4. PAPILLON: Designing Curved Display Surfaces With Printed Optics

    E-Print Network [OSTI]

    Poupyrev, Ivan

    . It is based on 3D printed optics, where the surface of the display is constructed as a bundle of printed light Interfaces - Graphical user interfaces; Input devices and strategies. Keywords: 3D printing, fabrication

  5. Creep and Creep-Fatigue Crack Growth at Structural Discontinuities and Welds

    SciTech Connect (OSTI)

    Dr. F. W. Brust; Dr. G. M. Wilkowski; Dr. P. Krishnaswamy; Mr. Keith Wichman

    2010-01-27T23:59:59.000Z

    The subsection ASME NH high temperature design procedure does not admit crack-like defects into the structural components. The US NRC identified the lack of treatment of crack growth within NH as a limitation of the code and thus this effort was undertaken. This effort is broken into two parts. Part 1, summarized here, involved examining all high temperature creep-fatigue crack growth codes being used today and from these, the task objective was to choose a methodology that is appropriate for possible implementation within NH. The second part of this task, which has just started, is to develop design rules for possible implementation within NH. This second part is a challenge since all codes require step-by-step analysis procedures to be undertaken in order to assess the crack growth and life of the component. Simple rules for design do not exist in any code at present. The codes examined in this effort included R5, RCC-MR (A16), BS 7910, API 579, and ATK (and some lesser known codes). There are several reasons that the capability for assessing cracks in high temperature nuclear components is desirable. These include: (1) Some components that are part of GEN IV reactors may have geometries that have sharp corners - which are essentially cracks. Design of these components within the traditional ASME NH procedure is quite challenging. It is natural to ensure adequate life design by modeling these features as cracks within a creep-fatigue crack growth procedure. (2) Workmanship flaws in welds sometimes occur and are accepted in some ASME code sections. It can be convenient to consider these as flaws when making a design life assessment. (3) Non-destructive Evaluation (NDE) and inspection methods after fabrication are limited in the size of the crack or flaw that can be detected. It is often convenient to perform a life assessment using a flaw of a size that represents the maximum size that can elude detection. (4) Flaws that are observed using in-service detection methods often need to be addressed as plants age. Shutdown inspection intervals can only be designed using creep and creep-fatigue crack growth techniques. (5) The use of crack growth procedures can aid in examining the seriousness of creep damage in structural components. How cracks grow can be used to assess margins on components and lead to further safe operation. After examining the pros and cons of all these methods, the R5 code was chosen as the most up-to-date and validated high temperature creep and creep fatigue code currently used in the world at present. R5 is considered the leader because the code: (1) has well established and validated rules, (2) has a team of experts continually improving and updating it, (3) has software that can be used by designers, (4) extensive validation in many parts with available data from BE resources as well as input from Imperial college's database, and (5) was specifically developed for use in nuclear plants. R5 was specifically developed for use in gas cooled nuclear reactors which operate in the UK and much of the experience is based on materials and temperatures which are experienced in these reactors. If the next generation advanced reactors to be built in the US used these same materials within the same temperature ranges as these reactors, then R5 may be appropriate for consideration of direct implementation within ASME code NH or Section XI. However, until more verification and validation of these creep/fatigue crack growth rules for the specific materials and temperatures to be used in the GEN IV reactors is complete, ASME should consider delaying this implementation. With this in mind, it is this authors opinion that R5 methods are the best available for code use today. The focus of this work was to examine the literature for creep and creep-fatigue crack growth procedures that are well established in codes in other countries and choose a procedure to consider implementation into ASME NH. It is very important to recognize that all creep and creep fatigue crack growth procedures that are part of high temperature

  6. Mechanisms for fatigue and wear of polysilicon structural thinfilms

    SciTech Connect (OSTI)

    Alsem, Daniel Henricus

    2006-12-01T23:59:59.000Z

    Fatigue and wear in micron-scale polysilicon structural films can severely impact the reliability of microelectromechanical systems (MEMS). Despite studies on fatigue and wear behavior of these films, there is still an on-going debate regarding the precise physical mechanisms for these two important failure modes. Although macro-scale silicon does not fatigue, this phenomenon is observed in micron-scale silicon. It is shown that for polysilicon devices fabricated in the MUMPs foundry and SUMMiT process stress-lifetime data exhibits similar trends in ambient air, shorter lifetimes in higher relative humidity environments and no fatigue failure at all in high vacuum. Transmission electron microscopy of the surface oxides of the samples show an approximate four-fold thickening of the oxide at stress concentrations after fatigue failure, but no thickening after fracture in air or after fatigue cycling in vacuo. It is found that such oxide thickening and fatigue failure (in air) occurs in devices with initial oxide thicknesses of {approx}4-20 nm. Such results are interpreted and explained by a reaction layer fatigue mechanism; specifically, moisture-assisted subcritical cracking within a cyclic stress-assisted thickened oxide layer occurs until the crack reaches a critical size to cause catastrophic failure. Polysilicon specimens from the SUMMiT process are used to study wear mechanisms in micron-scale silicon in ambient air. Worn parts are examined by analytical scanning and transmission electron microscopy, while temperature changes are monitored using infrared microscopy. These results are compared with the development of values of static coefficients of friction (COF) with number of wear cycles. Observations show amorphous debris particles ({approx}50-100 nm) created by fracture through the silicon grains ({approx}500 nm), which subsequently oxidize, agglomerate into clusters and create plowing tracks. A nano-crystalline layer ({approx}20-200 nm) forms at worn regions. No dislocations or extreme temperature increases are found, ruling out plasticity and temperature-assisted mechanisms. The COF reaches a steady-state value of {approx}0.20{+-}0.05 after a short time at an initial value of {approx}0.11{+-}0.01. Plowing tracks are found before the steady-state value of the COF is reached, suggesting only a short adhesive wear regime. This suggests a predominantly abrasive wear mechanism, controlled by fracture, which commences by the first particles created by adhesive wear.

  7. Mental fatigue evaluation by steroid level measurement in Parotid fluid

    E-Print Network [OSTI]

    Singh, Harpal

    1968-01-01T23:59:59.000Z

    Play 1968 Major Subject. : Inc'ustrial Engineering MENTAL FATIGUE EVALUATION BY STEROID LEVEL MEASURLMENT. IN PAROTID FLUID A Thesis by HARPAL SINGH ApproveH as to tyle and. content by: P'hpirman of Committee) (Memb sr ) 1 1 PREFACE Alta...&ough indu trial engineering has had a phenomenal growth rate, a certain basic avenue has not been explored. The avenue 1 am refer- ring to is that of human fatigue and related phenomena. The reasons for this neglect are basically two: (1) Tnvestigation...

  8. Modeling Thermal Fatigue in CPV Cell Assemblies: Preprint

    SciTech Connect (OSTI)

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

    2011-07-01T23:59:59.000Z

    A finite element model has been created to quantify the thermal fatigue damage of the CPV die attach. Simulations are used to compare to results of empirical thermal fatigue equations originally developed for accelerated chamber cycling. While the empirical equations show promise when extrapolated to the lower temperature cycles characteristic of weather-induced temperature changes in the CPV die attach, it is demonstrated that their damage does not accumulate linearly: the damage a particular cycle contributes depends on the preceding cycles. Simulations of modeled CPV cell temperature histories provided for direct comparison of the FEM and empirical methods, and for calculation of equivalent times provided by standard accelerated test sequences.

  9. Projection-based curve clustering Benjamin AUDER

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    -hydraulic computer code CATHARE is used to study the re- liability of reactor vessels. The code inputs are physical parameters and the outputs are time evolution curves of a few other physical quantities. As the CATHARE code process involves a clustering step. In the present paper, CATHARE output curves are clustered using a k

  10. Modeling Creep-Fatigue-Environment Interactions in Steam Turbine Rotor Materials for Advanced Ultra-supercritical Coal Power Plants

    SciTech Connect (OSTI)

    Shen, Chen

    2014-01-20T23:59:59.000Z

    The goal of this project is to model creep-fatigue-environment interactions in steam turbine rotor materials for advanced ultra-supercritical (A-USC) coal power Alloy 282 plants, to develop and demonstrate computational algorithms for alloy property predictions, and to determine and model key mechanisms that contribute to the damages caused by creep-fatigue-environment interactions. The nickel based Alloy 282 is selected for this project because it is one of the leading candidate materials for the high temperature/pressure section of an A-USC steam turbine. The methods developed in the project are expected to be applicable to other metal alloys in similar steam/oxidation environments. The major developments are: ? failure mechanism and microstructural characterization ? atomistic and first principles modeling of crack tip oxygen embrittlement ? modeling of gamma prime microstructures and mesoscale microstructure-defect interactions ? microstructure and damage-based creep prediction ? multi-scale crack growth modeling considering oxidation, viscoplasticity and fatigue The technology developed in this project is expected to enable more accurate prediction of long service life of advanced alloys for A-USC power plants, and provide faster and more effective materials design, development, and implementation than current state-of-the-art computational and experimental methods. This document is a final technical report for the project, covering efforts conducted from January 2011 to January 2014.

  11. A combined mode fatigue model for glass reinforced nylon as applied to molded engine cooling fans

    SciTech Connect (OSTI)

    Smith, J.D.; Bennet, M.L.

    1985-01-01T23:59:59.000Z

    The use of glass reinforced nylon in fatigue inducing environments calls for a new method of stress analysis. With an engine cooling fan, both mean and vibratory stresses need to be examined. Speed cycling can cause tensile fatigue, while vibration can cause flexural fatigue. Since tensile and flexural stresses exist in the fan simultaneously, a combined mode fatigue model is needed. The proposed model is based on high cycle flexural and tensile fatigue strengths, and tensile strength. It relates measurable strain to stress using temperature dependent flexural and tensile moduli, and treats underhood temperature and desired product life as variables.

  12. Finding the Energy Efficient Curve: Gate Sizing for Minimum Power under Delay Constraints

    E-Print Network [OSTI]

    Kolodny, Avinoam

    Finding the Energy Efficient Curve: Gate Sizing for Minimum Power under Delay Constraints Yoni in a fast circuit by the same factor does not yield an energy-efficient design, and we characterize efficient. A design implementation is considered to be energy efficient when it has the highest performance

  13. Crack Path Selection Fatigue crack path imaged via SEM

    E-Print Network [OSTI]

    Rollins, Andrew M.

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

  14. Selection of Wind Turbine Blade Materials for Fatigue Resistance

    E-Print Network [OSTI]

    Selection of Wind Turbine Blade Materials for Fatigue Resistance John Mandell Montana State center to center26 inch center to center #12;Blade Infusion L Lab InfusionLab Infusion #12;Schematic blade laminates Complex structured coupons with ply drops­ Complex structured coupons with ply drops

  15. Ris-R-1261(EN) Fatigue Degradation and Failure of

    E-Print Network [OSTI]

    . Such applications are for instance rotor blades in wind turbines, helicopter rotor blades, flywheels for energyRisø-R-1261(EN) Fatigue Degradation and Failure of Rotating Composite Structures ­ Materials Characterisation and Underlying Mechanisms E. Kristofer Gamstedt and Svend Ib Andersen Materials Research

  16. amplitude fatigue test: Topics by E-print Network

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

    amplitude fatigue test First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 Standard practice for...

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

    E-Print Network [OSTI]

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

  18. Fatigue tests of under-strenghth timber railroad bridge stringers

    E-Print Network [OSTI]

    Borchers, Christopher Ryan

    2002-01-01T23:59:59.000Z

    , experimentally, the fatigue behavior of under-strength timber railroad bridge stringers. The sample group that was tested included nineteen southern pine solid-sawn stringers that were 178 mm (7 in.) wide by 356 mm (14 in.) deep by 4.8 m (16 ft) long...

  19. Fatigue Enhancement of Undersized, Drilled Crack-Arrest Holes

    E-Print Network [OSTI]

    Simmons, Gary Gene

    2013-12-31T23:59:59.000Z

    Precision Manufacturing, Inc. 401 E. High Street, Baldwin City, KS 66006 provided expertise and advice on fabricating the PICK tool and fatigue specimens. Clifford C. Biglow and Steve A. Sanders of Engineering Systems Inc. 923-A Terra Lane, O’Fallon, MO... ---------------------------------------------------------------------------------71 Objective -----------------------------------------------------------------------------------------------74 Development of PICK TOOL ----------------------------------------------------------------------75 Methodology...

  20. Gauge Invariant Geometry of Closed Space Curves: Applications to Boundary Curves of Mobius-type Strips

    E-Print Network [OSTI]

    Radha Balakrishnan; Indubala I Satija

    2005-07-15T23:59:59.000Z

    We derive gauge-invariant expressions for the twist $Tw$ and the linking number $Lk$ of a closed space curve, that are independent of the frame used to describe the curve, and hence characterize the intrinsic geometry of the curve. We are thus led to a {\\it frame-independent} version of the C\\u{a}lug\\u{a}reanu-White-Fuller theorem $Lk =Tw + Wr$ for a curve, where $Wr$ is the writhe of the curve. The gauge-invariant twist and writhe are related to two types of geometric phases associated with the curve. As an application, we study the geometry of the boundary curves of closed twisted strips. Interestingly, the M\\"obius strip geometry is singled out by a characteristic maximum that appears in the geometric phases, at a certain critical width of the strip.

  1. Refinements and Tests of an Advanced Controller to Mitigate Fatigue Loads in the Controls Advanced Research Turbine: Preprint

    SciTech Connect (OSTI)

    Wright, A.; Fleming, P.

    2010-12-01T23:59:59.000Z

    Wind turbines are complex, nonlinear, dynamic systems forced by aerodynamic, gravitational, centrifugal, and gyroscopic loads. The aerodynamics of wind turbines are nonlinear, unsteady, and complex. Turbine rotors are subjected to a complicated 3-D turbulent wind inflow field, with imbedded coherent vortices that drive fatigue loads and reduce lifetime. Design of control algorithms for wind turbines must account for multiple control objectives. Future large multi-megawatt turbines must be designed with lighter weight structures, using active controls to mitigate fatigue loads, while maximizing energy capture. Active damping should be added to these dynamic structures to maintain stability for operation in a complex environment. At the National Renewable Energy Laboratory (NREL), we have designed, implemented, and tested advanced controls to maximize energy extraction and reduce structural dynamic loads. These control designs are based on linear models of the turbine that are generated by specialized modeling software. In this paper, we present field test results of an advanced control algorithm to mitigate blade, tower, and drivetrain loads in Region 3.

  2. Abstract--this paper proposes a MIMO linear quadratic regulator (LQR) controller designed for a horizontal variable

    E-Print Network [OSTI]

    Boyer, Edmond

    with the trade-off between the wind energy conversion maximization and the minimization of the fatigue Tipical wind turbine power curve Therefore, in this regime, the system is multivariable and multi for a horizontal variable speed wind turbine with focus on the operating range referring to the above rated wind

  3. Thermomechanical fatigue behavior of three CFCC`s. Final contractor report

    SciTech Connect (OSTI)

    Worthem, D.W.

    1995-03-01T23:59:59.000Z

    The thermomechanical fatigue (TMF) behavior of three continuous-fiber ceramic composites (CFCC`s) was examined. The three matrices consisted of two different glass-ceramics and silicon carbide, respectively. The matrices of some of the specimens with the silicon carbide matrix were enhanced to improve oxidation resistance. All three were reinforced with Nicalon fibers with various fiber architectures. The thermoelastic properties of the matrix relative to the fibers, the elastic moduli and coefficients of thermal expansion (CTE), were different in each composite, providing a comparison of the effects of these critical properties. The specimens were tested under in-phase (IP) and out-of-phase (OP) cyclic loadings with respect to thermal cycling between 600 C and 1100 C. One of the glass-ceramic composites had greatly increased TMF lives compared to the other glass-ceramic matrix composites. This was probably caused by the reversal of the CTE mismatch between the fibers and the matrices and caused by the different oxidation resistances of the composites. For the same TMF lives a cross-ply reinforced composite had a maximum cyclic stress half as great, as that of unidirectionally reinforced composite. This indicated that the (0 deg) ply fibers had a strong influence of TMF life. Both the glass ceramic matrix composites had shallow-slope stress-life plots that indicated sensitivity to damage and therefore low damage tolerance. The composites with an unenhanced silicon carbide matrix experienced the shortest TMF lives of all the CFCC`s tested. However, the enhanced composite had the longest. Also, the enhanced composite demonstrated the best damage tolerance as evidenced by a stress-life curve that curves sharply upward to the left. In all the composites, out-of-phase cyclic loading was worse than in-phase cyclic loadings despite the CTE mismatch between fiber and matrix.

  4. Fatigue in martensitic 100Cr6: Relationship between rolling contact fatigue microstructural transitions and repetitive push testing

    E-Print Network [OSTI]

    Kang, Jee-Hyun; Rivera-Díaz-del-Castillo, Pedro E. J.

    2014-07-14T23:59:59.000Z

    and Materials Transac- tions A 21 (1990) 653–665. [4] H. J. Christ, C. Sommer, H. Mughrabi, A. P. Voskamp, J. M. Beswick, F. Hengerer, Fatigue and Fracture of Engineering Materials and Struc- tures 15 (1992) 855–870. [5] A. Warhadpande, F. Sadeghi, M. N...

  5. Classification and forecasting of load curves Nolwen Huet

    E-Print Network [OSTI]

    Cuesta, Juan Antonio

    Classification and forecasting of load curves Nolwen Huet Abstract The load curve, which gives of electricity customer uses. This load curve is only available for customers with automated meter reading. For the others, EDF must estimate this curve. Usually a clustering of the load curves is performed, followed

  6. Diffusion-Limited Aggregation on Curved Surfaces

    E-Print Network [OSTI]

    Choi, J.

    We develop a general theory of transport-limited aggregation phenomena occurring on curved surfaces, based on stochastic iterated conformal maps and conformal projections to the complex plane. To illustrate the theory, we ...

  7. Learning Curve Management in Educational Programming Environments

    E-Print Network [OSTI]

    Goldman, Kenneth J.

    Learning Curve Management in Educational Programming Environments Benjamin H. Brinckerhoff Computer programmers are best served by integrated development environments that adapt to their growing sophistication programming environments. We provide pedagogical justification for each goal, describe possible supporting

  8. Fatigue flaw growth assessment and inclusion of stratification to the LBB assessment

    SciTech Connect (OSTI)

    Samohyl, P.

    1997-04-01T23:59:59.000Z

    The application of the LBB requires also fatigue flaw growth assessment. This analysis was performed for PWR nuclear power plants types VVER 440/230, VVER 440/213c, VVER 1000/320. Respecting that these NPP`s were designed according to Russian codes that differ from US codes it was needed to compare these approaches. Comparison with our experimental data was accomplished, too. Margins of applicability of the US methods and their modifications for the materials used for construction of Czech and Slovak NPP`s are shown. Computer code accomplishing the analysis according to described method is presented. Some measurement and calculations show that thermal stratifications in horizontal pipelines can lead to additive loads that are not negligible and can be dangerous. An attempt to include these loads induced by steady-state stratification was made.

  9. Assessing Fatigue and Ultimate Load Uncertainty in Floating Offshore Wind Turbines Due to Varying Simulation Length

    SciTech Connect (OSTI)

    Stewart, G.; Lackner, M.; Haid, L.; Matha, D.; Jonkman, J.; Robertson, A.

    2013-07-01T23:59:59.000Z

    With the push towards siting wind turbines farther offshore due to higher wind quality and less visibility, floating offshore wind turbines, which can be located in deep water, are becoming an economically attractive option. The International Electrotechnical Commission's (IEC) 61400-3 design standard covers fixed-bottom offshore wind turbines, but there are a number of new research questions that need to be answered to modify these standards so that they are applicable to floating wind turbines. One issue is the appropriate simulation length needed for floating turbines. This paper will discuss the results from a study assessing the impact of simulation length on the ultimate and fatigue loads of the structure, and will address uncertainties associated with changing the simulation length for the analyzed floating platform. Recommendations of required simulation length based on load uncertainty will be made and compared to current simulation length requirements.

  10. Wavelet Analysis of Galactic Rotation Curves

    E-Print Network [OSTI]

    M. Kuassivi

    2011-04-28T23:59:59.000Z

    The spatial wavelet spectra of 73 published spiral galaxies's rotation curves are computed and their associated scaleograms are presented. Scaleograms are used to detect and isolate local features observed in spiral galaxies's rotation curves. Although wiggles and bumps are usually interpreted as signs of recent and on-going merging, the analysis of the scaleograms reveals regular patterns consistent with the presence of large-scale modes throughout the disk.

  11. Chiral gap effect in curved space

    E-Print Network [OSTI]

    Antonino Flachi; Kenji Fukushima

    2014-06-25T23:59:59.000Z

    We discuss a new type of QCD phenomenon induced in curved space. In the QCD vacuum a mass gap of Dirac fermions is attributed to the spontaneous breaking of chiral symmetry. If the curvature is positive large, the chiral condensate melts but a chiral invariant mass gap can still remain, which we name the chiral gap effect in curved space. This leads to decoupling of quark deconfinement which implies a view of black holes surrounded by a first-order QCD phase transition.

  12. Environmental bias and elastic curves on surfaces

    E-Print Network [OSTI]

    Jemal Guven; Dulce María Valencia; Pablo Vázquez-Montejo

    2014-08-15T23:59:59.000Z

    The behavior of an elastic curve bound to a surface will reflect the geometry of its environment. This may occur in an obvious way: the curve may deform freely along directions tangent to the surface, but not along the surface normal. However, even if the energy itself is symmetric in the curve's geodesic and normal curvatures, which control these modes, very distinct roles are played by the two. If the elastic curve binds preferentially on one side, or is itself assembled on the surface, not only would one expect the bending moduli associated with the two modes to differ, binding along specific directions, reflected in spontaneous values of these curvatures, may be favored. The shape equations describing the equilibrium states of a surface curve described by an elastic energy accommodating environmental factors will be identified by adapting the method of Lagrange multipliers to the Darboux frame associated with the curve. The forces transmitted to the surface along the surface normal will be determined. Features associated with a number of different energies, both of physical relevance and of mathematical interest, are described. The conservation laws associated with trajectories on surface geometries exhibiting continuous symmetries are also examined.

  13. Electrospray characteristic curves: in pursuit of improved performance...

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

    Electrospray characteristic curves: in pursuit of improved performance in the nano-flow regime. Electrospray characteristic curves: in pursuit of improved performance in the...

  14. Freedom from Pollution? The State, the People, and the Environmental Kuznets Curve

    E-Print Network [OSTI]

    Bond, Craig A.; Farzin, Y. Hossein

    2004-01-01T23:59:59.000Z

    and the environmental Kuznets curve for deforestation: aand the environmental Kuznets curve. Ecological Economicsbias in environmental Kuznets curves. Ecological Economics

  15. Final Report on In-Reactor Creep-Fatigue Deformation Behaviour of a

    E-Print Network [OSTI]

    .5% with holdtimes of 10 and 100s, respectively. For comparison purposes, similar creep-fatigue tests were performed Procedure 5 2.1 Materials 5 2.2 Test module and irradiation rig 5 2.3 In-reactor creep-fatigue tests 6 2Final Report on In-Reactor Creep- Fatigue Deformation Behaviour of a CuCrZr Alloy: COFAT 1 B

  16. Updated U.S. Geothermal Supply Curve

    SciTech Connect (OSTI)

    Augustine, C.; Young, K. R.; Anderson, A.

    2010-02-01T23:59:59.000Z

    This paper documents the approach used to update the U.S. geothermal supply curve. The analysis undertaken in this study estimates the supply of electricity generation potential from geothermal resources in the United States and the levelized cost of electricity (LCOE), capital costs, and operating and maintenance costs associated with developing these geothermal resources. Supply curves were developed for four categories of geothermal resources: identified hydrothermal (6.4 GWe), undiscovered hydrothermal (30.0 GWe), near-hydrothermal field enhanced geothermal systems (EGS) (7.0 GWe) and deep EGS (15,900 GWe). Two cases were considered: a base case and a target case. Supply curves were generated for each of the four geothermal resource categories for both cases. For both cases, hydrothermal resources dominate the lower cost range of the combined geothermal supply curve. The supply curves indicate that the reservoir performance improvements assumed in the target case could significantly lower EGS costs and greatly increase EGS deployment over the base case.

  17. Tensile and torsional fatigue of fiber-reinforced composites at cryogenic temperatures. [Superconducting magnetic fusion energy

    SciTech Connect (OSTI)

    Wang, S.S.; Chim, E.S.M.; Socie, D.F.; Gauchel, J.V.; Olinger, J.L.

    1982-04-01T23:59:59.000Z

    A study of the fundamental fatigue behavior of G-10 grade, glass fiber-reinforced composite laminate in a liquid nitrogen environment is presented. Both uniaxial tensile and pure torsional fatigue failure of the fiber composite are investigated. Cryogenic fatigue degradation of the composite in terms of stiffness reduction, energy dissipation, and cyclic fracture is examined in detail. Influences of loading mode, fiber orientation, surface condition, and geometric variables are studied also. Fatigue damage mechanisms at cryogenic temperatures under various loading conditions are discussed. 29 refs.

  18. Modeling Metal Fatigue As a Key Step in PV Module Life Time Prediction (Presentation)

    SciTech Connect (OSTI)

    Bosco, N.

    2012-02-01T23:59:59.000Z

    This presentation covers modeling metal fatigue as a key step in photovoltaic (PV) module lifetime predictions. Described are time-dependent and time-independent case studies.

  19. High temperature erosion and fatigue resistance of a detonation gun chromium carbide coating for steam turbines

    SciTech Connect (OSTI)

    Quets, J.M.; Walsh, P.N. [Praxair Surface Technologies, Inc., Indianapolis, IN (United States); Srinivasan, V. [Westinghouse Electric Corp., Orlando, FL (United States); Tucker, R.C. Jr. [Praxair Surface Technologies, Inc., Indianapolis, IN (United States)

    1994-12-31T23:59:59.000Z

    Chromium carbide based detonation gun coatings have been shown to be capable of protecting steam turbine components from particle erosion. To be usable, however, erosion resistant coatings must not degrade the fatigue characteristics of the coated components. Recent studies of the fatigue properties of a detonation gun coated martensitic substrate at 538 C (1,000 F) will be presented with an emphasis on its long term performance. This study will show the retention of acceptable fatigue performance of coated substrates into the high cycle regime, and will include a discussion on the mechanism of fatigue.

  20. Mixed Mode Static and Fatigue Crack Growth in Wind Blade Paste Adhesives

    E-Print Network [OSTI]

    , static GIc and mixed mode fracture, and fatigue crack growth resistance. I. Introduction Wind turbine blades are large composite structures which are typically resin infusion molded in sections

  1. The marine biodiversity curve is an icon of paleobiology. The familiar curve shows

    E-Print Network [OSTI]

    Waxman, David

    the temperate phage infects Escherichia coli, it enters one of two pathways: lytic (replicates and killsThe marine biodiversity curve is an icon of paleobiology. The familiar curve shows increasing (distinct rock units) as a proxy for the amount of marine rock available for paleontological sampling

  2. Quantum Coherence and Closed Timelike Curves

    E-Print Network [OSTI]

    S. W. Hawking

    1995-02-08T23:59:59.000Z

    Various calculations of the $S$ matrix have shown that it seems to be non unitary for interacting fields when there are closed timelike curves. It is argued that this is because there is loss of quantum coherence caused by the fact that part of the quantum state circulates on the closed timelike curves and is not measured at infinity. A prescription is given for calculating the superscattering matrix $\\$ $ on space times whose parameters can be analytically continued to obtain a Euclidean metric. It is illustrated by a discussion of a spacetime in with two disks in flat space are identified. If the disks have an imaginary time separation, this corresponds to a heat bath. An external field interacting with the heat bath will lose quantum coherence. One can then analytically continue to an almost real separation of the disks. This will give closed timelike curves but one will still get loss of quantum coherence.

  3. An investigation on stochastic specific activity curves

    E-Print Network [OSTI]

    Lee, Dominic Yat-Hung

    1973-01-01T23:59:59.000Z

    . into homogeneous components called. compartment s. (3) The system is in steady state, i. e. , compartments have a constant size and. are connected by fixed. flow rates. (4) The introduction of tracer does not alter the behavior of the system. (5) The system... 0. 10 SA (t) SA (t) Figure 3. 2. 2 Deterministic Specific Activity-Time Curve With stochastic flow of the tracer, the curves shown in Figure 3. 2. 2 (p. 10) would not be smooth, instead. they take the form as shown in Figure 4. 2. 1 (p. 18...

  4. Chiral gap effect in curved space

    E-Print Network [OSTI]

    Antonino Flachi; Kenji Fukushima

    2015-05-29T23:59:59.000Z

    We discuss a new type of QCD phenomenon induced in curved space. In the QCD vacuum, a mass-gap of Dirac fermions is attributed to the spontaneous breaking of chiral symmetry. If the curvature is positive large, the chiral condensate melts but a chiral invariant mass-gap can still remain, which we name the chiral gap effect in curved space. This leads to decoupling of quark deconfinement which implies a view of black holes surrounded by a first-order QCD phase transition.

  5. Complex Fluid Analysis with the Advanced Distillation Curve Approach

    E-Print Network [OSTI]

    Complex Fluid Analysis with the Advanced Distillation Curve Approach Thomas J. Bruno, Lisa S. Ott for measuring distillation curves reveals the physicochemical properties of complex fluids such as fuels distillation curves of complex fluids. The distillation curve provides the only practical avenue to assess

  6. Conservation Screening Curves to Compare Efficiency Investments to Power Plants

    E-Print Network [OSTI]

    methodology to compare supply and demand-side resources. The screening curve approach supplements with load curve approach supplements with load shape information the data contained in a supply curve of conservedLBL-27286 Conservation Screening Curves to Compare Efficiency Investments to Power Plants Jonathan

  7. Beauty waves: an artistic representation of ocean waves using Bezier curves

    E-Print Network [OSTI]

    Faulkner, Jay Allen

    2007-04-25T23:59:59.000Z

    In this thesis, we present a method for computing an artistic representation of ocean waves using Bezier curves. Wave forms are loosely based on procedural wave models and are designed to emulate those found in both art and nature. The wave forms...

  8. Research Summary Estimating Woodfuel Resource Cost Curves

    E-Print Network [OSTI]

    and extraction methods. Background Just under half of the final energy consumed in the UK (49%) is in the formResearch Summary Estimating Woodfuel Resource Cost Curves As a renewable energy source, woodfuel. The woodfuel strategy adopted by Forestry Commission England supports delivery of these. It aims to sustainably

  9. Closed timelike curves in general relativity

    E-Print Network [OSTI]

    W. B. Bonnor

    2002-11-13T23:59:59.000Z

    Many solutions of Einstein's field equations contain closed timelike curves (CTC). Some of these solutions refer to ordinary materials in situations which might occur in the laboratory, or in astrophysics. It is argued that, in default of a reasonable interpretation of CTC, general relativity does not give a satisfactory account of all phenomena within its terms of reference.

  10. WILD MODELS OF CURVES DINO LORENZINI

    E-Print Network [OSTI]

    Lorenzini, Dino J.

    WILD MODELS OF CURVES DINO LORENZINI Abstract. Let K be a complete discrete valuation field of X/K obtained by desingularizing the wild quotient singularities of the quotient Y/H. The most of wild quotient singularities having pairwise distinct resolution graphs. The information on the regular

  11. Virtual Welded-Joint Design Integrating Advanced Materials and Processing Technologies

    SciTech Connect (OSTI)

    Yang, Z.; Dong, P.; Liu, S.; Babu, S.; Olson, G.; DebRoy, T.

    2005-04-15T23:59:59.000Z

    The primary goal of this project is to increase the fatigue life of a welded-joint by 10 times and to reduce energy use by 25% through product performance and productivity improvements using an integrated modeling approach. The fatigue strength of a welded-joint is currently the bottleneck to design high performance and lightweight welded structures using advanced materials such as high strength steels. In order to achieve high fatigue strength in a welded-joint it is necessary to manage the weld bead shape for lower stress concentration, produce preferable residual stress distribution, and obtain the desired microstructure for improved material toughness and strength. This is a systems challenge that requires the optimization of the welding process, the welding consumable, the base material, as well as the structure design. The concept of virtual welded-joint design has been proposed and established in this project. The goal of virtual welded-joint design is to develop a thorough procedure to predict the relationship of welding process, microstructure, property, residual stress, and the ultimate weld fatigue strength by a systematic modeling approach. The systematic approach combines five sub-models: weld thermal-fluid model, weld microstructure model, weld material property model, weld residual stress model, and weld fatigue model. The systematic approach is thus based on interdisciplinary applied sciences including heat transfer, computational fluid dynamics, materials science, engineering mechanics, and material fracture mechanics. The sub-models are based on existing models with further development. The results from modeling have been validated with critical experiments. The systematic modeling approach has been used to design high fatigue resistant welds considering the combined effects of weld bead geometry, residual stress, microstructure, and material property. In particular, a special welding wire has been developed in this project to introduce compressive residual stress at weld toe for weld fatigue resistance.

  12. In-situ fatigue damage monitoring using symbolic dynamic filtering of ultrasonic signals

    E-Print Network [OSTI]

    Ray, Asok

    in polycrystalline alloys that are commonly used in aerospace structures. The concept is built upon analytic signal because of the evolving fatigue damage in polycrystalline alloys. Keywords: aircraft structures, fatigue of the most com- monly encountered sources of structural degradation in aerospace structures that are often

  13. November 1998 NREL/SR-500-24379 Fatigue of Composite Material Beam

    E-Print Network [OSTI]

    No. DE-AC36-83CH10093 #12;Fatigue of Composite Material Beam Elements Representative of Wind TurbineNovember 1998 · NREL/SR-500-24379 Fatigue of Composite Material Beam Elements Representative of Wind Turbine Blade Substructure John F. Mandell, Daniel D. Samborsky, David W. Combs, M. Ethan Scott

  14. The SNL/MSU/DOE Fatigue of Composite Materials Database: Recent Trends

    E-Print Network [OSTI]

    in three areas are described for wind blade materials in the SNL/MSU/DOE fatigue of composite materials from over 250 materials systems relevant to wind blades, is now formatted in Excel, allowing more of the tensile fatigue sensitivity of various blade materials including laminate in-plane and interlaminar

  15. Comparing Estimates of Wind Turbine Fatigue Loads using Time-Domain and Spectral Methods

    E-Print Network [OSTI]

    Manuel, Lance

    for edgewise blade loads. NOMENCLATURE f = frequency in Hertz m = material exponent for fatigue mn = nthComparing Estimates of Wind Turbine Fatigue Loads using Time-Domain and Spectral Methods by Patrick Ragan and Lance Manuel REPRINTED FROM WIND ENGINEERING VOLUME 31, NO. 2, 2007 MULTI-SCIENCE PUBLISHING

  16. Environmental effects on fatigue and lifetime predictions for silica optical fibers

    E-Print Network [OSTI]

    Matthewson, M. John

    Environmental effects on fatigue and lifetime predictions for silica optical fibers M. John optical fiber on the environmental parameters temperature, humidity and pH. It is shown that the stress used by the fiber optics industry provides a good fit to fatigue data for high strength fiber

  17. DEATH BY SMALL FORCES: FAILURE BY FATIGUE IN WAVE-SWEPT MACROALGAE

    E-Print Network [OSTI]

    Denny, Mark

    cases the intertidal region supports rich communities of organisms, the compositions of which depend through the process of fatigue. Through laboratory tests employing standard techniques from fracture mechanics and fatigue analysis, I found that cracks introduced into flat-bladed macroalgae grow in length

  18. Ego Depletion Is Not Just Fatigue: Evidence From A Total Sleep Deprivation Experiment

    E-Print Network [OSTI]

    Maddox, W. Todd

    , not fatigue. Keywords: self-regulation, self-control, sleep deprivation, fatigue, aggression A report to show poor self-regulation subsequently. This pattern has been said to support a limited-resource model not. In combination, some of our participants were instructed to use self-regulation to control

  19. Fatigue-crack propagation in Nitinol, a shape-memory and superelastic endovascular stent material

    E-Print Network [OSTI]

    Ritchie, Robert

    Fatigue-crack propagation in Nitinol, a shape-memory and superelastic endovascular stent material A; fatigue; shape-memory; super- elastic INTRODUCTION There has been increasing interest in the biomedical during the 1960s for its shape-memory behavior (Fig. 1).1,2 This effect is a result of an athermal

  20. FACTORS THAT AFFECT THE FATIGUE LIFE OF RUBBER: A LITERATURE SURVEY

    E-Print Network [OSTI]

    Fatemi, Ali

    FACTORS THAT AFFECT THE FATIGUE LIFE OF RUBBER: A LITERATURE SURVEY W. V. MARS* ADVANCED RESEARCH ENGINEER COOPER TIRE & RUBBER COMPANY, 701 LIMA AVE., FINDLAY, OHIO, 45840 A. FATEMI UNIVERSITY OF TOLEDO, TOLEDO, OHIO, 43606 ABSTRACT Many factors are known to influence the mechanical fatigue life of rubber

  1. Modeling cyclic ratcheting based fatigue life of HSLA steels using crystal plasticity FEM simulations and experiments

    E-Print Network [OSTI]

    Ghosh, Somnath

    Modeling cyclic ratcheting based fatigue life of HSLA steels using crystal plasticity FEM This paper develops a plastic ratcheting based fatigue failure model for HSLA steels from a combination. It predicts the nucleation of major cracks in the microstruc- ture in ratcheting. Subsequently, the total life

  2. Effect of diaphragmatic fatigue on control of the respiratory muscles during CO sub 2 rebreathing

    SciTech Connect (OSTI)

    Yan, S.; Lichros, I.; Macklem, P.T. (McGill Univ., Montreal, Quebec (Canada) Montreal Chest Hospital, Quebec (Canada))

    1991-03-11T23:59:59.000Z

    The authors measured respiratory muscle recruitment and ventilation ({dot V}{sub E}) during CO{sub 2} rebreathing before and after diaphragmatic fatigue in normal subjects. Muscle activity was assessed by measuring pleural, abdominal, and transdiaphragmatic pressures (Ppl, Pab, and Pdi, resp). The results showed that (1) there was a progressive increase in Pdi with increasing end-tidal PCO{sub 2} (P{sub ET}CO{sub 2}); the rate of increase was usually greater before than after fatigue, however, in some it was less because of longer operating length and/or passive stretching of the diaphragm due to strong rib cage muscle (RCM) activity induced by fatigue; (2) Pdi increased mainly due to greater fall in Ppl; {Delta}Pab increased little during CO{sub 2} rebreathing or even decreased with P{sub ET}CO{sub 2} over 50-55 mmHg; this pattern was exaggerated by fatigue; (3) at the end of each trial, the ratio {minus}{Delta}Ppl/{Delta}Pab increased by {approximately}140% before and {approximately}850% after fatigue; (4) CO{sub 2} induced expiratory abdominal muscle activity; and (5) as a group, {dot V}{sub E} and its pattern did not change appreciably with fatigue. The authors conclude that RCM are recruited proportionately more than the diaphragm by CO{sub 2} and that diaphragmatic fatigue shifts the central drive from the fatigued diaphragm to TCM to preserve ventilation.

  3. THERMAL FATIGUE AND FAILURE OF ELECTRONIC POWER DEVICE SUBSTRATES. S. Pietranico1&2

    E-Print Network [OSTI]

    - 1 - THERMAL FATIGUE AND FAILURE OF ELECTRONIC POWER DEVICE SUBSTRATES. S. Pietranico1&2 , S, avenue du Président Wilson, 94235 Cachan, France Abstract: Electronic power devices used shows that the fatigue life and the reliability of power electronic devices could be optimized using

  4. Damage mechanics characterization on fatigue behavior of a solder joint material

    SciTech Connect (OSTI)

    Chow, C.L.; Yang, F. [Univ. of Michigan, Dearborn, MI (United States). Dept. of Mechanical Engineering; Fang, H.E. [Sandia National Labs., Albuquerque, NM (United States). Computational Physics Dept.

    1998-08-01T23:59:59.000Z

    This paper presents the first part of a comprehensive mechanics approach capable of predicting the integrity and reliability of solder joint material under fatigue loading without viscoplastic damage considerations. A separate report will be made to present a comprehensive damage model describing life prediction of the solder material under thermomechanical fatigue loading. The method is based on a theory of damage mechanics which makes possible a macroscopic description of the successive material deterioration caused by the presence of microcracks/voids in engineering materials. A damage mechanics model based on the thermodynamic theory of irreversible processes with internal state variables is proposed and used to provide a unified approach in characterizing the cyclic behavior of a typical solder material. With the introduction of a damage effect tensor, the constitutive equations are derived to enable the formulation of a fatigue damage dissipative potential function and a fatigue damage criterion. The fatigue evolution is subsequently developed based on the hypothesis that the overall damage is induced by the accumulation of fatigue and plastic damage. This damage mechanics approach offers a systematic and versatile means that is effective in modeling the entire process of material failure ranging from damage initiation and propagation leading eventually to macro-crack initiation and growth. As the model takes into account the load history effect and the interaction between plasticity damage and fatigue damage, with the aid of a modified general purpose finite element program, the method can readily be applied to estimate the fatigue life of solder joints under different loading conditions.

  5. Mitigation of Fatigue Loads Using Individual Pitch Control of Wind Turbines Based on FAST

    E-Print Network [OSTI]

    Chen, Zhe

    Mitigation of Fatigue Loads Using Individual Pitch Control of Wind Turbines Based on FAST Yunqian University, China jiz@seu.edu.cn Abstract-With the increase of wind turbine dimension and capacity, the wind turbine structures are subjected to prominent loads and fatigue which would reduce the lifetime of wind

  6. FATIGUE FAILURE OF AN OPEN CELL AND A CLOSED CELL ALUMINIUM ALLOY FOAM

    E-Print Network [OSTI]

    Fleck, Norman A.

    FATIGUE FAILURE OF AN OPEN CELL AND A CLOSED CELL ALUMINIUM ALLOY FOAM A.-M. HARTE, N. A. FLECK reserved. Keywords: Aluminium alloys; Foams; Fatigue; Plastic collapse 1. INTRODUCTION Metallic foams such as aluminium alloy foams show potential for use in ultra-lightweight metallic structures. Recently, a number

  7. CONTINUOUS FATIGUE ASSESSMENT OF AN OFFSHORE WIND TURBINE USING A LIMITED NUMBER OF VIBRATION SENSORS

    E-Print Network [OSTI]

    Boyer, Edmond

    CONTINUOUS FATIGUE ASSESSMENT OF AN OFFSHORE WIND TURBINE USING A LIMITED NUMBER OF VIBRATION, Modal decomposition and expansion, Finite Element Model INTRODUCTION Offshore wind turbines are exposed locations along the structure. This is not the case though in monopile offshore wind turbines, where fatigue

  8. Proceeding of Energy Week 1996, ASME APPLICATION OF THE U.S. HIGH CYCLE FATIGUE DATA BASE

    E-Print Network [OSTI]

    TURBINE BLADE LIFETIME PREDICTIONS Herbert J. Sutherland Wind Energy Technology Sandia National the service lifetime of wind turbine blades using the high-cycle fatigue data base for typical U.S. blade blades. The LIFE2 fatigue analysis code for wind turbines is then used for the fatigue analysis

  9. Eye-Tracking Evolutionary Algorithm to minimize user fatigue in IEC applied to Interactive One-Max problem

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Eye-Tracking Evolutionary Algorithm to minimize user fatigue in IEC applied to Interactive One Computation (IEC) often suffers from user fatigue. In this paper, we present a new technique, totally independent of the domain used, to minimize this fatigue by combining an IEC and an input device. This device

  10. A new muscle fatigue and recovery model and its ergonomics application in human simulation

    E-Print Network [OSTI]

    Ma, Liang; Bennis, Fouad; Zhang, Wei; Guillaume, François; 10.1080/17452759.2010.504056

    2010-01-01T23:59:59.000Z

    Although automatic techniques have been employed in manufacturing industries to increase productivity and efficiency, there are still lots of manual handling jobs, especially for assembly and maintenance jobs. In these jobs, musculoskeletal disorders (MSDs) are one of the major health problems due to overload and cumulative physical fatigue. With combination of conventional posture analysis techniques, digital human modelling and simulation (DHM) techniques have been developed and commercialized to evaluate the potential physical exposures. However, those ergonomics analysis tools are mainly based on posture analysis techniques, and until now there is still no fatigue index available in the commercial software to evaluate the physical fatigue easily and quickly. In this paper, a new muscle fatigue and recovery model is proposed and extended to evaluate joint fatigue level in manual handling jobs. A special application case is described and analyzed by digital human simulation technique.

  11. A new muscle fatigue and recovery model and its ergonomics application in human simulation

    E-Print Network [OSTI]

    Ma, Liang; Bennis, Fouad; Zhang, Wei; Guillaume, François

    2009-01-01T23:59:59.000Z

    Although automatic techniques have been employed in manufacturing industries to increase productivity and efficiency, there are still lots of manual handling jobs, especially for assembly and maintenance jobs. In these jobs, musculoskeletal disorders (MSDs) are one of the major health problems due to overload and cumulative physical fatigue. With combination of conventional posture analysis techniques, digital human modelling and simulation (DHM) techniques have been developed and commercialized to evaluate the potential physical exposures. However, those ergonomics analysis tools are mainly based on posture analysis techniques, and until now there is still no fatigue index available in the commercial software to evaluate the physical fatigue easily and quickly. In this paper, a new muscle fatigue and recovery model is proposed and extended to evaluate joint fatigue level in manual handling jobs. A special application case is described and analyzed by digital human simulation technique.

  12. Determining equivalent damage loading for full-scale wind turbine blade fatigue tests

    SciTech Connect (OSTI)

    Freebury, G.; Musial, W.

    2000-03-13T23:59:59.000Z

    This paper describes a simplified method for converting wind turbine rotor design loads into equivalent-damage, constant-amplitude loads and load ratios for both flap and lead-lag directions. It is an iterative method that was developed at the National Renewable Energy Laboratory (NREL) using Palmgren-Miner's linear damage principles. The general method is unique because it does not presume that any information about the materials or blade structural properties is precisely known. According to this method, the loads are never converted to stresses. Instead, a family of M-N curves (moment vs. cycles) is defined with reasonable boundaries for load-amplitude and slope. An optimization program iterates and converges on the constant amplitude test load and load ratio that minimizes the sensitivity to the range of M-N curves for each blade section. The authors constrained the general method to match the NedWind 25 design condition for the Standards, Measurements, and Testing (SMT) blade testing pro gram. SMT participants agreed to use the fixed S-N slope of m = 10 from the original design to produce consistent test-loads among the laboratories. Unconstrained, the general method suggests that slightly higher test loads should be used for the NedWind 25 blade design spectrum. NedWind 25 blade test loads were computed for lead-lag and flap under single-axis and two-axis loading.

  13. Structural Design Criteria Irving J. Zatz, PPPL

    E-Print Network [OSTI]

    unresolvable behavior, perform detailed analysis to determine limit load and apply safety factor of 2 #12 difference in principal stresses · On an S-n curve, allowable stress amplitude limited to the lesser of: ­ 1 and combined via a linear damage relationship and based on the design S-n curve ­ For FIRE, the 3000 full power

  14. Variations in gear fatigue life for different wind turbine braking strategies

    SciTech Connect (OSTI)

    McNiff, B.P. (Second Wind, Inc., Somerville, MA (USA)); Musial, W.D. (Solar Energy Research Inst., Golden, CO (USA)); Errichello, R. (GEARTECH, Albany, CA (USA))

    1991-06-01T23:59:59.000Z

    A large number of gearbox failures have occurred in the wind industry in a relatively short period, many because service loads were underestimated. High-torque transients that occur during starting and stopping are difficult to predict and may be overlooked in specifying gearbox design. Although these events comprise a small portion of total load cycles, they can be the most damaging. The severity of these loads varies dramatically with the specific configuration of the wind turbine. The large number of failures in Danish-designed Micon 65 wind turbines prompted this investigation. The high-speed and low-speed shaft torques were measured on a two-stage helical gearbox of a single Micon 65 turbine. Transient events and normal running loads were combined statistically to obtain a typical annual load spectrum. The pitting and bending fatigue lives of the gear teeth were calculated by using Miner's rule for four different high-speed shaft brake configurations. Each breaking scenario was run for both a high- and a low-turbulence normal operating load spectrum. The analysis showed increases in gear life by up to a factor of 25 when the standard high-speed shaft brake is replaced with a dynamic brake or modified with a damper. 9 refs., 9 figs., 3 tabs.

  15. Turbulence descriptors for scaling fatigue loading spectra of wind turbine structural components

    SciTech Connect (OSTI)

    Kelley, N.D.

    1994-07-01T23:59:59.000Z

    The challenge for the designer in developing a new wind turbine is to incorporate sufficient strength in its components to safely achieve a 20- or 30-year service life. To accomplish this, the designer must understand the load and stress distributions (in a statistical sense at least) that the turbine is likely to encounter during its operating life. Sources of loads found in the normal operating environment include start/stop cycles, emergency shutdowns, the turbulence environment associated with the specific site and turbine location, and extreme or ``rare`` events that can challenge the turbine short-term survivability. Extreme events can result from an operational problem (e.g., controller failure) or violent atmospheric phenomena (tornadic circulations, strong gust fronts). For the majority of the operating time, however, the character of the turbulent inflow is the dominant source of the alternating stress distributions experienced by the structural components. Methods of characterizing or scaling the severity of the loading spectra (or the rate of fatigue damage accumulation) must be applicable to a wide range of turbulent inflow environments -- from solitary isolation to the complex flows associated with multi-row wind farms. The metrics chosen must be related to the properties of the turbulent inflow and independent of the nature of local terrain features.

  16. Curved butterfly bileaflet prosthetic cardiac valve

    DOE Patents [OSTI]

    McQueen, David M. (185 Hillside Ave., Chatham, NJ 07928); Peskin, Charles S. (186 Harrard Dr., Hartsdale, NY 10530)

    1991-06-25T23:59:59.000Z

    An annular valve body having a central passageway for the flow of blood therethrough with two curved leaflets each of which is pivotally supported on an accentric positioned axis in the central passageway for moving between a closed position and an open position. The leaflets are curved in a plane normal to the eccentric axis and positioned with the convex side of the leaflets facing each other when the leaflets are in the open position. Various parameters such as the curvature of the leaflets, the location of the eccentric axis, and the maximum opening angle of the leaflets are optimized according to the following performance criteria: maximize the minimum peak velocity through the valve, maximize the net stroke volume, and minimize the mean forward pressure difference, thereby reducing thrombosis and improving the hemodynamic performance.

  17. Field Theory on Curved Noncommutative Spacetimes

    E-Print Network [OSTI]

    Alexander Schenkel; Christoph F. Uhlemann

    2010-08-03T23:59:59.000Z

    We study classical scalar field theories on noncommutative curved spacetimes. Following the approach of Wess et al. [Classical Quantum Gravity 22 (2005), 3511 and Classical Quantum Gravity 23 (2006), 1883], we describe noncommutative spacetimes by using (Abelian) Drinfel'd twists and the associated *-products and *-differential geometry. In particular, we allow for position dependent noncommutativity and do not restrict ourselves to the Moyal-Weyl deformation. We construct action functionals for real scalar fields on noncommutative curved spacetimes, and derive the corresponding deformed wave equations. We provide explicit examples of deformed Klein-Gordon operators for noncommutative Minkowski, de Sitter, Schwarzschild and Randall-Sundrum spacetimes, which solve the noncommutative Einstein equations. We study the construction of deformed Green's functions and provide a diagrammatic approach for their perturbative calculation. The leading noncommutative corrections to the Green's functions for our examples are derived.

  18. Light Curves of Swift Gamma Ray Bursts

    E-Print Network [OSTI]

    Paolo Cea

    2006-09-22T23:59:59.000Z

    Recent observations from the Swift gamma-ray burst mission indicate that a fraction of gamma ray bursts are characterized by a canonical behaviour of the X-ray afterglows. We present an effective theory which allows us to account for X-ray light curves of both (short - long) gamma ray bursts and X-ray rich flashes. We propose that gamma ray bursts originate from massive magnetic powered pulsars.

  19. Detection of interlayer communication using type curves

    E-Print Network [OSTI]

    Tiefenthal, Sven A.

    1988-01-01T23:59:59.000Z

    with the adjacent formation through type curve analysis. The response caused by the essentially infinite acting producing zone alone can be filtered out using desuperposition. The remaining response is the "deviation function" caused by the leaking fault. Type.... TABLE OF CONTENTS Page ABSTRACT. ACKNOWLEDGEMENTS TABLE OF CONTENTS. LIST OF TABLES . V1 . viii LIST OF FIGURES. . . . . IX INTRODUCTION BACKGROUND THEORY Infinite Acting Reservoir. Linear Discontinuities. Fault Parameterization. . . . 8 9...

  20. OPTICAL PHASE CURVES OF KEPLER EXOPLANETS

    SciTech Connect (OSTI)

    Esteves, Lisa J.; De Mooij, Ernst J. W.; Jayawardhana, Ray, E-mail: esteves@astro.utoronto.ca, E-mail: demooij@astro.utoronto.ca, E-mail: rayjay@astro.utoronto.ca [Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, Ontario M5S 3H4 (Canada)

    2013-07-20T23:59:59.000Z

    We conducted a comprehensive search for optical phase variations of all close-in (a/R{sub *} < 10) planet candidates in 15 quarters of Kepler space telescope data. After correcting for systematics, we found eight systems that show secondary eclipses as well as phase variations. Of these, five (Kepler-5, Kepler-6, Kepler-8, KOI-64, and KOI-2133) are new and three (TrES-2, HAT-P-7, and KOI-13) have published phase curves, albeit with many fewer observations. We model the full phase curve of each planet candidate, including the primary and secondary transits, and derive their albedos, dayside and nightside temperatures, ellipsoidal variations, and Doppler beaming. We find that KOI-64 and KOI-2133 have nightside temperatures well above their equilibrium values (while KOI-2133 also has an albedo, >1), so we conclude that they are likely to be self-luminous objects rather than planets. The other six candidates have characteristics consistent with their being planets with low geometric albedos (<0.3). For TrES-2 and KOI-13, the Kepler bandpass appears to probe atmospheric layers hotter than the planet's equilibrium temperature. For KOI-13, we detect a never-before-seen third cosine harmonic with an amplitude of 6.7 {+-} 0.3 ppm and a phase shift of -1.1 {+-} 0.1 rad in the phase curve residual, possibly due to its spin-orbit misalignment. We report derived planetary parameters for all six planets, including masses from ellipsoidal variations and Doppler beaming, and compare our results to published values when available. Our results nearly double the number of Kepler exoplanets with measured phase curve variations, thus providing valuable constraints on the properties of hot Jupiters.

  1. Galaxy rotation curves in de Sitter space

    E-Print Network [OSTI]

    Maurice H. P. M. van Putten

    2015-01-27T23:59:59.000Z

    Dark energy inferred from the observed negative deceleration parameter introduces a small mass of the graviton, that satisfies the Higuchi stability condition. It implies an infra-red modification of gravitation that produces Milgrom's inverse distance law of gravitational attraction in excellent agreement with the observed galaxy rotation curves. We conclude that dark matter is present cosmologically with no need for local clustering in galaxies.

  2. Rotation Curve Measurement using Cross-Correlation

    E-Print Network [OSTI]

    Elizabeth J. Barton; Sheila J. Kannappan; Michael J. Kurtz; Margaret J. Geller

    2000-06-20T23:59:59.000Z

    Longslit spectroscopy is entering an era of increased spatial and spectral resolution and increased sample size. Improved instruments reveal complex velocity structure that cannot be described with a one-dimensional rotation curve, yet samples are too numerous to examine each galaxy in detail. Therefore, one goal of rotation curve measurement techniques is to flag cases in which the kinematic structure of the galaxy is more complex than a single-valued curve. We examine cross-correlation as a technique that is easily automated and works for low signal-to-noise spectra. We show that the technique yields well-defined errors which increase when the simple spectral model (template) is a poor match to the data, flagging those cases for later inspection. We compare the technique to the more traditional, parametric technique of simultaneous emission line fitting. When the line profile at a single slit position is non-Gaussian, the techniques disagree. For our model spectra with two well-separated velocity components, assigned velocities from the two techniques differ by up to ~52% of the velocity separation of the model components. However, careful use of the error statistics for either technique allows one to flag these non-Gaussian spectra.

  3. Capillary migration of microdisks on curved interfaces

    E-Print Network [OSTI]

    Lu Yao; Nima Sharifi-Mood; Iris B. Liu; Kathleen J. Stebe

    2014-12-23T23:59:59.000Z

    The capillary energy landscape for particles on curved fluid interfaces is strongly influenced by the particle wetting conditions. Contact line pinning has now been widely reported for colloidal particles, but its implications in capillary interactions have not been addressed. Here, we present experiment and analysis for disks with pinned contact lines on curved fluid interfaces. In experiment, we study microdisk migration on a host interface with zero mean curvature; the microdisks have contact lines pinned at their sharp edges and are sufficiently small that gravitational effects are negligible. The disks migrate away from planar regions toward regions of steep curvature with capillary energies inferred from the dissipation along particle trajectories which are linear in the deviatoric curvature. We derive the curvature capillary energy for an interface with arbitrary curvature, and discuss each contribution to the expression. By adsorbing to a curved interface, a particle eliminates a patch of fluid interface and perturbs the surrounding interface shape. Analysis predicts that perfectly smooth, circular disks do not migrate, and that nanometric deviations from a planar circular, contact line, like those around a weakly roughened planar disk, will drive migration with linear dependence on deviatoric curvature, in agreement with experiment.

  4. Incorporating Experience Curves in Appliance Standards Analysis

    SciTech Connect (OSTI)

    Garbesi, Karina; Chan, Peter; Greenblatt, Jeffery; Kantner, Colleen; Lekov, Alex; Meyers, Stephen; Rosenquist, Gregory; Buskirk, Robert Van; Yang, Hung-Chia; Desroches, Louis-Benoit

    2011-10-31T23:59:59.000Z

    The technical analyses in support of U.S. energy conservation standards for residential appliances and commercial equipment have typically assumed that manufacturing costs and retail prices remain constant during the projected 30-year analysis period. There is, however, considerable evidence that this assumption does not reflect real market prices. Costs and prices generally fall in relation to cumulative production, a phenomenon known as experience and modeled by a fairly robust empirical experience curve. Using price data from the Bureau of Labor Statistics, and shipment data obtained as part of the standards analysis process, we present U.S. experience curves for room air conditioners, clothes dryers, central air conditioners, furnaces, and refrigerators and freezers. These allow us to develop more representative appliance price projections than the assumption-based approach of constant prices. These experience curves were incorporated into recent energy conservation standards for these products. The impact on the national modeling can be significant, often increasing the net present value of potential standard levels in the analysis. In some cases a previously cost-negative potential standard level demonstrates a benefit when incorporating experience. These results imply that past energy conservation standards analyses may have undervalued the economic benefits of potential standard levels.

  5. Human performance modeling for system of systems analytics :soldier fatigue.

    SciTech Connect (OSTI)

    Lawton, Craig R.; Campbell, James E.; Miller, Dwight Peter

    2005-10-01T23:59:59.000Z

    The military has identified Human Performance Modeling (HPM) as a significant requirement and challenge of future systems modeling and analysis initiatives as can be seen in the Department of Defense's (DoD) Defense Modeling and Simulation Office's (DMSO) Master Plan (DoD 5000.59-P 1995). To this goal, the military is currently spending millions of dollars on programs devoted to HPM in various military contexts. Examples include the Human Performance Modeling Integration (HPMI) program within the Air Force Research Laboratory, which focuses on integrating HPMs with constructive models of systems (e.g. cockpit simulations) and the Navy's Human Performance Center (HPC) established in September 2003. Nearly all of these initiatives focus on the interface between humans and a single system. This is insufficient in the era of highly complex network centric SoS. This report presents research and development in the area of HPM in a system-of-systems (SoS). Specifically, this report addresses modeling soldier fatigue and the potential impacts soldier fatigue can have on SoS performance.

  6. Passive solar design handbook

    SciTech Connect (OSTI)

    Jones, R.W.

    1981-01-01T23:59:59.000Z

    The Passive Solar Design Handbook, Volume Three updates Volume Two by presenting extensive new data on the optimum mix of conservation and solar direct gain, sunspaces, thermal storage walls, and solar radiation. The direct gain, thermal storage wall, and solar radiation data are greatly expanded relative to the Volume 2 coverage. The needed flexibility to analyze a variety of system designs is accommodated by the large number of reference designs to be encompassed - 94 in contrast to 6 in Volume two - and the large amount of sensitivity data for direct gain and sunspace systems - approximately 1100 separate curves.

  7. Experience curves for power plant emission control technologies

    E-Print Network [OSTI]

    Rubin, Edward S.; Yeh, Sonia; Hounshell, David A; Taylor, Margaret R

    2007-01-01T23:59:59.000Z

    Inc. Experience curves for power plant emission controlfor Coal-Fired Utility Power Plants, U.S. Environmental1/2, 2004 Experience curves for power plant emission control

  8. Visual Attention and Driver Performance at Horizontal Curves

    E-Print Network [OSTI]

    Brimley, Bradford K.

    2014-12-02T23:59:59.000Z

    Despite the frequency with which drivers encounter curves on highways, curves are regularly identified as locations that experience disproportionately high crash rates. Crash data suggest that inattention is one of the leading causes of crashes...

  9. O set Approximation Improvment G. Elber and E. Cohen 10 9] J. Hoschek and N .Wissel. Optimal approximate conversion of spline curves and

    E-Print Network [OSTI]

    Utah, University of

    . Journal de Mathematique Pures et Appliquees, 15 (1850), 332-350. 3] B .Cobb Design of Sculptured Surfaces. Elber and E. Cohen 8 Figure 4: The error function does not convergence to zero, for general curves. Step

  10. COMPUTER GENERATION OF TYPE CURVES SUBMITIED TO THE DEPARTMENTOF PETROLEUMENGINEERING

    E-Print Network [OSTI]

    Stanford University

    COMPUTER GENERATION OF TYPE CURVES A REPORT SUBMITIED TO THE DEPARTMENTOF PETROLEUMENGINEERING data. This paper presents some previously published type curves and the computer programs that were between two parallel sealing faults. The governing equations for these curves are derived. The computer

  11. Length and Energy of Quadratic Bezier Curves and Applications

    E-Print Network [OSTI]

    Hoffmann, Christoph M.

    Length and Energy of Quadratic B´ezier Curves and Applications Young Joon Ahn a , Christoph for the arc length and the bending energy of quadratic B´ezier curves. The formulae are in terms control point is analyzed for curves of fixed arc length or bending energy. In the case of arc length

  12. RANKS OF ELLIPTIC CURVES WITH PRESCRIBED TORSION OVER NUMBER FIELDS

    E-Print Network [OSTI]

    Dujella, Andrej

    RANKS OF ELLIPTIC CURVES WITH PRESCRIBED TORSION OVER NUMBER FIELDS JOHAN BOSMAN, PETER BRUIN of all elliptic curves over quadratic fields with torsion subgroup T is empty, or it contains curves number fields. More explicitly, we will be interested in the following question: given a torsion group

  13. Algorithms for Mumford Curves Ralph Morrison and Qingchun Ren

    E-Print Network [OSTI]

    Boyer, Edmond

    discuss specific methods and future work for hyperelliptic Mumford curves. 1. Introduction Curves over non geometry, which looks at the images in Rn of curves under coordinate-wise valuation, these are balanced complete with respect to a nontrivial non-archimedean valuation. Unless otherwise stated, | · | will denote

  14. Tracking Endocardium Using Optical Flow along Iso-Value Curve

    E-Print Network [OSTI]

    1 Tracking Endocardium Using Optical Flow along Iso-Value Curve Qi Duan1, Elsa D. Angelini2 indicators. · A framework of optical flow along iso-value curves is proposed and applied to several cardiac;9 OF along Iso-value Curves · In myocardial motion analysis, motion fields are projected along specific

  15. Effect of laser shock processing (LSP) on the fatigue resistance of an aluminum alloy

    SciTech Connect (OSTI)

    Yaxin, T.; Yongkang, Z.; Hong, Z.; Chengye, Y.

    2000-01-01T23:59:59.000Z

    The laser shock induced stress wave is described and measured with a polyvinylidene fluoride (PVDF) transducer. A principle for selecting laser parameters is proposed. A small sized laser with a high power is used for Laser Shock Processing (LSP). The fatigue life of the aluminum alloy 2024T62 is greatly improved after LSP. With 95% confidence, the mean fatigue life of LSP specimens is 4.5--9.8 times that of unshocked ones. The fatigue and fracture resistance mechanisms of LSP such as the variation of the surface hardness, the microstructure and the fracture section of specimens before and after LSP are analyzed.

  16. Cement fatigue and HPHT well integrity with application to life of well prediction

    E-Print Network [OSTI]

    Ugwu, Ignatius Obinna

    2009-05-15T23:59:59.000Z

    to the cyclic loading and few data sets may not be sufficient to give an adequate description of cement behavior under fatigue loading. Studies were conducted by Kim and Kim 2 on the fatigue behavior of high strength concrete using a type I Portland cement....3: Comparison of Max Stress Levels to Number of Cycles for Different Cement Strengths [2] Antrim 3 conducted fatigue studies on hardened ordinary Portland (type I) cement paste using 2 specimens; one with a high-water cement ratio of 0.7 and another...

  17. Decline curve analysis for horizontal wells

    E-Print Network [OSTI]

    Shih, Min-Yu

    1994-01-01T23:59:59.000Z

    support kept me from losing sight of my goals. Thanks to Sam Hou, Joseph Wang, Robert Liau, James Wang, and Shou for their company and in particular to Li Fan and Mrs. Shou-Lee Chang for their caring and delicious meals when I forgot my dinner. Thanks... Pressure (L/2xe= 0. 2) Composite Dimensionless Flow Rate Integral and Flow Rate Integral Derivative Functions Type Curve for an Infinite-Conductivity Horizontal Well Located in the Center of a Square Drainage Area, Producing at Constant Bottomhole...

  18. Negative decline curves of coalbed degasification wells

    SciTech Connect (OSTI)

    Harrison, G.C.; Gordon, R.B.

    1984-05-01T23:59:59.000Z

    Production data from coalbed degasification wells characteristically exhibit a negative decline curve. The dynamics of this methane production are complex and interrelated. As production begins, water and free gas are often first recovered. Continued production lowers pressure and increases permeability to gas, allowing adsorbed gas to flow. This pressure drop within the formation causes sublimation whereby gas, which is absorbed within the coal, forms on the walls of the micropores. Finally, the desorption through production disturbs the chemical and physical equilibrium of the coal, thus enabling the coal to resume generation of methane.

  19. Modeling the Phillips curve with unobserved components

    E-Print Network [OSTI]

    Harvey, Andrew C

    is then nonstationary. However, writing the equation as #1;#25;t = #12;xt+"t makes it clear that what we have is not really a Phillips curve (though adding lags of xt and incorporating a unit root could retrieve the situation). On the other hand, a stationary model... -looking. The conditions under which a model with an expectational term reverts to (10) are derived below. The fact that the forecast function for a random walk component is constant simpli?es matters considerably. The reduced form of (10) is an ARMAX model in which #1;#25...

  20. Wave regularity in curve integrable spacetimes

    E-Print Network [OSTI]

    Yafet Sanchez Sanchez

    2015-02-23T23:59:59.000Z

    The idea of defining a gravitational singularity as an obstruction to the dynamical evolution of a test field (described by a PDE) rather than the dynamical evolution of a particle (described by a geodesics) is explored. In particular, the concept of wave regularity is introduced which serves to show that the classical singularities in curve integrable spacetimes do not interrupt the well-posedness of the wave equation. The techniques used also provide arguments that can be extended to establish when a classically singular spacetime remains singular in a semi-classical picture.

  1. Equivalence of Real Elliptic CurvesEquivalence of Real Elliptic Curves Part 2Part 2 --Birational EquivalenceBirational Equivalence

    E-Print Network [OSTI]

    Broughton, S. Allen

    1 Equivalence of Real Elliptic CurvesEquivalence of Real Elliptic Curves Part 2Part 2 -- Birational EquivalenceBirational Equivalence Allen Broughton Rose-Hulman Institute of Technology #12;2 CreditsCredits Discussion with Ken McMurdy #12;3 OutlineOutline -- 11 Recap of linear equivalence Complex elliptic curves

  2. The crystallography of fatigue crack initiation in Incoloy-908 and A-286 steel

    SciTech Connect (OSTI)

    Krenn, C.R. [Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering]|[Lawrence Berkeley National Lab., CA (United States)

    1996-12-01T23:59:59.000Z

    Fatigue crack initiation in the austenitic Fe-Ni superalloys Incoloy-908 and A-286 is examined using local crystallographic orientation measurements. Results are consistent with sharp transgranular initiation and propagation occurring almost exclusively on {l_brace}111{r_brace} planes in Incoloy-908 but on a variety of low index planes in A-286. This difference is attributed to the influence of the semicoherent grain boundary {eta} phase in A-286. Initiation in each alloy occurred both intergranularly and transgranularly and was often associated with blocky surface oxide and carbide inclusions. Taylor factor and resolved shear stress and strain crack initiation hypotheses were tested, but despite an inconclusive suggestion of a minimum required {l_brace}111{r_brace} shear stress, none of the hypotheses were found to convincingly describe preferred initiation sites, even within the subsets of transgranular cracks apparently free from the influence of surface inclusions. Subsurface inclusions are thought to play a significant role in crack initiation. These materials have applications for use in structural conduit for high field superconducting magnets designed for fusion energy use.

  3. Axiomatic quantum field theory in curved spacetime

    E-Print Network [OSTI]

    S. Hollands; R. M. Wald

    2008-03-13T23:59:59.000Z

    The usual formulations of quantum field theory in Minkowski spacetime make crucial use of features--such as Poincare invariance and the existence of a preferred vacuum state--that are very special to Minkowski spacetime. In order to generalize the formulation of quantum field theory to arbitrary globally hyperbolic curved spacetimes, it is essential that the theory be formulated in an entirely local and covariant manner, without assuming the presence of a preferred state. We propose a new framework for quantum field theory, in which the existence of an Operator Product Expansion (OPE) is elevated to a fundamental status, and, in essence, all of the properties of the quantum field theory are determined by its OPE. We provide general axioms for the OPE coefficients of a quantum field theory. These include a local and covariance assumption (implying that the quantum field theory is locally and covariantly constructed from the spacetime metric), a microlocal spectrum condition, an "associativity" condition, and the requirement that the coefficient of the identity in the OPE of the product of a field with its adjoint have positive scaling degree. We prove curved spacetime versions of the spin-statistics theorem and the PCT theorem. Some potentially significant further implications of our new viewpoint on quantum field theory are discussed.

  4. Light curves from rapidly rotating neutron stars

    E-Print Network [OSTI]

    Numata, Kazutoshi

    2010-01-01T23:59:59.000Z

    We calculate light curves produced by a hot spot of a rapidly rotating neutron star, assuming that the spot is perturbed by a core $r$-mode, which is destabilized by emitting gravitational waves. To calculate light curves, we take account of relativistic effects such as the Doppler boost due to the rapid rotation and light bending assuming the Schwarzschild metric around the neutron star. We assume that the core $r$-modes penetrate to the surface fluid ocean to have sufficiently large amplitudes to disturb the spot. For a $l'=m$ core $r$-mode, the oscillation frequency $\\omega\\approx2m\\Omega/[l'(l'+1)]$ defined in the co-rotating frame of the star will be detected by a distant observer, where $l'$ and $m$ are respectively the spherical harmonic degree and the azimuthal wave number of the mode, and $\\Omega$ is the spin frequency of the star. In a linear theory of oscillation, using a parameter $A$ we parametrize the mode amplitudes such that ${\\rm max}\\left(|\\xi_\\theta|,|\\xi_\\phi|\\right)/R=A$ at the surface, w...

  5. Algebraic quantum field theory in curved spacetimes

    E-Print Network [OSTI]

    Christopher J. Fewster; Rainer Verch

    2015-04-02T23:59:59.000Z

    This article sets out the framework of algebraic quantum field theory in curved spacetimes, based on the idea of local covariance. In this framework, a quantum field theory is modelled by a functor from a category of spacetimes to a category of ($C^*$)-algebras obeying supplementary conditions. Among other things: (a) the key idea of relative Cauchy evolution is described in detail, and related to the stress-energy tensor; (b) a systematic "rigidity argument" is used to generalise results from flat to curved spacetimes; (c) a detailed discussion of the issue of selection of physical states is given, linking notions of stability at microscopic, mesoscopic and macroscopic scales; (d) the notion of subtheories and global gauge transformations are formalised; (e) it is shown that the general framework excludes the possibility of there being a single preferred state in each spacetime, if the choice of states is local and covariant. Many of the ideas are illustrated by the example of the free Klein-Gordon theory, which is given a new "universal definition".

  6. Essays on the Economics of Environmental Issues: The Environmental Kuznets Curve to Optimal Energy Portfolios

    E-Print Network [OSTI]

    Meininger, Aaron G.

    2012-01-01T23:59:59.000Z

    Issues: The Environmental Kuznets Curve to Optimal EnergyE. (2005), “An environmental kuznets curve analysis of u.s.proach to environmental kuznets curves using the ecological

  7. Searching for Empirical Regularity and Theoretical Structure: The Environmental Kuznets Curve

    E-Print Network [OSTI]

    Carson, Richard T

    2009-01-01T23:59:59.000Z

    of the environmental Kuznets curve. Journal of Publicof the environmental Kuznets curve studies. Agriculture andhypothesis and environmental Kuznets Curve: examining the

  8. DEVELOPING FLOW AND HEAT TRANSFER IN STRONGLY CURVED DUCTS OF RECTANGULAR CROSS-SECTION

    E-Print Network [OSTI]

    Yee, G.

    2010-01-01T23:59:59.000Z

    DEVELOpiNG FLOW AND HEAT TRANSFER IN STRONGLY CURVED DUCTS9092 Developing Flow and Heat Transfer in Strongly CurvedForced Convection Heat Transfer in Curved Rectangular

  9. Reliability-based framework for fatigue damage prognosis of bonded structural elements in aerospace composite structures

    E-Print Network [OSTI]

    Gobbato, Maurizio

    2011-01-01T23:59:59.000Z

    and J.D. Achenbach, Structural health monitoring and damagein fatigue, Structural Health Monitoring, 7(1), 37-49, 2008.and J.D. Achenbach, Structural health monitoring and damage

  10. Effect of nano-scale twinning on the fracture, fatigue and wear properties of copper

    E-Print Network [OSTI]

    Singh, Aparna, Ph.D. Massachusetts Institute of Technology

    2011-01-01T23:59:59.000Z

    Grain refinement in materials has been one of the most common strategies for improving the strength of materials. However this comes at the price of reduced ductility, fracture toughness and stable fatigue crack propagation ...

  11. An analytical study of rail grinding optimization for rail-head fatigue defect prevention

    E-Print Network [OSTI]

    Jones, Scott Laurence

    1997-01-01T23:59:59.000Z

    and increased train traffic on the remaining routes. These changes in railroad industry practice have caused an increase in the rate of occurrence of rail head fatigue defects, one potential cause of train derailment. The primary form of maintenance employed...

  12. Stochastic Damage Evolution under Static and Fatigue Loading in Composites with Manufacturing Defects

    E-Print Network [OSTI]

    Huang, Yongxin

    2012-07-16T23:59:59.000Z

    In this dissertation, experimental investigations and theoretical studies on the stochastic matrix cracking evolution under static and fatigue loading in composite laminates with defects are presented. The presented work demonstrates a methodology...

  13. Rolling contact fatigue in martensitic 100Cr6: Subsurface hardening and crack formation

    E-Print Network [OSTI]

    Kang, Jee-Hyun; Vegter, R. H.; Rivera-Díaz-del-Castillo, Pedro E. J.

    2014-04-13T23:59:59.000Z

    steels and free-cutting steels Part 17: ball and roller bearing steels, Technical Report 683–17:1999, International Organization for Standardization, 1991. [11] D. Glover, in: Rolling Contact Fatigue Testing of Bearing Steels, volume 771 of ASTM STP...

  14. The effectiveness of floor mats as an intervention for standing fatigue of light fabrication workers

    E-Print Network [OSTI]

    O'Brien, Michael Shannon

    1996-01-01T23:59:59.000Z

    A field study was conducted in a light fabrication plant to determine the effectiveness of floor mats on reducing the symptoms of standing fatigue. Specific physiological variables measured include skin temperature of the foot, blood pooling...

  15. Mechanisms of bioprosthetic heart valve failure: Fatigue causes collagen denaturation and glycosaminoglycan loss

    E-Print Network [OSTI]

    Zand, Robert

    Mechanisms of bioprosthetic heart valve failure: Fatigue causes collagen denaturation heart valve (BPHV) degeneration, characterized by extracellular matrix deterioration, remod- eling) with glutaraldehyde fixed porcine aortic valve bioprostheses, that the mechanical function of cardiac valve cusps

  16. FATIGUE OF SKIN-STIFFENER INTERSECTIONS IN COMPOSITE WIND TURBINE BLADE STRUCTURES

    E-Print Network [OSTI]

    FATIGUE OF SKIN-STIFFENER INTERSECTIONS IN COMPOSITE WIND TURBINE BLADE STRUCTURES by Robert B in the Instron and Composite Laboratories toward the end of the experimental research. Finally, special thanks

  17. SciTech Connect: Prediction of the Creep-Fatigue Lifetime of...

    Office of Scientific and Technical Information (OSTI)

    approach would be relevant to calculate the remaining useful life to a component like a steam generator that might fail by the creep-fatigue mechanism. Authors: Vivek Agarwal;...

  18. Static and fatigue bending behavior of pultruded GFRP sandwich panels with through-thickness fiber insertions

    E-Print Network [OSTI]

    to evaluate the static and fatigue characteristics of an innovative 3-D glass fiber reinforced polymer (GFRP materials typically include polymeric foams, balsa wood, light- weight honeycomb structures or FRP shear

  19. Physical modeling of the soil swelling curve vs. the shrinkage curve

    E-Print Network [OSTI]

    V. Y. Chertkov

    2014-04-14T23:59:59.000Z

    Physical understanding of the links between soil swelling, texture, structure, cracking, and sample size is of great interest for the physical understanding of many processes in the soil-air-water system and for applications in civil, agricultural, and environmental engineering. The background of this work is an available chain of interconnected physical shrinkage curve models for clay, intra-aggregate matrix, aggregated soil without cracks, and soil with cracks. The objective of the work is to generalize these models to the case of swelling, and to construct the physical-swelling-model chain with a step-by-step transition from clay to aggregated soil with cracks. The generalization is based on thorough accounting for the analogies and differences between shrinkage and swelling and the corresponding use, modification, or replacement of the soil shrinkage features. Two specific soil swelling features to be used are: (i) air entrapping in pores of the contributing clay; and (ii) aggregate destruction with the formation of new aggregate surfaces. The input for the prediction of the swelling curve of an aggregated soil coincides with that of the available model of the shrinkage curve. The analysis of available data on the maximum shrink-swell cycle of two soils with different texture and structure, accounting for sample size is conducted as applied to swelling curves and to the residual crack volume and maximum-swelling-volume decrease after the shrink-swell cycle. Results of the analysis show evidence in favor of the swelling model chain.

  20. Curved Spacetimes and Curved Graphene: a status report of the Weyl-symmetry approach

    E-Print Network [OSTI]

    Alfredo Iorio

    2014-12-15T23:59:59.000Z

    This is a status report about the ongoing work on the realization of quantum field theory on curved graphene spacetimes that uses Weyl symmetry. The programme is actively pursued from many different perspectives. Here we point to what has been done, and to what needs to be done.

  1. Sensitivity Variation on Low Cycle Fatigue Cracks Using Level 4/Method B Penetrant

    SciTech Connect (OSTI)

    FULWOOD,HARRY; MOORE,DAVID G.

    1999-09-02T23:59:59.000Z

    The Federal Aviation Administration's Airworthiness Assurance NDI Validation Center (AANC) is currently conducting experiments with Level 4, Method B penetrant on low cycle fatigue specimens. The main focus of these experiments is to document the affect on penetrant brightness readings by varying inspection parameters. This paper discusses the results of changing drying temperature, drying time, and dwell time of both penetrant and emulsifier on low cycle fatigue specimens.

  2. Fatigue behavior of full-size soild-sawn timber railroad stringers

    E-Print Network [OSTI]

    Maingot, Martin Rex

    1999-01-01T23:59:59.000Z

    12 . . . . . . . 1 5 , . . . 16 . . . . . 20 . . . . . 21 . . . 21 23 . . . . . . . 24 3. EXPERIMENTAL PROGRAM Page 3. 1 General Specimen Details . . 3. 2 Experimental Setup 3. 2. 1 Static Loading System. 3. 2. 2 Fatigue Loading System.... . 3. 3 Non-Destructive Evaluation of Timber Specimens. . . . . 3. 3. 1 Grouping of Timber Specimens. 3. 3. 2 Specimen Strength vs. Specimen Stiffness. 3. 4 Testing Procedure 3. 4. 1 Data Acquisition. . 3. 4. 2 Static Testing. 3. 4. 3 Fatigue...

  3. Design of Wind Turbines in an Area with Tropical Cyclones Niels-Erik Clausen, niels-erik.clausen@risoe.dk, Sren Ott, Niels-Jacob Tarp-Johansen, Per Nrgrd and

    E-Print Network [OSTI]

    Design of Wind Turbines in an Area with Tropical Cyclones Niels-Erik Clausen, niels and cost of wind turbines is influenced by a combination of fatigue and extreme loads and the applied design codes. In general wind turbines are designed for 20 years of operation using design standards

  4. Engineering Predictions in Industrial and Power Flows Using the Retrograde Condensation Curve. Part I-Methodology

    E-Print Network [OSTI]

    Labinov, Mark S

    2014-01-01T23:59:59.000Z

    Industrial and power systems rely on engineering predictions of the flow properties of working fluids. The paper proposes a way of the utilization of the vapor quality values along the new retrograde condensation curve in the generation of the void fraction design guidelines and reliable prediction of the saturated liquid specific volumes/densities. The new procedure eliminates the involvement of semi-empirical relationships like rectilinear diameter and other similar models.

  5. Influence of fatigue on the nanohardness of NiTiCr-wires

    SciTech Connect (OSTI)

    Frotscher, M. [Ruhr University, Bochum, Germany; Young, M. L. [Ruhr University, Bochum, Germany; Bei, Hongbin [ORNL; George, Easo P [ORNL; Neuking, K. [Ruhr University, Bochum, Germany; Eggeler, G. [Ruhr University, Bochum, Germany

    2009-01-01T23:59:59.000Z

    Testing parameters, such as rotational speed and bending radius, have a strong influence on the fatigue life of pseudoelastic NiTi shape-memory alloys during bending rotation fatigue (BRF) experiments [M. F. X. Wagner, Int. J. Mat. Res. 97 (2006), p. 1687-1696. and M. Frotscher, et al., Thermomechanical processing, microstructure and bending rotation fatigue of ultra-fine grained NiTiCr-wires, Proceedings of the International Conference for Shape Memory and Superelastic Technologies (SMST 2007), Tsukuba, Japan, ASM International, (2008), p. 149-158.]. Previous studies showed a decrease in the fatigue life for smaller bending radius (i.e. higher equivalent strain) and larger rotational speed. This observation is associated with an increase of dislocation density, the stabilization of stressinduced martensite during cycling, and an increase of the plateau stresses due to self-heating. In the present study, we examine the influence of these fatigue parameters on the nanohardness and shape recovery of pseudoelastic NiTiCr shape-memory alloy wires by nanoindentation. We show that nanoindentation is a suitable method for the characterization of fatigue-related microstructural changes, which affect the mechanical properties.

  6. Hydrogen atom on curved noncommutative space

    E-Print Network [OSTI]

    V. G. Kupriyanov

    2013-06-05T23:59:59.000Z

    We have calculated the hydrogen atom spectrum on curved noncommutative space defined by the commutation relations $\\left[ \\hat {x}^{i},\\hat{x}^{j}\\right] =i\\theta\\hat{\\omega}^{ij}\\left( \\hat {x}\\right) $, where $\\theta$ is the parameter of noncommutativity. The external antisymmetric field which determines the noncommutativity is chosen as $\\omega^{ij}(x) =\\varepsilon^{ijk}{x}_{k}f\\left( {x_i}x^{i}\\right) $. In this case the rotational symmetry of the system is conserved, preserving the degeneracy of the energy spectrum. The contribution of the noncommutativity appears as a correction to the fine structure. The corresponding nonlocality is calculated: $\\Delta x\\Delta y \\geq \\frac{\\theta^2}{4} |m\\langle f^2\\rangle| $, where $m$ is a magnetic quantum number.

  7. Remote quantum states in curved spacetime

    E-Print Network [OSTI]

    Charles Francis

    2014-07-06T23:59:59.000Z

    It is seen that issues of the evolution of the wave function in curved spacetime can be resolved by describing the evolution of quantum states in Minkowski tangent space, in accordance with the orthodox interpretation that the wave function is not physical but is part of a mathematical method for the calculation of probabilities of measurement results. The teleconnection is defined between Hilbert spaces at different points in spacetime motivated by arguments from the probability interpretation. The teleconnection is analogous to a connection between vector spaces and reduces to the Levi-Civita connection in the limit of near initial and final measurements. Gravitational redshift is as in classical general relativity, as is the redshift for the cosmological microwave background. An argument is given that the cosmological redshift of photons treated as quantum particles should be treated differently. If correct this argument has important implications for the age of the universe, galaxy evolution and missing matter.

  8. SUPERNOVA LIGHT CURVES POWERED BY FALLBACK ACCRETION

    SciTech Connect (OSTI)

    Dexter, Jason; Kasen, Daniel, E-mail: jdexter@berkeley.edu [Departments of Physics and Astronomy, University of California, Berkeley, CA 94720 (United States)

    2013-07-20T23:59:59.000Z

    Some fraction of the material ejected in a core collapse supernova explosion may remain bound to the compact remnant, and eventually turn around and fall back. We show that the late time ({approx}>days) power potentially associated with the accretion of this 'fallback' material could significantly affect the optical light curve, in some cases producing super-luminous or otherwise peculiar supernovae. We use spherically symmetric hydrodynamical models to estimate the accretion rate at late times for a range of progenitor masses and radii and explosion energies. The accretion rate onto the proto-neutron star or black hole decreases as M-dot {proportional_to}t{sup -5/3} at late times, but its normalization can be significantly enhanced at low explosion energies, in very massive stars, or if a strong reverse shock wave forms at the helium/hydrogen interface in the progenitor. If the resulting super-Eddington accretion drives an outflow which thermalizes in the outgoing ejecta, the supernova debris will be re-energized at a time when photons can diffuse out efficiently. The resulting light curves are different and more diverse than previous fallback supernova models which ignored the input of accretion power and produced short-lived, dim transients. The possible outcomes when fallback accretion power is significant include super-luminous ({approx}> 10{sup 44} erg s{sup -1}) Type II events of both short and long durations, as well as luminous Type I events from compact stars that may have experienced significant mass loss. Accretion power may unbind the remaining infalling material, causing a sudden decrease in the brightness of some long duration Type II events. This scenario may be relevant for explaining some of the recently discovered classes of peculiar and rare supernovae.

  9. Fatigue-induced phase formation and its deformation behavior in a cobalt-based superalloy (prop. 2002-090)

    SciTech Connect (OSTI)

    Choo, Hahn [ORNL; Benson, M. L. [University of Tennessee, Knoxville (UTK); Saleh, T A [University of Tennessee, Knoxville (UTK); Liaw, Peter K [University of Tennessee, Knoxville (UTK); Brown, D. W. [Los Alamos National Laboratory (LANL); Daymond, M R [Queen's University, Ontario, Canada; Wang, Xun-Li [ORNL; Stoica, A. D. [Oak Ridge Associated Universities (ORAU); Buchanan, R. A. [University of Tennessee, Knoxville (UTK); Klarstrom, D L [Haynes International, Inc.

    2005-03-01T23:59:59.000Z

    The low-cycle fatigue behavior of a cobalt-based superalloy was studied in situ using neutron-diffraction experiments. The alloy exhibited stress-induced formation of a hexagonal-close-packed (hcp) phase within its parent face-centered-cubic (fcc) phase at ambient temperature under strain-controlled fatigue conditions with a total strain range, {Delta}{var_epsilon} = 2.5%. The (101) hcp peak was first observed during the 12th fatigue cycle under the given conditions following a period during which no hcp phase was detected. Subsequently, the intensity of the hcp peaks increased as fatigue progressed. Furthermore, within a single fatigue cycle, the intensity of the (101) hcp peak decreased during the compression half-cycle and increased again when the specimen was subjected to a subsequent tensile strain. The result suggests that the fcc to hcp transformation is partially reversible within one fatigue cycle.

  10. Construction of Fractal Surfaces by Recurrent Fractal Interpolation Curves

    E-Print Network [OSTI]

    Chol-hui Yun; Hyong-chol O.; Hui-chol Choi

    2014-08-12T23:59:59.000Z

    A method to construct fractal surfaces by recurrent fractal curves is provided. First we construct fractal interpolation curves using a recurrent iterated functions system(RIFS) with function scaling factors and estimate their box-counting dimension. Then we present a method of construction of wider class of fractal surfaces by fractal curves and Lipschitz functions and calculate the box-counting dimension of the constructed surfaces. Finally, we combine both methods to have more flexible constructions of fractal surfaces.

  11. Fabrication procedure effects on fatigue resistance of rib -to-deck welded joints of steel orthotropic bridge decks

    E-Print Network [OSTI]

    Sim, Hyoung-Bo

    2010-01-01T23:59:59.000Z

    details of orthotropic steel deck. ” Proc. , Internationalnew approaches to fatigue evaluation of steel bridges. ”International Journal of Steel Structures, KSSC, Vol. 6, No.

  12. Kummel Disease Treatment by Unipedicular Vertebral Augmentation Using Curved Injection Cannula

    SciTech Connect (OSTI)

    Masala, Salvatore, E-mail: salva.masala@tiscali.it; Nano, Giovanni; Mammucari, Matteo; Simonetti, Giovanni [University 'Tor Vergata', Department of Diagnostic and Molecular Imaging, Interventional Radiology and Radiotherapy (Italy)

    2011-10-15T23:59:59.000Z

    Purpose: This study was designed to evaluate the efficacy of the blunt-tipped curved injection needle (BCN) AVAflex (Care Fusion) for vertebral augmentation in cases of Kummel's disease. Methods: We performed 25 vertebral augmentation procedures on 25 consecutive patients (11 men/14 women; mean age, 67 years) with Kummel's disease using the blunt-tipped curved injection needle with PMMA cement. We performed all 25 procedures by unipedicular left approach with patients in prone position under local anesthesia and mild sedation. In all cases, an intravertebral cleft was evident on preprocedural imaging. We evaluated pain intensities by Visual Analogic Scale (VAS) before and at first day, 6 months, and 1 year after procedure. Results: In all cases the curved injection cannula permitted the filling of the clefts and surrounding cancellous bone without any complication. A significant reduction of kyphotic deformities of the treated vertebral bodies was evident. A significance decrease in VAS values at 1 year also was evident (mean decrease 7.2). At plain dynamic postprocedural X-rays checks, there was no sign of pathologic intravertebral motion as evidence of optimal stabilization. Conclusions: BCN AVAflex is a safe and effective device for targeted vertebral augmentation in cases of Kummel's disease. Its distinctive characteristic is the curved injection cannula, which enables targeting the cement injection to areas far off the trajectory of the straight access cannula, thus providing excellent cement spread throughout the entire volume of vertebral body.

  13. A Curved Boundary Treatment for Discontinuous Galerkin Schemes ...

    E-Print Network [OSTI]

    2015-03-09T23:59:59.000Z

    memory costs in curved elements will be increased due to integration on ...... Optimal energy conserving local ... Springer Science & Business Media, 2009. 23

  14. THE CENTRAL CURVE IN LINEAR PROGRAMMING 1. Introduction ...

    E-Print Network [OSTI]

    2010-12-17T23:59:59.000Z

    Section 2 offers an analysis of central curves in the plane, with emphasis on the dual ...... path is generated by the circuit polynomials (21) and the d linear ...

  15. Semistable Models of Curves Resolution of singularities on the tower of modular

    E-Print Network [OSTI]

    Semistable Models of Curves Resolution of singularities on the tower of modular curves Jared on the tower of modular curves #12;Semistable Models of Curves Semistable models: Definition Let R Resolution of singularities on the tower of modular curves #12;Semistable Models of Curves Semistable models

  16. D-Branes in Curved Space

    SciTech Connect (OSTI)

    McGreevy, John Austen; /Stanford U., Phys. Dept.

    2005-07-06T23:59:59.000Z

    This thesis is a study of D-branes in string compactifications. In this context, D-branes are relevant as an important component of the nonperturbative spectrum, as an incisive probe of these backgrounds, and as a natural stringy tool for localizing gauge interactions. In the first part of the thesis, we discuss half-BPS D-branes in compactifications of type II string theory on Calabi-Yau threefolds. The results we describe for these objects are pertinent both in their role as stringy brane-worlds, and in their role as solitonic objects. In particular, we determine couplings of these branes to the moduli determining the closed-string geometry, both perturbatively and non-perturbatively in the worldsheet expansion. We provide a local model for transitions in moduli space where the BPS spectrum jumps, and discuss the extension of mirror symmetry between Calabi-Yau manifolds to the case when D-branes are present. The next section is an interlude which provides some applications of D-branes to other curved backgrounds of string theory. In particular, we discuss a surprising phenomenon in which fundamental strings moving through background Ramond-Ramond fields dissolve into large spherical D3-branes. This mechanism is used to explain a previously-mysterious fact discovered via the AdS-CFT correspondence. Next, we make a connection between type IIA string vacua of the type discussed in the first section and M-theory compactifications on manifolds of G{sub 2} holonomy. Finally we discuss constructions of string vacua which do not have large radius limits. In the final part of the thesis, we develop techniques for studying the worldsheets of open strings ending on the curved D-branes studied in the first section. More precisely, we formulate a large class of massive two-dimensional gauge theories coupled to boundary matter, which flow in the infrared to the relevant boundary conformal field theories. Along with many other applications, these techniques are used to describe world-volume theories of point-like D-probes of various Calabi-Yau threefolds.

  17. Seventh International Conference on Biaxial/Multiaxial Fatigue and Fracture, Berlin, 2004, pp. 329-334 FATIGUE CRACK NUCLEATION AND GROWTH IN FILLED NATURAL RUBBER

    E-Print Network [OSTI]

    Fatemi, Ali

    -334 FATIGUE CRACK NUCLEATION AND GROWTH IN FILLED NATURAL RUBBER SUBJECTED TO MULTIAXIAL STRESS STATES W.V. Mars1 and A. Fatemi2 1 Cooper Tire and Rubber Company, 701 Lima Ave., Findlay, Ohio 45840, USA 2 crack nucleation and growth in filled natural rubber under a wide range of multiaxial stress

  18. Properties of branes in curved spacetimes

    E-Print Network [OSTI]

    Kostas Skenderis; Marika Taylor

    2003-11-20T23:59:59.000Z

    A generic property of curved manifolds is the existence of focal points. We show that branes located at focal points of the geometry satisfy special properties. Examples of backgrounds to which our discussion applies are AdS_m x S^n and plane wave backgrounds. As an example, we show that a pair of AdS_2 branes located at the north and south pole of the S^5 in AdS_5 x S^5 are half supersymmetric and that they are dual to a two-monopole solution of N=4 SU(N) SYM theory. Our second example involves spacelike branes in the (Lorentzian) plane wave. We develop a modified lightcone gauge for the open string channel, analyze in detail the cylinder diagram and establish open-closed duality. When the branes are located at focal points of the geometry the amplitude acquires most of the characteristics of flat space amplitudes. In the open string channel the special properties are due to stringy modes that become massless.

  19. Ghost condensate model of flat rotation curves

    E-Print Network [OSTI]

    V. V. Kiselev

    2005-07-29T23:59:59.000Z

    An effective action of ghost condensate with higher derivatives creates a source of gravity and mimics a dark matter in spiral galaxies. We present a spherically symmetric static solution of Einstein--Hilbert equations with the ghost condensate at large distances, where flat rotation curves are reproduced in leading order over small ratio of two energy scales characterizing constant temporal and spatial derivatives of ghost field: $\\mu_*^2$ and $\\mu_\\star^2$, respectively, with a hierarchy $\\mu_\\star\\ll \\mu_*$. We assume that a mechanism of hierarchy is provided by a global monopole in the center of galaxy. An estimate based on the solution and observed velocities of rotations in the asymptotic region of flatness, gives $\\mu_*\\sim 10^{19}$ GeV and the monopole scale in a GUT range $\\mu_\\star\\sim 10^{16}$ GeV, while a velocity of rotation $v_0$ is determined by the ratio: $ \\sqrt{2} v_0^2= \\mu_\\star^2/\\mu_*^2$. A critical acceleration is introduced and naturally evaluated of the order of Hubble rate, that represents the Milgrom's acceleration.

  20. Instanton effects and quantum spectral curves

    E-Print Network [OSTI]

    Johan Kallen; Marcos Marino

    2014-04-16T23:59:59.000Z

    We study a spectral problem associated to the quantization of a spectral curve arising in local mirror symmetry. The perturbative WKB quantization condition is determined by the quantum periods, or equivalently by the refined topological string in the Nekrasov-Shatashvili (NS) limit. We show that the information encoded in the quantum periods is radically insufficient to determine the spectrum: there is an infinite series of instanton corrections, which are non-perturbative in \\hbar, and lead to an exact WKB quantization condition. Moreover, we conjecture the precise form of the instanton corrections: they are determined by the standard or un-refined topological string free energy, and we test our conjecture successfully against numerical calculations of the spectrum. This suggests that the non-perturbative sector of the NS refined topological string contains information about the standard topological string. As an application of the WKB quantization condition, we explain some recent observations relating membrane instanton corrections in ABJM theory to the refined topological string.

  1. Calibration curves for some standard Gap Tests

    SciTech Connect (OSTI)

    Bowman, A.L.; Sommer, S.C.

    1989-01-01T23:59:59.000Z

    The relative shock sensitivities of explosive compositions are commonly assessed using a family of experiments that can be described by the generic term ''Gap Test.'' Gap tests include a donor charge, a test sample, and a spacer, or gap, between two explosives charges. The donor charge, gap material, and test dimensions are held constant within each different version of the gap test. The thickness of the gap is then varied to find the value at which 50% of the test samples will detonate. The gap tests measure the ease with a high-order detonation can be established in the test explosive, or the ''detonability,'' of the explosive. Test results are best reported in terms of the gap thickness at the 50% point. It is also useful to define the shock pressure transmitted into the test sample at the detonation threshold. This requires calibrating the gap test in terms of shock pressure in the gap as a function of the gap thickness. It also requires a knowledge of the shock Hugoniot of the sample explosive. We used the 2DE reactive hydrodynamic code with Forest Fire burn rates for the donor explosives to calculate calibration curves for several gap tests. The model calculations give pressure and particle velocity on the centerline of the experimental set-up and provide information about the curvature and pulse width of the shock wave. 10 refs., 1 fig.

  2. Status for Learning Curves indlg ved BES temadag om

    E-Print Network [OSTI]

    cost of Danish wind turbines 0 200 400 600 800 1970 1980 1990 2000 2010 2020 Ratedpower[kW] 0 5 10 15 Curves - cost of wind energy technology 0,100 1,000 100 1000 10000 100000 Danish wind industry's global's Law": Size - in rated power - doubles every four years #12;On Experience Curves · Cost decreases

  3. Cortical Hemisphere Registration Via Large Deformation Diffeomorphic Metric Curve

    E-Print Network [OSTI]

    Qiu, Anqi

    on the relation between individual brains and the atlas. This is a powerful approach allowing us to study a largeCortical Hemisphere Registration Via Large Deformation Diffeomorphic Metric Curve Mapping Anqi Qiu1 Science, Johns Hopkins University Abstract. We present large deformation diffeomorphic metric curve

  4. Array E Calibration Curves PAGE 1 OF 22

    E-Print Network [OSTI]

    Rathbun, Julie A.

    REV. MO. ATM1095 Array E Calibration Curves PAGE 1 OF 22 DATE 11 April 197 2 This A TM summarizes the scope and contents of the calibration curve data book and calibration magnetic tape which special conversions which are out of scope of the Apollo/Saturn Calibration Tape Format Mod 1; special

  5. HONDA-TATE THEOREM FOR ELLIPTIC CURVES MIHRAN PAPIKIAN

    E-Print Network [OSTI]

    Papikian, Mihran

    HONDA-TATE THEOREM FOR ELLIPTIC CURVES MIHRAN PAPIKIAN 1. Introduction These are the notes from the 2011-12 academic year. Tate's isogeny theorem over finite fields, and the related Honda-Tate theorem theorem and Honda-Tate theorem for elliptic curves, and then to prove these theorems using only tools from

  6. CURVES OF GENUS 2 WITH p 2 MULTIPLICATION

    E-Print Network [OSTI]

    thesis, which looks at curves of genus 2 whose jacobians have p 2 multiplication, with the generalisedCURVES OF GENUS 2 WITH p 2 MULTIPLICATION PETER R. BENDING Abstract We give a universal family, and let f be a newform on \\Gamma 1 (N) whose field of Fourier coefficients is F (F is a totally real field

  7. Fast Multipole Representation of Diffusion Curves and Points Timothy Sun

    E-Print Network [OSTI]

    Grinspun, Eitan

    Fast Multipole Representation of Diffusion Curves and Points Timothy Sun Papoj Thamjaroenporn performed on the fast multipole representation. Abstract We propose a new algorithm for random-access evaluation of diffu- sion curve images (DCIs) using the fast multipole method. Unlike all previous methods

  8. Oil production models with normal rate curves Dudley Stark

    E-Print Network [OSTI]

    Stark, Dudley

    Oil production models with normal rate curves Dudley Stark School of Mathematical Sciences Queen;Abstract The normal curve has been used to fit the rate of both world and U.S.A. oil production sizes are lognormally distributed, and the starting time of the production of a field is approximately

  9. TORSION OF RATIONAL ELLIPTIC CURVES OVER QUADRATIC FIELDS

    E-Print Network [OSTI]

    González, Enrique

    TORSION OF RATIONAL ELLIPTIC CURVES OVER QUADRATIC FIELDS ENRIQUE GONZÁLEZ­JIMÉNEZ AND JOSÉ M the torsion subgroup E(Q)tors and the torsion subgroup E(K)tors, where K is a quadratic number field. 1 of primes that can appear as the order of a torsion point of an elliptic curve E defined over a number field

  10. AVERAGE RANKS OF ELLIPTIC CURVES: TENSION BETWEEN DATA AND CONJECTURE

    E-Print Network [OSTI]

    Stein, William

    curves of conductor X} converge as X tends to infinity, and if so, what is the limit P = lim X PAVERAGE RANKS OF ELLIPTIC CURVES: TENSION BETWEEN DATA AND CONJECTURE BAUR BEKTEMIROV, BARRY MAZUR, and · to list them in order of increasing conductor, banking on the theorem that tells us that there are only

  11. Stochastic Analysis of Wind Turbine Power Curves Edgar Anahua

    E-Print Network [OSTI]

    Peinke, Joachim

    Stochastic Analysis of Wind Turbine Power Curves Edgar Anahua Oldenburg 2007 Zur Homepage der Dissertation #12;#12;Stochastic Analysis of Wind Turbine Power Curves Edgar Anahua Von der Fakult¨at f the wind turbine's power per- formance directly from high frequency fluctuating measurements. In particular

  12. SHM BASED SYSTEM DESIGN OFA WIND TURBINE TOWER USING A MODAL SENSITIVITY BASED BAYES DETECTOR

    E-Print Network [OSTI]

    Boyer, Edmond

    SHM BASED SYSTEM DESIGN OFA WIND TURBINE TOWER USING A MODAL SENSITIVITY BASED BAYES DETECTOR Mads@ramboll.com ABSTRACT It is investigated if material based structural safety can be replaced with safety obtained from of the NREL 5MW wind turbine tower subjected to bending fatigue and horizontal circumferential cracking

  13. Novel Experiments to Characterize Creep-Fatigue Degradation in VHTR Alloys

    SciTech Connect (OSTI)

    J. K. Wright; J. A. Simpson; L. J. Carroll; R. N. Wright; T.-L. Sham

    2013-10-01T23:59:59.000Z

    It is well known in energy systems that the creep lifetime of high temperature alloys is significantly degraded when a cyclic load is superimposed on components operating in the creep regime. A test method has been developed in an attempt to characterize creep-fatigue behavior of alloys at high temperature. The test imposes a hold time during the tensile phase of a fully reversed strain-controlled low cycle fatigue test. Stress relaxation occurs during the strain-controlled hold period. This type of fatigue stress relaxation test tends to emphasize the fatigue portion of the total damage and does not necessarily represent the behavior of a component in-service well. Several different approaches to laboratory testing of creep-fatigue at 950°C have been investigated for Alloy 617, the primary candidate for application in VHTR heat exchangers. The potential for mode switching in a cyclic test from strain control to load control, to allow specimen extension by creep, has been investigated to further emphasize the creep damage. In addition, tests with a lower strain rate during loading have been conducted to examine the influence of creep damage occurring during loading. Very short constant strain hold time tests have also been conducted to examine the influence of the rapid stress relaxation that occurs at the beginning of strain holds.

  14. Fatigue Crack Growth Rate Model for Metallic Alloys R. C. Dimitriu and H. K. D. H. Bhadeshia

    E-Print Network [OSTI]

    Cambridge, University of

    and aluminium alloys. It appears therefore that a large proportion of the differences in the fatigue crack against iron, aluminium and titanium alloys; it does however require a prior knowledge of the thresholdFatigue Crack Growth Rate Model for Metallic Alloys R. C. Dimitriu and H. K. D. H. Bhadeshia

  15. Locking of electric-field-induced non-180 domain switching and phase transition in ferroelectric materials upon cyclic electric fatigue

    E-Print Network [OSTI]

    Hsia, K Jimmy

    change in piezoelectric coefficients in these materials upon cyclic electric field. © 2003 American of ferroelectric fatigue. One approach is through investiga- tion of the change of the material properties with respect to the cause of ferroelectric fatigue. The change in materials constants usually indicates

  16. Precipitation and Thermal Fatigue in Ni-Ti-Zr Shape Memory Alloy Thin Films by Combinatorial nanoCalorimetry

    E-Print Network [OSTI]

    1 Precipitation and Thermal Fatigue in Ni-Ti-Zr Shape Memory Alloy Thin Films by Combinatorial nano Mongolia University of Technology Hohhot 010051, China Abstract: Thin-film samples of Ni-Ti-Zr shape memory the composition and the stress state of the shape memory phase. Thermal fatigue behavior, induced by thermal

  17. Fracture and Fatigue Behavior at Ambient and Elevated Temperatures of Alumina Bonded with Copper/Niobium/Copper Interlayers

    E-Print Network [OSTI]

    Ritchie, Robert

    Fracture and Fatigue Behavior at Ambient and Elevated Temperatures of Alumina Bonded with Copper/Niobium-phase bonded using copper/niobium/copper interlayers have been investigated at both room and elevated, with failure primarily at the alumina/niobium interfaces. At room temperature, cyclic fatigue-crack propagation

  18. High-Frequency Fatigue Behavior of Woven-Fiber-Fabric-Reinforced Polymer-Derived Ceramic-Matrix Composites

    E-Print Network [OSTI]

    Barber, James R.

    High-Frequency Fatigue Behavior of Woven-Fiber-Fabric-Reinforced Polymer-Derived Ceramic-Matrix heat exchangers, continuous-fiber-reinforced ceramic- matrix composites (CFCMCs) will encounter cyclic glass-matrix composite showed that, unlike monolithic ceramics, fatigue life of this composite decreased

  19. Atmospheric and Wake Turbulence Impacts on Wind Turbine Fatigue Loading: Preprint

    SciTech Connect (OSTI)

    Lee, S.; Churchfield, M.; Moriarty, P.; Jonkman, J.; Michalakes, J.

    2011-12-01T23:59:59.000Z

    Large-eddy simulations of atmospheric boundary layers under various stability and surface roughness conditions are performed to investigate the turbulence impact on wind turbines. In particular, the aeroelastic responses of the turbines are studied to characterize the fatigue loading of the turbulence present in the boundary layer and in the wake of the turbines. Two utility-scale 5 MW turbines that are separated by seven rotor diameters are placed in a 3 km by 3 km by 1 km domain. They are subjected to atmospheric turbulent boundary layer flow and data is collected on the structural response of the turbine components. The surface roughness was found to increase the fatigue loads while the atmospheric instability had a small influence. Furthermore, the downstream turbines yielded higher fatigue loads indicating that the turbulent wakes generated from the upstream turbines have significant impact.

  20. Effects of wear-resistant coatings on the fatigue strength of 4340 steel

    SciTech Connect (OSTI)

    Duffy, E.R. [Naval Aviation Depot North Island, San Diego, CA (United States)

    1998-12-31T23:59:59.000Z

    For applications using 4340 steel where hardened surfaces are required in a marine environment, surface coatings are necessary. Coatings that resist corrosion and provide wear resistance generally degrade the fatigue performance of the substrate metal. Shot peening before plating was ineffective in preventing a loss of fatigue life of plated steel bars compared to bare steel test bars which were not shot peened. The maximum residual compressive strength produced by shot peening was measured and was less than the maximum applied tensile stress in fatigue. As-plated electroless nickel has poor sliding wear resistance compared to either electroplated nickel or chromium in sliding wear at a contact stress of 37 Mpa. The tensile strength decreased in proportion to the volume fraction of coating applied to the steel substrate.

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

    SciTech Connect (OSTI)

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

    1994-09-01T23:59:59.000Z

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

  2. Corrosion-fatigue behavior of an annealed AISI 1045 carbon steel coated with electroless nickel-phosphorus

    SciTech Connect (OSTI)

    Pertuz, A.; Chitty, J.A.; Puchi, E.S. (Central Univ. of Venezuela, Caracas (Venezuela)); Hintermann, H. (Univ. of Neuchatel (Switzerland). Faculty of Sciences)

    1999-08-01T23:59:59.000Z

    The influence of an industrial electroless nickel-phosphorus deposit on the corrosion-fatigue properties of an annealed AISI 1045 steel has been investigated. For this purpose, three corrosive media were selected: distilled water and two NaCl solutions of different concentration (3 and 5%) in distilled water. Corrosion-fatigue tests were conducted at alternating stress levels ranging between 219 and 329 MPa at a frequency of 50 Hz. The corrosion-fatigue properties of the coated and uncoated substrates are very similar when testing is conducted in salty water. However, for testing in distilled water the corrosion-fatigue properties of coated substrates were diminished in relation to the uncoated material. The fractographic analysis of the fracture surfaces revealed the presence of fatigue marks within the electroless nickel-phosphorus deposit, which indicate that the fracture mechanism of the coating is associated to the cyclic loading of the material.

  3. Materials degradation and fatigue under extreme conditions. Final report, 1 April 1994-31 August 1997

    SciTech Connect (OSTI)

    Jonas, J.

    1997-10-29T23:59:59.000Z

    This AFOSR URI addressed complex research problems of materials degradation and fatigue in aerospace structures in severe or extreme environments. A better understanding of materials degradation and flaw initiation dynamics was achieved through a multi-disciplinary research program encompassing chemistry, surface physics, materials science and mechanics, both experimental and theoretical. The Subprojects were as follows: (1) Surface Induced Degradation of Fluorocarbon Lubricants; (2) Molecular Tribology of Perfluoroether Lubricants; (3) Fluids, Including Lubricants Under Extreme Conditions of High Pressure/High Temperature and Confinement; (4) Surface Crack Propagation Under Combined Mechanical and High Pressure Fluid Loading; and (5) Lubricant Assisted Fatigue Crack Growth in Ceramics.

  4. Failure by fracture and fatigue in 'NANO' and 'BIO'materials

    SciTech Connect (OSTI)

    Ritchie, R.O.; Muhlstein, C.L.; Nalla, R.K.

    2003-12-19T23:59:59.000Z

    The behavior of nanostructured materials/small-volumestructures and biologi-cal/bio-implantable materials, so-called "nano"and "bio" materials, is currently much in vogue in materials science. Oneaspect of this field, which to date has received only limited attention,is their fracture and fatigue properties. In this paper, we examine twotopics in this area, namely the premature fatigue failure ofsilicon-based micron-scale structures for microelectromechanical systems(MEMS), and the fracture properties of mineralized tissue, specificallyhuman bone.

  5. Transformation Induced Fatigue of Ni-Rich NiTi Shape Memory Alloy Actuators

    E-Print Network [OSTI]

    Schick, Justin Ryan

    2011-02-22T23:59:59.000Z

    TRANSFORMATION INDUCED FATIGUE OF NI-RICH NITI SHAPE MEMORY ALLOY ACTUATORS A Thesis by JUSTIN RYAN SCHICK Submitted to the O ce of Graduate Studies of Texas A&M University in partial ful llment of the requirements for the degree of MASTER... OF SCIENCE December 2009 Major Subject: Aerospace Engineering TRANSFORMATION INDUCED FATIGUE OF NI-RICH NITI SHAPE MEMORY ALLOY ACTUATORS A Thesis by JUSTIN RYAN SCHICK Submitted to the O ce of Graduate Studies of Texas A&M University in partial ful llment...

  6. Analysis of the effect of matrix degradation on fatigue behavior of a graphite/epoxy laminate

    E-Print Network [OSTI]

    Arenburg, Robert Thomas

    1982-01-01T23:59:59.000Z

    ANALYSIS OF THE EFFECT OF MATRIX DEGRADATION ON FATIGUE BEHAVIOR OF A GRAPHITE/EPOXY LAMINATE A Thesis by ROBERT THOMAS ARENBURG Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE May 1982 Major Subject: Civil Engineering ANALYSiS OF THE EFFECT OF MATRIX DEGRAOATION ON FATIGUE BEHAVIOR OF A GRAPHITE/EPOXY LAMINATE A Thesis by ROBERT THOMAS ARENBURG Approved as to style and content by: (Chairman...

  7. Fatigue analysis of WECS (Wind Energy Conversion System) components using a rainflow counting algorithm

    SciTech Connect (OSTI)

    Sutherland, H.J.; Schluter, L.L.

    1990-01-01T23:59:59.000Z

    A rainflow counting algorithm'' has been incorporated into the LIFE2 fatigue/fracture analysis code for wind turbines. The count algorithm, with its associated pre- and post-count algorithms, permits the code to incorporate time-series data into its analysis scheme. After a description of the algorithms used here, their use is illustrated by the examination of stress-time histories from the Sandia 34-m Test Bed vertical axis wind turbine. The results of the rainflow analysis are compared and contrasted to previously reported predictions for the service lifetime of the fatigue critical component for this turbine. 14 refs., 8 figs., 3 tabs.

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

    SciTech Connect (OSTI)

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

    2012-05-01T23:59:59.000Z

    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.

  9. Tensile and fatigue behaviors of printed Ag thin films on flexible substrates

    SciTech Connect (OSTI)

    Sim, Gi-Dong; Won, Sejeong; Lee, Soon-Bok [Department of Mechanical Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of)

    2012-11-05T23:59:59.000Z

    Flexible electronics using nanoparticle (NP) printing has been highlighted as a key technology enabling eco-friendly, low-cost, and large-area fabrication. For NP-based printing to be used as a successive alternative to photolithography and vacuum deposition, stretchability and long term reliability must be considered. This paper reports the stretchability and fatigue behavior of 100 nm thick NP-based silver thin films printed on polyethylene-terephthalate substrate and compares it to films deposited by electron-beam evaporation. NP-based films show stretchability and fatigue life comparable to evaporated films with intergranular fracture as the dominant failure mechanism.

  10. Analysis of the effect of matrix degradation on fatigue behavior of a graphite/epoxy laminate 

    E-Print Network [OSTI]

    Arenburg, Robert Thomas

    1982-01-01T23:59:59.000Z

    ANALYSIS OF THE EFFECT OF MATRIX DEGRADATION ON FATIGUE BEHAVIOR OF A GRAPHITE/EPOXY LAMINATE A Thesis by ROBERT THOMAS ARENBURG Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE May 1982 Major Subject: Civil Engineering ANALYSiS OF THE EFFECT OF MATRIX DEGRAOATION ON FATIGUE BEHAVIOR OF A GRAPHITE/EPOXY LAMINATE A Thesis by ROBERT THOMAS ARENBURG Approved as to style and content by: (Chairman...

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

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

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

  12. alloy fatigue strength: Topics by E-print Network

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

    of weldments of a high strength low alloy(HSLA) steel in a simulated seawater environment. This steel, designated HSLA80, was developed by the United ... Needham, William...

  13. Application of the decline curve method to aquifers

    E-Print Network [OSTI]

    Potnis, Girish Vijay

    1992-01-01T23:59:59.000Z

    k = value of pointin time = value of point in time n = value of point in time 39 REFERENCES 1. Fetkovich, M. J. : "Decline Curve Analysis Using Type Curves, " JPT (June 1980) 1065-1077. 2. Havlena, D. and Odeh, A. S. : "The Material Balance...APPLICATION OF THE DECLINE CURVE METHOD TO AQUIFERS A Thesis by GIRISH VIJAY POTNIS Submitted to the Office of Graduate Studies of Texas ADAM University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE December...

  14. Bolometric and UV light curves of core-collapse supernovae

    SciTech Connect (OSTI)

    Pritchard, T. A.; Roming, P. W. A. [Department of Astronomy and Astrophysics, Penn State University, 525 Davey Lab, University Park, PA 16802 (United States); Brown, Peter J. [Department of Physics and Astronomy, George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Texas A. and M. University, 4242 TAMU, College Station, TX 77843 (United States); Bayless, Amanda J. [Southwest Research Institute, Department of Space Science, 6220 Culebra Road, San Antonio, TX 78238 (United States); Frey, Lucille H. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2014-06-01T23:59:59.000Z

    The Swift UV-Optical Telescope (UVOT) has been observing core-collapse supernovae (CCSNe) of all subtypes in the UV and optical since 2005. Here we present 50 CCSNe observed with the Swift UVOT, analyzing their UV properties and behavior. Where we have multiple UV detections in all three UV filters (? {sub c} = 1928-2600 Å), we generate early time bolometric light curves, analyze the properties of these light curves and the UV contribution to them, and derive empirical corrections for the UV-flux contribution to optical-IR based bolometric light curves.

  15. Exhaustive search system and method using space-filling curves

    DOE Patents [OSTI]

    Spires, Shannon V.

    2003-10-21T23:59:59.000Z

    A search system and method for one agent or for multiple agents using a space-filling curve provides a way to control one or more agents to cover an area of any space of any dimensionality using an exhaustive search pattern. An example of the space-filling curve is a Hilbert curve. The search area can be a physical geography, a cyberspace search area, or an area searchable by computing resources. The search agent can be one or more physical agents, such as a robot, and can be software agents for searching cyberspace.

  16. Estimating type curve parameters with the cumulative curvature method

    E-Print Network [OSTI]

    Harris, Dan Edward

    1986-01-01T23:59:59.000Z

    curvature of Ramey type curves at a forward span of 40'$ . 32 15 Cumulative curvature of Ramey type curves at a forward span of 50$ . 33 16 Cumulative curvature of Ramey type curves at a forward span of 60$ 34 ix LIST OF FIGURES icontinued) 17..."wand spans ranging f;om 15$ to 60$ are presented in Figure 10 through 12. Since data that bately reaches past the end of the unit slope region is too vague even for this technique, the graph with a forward span of 0$ to 15$ is omitied here because...

  17. ASME95_CurveFit.PDF

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041cloth DocumentationProducts (VAP) VAP7-0973 1 Introduction In the design of aD. P. Burwinkle,83-90.

  18. ASME95_CurveFit.PDF

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041cloth DocumentationProducts (VAP) VAP7-0973 1 Introduction In the design of aD. P.

  19. Multiobjective Design and Optimization of Polymer Flood Performance

    E-Print Network [OSTI]

    Ekkawong, Peerapong

    2013-07-22T23:59:59.000Z

    The multiobjective genetic algorithm can be used to optimize two conflicting objectives, oil production and polymer utility factor in polymer flood design. This approach provides a set of optimal solutions which can be considered as trade-off curve...

  20. Optimization of the Collection Efficiency of a Hexagonal Light Collector using Quadratic and Cubic Bézier Curves

    E-Print Network [OSTI]

    Akira Okumura

    2012-06-04T23:59:59.000Z

    Reflective light collectors with hexagonal entrance and exit apertures are frequently used in front of the focal-plane camera of a very-high-energy gamma-ray telescope to increase the collection efficiency of atmospheric Cherenkov photons and reduce the night-sky background entering at large incident angles. The shape of a hexagonal light collector is usually based on Winston's design, which is optimized for only two-dimensional optical systems. However, it is not known whether a hexagonal Winston cone is optimal for the real three-dimensional optical systems of gamma-ray telescopes. For the first time we optimize the shape of a hexagonal light collector using quadratic and cubic B\\'ezier curves. We demonstrate that our optimized designs simultaneously achieve a higher collection efficiency and background reduction rate than traditional designs.

  1. Atomistic modeling of nanowires, small-scale fatigue damage in cast magnesium, and materials for MEMS.

    SciTech Connect (OSTI)

    Dunn, Martin L. (University of Colorado, Boulder, CO); Talmage, Mellisa J. (University of Colorado, Boulder, CO); McDowell, David L., 1956- (,-Georgia Institute of Technology, Atlanta, GA); West, Neil (University of Colorado, Boulder, CO); Gullett, Philip Michael (Mississippi State University , MS); Miller, David C. (University of Colorado, Boulder, CO); Spark, Kevin (University of Colorado, Boulder, CO); Diao, Jiankuai (University of Colorado, Boulder, CO); Horstemeyer, Mark F. (Mississippi State University , MS); Zimmerman, Jonathan A.; Gall, K (Georgia Institute of Technology, Atlanta, GA)

    2006-10-01T23:59:59.000Z

    Lightweight and miniaturized weapon systems are driving the use of new materials in design such as microscale materials and ultra low-density metallic materials. Reliable design of future weapon components and systems demands a thorough understanding of the deformation modes in these materials that comprise the components and a robust methodology to predict their performance during service or storage. Traditional continuum models of material deformation and failure are not easily extended to these new materials unless microstructural characteristics are included in the formulation. For example, in LIGA Ni and Al-Si thin films, the physical size is on the order of microns, a scale approaching key microstructural features. For a new potential structural material, cast Mg offers a high stiffness-to-weight ratio, but the microstructural heterogeneity at various scales requires a structure-property continuum model. Processes occurring at the nanoscale and microscale develop certain structures that drive material behavior. The objective of the work presented in this report was to understand material characteristics in relation to mechanical properties at the nanoscale and microscale in these promising new material systems. Research was conducted primarily at the University of Colorado at Boulder to employ tightly coupled experimentation and simulation to study damage at various material size scales under monotonic and cyclic loading conditions. Experimental characterization of nano/micro damage will be accomplished by novel techniques such as in-situ environmental scanning electron microscopy (ESEM), 1 MeV transmission electron microscopy (TEM), and atomic force microscopy (AFM). New simulations to support experimental efforts will include modified embedded atom method (MEAM) atomistic simulations at the nanoscale and single crystal micromechanical finite element simulations. This report summarizes the major research and development accomplishments for the LDRD project titled 'Atomistic Modeling of Nanowires, Small-scale Fatigue Damage in Cast Magnesium, and Materials for MEMS'. This project supported a strategic partnership between Sandia National Laboratories and the University of Colorado at Boulder by providing funding for the lead author, Ken Gall, and his students, while he was a member of the University of Colorado faculty.

  2. Physical modeling of the soil swelling curve vs. the shrinkage curve

    E-Print Network [OSTI]

    Chertkov, V Y

    2014-01-01T23:59:59.000Z

    Physical understanding of the links between soil swelling, texture, structure, cracking, and sample size is of great interest for the physical understanding of many processes in the soil-air-water system and for applications in civil, agricultural, and environmental engineering. The background of this work is an available chain of interconnected physical shrinkage curve models for clay, intra-aggregate matrix, aggregated soil without cracks, and soil with cracks. The objective of the work is to generalize these models to the case of swelling, and to construct the physical-swelling-model chain with a step-by-step transition from clay to aggregated soil with cracks. The generalization is based on thorough accounting for the analogies and differences between shrinkage and swelling and the corresponding use, modification, or replacement of the soil shrinkage features. Two specific soil swelling features to be used are: (i) air entrapping in pores of the contributing clay; and (ii) aggregate destruction with the f...

  3. Constructing Pairing-Friendly Elliptic Curves with Embedding Degree 10.

    E-Print Network [OSTI]

    on the application. In order to vary the security level or adapt to future improvements in discrete log technology with k = 12. There is a gen- eral construction, originally due to Cocks and Pinch [8], for curves

  4. Small distance expansion for radiative heat transfer between curved objects

    E-Print Network [OSTI]

    Golyk, Vladyslav A.

    We develop a small distance expansion for the radiative heat transfer between gently curved objects, in terms of the ratio of distance to radius of curvature. A gradient expansion allows us to go beyond the lowest-order ...

  5. On spontaneous emission into guided modes with curved wavefronts

    SciTech Connect (OSTI)

    Yariv, A.; Margalit, S.

    1982-11-01T23:59:59.000Z

    The problem of spontaneous emission into guided modes with curved wavefronts is examined quantum mechanically. A classical result due to Petermann, which shows an increased emission rate relative to modes with planar phase fronts, is corroborated.

  6. astronomical light curves: Topics by E-print Network

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

    the majority of the light curves e.g. active galactic nuclei, X-ray binaries, gamma-ray bursts show strong deviations from Gaussianity exhibiting burst-like' events in their...

  7. Knowledge fusion: Comparison of fuzzy curve smoothers to statistically motivated curve smoothers

    SciTech Connect (OSTI)

    Burr, T.; Strittmatter, R.B.

    1996-03-01T23:59:59.000Z

    This report describes work during FY 95 that was sponsored by the Department of Energy, Office of Nonproliferation and National Security (NN) Knowledge Fusion (KF) Project. The project team selected satellite sensor data to use as the one main example to which its analysis algorithms would be applied. The specific sensor-fusion problem has many generic features, which make it a worthwhile problem to attempt to solve in a general way. The generic problem is to recognize events of interest from multiple time series that define a possibly noisy background. By implementing a suite of time series modeling and forecasting methods and using well-chosen alarm criteria, we reduce the number of false alarms. We then further reduce the number of false alarms by analyzing all suspicious sections of data, as judged by the alarm criteria, with pattern recognition methods. This report gives a detailed comparison of two of the forecasting methods (fuzzy forecaster and statistically motivated curve smoothers as forecasters). The two methods are compared on five simulated and five real data sets. One of the five real data sets is satellite sensor data. The conclusion is the statistically motivated curve smoother is superior on simulated data of the type we studied. The statistically motivated method is also superior on most real data. In defense of the fuzzy-logic motivated methods, we point out that fuzzy-logic methods were never intended to compete with statistical methods on numeric data. Fuzzy logic was developed to handle real-world situations where either real data was not available or was supplemented with either ``expert opinion`` or some sort of linguistic information.

  8. Application of the decline curve method to aquifers 

    E-Print Network [OSTI]

    Potnis, Girish Vijay

    1992-01-01T23:59:59.000Z

    APPLICATION OF THE DECLINE CURVE METHOD TO AQUIFERS A Thesis by GIRISH VIJAY POTNIS Submitted to the Office of Graduate Studies of Texas ADAM University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE December... 1992 Major Subject: Petroleum Engineering APPLICATION OF THE DECLINE CURVE METHOD TO AQUIFERS A Thesis by GIRISH VIJAY POTNIS Approved as to style and content by: Steven W. Poston (Chair of Committee) Thomas . Blasingame (member) James E...

  9. Intern experience at Brown & Root, Incorporated: an internship report

    E-Print Network [OSTI]

    Roengnarong Ratanaprichavej, 1949-

    2013-03-13T23:59:59.000Z

    . Curved Conductor Geometry.............................. 36 13. BMCOL Model.............. ................................ 39 HTI DAMS Model................................................ TP 15. Axial Load vs. Settlement.... Uozniak, the project engineer of the Chevron project, the author participated in the following assignments: 1. Boat landing design 2. Curved conductor design 3. Jacket design 4. Fatigue analysis 5. Transportation design 6. Joint analysis...

  10. Submitted to the International Journal of Fatigue, June 2005 Revised, May 2006

    E-Print Network [OSTI]

    specimen under mechanical cyclic loadings. The results of so-called "heating tests" (i.e., thermal effects [7, 8] or infrared (IR) cameras [2-6]. If the dissipated energy is induced by microplasticity, which-cycle fatigue (HCF) failure is caused by microplasticity, correlation between the two tests (i.e., "heating test

  11. Effects of creatine loading on electromyographic fatigue threshold during cycle ergometry in college-aged women

    E-Print Network [OSTI]

    Smith, Abbie E.; Walter, Ashley A.; Herda, Trent J.; Ryan, Eric D.; Moon, Jordan R.; Cramer, Joel T.; Stout, Jeffrey R.

    2007-01-01T23:59:59.000Z

    The purpose of this study was to examine the effects of 5 days of Creatine (Cr) loading on the electromyographic fatigue threshold (EMGFT) in college-aged women. Fifteen healthy college-aged women (mean ± SD = 22.3 ± 1.7 yrs) volunteered...

  12. Fracture and fatigue resistance of MoSiB alloys for ultrahigh-temperature structural applications

    E-Print Network [OSTI]

    Ritchie, Robert

    Fracture and fatigue resistance of Mo­Si­B alloys for ultrahigh-temperature structural applications­Mo3Si­Mo5SiB2 alloys, which utilize a continuous a-Mo matrix to achieve unprecedented room. Introduction For applications such as aerospace engines and power generation, future advancements are limited

  13. Graphene coating makes carbon nanotube aerogels superelastic and resistant to fatigue

    E-Print Network [OSTI]

    McGaughey, Alan

    Graphene coating makes carbon nanotube aerogels superelastic and resistant to fatigue Kyu Hun Kim one and five layers of graphene nanoplates. The graphene-coated aerogel exhibits no change , but collapse under stress15 . We fabricated graphene-coated single-walled carbon nanotube aerogels by coating

  14. Damage estimates for European and US sites using the US high-cycle fatigue data base

    SciTech Connect (OSTI)

    Sutherland, H.J.

    1996-02-01T23:59:59.000Z

    This paper uses two high-cycle fatigue data bases, US blade materials and one for European materials the service lifetime of a wind turbine blade sit WISPER load spectrum for northern European sit 19921 and the WISPER protocol load spectrum farm sites. The US data base, developed by Mandell, et al. (1995), contains over 2200 data points that were obtained using coupon testing procedures. These data are used to construct a Goodman diagram that is suitable for analyzing wind turbine blades. This result is compared to the Goodman diagram derived from the European fatigue data base FACT. The LIFE2 fatigue analysis code for wind turbines is then used to predict the service lifetime of a turbine blade subjected to the two loading histories. The results of this study indicate that the WISPER load spectrum from northern European sites significantly underestimates the WISPER protocol load spectrum from a US wind farm site; i.e., the WISPER load spectrum significantly underestimates the number and magnitude of the loads observed at a US wind farm site. Further, the analyses demonstrate that the European and the US fatigue material data bases are in general agreement for the prediction of tensile failures. However, for compressive failures, the two data bases are significantly different, with the US data base predicting significantly shorter service lifetimes than the European data base.

  15. Elevated temperature static fatigue of a Nicalon fiber-reinforced SiC composite

    SciTech Connect (OSTI)

    Lin, H.T.; Becher, P.F.; Tortorelli, P.F. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

    1994-12-31T23:59:59.000Z

    Static fatigue tests of a Nicalon fiber-reinforced SiC matrix composite were conducted in four-point bending over a temperature range of 425 to 1,150 C in air at selected stress levels. The composite consisted of a Nicalon cloth with a 0.3 {mu}m graphite interfacial coating and a Forced Chemical Vapor Infiltration (FCVI) SiC matrix composite; samples were tested with or without a final protective SiC seal coat. The results indicated that the fatigue life of the Nicalon-SiC composite decreased with an increase in either applied stresses or test temperatures. However, the composite exhibited a fatigue limit of {approximately} 100 MPa at temperatures < 950 C which decreased to {approximately} 70 MPa at 1,150 C. Both electron microscopy and thermogravimetric studies suggested that the lifetime of the composites was dictated by the oxidation of graphite interfacial layer at temperatures {le} 700 C and by oxidation of graphite coating accompanied by formation of silicate interfacial layer via oxidation of the Nicalon fiber (and the SiC matrix) at temperatures {ge} 950 C. Use of a SiC seal coat effectively retarded the oxidation reactions and increased the lifetime by at least one order of magnitude at 425 C. On the other hand, the SiC seal coat made little (if any) difference in fatigue life at 950 C.

  16. Determination of torsional fatigue life of large turbine generator shafts. Final report

    SciTech Connect (OSTI)

    Placek, R.J.; Williams, R.A.; Adams, S.L.; Klufas, O.

    1984-04-01T23:59:59.000Z

    This report presents the results of a study to develop a methodology for predicting torsional fatigue damage to a turbine generator rotor subjected to transient electrical disturbances. This methodology used torsional properties obtained from constant amplitude tests on one-inch diameter specimens. The predictions were verified with constant amplitude and variable amplitude tests of specimens up to six inches in diameter.

  17. RIS-R-1358(EN) Accelerated Fatigue Testing of LM 19.1

    E-Print Network [OSTI]

    May 2003 #12;Abstract A series of 19.1 metre wind turbine blades manufactured by LM Glasfiber A with thermal imaging equipment to determine how an increase in fatigue load affects the blade material FOR STRAIN GAUGES 71 RISØ-R-1358(EN)4 #12;1 Introduction Traditionally a wind turbine blade is tested as part

  18. SOL-XX-XXXX, Samborsky,1 Comparison of Tensile Fatigue Resistance and Constant Life

    E-Print Network [OSTI]

    for Several Potential Wind Turbine Blade Laminates Daniel D. Samborsky* , Timothy J. Wilson, and John F and potential interest for wind turbine blades, representing three types of fibers: E-glass, WindStrandTM glass are then used to predict the performance under spectrum fatigue loading relative to an earlier material

  19. 2013 AIAA SDM Wind Energy Session Creep/Fatigue Behavior of Resin Infused Biaxial Glass

    E-Print Network [OSTI]

    /epoxy biaxial (±45o ) fabric laminates typical of shell/web areas of wind blades. Loading conditions were cyclic in the shell. Thus, the biaxial materials must resist the maximum blade strains under static and fatigue loads without failure or softening enough to reduce the blade stiffness or overload adjacent UD material

  20. Author's personal copy Statistical pattern analysis of ultrasonic signals for fatigue damage detection

    E-Print Network [OSTI]

    Ray, Asok

    by laboratory experimentation in real time on a computer-controlled fatigue damage testing apparatus which is equipped with a variety of measuring instruments including an optical travelling microscope of life and expensive equipment. Therefore, it is necessary to develop capabilities for online detection

  1. In: Fatigue Crack Growth... Editor: Alphonse F. Lignelli, pp. 3-48

    E-Print Network [OSTI]

    Ray, Asok

    fatigue test apparatus, equipped with ultrasonic sensors and an optical microscope, has been used sensing technique that is sensitive to small microstructural changes, robust to measurement noise-state machine that captures the dynamical system behavior by information compression. A computer-controlled

  2. Online fatigue damage monitoring by ultrasonic measurements: A symbolic dynamics approach q

    E-Print Network [OSTI]

    Ray, Asok

    experimentally validated on a special-purpose test apparatus that is equipped with ultrasonic flaw detectionOnline fatigue damage monitoring by ultrasonic measurements: A symbolic dynamics approach q Shalabh alloy specimens, where the experiments have been conducted under load-controlled constant amplitude sinu

  3. Ionic effects on silica optical fiber strength and models for fatigue V. V. Rondinella

    E-Print Network [OSTI]

    Matthewson, M. John

    Ionic effects on silica optical fiber strength and models for fatigue V. V. Rondinella M. J. Matthewson Rutgers University, Fiber Optic Materials Research Program P. 0. Box 909, Piscataway, NJ 08855, flaw free silica optical fiber shows significant differences from the bulk material for poorly

  4. Optical fiber reliability implications of uncertainty in the fatigue crack growth model

    E-Print Network [OSTI]

    Matthewson, M. John

    Optical fiber reliability implications of uncertainty in the fatigue crack growth model G. M. Bubel University Fiber Optic Materials Research Program Ceramic Science and Engineering P.O. Box 909 Piscataway, furthermore, that such flaws can grow in time so that an initially intact silica optical fiber may undergo

  5. 2009 ASME WIND ENERGY SYMPOSIUM Static and Fatigue Testing of Thick Adhesive Joints for

    E-Print Network [OSTI]

    1 2009 ASME WIND ENERGY SYMPOSIUM Static and Fatigue Testing of Thick Adhesive Joints for Wind as wind blade size has increased. Typical blade joints use paste adhesives several millimeters thick aircraft, which are also of relevance to wind blades in many instances. The strengths of lap-shear and many

  6. Thermo-optical modulation for improved ultrasonic fatigue crack detection in Ti6Al4V

    E-Print Network [OSTI]

    Nagy, Peter B.

    scatterers, such as surface grooves, corrosion pits, coarse grains, etc. that might hide the fatigue crack to grow at unexpectedly high growth rates well below the large-crack threshold in aluminum, aluminum­lithium) and secondary irregulari- ties (e.g. uneven machining, mechanical wear, corrosion, etc.). Second

  7. Investigating the Effects of Corrosion on the Fatigue Life of Welded Steel Attachments

    E-Print Network [OSTI]

    Soape, Jack

    2012-07-16T23:59:59.000Z

    of dollars each year for the railroad industry in terms of maintenance and inspection. Since a large number of these bridges are steel and their service life is typically governed by fatigue of welded details, it is important to determine the interactions...

  8. Influence of Hold Time on Creep-Fatigue Behavior of an Advanced Austenitic Alloy

    SciTech Connect (OSTI)

    Mark Carroll; Laura Carroll

    2011-09-01T23:59:59.000Z

    An advanced austenitic alloy, HT-UPS (high temperature-ultrafine precipitate strengthened), is a candidate material for the structural components of fast reactors and energy-conversion systems. HT-UPS provides improved creep resistance through a composition based on 316 stainless steel (SS) with additions of Ti and Nb to form nano-scale MC precipitates in the austenitic matrix. The low cycle fatigue and creep-fatigue behavior of a HT-UPS alloy has been investigated at 650 C, 1.0% total strain, and an R ratio of -1 with hold times as long as 9000 sec at peak tensile strain. The cyclic deformation response of HT-UPS is compared to that of 316 SS. The cycles to failure are similar, despite differences in peak stress profiles and the deformed microstructures. Cracking in both alloys is transgranular (initiation and propagation) in the case of continuous cycle fatigue, while the primary cracks also propagate transgranularly during creep-fatigue cycling. Internal grain boundary damage as a result of the tensile hold is present in the form of fine cracks for hold times of 3600 sec and longer and substantially more internal cracks are visible in 316 SS than HT-UPS. The dislocation substructures observed in the deformed material are different. An equiaxed cellular structure is observed in 316 SS, whereas tangles of dislocations are present at the nanoscale MC precipitates in HT-UPS and no cellular substructure is observed.

  9. Kinetics of degradation during fatigue and aging of fused silica optical fiber M. John Matthewson

    E-Print Network [OSTI]

    Matthewson, M. John

    Kinetics of degradation during fatigue and aging of fused silica optical fiber M. John Matthewson; degradation proceeds at an accelerated rate beyond the knee. This behavior leads to shorter lifetimes than predicted from short term data and to strength degradation even in the absence of an applied stress which

  10. Influence of Nonlinear Irregular Waves on the Fatigue Loads of an Offshore Wind Turbine

    E-Print Network [OSTI]

    Papalambros, Panos

    it acts as a bottleneck to the realization of offshore wind farms that can compete with traditional energy sources [3]. Currently, offshore wind farms are typically sited in coastal areas with water depths aroundInfluence of Nonlinear Irregular Waves on the Fatigue Loads of an Offshore Wind Turbine Michiel B

  11. A Model to Assess Fatigue at Joint-Level Using the Half-Joint Concept

    E-Print Network [OSTI]

    Rodríguez, Inmaculada

    and simulations generated by our animation environment. 1. Introduction The human body is continuously under b Virtual Reality Laboratory. Swiss Federal Institute of Technology Lausanne, Switzerland In this paper we focus on the modeling and evaluation of performance factors as human fatigue at joint level. We

  12. Multiaxial stress effects on fatigue behavior of filled natural rubber W.V. Mars a

    E-Print Network [OSTI]

    Fatemi, Ali

    Multiaxial stress effects on fatigue behavior of filled natural rubber W.V. Mars a , A. Fatemi b, * a Cooper Tire and Rubber Company, Findlay, OH 45840, USA b Mechanical, Industrial and Manufacturing in filled natural rubber based on experiments using short thin-walled cylindrical specimens subjected

  13. Oral/Poster Reference: FT242 FATIGUE CRACK GROWTH OF RUBBER UNDER

    E-Print Network [OSTI]

    Fatemi, Ali

    Oral/Poster Reference: FT242 FATIGUE CRACK GROWTH OF RUBBER UNDER VARIABLE AMPLITUDE LOADING R. Harbour1 , A. Fatemi1 , W. V. Mars2 1 The University of Toledo, Toledo, OH, USA 2 Cooper Tire and Rubber Company, Findlay, OH, USA ABSTRACT Realistic loading conditions for rubber components are often more

  14. Fatigue and Overloading Behavior of SteelConcrete Composite Flexural Members Strengthened with High

    E-Print Network [OSTI]

    strengthened with new high modulus carbon fiber-reinforced polymer HM CFRP materials. The behavior of the beams.1061/ ASCE 1090-0268 2007 11:6 659 CE Database subject headings: Fatigue; Composite materials; Fiber carbon FRP CFRP materials for the repair and strength- ening of steel bridges and structures. A number

  15. Fatigue-related Gene-Networks identified in CD14+ cells isolated from HIV infected Patients -

    E-Print Network [OSTI]

    Dobra, Adrian

    : Genes including the actin cytoskeletal regulatory proteins prokineticin 2 and cofilin 2 along with mitochondrial inner membrane proteins are involved in multiple pathways and were predictors of fatigue status and between 80-100% of persons living with HIV disease complaint of ongoing lack of energy and exhaustion

  16. Investigating the Effects of Corrosion on the Fatigue Life of Welded Steel Attachments 

    E-Print Network [OSTI]

    Soape, Jack

    2012-07-16T23:59:59.000Z

    of dollars each year for the railroad industry in terms of maintenance and inspection. Since a large number of these bridges are steel and their service life is typically governed by fatigue of welded details, it is important to determine the interactions...

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

    SciTech Connect (OSTI)

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

    1996-12-31T23:59:59.000Z

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

  18. BAYESIAN UPDATING OF PROBABILISTIC TIME-DEPENDENT FATIGUE MODEL: APPLICATION TO JACKET FOUNDATIONS OF WIND TURBINES

    E-Print Network [OSTI]

    Boyer, Edmond

    OF WIND TURBINES Benjamin Rocher1,2 , Franck Schoefs1 , Marc François1 , Arnaud Salou2 1 LUNAM Université.rocher@univ-nantes.fr ABSTRACT Due to both wave and wind fluctuation, the metal foundations of offshore wind turbines are highly algorithm. KEYWORDS: Fatigue, Damage, Reliability, Bayesian updating. INTRODUCTION In offshore wind turbines

  19. Cavitation Fatigue. Embolism and Refilling Cycles Can Weaken the Cavitation Resistance of Xylem1

    E-Print Network [OSTI]

    Stiller, Volker

    Cavitation Fatigue. Embolism and Refilling Cycles Can Weaken the Cavitation Resistance of Xylem1Culloh Department of Biology, University of Utah, Salt Lake City, Utah 84112 Although cavitation and refilling cycles could be common in plants, it is unknown whether these cycles weaken the cavitation resistance

  20. Fatigue of aluminium-lithium alloys K. T. Venkateswara Rao and R. O. Ritchie

    E-Print Network [OSTI]

    Ritchie, Robert

    Fatigue of aluminium-lithium alloys K. T. Venkateswara Rao and R. O. Ritchie Aluminium been identified as prime candidates for replacing 2000 and 7000 series aluminium alloys currently used characteristics of aluminium-lithium alloys are reviewed in detail with emphasis on the underlying micromechanisms

  1. SUBSPACE-BASED DETECTION OF FATIGUE DAMAGE ON JACKET SUPPORT STRUCTURES OF OFFSHORE WIND TURBINES

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    SUBSPACE-BASED DETECTION OF FATIGUE DAMAGE ON JACKET SUPPORT STRUCTURES OF OFFSHORE WIND TURBINES-based Damage Detec- tion (SSDD) method on model structures for an utilization of this approach on offshore wind damage in real size structural components of offshore wind turbines. KEYWORDS : Damage detection

  2. Time-domain Fatigue Response and Reliability Analysis of Offshore Wind Turbines with

    E-Print Network [OSTI]

    Nørvåg, Kjetil

    Time-domain Fatigue Response and Reliability Analysis of Offshore Wind Turbines with Emphasis of offshore wind turbines Defense: 09.12.2012 2012 - : Structural Engineer in Det Norske Veritas (DNV) 2007 and higher wind speed, and less visual disturbance and noise for offshore wind energy. Offshore wind

  3. Environmental Kuznets Curve for carbon dioxide emissions: lack of robustness to heterogeneity?

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 Environmental Kuznets Curve for carbon dioxide emissions: lack of robustness to heterogeneity applying the iterative Bayesian shrinkage procedure. The environmental Kuznets curve (EKC) hypothesis. Keywords: Environmental Kuznets curve; Bayesian shrinkage estimator; Heterogeneity JEL classification: O13

  4. Determination of the Price-Load Curve by Using Smoothing Splines Under Tension

    E-Print Network [OSTI]

    Determination of the Price-Load Curve by Using Smoothing Splines Under Tension Master Thesis 4.2. Price-Load Curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 4 load and price . . . . . . . . . . . . . . . . . . . . . . 6 1.5. Merit order curve with operating

  5. Analysis of SNL/MSU/DOE fatigue database trends for wind turbine blade materials.

    SciTech Connect (OSTI)

    Mandell, John F. (Montana State University, Bozeman, MT); Ashwill, Thomas D.; Wilson, Timothy J. (Montana State University, Bozeman, MT); Sears, Aaron T. (Montana State University, Bozeman, MT); Agastra, Pancasatya (Montana State University, Bozeman, MT); Laird, Daniel L.; Samborsky, Daniel D. (Montana State University, Bozeman, MT)

    2010-12-01T23:59:59.000Z

    This report presents an analysis of trends in fatigue results from the Montana State University program on the fatigue of composite materials for wind turbine blades for the period 2005-2009. Test data can be found in the SNL/MSU/DOE Fatigue of Composite Materials Database which is updated annually. This is the fifth report in this series, which summarizes progress of the overall program since its inception in 1989. The primary thrust of this program has been research and testing of a broad range of structural laminate materials of interest to blade structures. The report is focused on current types of infused and prepreg blade materials, either processed in-house or by industry partners. Trends in static and fatigue performance are analyzed for a range of materials, geometries and loading conditions. Materials include: sixteen resins of three general types, five epoxy based paste adhesives, fifteen reinforcing fabrics including three fiber types, three prepregs, many laminate lay-ups and process variations. Significant differences in static and fatigue performance and delamination resistance are quantified for particular materials and process conditions. When blades do fail, the likely cause is fatigue in the structural detail areas or at major flaws. The program is focused strongly on these issues in addition to standard laminates. Structural detail tests allow evaluation of various blade materials options in the context of more realistic representations of blade structure than do the standard test methods. Types of structural details addressed in this report include ply drops used in thickness tapering, and adhesive joints, each tested over a range of fatigue loading conditions. Ply drop studies were in two areas: (1) a combined experimental and finite element study of basic ply drop delamination parameters for glass and carbon prepreg laminates, and (2) the development of a complex structured resin-infused coupon including ply drops, for comparison studies of various resins, fabrics and pry drop thicknesses. Adhesive joint tests using typical blade adhesives included both generic testing of materials parameters using a notched-lap-shear test geometry developed in this study, and also a series of simulated blade web joint geometries fabricated by an industry partner.

  6. Analysis and detection of driver fatigue caused by sleep deprivation

    E-Print Network [OSTI]

    Yang, Ji Hyun, 1978-

    2007-01-01T23:59:59.000Z

    Human errors in attention and vigilance are among the most common causes of transportation accidents. Thus, effective countermeasures are crucial for enhancing road safety. By pursuing a practical and reliable design of ...

  7. Rutting and drainage design methodology for a concrete block pavement

    E-Print Network [OSTI]

    Poduska, Daryl Jason

    1998-01-01T23:59:59.000Z

    . Organization of Thesis. . 2 3 5 II LITERATURE REVIEW. . Analysis of Concrete Block Pavements. . . . . . . . . . , . . . . . . Previous Design Procedures . Factors Affecting the Pavement's Performance. . . . . 7 9 18 III COLLECTION OF FIELD DATA. 28.... . . . 2 Experience based design chart used in Denmark. . . . . 10 3 Experience based design chart used in South Africa. . . . . . . . . . . . . . 4 Marais' design curve based on Westergaard's slab theory. . . . . 12 5 CCA design chart used in Great...

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

    SciTech Connect (OSTI)

    Julian K. Benz; Richard N. Wright

    2013-10-01T23:59:59.000Z

    The crack propagation behaviour of Alloy 617 was studied under various conditions. Elevated temperature fatigue and creep-fatigue crack growth experiments were conducted at 650 and 800 degrees C under constant stress intensity (triangle K) conditions and triangular or trapezoidal waveforms at various frequencies on as-received, aged, and carburized material. Environmental conditions included both laboratory air and characteristic VHTR impure helium. As-received Alloy 617 displayed an increase in the crack growth rate (da/dN) as the frequency was decreased in air which indicated a time-dependent contribution component in fatigue crack propagation. Material aged at 650°C did not display any influence on the fatigue crack growth rates nor the increasing trend of crack growth rate with decreasing frequency even though significant microstructural evolution, including y’ (Ni3Al) after short times, occurred during aging. In contrast, carburized Alloy 617 showed an increase in crack growth rates at all frequencies tested compared to the material in the standard annealed condition. Crack growth studies under quasi-constant K (i.e. creep) conditions were also completed at 650 degrees C and a stress intensity of K = 40 MPa9 (square root)m. The results indicate that crack growth is primarily intergranular and increased creep crack growth rates exist in the impure helium environment when compared to the results in laboratory air. Furthermore, the propagation rates (da/dt) continually increased for the duration of the creep crack growth either due to material aging or evolution of a crack tip creep zone. Finally, fatigue crack propagation tests at 800 degrees C on annealed Alloy 617 indicated that crack propagation rates were higher in air than impure helium at the largest frequencies and lowest stress intensities. The rates in helium, however, eventually surpass the rates in air as the frequency is reduced and the stress intensity is decreased which was not observed at 650 degrees C.

  9. Multifrequency Eddy Current Inspection of Corrosion in Clad Aluminum Riveted Lap Joints and Its Effect on Fatigue Life

    SciTech Connect (OSTI)

    Okafor, A. C.; Natarajan, S. [Nondestructive Evaluation and Structural Health Monitoring Laboratory, Department of Mechanical and Aerospace Engineering, University of Missouri - Rolla, 1870 Miner Circle, Rolla, MO 65409-0050 (United States)

    2007-03-21T23:59:59.000Z

    Aging aircraft are prone to corrosion damage and fatigue cracks in riveted lap joints of fuselage skin panels. This can cause catastrophic failure if not detected and repaired. Hence detection of corrosion damage and monitoring its effect on structural integrity are essential. This paper presents multifrequency eddy current (EC) inspection of corrosion damage and machined material loss defect in clad A1 2024-T3 riveted lap joints and its effect on fatigue life. Results of eddy current inspection, corrosion product removal and fatigue testing are presented.

  10. The effect of environment, chemistry, and microstructure on the corrosion fatigue behavior of austenitic stainless steels in high temperature water

    E-Print Network [OSTI]

    O'Brien, Lindsay Beth

    2014-01-01T23:59:59.000Z

    The effect of sulfur on the corrosion fatigue crack growth of austenitic stainless steel was evaluated under Light Water Reactor (LWR) conditions of 288°C deaerated (less than 5ppb O?) water, to shed light on the accelerating ...

  11. Simulated Fatigue Damage Index on Mooring Lines of a Gulf of Mexico Truss Spar Determined from Recorded Field Data

    E-Print Network [OSTI]

    Kiecke, Adam Fuller

    2012-07-16T23:59:59.000Z

    . The platform is equipped with an Environmental Platform Response Monitoring System (EPRMS) which records real-time motions, environmental parameters and loads. These measurements were used to hind-cast the platform mooring tensions and estimate fatigue damage...

  12. The effects of laser trimming on the tensile strength and fatigue resistance properties of titanium - 6Al-4V

    E-Print Network [OSTI]

    Whitesel, Dean Adam

    1994-01-01T23:59:59.000Z

    The effect of laser trimming on the tensile strength and fatigue resistance of titanium-6% aluminum-4% vanadium specimens was investigated. Due to the nature of laser processing, the microstructure of the titanium alloy was altered in an area local...

  13. Fatigue resistance of hot-mix asphalt concrete (HMAC) mixtures using the calibrated mechanistic with surface energy (CMSE) measurements approach

    E-Print Network [OSTI]

    Ofori-Abebresse, Edward Kwame

    2006-10-30T23:59:59.000Z

    Fatigue cracking is one of the fundamental distresses that occur in the life of a Hot Mix Asphalt Concrete (HMAC) pavement. This load induced distress leads to structural collapse of the entire pavement ultimately and can only be remedied...

  14. Fatigue resistance of hot-mix asphalt concrete (HMAC) mixtures using the calibrated mechanistic with surface energy (CMSE) measurements approach 

    E-Print Network [OSTI]

    Ofori-Abebresse, Edward Kwame

    2006-10-30T23:59:59.000Z

    Fatigue cracking is one of the fundamental distresses that occur in the life of a Hot Mix Asphalt Concrete (HMAC) pavement. This load induced distress leads to structural collapse of the entire pavement ultimately and can ...

  15. Comptes Rendus des JNC 16 Toulouse 2009 Suivi de l'endommagement en fatigue des composites base de fibres

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    a thermoplastic matrix (Polypropylene) reinforced by short fibers (White Hemp and Chènevotte). This article fatigue / White Hemp / Acoustic emission / Stiffness loss/ hysteresis loops. hal-00429719,version1-4Nov

  16. Fatigue Life of Damaged Bridge Deck Panels Strengthened With Carbon Fiber Hongseob Oh, Jongsung Sim, and Christian Meyer

    E-Print Network [OSTI]

    Meyer, Christian

    , Jongsung Sim, and Christian Meyer ABSTRACT To simulate fatigue damage to bridge deck slabs, cyclic loading and recycling of concrete material. ACI Fellow Christian Meyer is a professor in the Department of Civil

  17. The influence of high harmonic force on fatigue life and its prediction via coupled inline-crossflow VIV modeling

    E-Print Network [OSTI]

    Zheng, Haining

    2014-01-01T23:59:59.000Z

    Vortex Induced Vibrations (VIV) of a flexibly mounted rigid cylinder placed in a flow is a canonical problem of fluid-structure interactions and the study of VIV and the resulting material fatigue is particularly important ...

  18. Automatic generation and analysis of solar cell IV curves

    SciTech Connect (OSTI)

    Kraft, Steven M.; Jones, Jason C.

    2014-06-03T23:59:59.000Z

    A photovoltaic system includes multiple strings of solar panels and a device presenting a DC load to the strings of solar panels. Output currents of the strings of solar panels may be sensed and provided to a computer that generates current-voltage (IV) curves of the strings of solar panels. Output voltages of the string of solar panels may be sensed at the string or at the device presenting the DC load. The DC load may be varied. Output currents of the strings of solar panels responsive to the variation of the DC load are sensed to generate IV curves of the strings of solar panels. IV curves may be compared and analyzed to evaluate performance of and detect problems with a string of solar panels.

  19. Electromagnetic field limits set by the V-Curve.

    SciTech Connect (OSTI)

    Warne, Larry Kevin; Jorgenson, Roy Eberhardt; Hudson, Howard Gerald

    2014-07-01T23:59:59.000Z

    When emitters of electromagnetic energy are operated in the vicinity of sensitive components, the electric field at the component location must be kept below a certain level in order to prevent the component from being damaged, or in the case of electro-explosive devices, initiating. The V-Curve is a convenient way to set the electric field limit because it requires minimal information about the problem configuration. In this report we will discuss the basis for the V-Curve. We also consider deviations from the original V-Curve resulting from inductive versus capacitive antennas, increases in directivity gain for long antennas, decreases in input impedance when operating in a bounded region, and mismatches dictated by transmission line losses. In addition, we consider mitigating effects resulting from limited antenna sizes.

  20. A unified method for the analysis of nonlinear viscoelasticity and fatigue cracking of asphalt mixtures using the dynamic mechanical analyzer

    E-Print Network [OSTI]

    Castelo Branco, Veronica Teixeira Franco

    2009-05-15T23:59:59.000Z

    A UNIFIED METHOD FOR THE ANALYSIS OF NONLINEAR VISCOELASTICITY AND FATIGUE CRACKING OF ASPHALT MIXTURES USING THE DYNAMIC MECHANICAL ANALYZER A Dissertation by VERONICA TEIXEIRA FRANCO CASTELO BRANCO Submitted to the Office... VISCOELASTICITY AND FATIGUE CRACKING OF ASPHALT MIXTURES USING THE DYNAMIC MECHANICAL ANALYZER A Dissertation by VERONICA TEIXEIRA FRANCO CASTELO BRANCO Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment...

  1. A Table of Areas Under Disease Progress Curves

    E-Print Network [OSTI]

    Johnson, Dennis A.; Wilcoxson, Roy D.

    1980-01-01T23:59:59.000Z

    [Blank Page in Original Bulletin] A TABLE OF AREAS UNDER DISEASE PROGRESS CURVES Technical Bullet in Texas Agricultural Experiment Station Texas A & M University System- [Blank Page in Original Bulletin] A TABLE OF AREAS UNDER D I S E A S E... Chillicothe-Vernon, TX 76384; and Professor Department of Plant Pathology University of Minnesota St. Paul, MN 55108 A T a b l e o f A r e a s Under D i s e a s e P r o g r e s s Curves 3 Denn i s A. J o h n s o n and Roy D . \\ W i l c o x s o...

  2. The Fusion Curve of Ammonia and Ethyl Alcohol

    E-Print Network [OSTI]

    Broderson, H.J.

    1911-01-01T23:59:59.000Z

    ’ Center for Digital Scholarship. http://kuscholarworks.ku.edu Submitted to the Graduate School of the University of Kansas for partial completion of Master of Arts. THE FUSION CURVE OF AMMONIA AND ETHYL ALCOHOL H. J. BRODERSON THE 2?03IOH CUHVB OP... AMMOHIA AND ETHXL ALCOHOL. A part of the requirement for the lh A. 2)egree. By K. J. Brodereon, University of Kangaa, May 1911, THE PUSIOB CURVS OP AliKOHlA AHD ETHYL ALCOHOL* Only within tho last fow ycara has any worlc boon done on tho fusion...

  3. Light bullets in nonlinear periodically curved waveguide arrays

    SciTech Connect (OSTI)

    Matuszewski, Michal; Garanovich, Ivan L. [Nonlinear Physics Centre, Research School of Physics and Engineering, Australian National University, Canberra, ACT 0200 (Australia); Sukhorukov, Andrey A. [Nonlinear Physics Centre, Research School of Physics and Engineering, Australian National University, Canberra, ACT 0200 (Australia); Centre for Ultra-high Bandwidth Devices for Optical Systems (CUDOS), Research School of Physics and Engineering, Australian National University, Canberra, ACT 0200 (Australia)

    2010-04-15T23:59:59.000Z

    We predict that stable mobile spatiotemporal solitons can exist in arrays of periodically curved optical waveguides. We find two-dimensional light bullets in planar arrays with harmonic waveguide bending and three-dimensional bullets in square lattices with helical waveguide bending using variational formalism. Stability of the light-bullet solutions is confirmed by the direct numerical simulations which show that the light bullets can freely move across the curved arrays. This mobility property is a distinguishing characteristic compared to previously considered discrete light bullets which were trapped to a specific lattice site. These results suggest new possibilities for flexible spatiotemporal manipulation of optical pulses in photonic lattices.

  4. Fitting the Galaxy Rotation Curves: Strings versus NFW profile

    E-Print Network [OSTI]

    Yeuk-Kwan E. Cheung; Feng Xu

    2008-10-14T23:59:59.000Z

    Remarkable fit of galaxy rotation curves is achieved using a simple model from string theory. The rotation curves of the same group of galaxies are also fit using dark matter model with the generalized Navarro-Frenk-White profile for comparison. String model utilizes three free parameters vs five in the dark matter model. The average chi-squared of the string model fit is 1.649 while that of the dark matter model is 1.513. The generalized NFW profile fits marginally better at a price of two more free parameters.

  5. Waste heat recovery steam curves with unfired HRSGs

    SciTech Connect (OSTI)

    Not Available

    1993-01-01T23:59:59.000Z

    A compilation of waste heat recovery steam curves for a sampling of gas turbines ranging in output from around 1 MW to more than 200 MW is presented. The gas turbine output data shown with each set of curves differs from the values given in the Performance Specifications section of the Handbook. That's because the values have been calculated to reflect the effects of a 4 inch inlet and 10 inch outlet pressure drop on power output (lower), heat rate (higher), mass flow (higher), and exhaust temperature (higher).

  6. The outer rotation curve of the Milky Way

    E-Print Network [OSTI]

    James Binney; Walter Dehnen

    1996-12-05T23:59:59.000Z

    A straightforward determination of the circular-speed curve vc(R) of the Milky Way suggests that near the Sun, vc starts to rise approximately linearly with R. If this result were correct, the Galactic mass density would have to be independent of radius at R ~> R0. We show that the apparent linear rise in v_c arises naturally if the true circular-speed curve is about constant or gently falling at R0 1.25 R0 are actually concentrated into a ring of radius ~1.6 R0.

  7. A SECOND LOOK AT THE SAFETY EFFECTIVENESS OF THE MYRTLE CREEK ADVANCED CURVE WARNING SYSTEM

    E-Print Network [OSTI]

    Bertini, Robert L.

    -1- A SECOND LOOK AT THE SAFETY EFFECTIVENESS OF THE MYRTLE CREEK ADVANCED CURVE WARNING SYSTEM as the "Myrtle Creek Curves." This location consists of a series of curves which have continually been a notable. The curves are located in a 50 mile per hour (mph) speed zone and are posted with an advisory speed of 45 mph

  8. A Comparison of Vehicle Speed at Day and Night Rural Horizontal Curves

    E-Print Network [OSTI]

    Quaium, Ridwan B.

    2010-07-14T23:59:59.000Z

    This thesis documents the linear mixed model developed for vehicle speed along two-lane two-way rural horizontal curves in the outside lane. Speed data at each curve was collected at four points along the curve including the midpoint of the curve...

  9. Four-Point Curve Subdivision Based on Iterated Chordal and Centripetal

    E-Print Network [OSTI]

    Zachmann, Gabriel

    Richter (Technical Computer Science) Prof. Dr. Gabriel Zachmann (Computer Graphics) #12;Four-Point Curve

  10. A Comparison of Vehicle Speed at Day and Night Rural Horizontal Curves 

    E-Print Network [OSTI]

    Quaium, Ridwan B.

    2010-07-14T23:59:59.000Z

    This thesis documents the linear mixed model developed for vehicle speed along two-lane two-way rural horizontal curves in the outside lane. Speed data at each curve was collected at four points along the curve including the midpoint of the curve...

  11. Progress Letter Report on Bending Fatigue Test System Development for Spent Nuclear Fuel Vibration Integrity Study (Out-of-cell fatigue testing development - Task 2.4)

    SciTech Connect (OSTI)

    Wang, Jy-An John [ORNL; Wang, Hong [ORNL; Cox, Thomas S [ORNL; Baldwin, Charles A [ORNL; Bevard, Bruce Balkcom [ORNL

    2013-08-01T23:59:59.000Z

    Vibration integrity of high burn-up spent nuclear fuel in transportation remains to be a critical component of US nuclear waste management system. The structural evaluation of package for spent fuel transportation eventually will need to see if the content or spent fuel is in a subcritical condition. However, a system for testing and characterizing such spent fuel is still lacking mainly due to the complication involved with dealing radioactive specimens in a hot cell environment. Apparently, the current state-of-the-art in spent fuel research and development is quite far away from the delivery of reliable mechanical property data for the assessment of spent fuels in the transport package evaluation. Under the sponsorship of US NRC, ORNL has taken the challenge in developing a robust testing system for spent fuel in hot cell. An extensive literature survey was carried out and unique requirements of such testing system were identified. The U-frame setup has come to the top among various designs examined for reverse bending fatigue test of spent fuel rod. The U-frame has many features that deserve mentioned here: Easy to install spent fuel rod in test; Less linkages than in conventional bending test setup such as three-point or four-point bending; Target the failure mode relevant to the fracture of spent fuel rod in transportation by focusing on pure bending; The continuous calibrations and modifications resulted in the third generation (3G) U-frame testing setup. Rigid arms are split along the LBB axis at rod sample ends. For each arm, this results in a large arm body and an end piece. Mating halves of bushings were modified into two V-shaped surfaces on which linear roller bearings (LRB) are embedded. The rod specimen is installed into the test fixture through opening and closing slide end-pieces. The 3G apparently has addressed major issues of setup identified in the previous stage and been proven to be eligible to be further pursued in this project. On the other hand, the purchase of universal testing machine or Bose dual LM2 TB was completed and the testing system was delivered to ORNL in August 2012. The preliminary confirmation of the system and on-site training were given by Bose field engineer and regional manager on 8/1-8/2/2012. The calibration of Bose testing system has been performed by ORNL because the integration of ORNL setup into the Bose TestBench occurred after the installation. Major challenge with this process arose from two aspects: 1) the load control involves two load cells, and 2) U-frame setup itself is a non-standard specimen. ORNL has been able to implement the load control through Cycle Indirect along with pinning the U-frame setup. Two meetings with ORNL hot-cell group (November 2012 and January 2013) were held to discuss the potential issues with both epoxy mounting of rigid sleeve and U-frame setup. Many suggestions were provided to make the procedure friendlier to the manipulator in hot cell. Addressing of these suggestions resulted in another cycle of modifications of both vise mold and setup. The initial meeting with ORNL I&C group occurred in November 2012 with regard to the Bose cable modification and design of central panel to integrate the cables and wires. The first round of cable modification and central panel fabrication was completed in February 2012. The testing with the modified cables exhibited substantial noises and the testing system was not shown to be stable. It was believed the cross talk was responsible to the noise, and a central panel with a better grounding and shielding was highly recommended. The central panel has been re-designed and fabricated in March 2013. In the subsequent period, the ORNL made substantial effort to debug the noises with the load cell channel, and to resolve the noises and nonlinearity with RDP LVDTs related to the integration of RDP LVDTs to Bose system. At the same time, ORNL has completed the verification tests of Bose test system, including cycle tests under reversal bending in load control, bending tests under monotonic load, and cycle test

  12. Fatigue Resistance of Asphalt Mixtures Affected by Water Vapor Movement

    E-Print Network [OSTI]

    Tong, Yunwei

    2013-11-08T23:59:59.000Z

    aggregate contact due to dust particles on the aggregate surface. The rupture may occur because of the construction loads and operating traffic during construction, or could be environmentally induced by freeze-thaw cycling. Once a break in the film... design, environment and traffic, can be defined as progressive degradation of asphalt mixture material due to the presence of water. The occurrence of moisture damage in asphalt material is a rather complex phenomenon, which involves chemical, physical...

  13. Surface Studies of Ultra Strength Drilling Steel after Corrosion Fatigue in Simulated Sour Environment

    SciTech Connect (OSTI)

    M. Ziomek-Moroz; J.A. Hawk; R. Thodla; F. Gui

    2012-05-06T23:59:59.000Z

    The Unites States predicted 60% growth in energy demand by 2030 makes oil and natural gas primary target fuels for energy generation. The fact that the peak of oil production from shallow wells (< 5000 m) is about to be reached, thereby pushing the oil and natural gas industry into deeper wells. However, drilling to depths greater than 5000 m requires increasing the strength-to weight ratio of the drill pipe materials. Grade UD-165 is one of the ultra- high yield strength carbon steels developed for ultra deep drilling (UDD) activities. Drilling UDD wells exposes the drill pipes to Cl{sup -}, HCO{sub 3}{sup -}/CO{sub 3}{sup 2-}, and H{sub 2}S-containig corrosive environments (i.e., sour environments) at higher pressures and temperatures compared to those found in conventional wells. Because of the lack of synergism within the service environment, operational stresses can result in catastrophic brittle failures characteristic for environmentally assisted cracking (EAC). Approximately 75% of all drill string failures are caused by fatigue or corrosion fatigue. Since there is no literature data on the corrosion fatigue performance of UD-165 in sour environments, research was initiated to better clarify the fatigue crack growth (FCGR) behavior of this alloy in UDD environments. The FCGR behavior of ultra-strength carbon steel, grade UD-165, was investigated by monitoring crack growth rate in deaerated 5%NaCl solution buffered with NaHCO{sub 3}/Na{sub 2}CO{sub 3} and in contact with H{sub 2}S. The partial pressure of H{sub 2}S (p{sub H2S}) was 0.83 kPa and pH of the solution was adjusted by NaOH to 12. The fatigue experiments were performed at 20 and 85 C in an autoclave with surface investigations augmented by scanning electron microscopy (SEM) and energy dispersive x-ray (EDX) spectroscopy. In this study, research focused on surface analyses supported by the fatigue crack growth rate measurements. Fig. 1 shows an SEM micrograph of the crack that propagated from the notch in the solution at 20 C. Accumulation of the corrosion products is visible along the crack. The EDX chemical analysis near the crack tip found iron, sulfur and oxygen in the passive layer. The surface of the sample after the fatigue test in the sour environment at 85{sup o}, Fig. 2, C looks different from that fatigued surface at 20 C. The crack propagates across the passive film that covers the surface fairly uniformly. Some spallation of the passive film is observed near the notch. The EDX chemical analysis of the passive film near the crack tip identified mainly iron, carbon and oxygen. It appears that temperature plays a very important role in formation of the passive film. This may be associated with different solubility of H{sub 2}S in the solution, which will be further studied.

  14. Implementation of a Biaxial Resonant Fatigue Test Method on a Large Wind Turbine Blade

    SciTech Connect (OSTI)

    Snowberg, D.; Dana, S.; Hughes, S.; Berling, P.

    2014-09-01T23:59:59.000Z

    A biaxial resonant test method was utilized to simultaneously fatigue test a wind turbine blade in the flap and edge (lead-lag) direction. Biaxial resonant blade fatigue testing is an accelerated life test method utilizing oscillating masses on the blade; each mass is independently oscillated at the respective flap and edge blade resonant frequency. The flap and edge resonant frequency were not controlled, nor were they constant for this demonstrated test method. This biaxial resonant test method presented surmountable challenges in test setup simulation, control and data processing. Biaxial resonant testing has the potential to complete test projects faster than single-axis testing. The load modulation during a biaxial resonant test may necessitate periodic load application above targets or higher applied test cycles.

  15. A Construction for Computer Visualization Certain Complex Curves

    E-Print Network [OSTI]

    Indiana University

    A Construction for Computer Visualization of Certain Complex Curves Andrew J. Hanson Computer representation of a manifold's geometry. Driven by this motivation, we found an extremely use- ful construction variables. Our construction is ideally suited for interactive computer graphics systems; in addition

  16. Monomial Embeddings of the Klein Curve \\Lambda Iwan M. Duursma

    E-Print Network [OSTI]

    Duursma, Iwan M.

    of the automor­ phism group. The curve has 24 flexpoints, i.e. points where the tangent intersects]. For the case N = 25, we first consider a configuration in PG(2; 8). Starting point are the seven points and seven lines of the Fano plane. Through the seven points pass 42 lines not in the Fano plane

  17. Twisted Ate Pairing on Hyperelliptic Curves and Applications

    E-Print Network [OSTI]

    of Information Science and Technology, Sun Yat-Sen University, Guangzhou 510275, P.R.China isszhfg@mail.sysu.edu.cn 2 Guangdong Key Laboratory of Information Security Technology Guangzhou 510275, P.R.China Abstract hyperelliptic curves over prime fields with ordinary Jacobians by modeling on the Cocks-Pinch method

  18. Twisted Ate Pairing on Hyperelliptic Curves and Applications

    E-Print Network [OSTI]

    of Information Science and Technology, Sun Yat­Sen University, Guangzhou 510275, P.R.China isszhfg@mail.sysu.edu.cn 2 Guangdong Key Laboratory of Information Security Technology Guangzhou 510275, P.R.China Abstract hyperelliptic curves over prime fields with ordinary Jacobians by modeling on the Cocks­Pinch method

  19. Learning Curve: A Simulation-based Approach to Dynamic Pricing

    E-Print Network [OSTI]

    Greenwald, Amy

    horizon. In this article, we refer to this type of changing of prices over time as dynamic pricing. Cost markets, the costs associated with making frequent, instantaneous price changes are greatly diminished [2Learning Curve: A Simulation-based Approach to Dynamic Pricing Joan Morris DiMicco, Amy Greenwald

  20. Neutrino flavor oscillations in a curved space-time

    E-Print Network [OSTI]

    Luca Visinelli

    2015-05-06T23:59:59.000Z

    Using a WKB approximation of the Dirac equation in a curved spacetime, we obtain the expression for the phase shift between two neutrino mass eigenstates in a generic gravitational field. We apply this expression to two specific space-time geometries, namely the Kerr-Newman metric describing a rotating and charged black hole, and the Friedmann-Robertson-Walker metric.

  1. Revising neutrino oscillations in a curved space-time

    E-Print Network [OSTI]

    Visinelli, Luca

    2014-01-01T23:59:59.000Z

    We revise the theory of neutrino oscillations in a gravitational field, starting from the WKB approximation of the Dirac equation in a curved spacetime. We discuss the expression for the phase shift in neutrino flavor oscillations in the geometry around a rotating, charged black hole (Kerr-Newman metric) and for cosmological neutrinos (Friedmann-Robertson-Walker metric).

  2. Wind Energy Learning Curves for Reference in Expert Elicitations

    E-Print Network [OSTI]

    Mountziaris, T. J.

    Wind Energy Learning Curves for Reference in Expert Elicitations Sarah Mangels, Erin Baker. Abstract: This study presents future projections of wind energy capacity and cost based on historical data. The study will be used during wind- energy expert elicitations (formal interviews aimed to quantify

  3. Efficient Algorithms for Implementing Elliptic Curve PublicKey Schemes

    E-Print Network [OSTI]

    Efficient Algorithms for Implementing Elliptic Curve Public­Key Schemes by Dan Beauregard A Thesis Cyganski Thesis Advisor Thesis Committee Dr. Stanley Selkow Dr. John Orr Thesis Committee Department Head #12; Preface This thesis describes the research which I conducted while completing my graduate work

  4. On the Use of Weber Polynomials in Elliptic Curve Cryptography

    E-Print Network [OSTI]

    Zaroliagis, Christos D.

    On the Use of Weber Polynomials in Elliptic Curve Cryptography Elisavet Konstantinou1,2 , Yannis C using the Complex Multiplication method which typically uses the roots of Hilbert or Weber polynomials and unifying manner a complete set of transformations of the roots of a Weber polynomial to the roots of its

  5. Experience Curves and Solar PV Fred Heutte, Senior Policy Associate

    E-Print Network [OSTI]

    Experience Curves and Solar PV Fred Heutte, Senior Policy Associate NW Energy Coalition September 3 resources costs as being ranges rather than fixed values. It is evident that the question of future solar PV small percentage of all resources at present, there is a strong sense that once solar PV reaches "grid

  6. ISOMORPHISM CLASSES OF PICARD CURVES OVER FINITE FIELDS

    E-Print Network [OSTI]

    for construction of cryptosystems based on the discrete logarithm problem, and elliptic curve cryptography is now for constructing public key cryptosystems by Galbraith, Paulus and Smart in [8]. Besides providing an algorithm, of a place p is defined as the extension degree of the residue field of p over k. For a divisor D = npp (that

  7. Computing local p-adic height pairings on hyperelliptic curves

    E-Print Network [OSTI]

    Balakrishnan, Jennifer S

    2010-01-01T23:59:59.000Z

    We describe an algorithm to compute the local component at p of the Coleman-Gross p-adic height pairing on divisors on hyperelliptic curves. As the height pairing is given in terms of a Coleman integral, we also provide new techniques to evaluate Coleman integrals of meromorphic differentials and present our algorithms as implemented in Sage.

  8. The Orbital Light Curve of Aquila X-1

    E-Print Network [OSTI]

    William F. Welsh; Edward L. Robinson; Patrick Young

    2000-04-25T23:59:59.000Z

    We obtained R- and I-band CCD photometry of the soft X-ray transient/neutron- star binary Aql X-1 in 1998 June while it was at quiescence. We find that its light curve is dominated by ellipsoidal variations, although the ellipsoidal variations are severely distorted and have unequal maxima. After we correct for the contaminating flux from a field star located only 0.46" away, the peak-to-peak amplitude of the modulation is ~0.25 mag in the R band, which requires the orbital inclination to be greater than 36 degrees. The orbital period we measure is consistent with the 18.95 h period measured by Chevalier & Ilovaisky (1998). During its outbursts the light curve of Aql X-1 becomes single humped. The outburst light curve observed by Garcia et al. (1999) agrees in phase with our quiescent light curve. We show that the single humped variation is caused by a ``reflection effect,'' that is, by heating of the side of the secondary star facing towards the neutron star.

  9. THE ECONOMICS OF CONSERVED-ENERGY "SUPPLY" CURVES

    E-Print Network [OSTI]

    California at Berkeley. University of

    is part of the working papers series of the Program on Workable Energy Regulation (POWER). POWERPWP-028 THE ECONOMICS OF CONSERVED-ENERGY "SUPPLY" CURVES Steven Stoft April 1995 This paper is a program of the University of California Energy Institute, a multicampus research unit of the University

  10. Fast hashing onto elliptic curves over elds of characteristic 3

    E-Print Network [OSTI]

    and Hae Y. Kim 2 1 Scopus Tecnologia S. A. Av. Mutinga, 4105 BR 05110{000 S~ao Paulo (SP), Brazil, tr. 3, 158 BR 05508-900, S~ao Paulo(SP), Brazil. hae@lps.usp.br Abstract. We describe a fast hash by patents. Currently, the BLS algorithm has only been instantiated for supersingular elliptic curves over F

  11. type Riemannian metric on the space of planar curves

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    of Computational Anatomy (MFCA'06) inria-00635881,version1-26Oct2011 Author manuscript, published in "1st MICCAI (MFCA'06) 41 inria-00635881,version1-26Oct2011 #12;2.2 Closure of open curves in H1 metric A generic z

  12. Efficient Techniques for High-Speed Elliptic Curve Cryptography

    E-Print Network [OSTI]

    Gebotys Department of Electrical and Computer Engineering, University of Waterloo, Canada, {plonga] is an integer, is the central and most time-consuming operation in Elliptic Curve Cryptography (ECC). Hence, its gained increasing importance in recent years. In this work, we combine several efficient techniques

  13. A COST BASED APPROACH TO DESIGN OF RESIDENTIAL STEEL ROOF SYSTEMS

    E-Print Network [OSTI]

    Mobasher, Barzin

    A COST BASED APPROACH TO DESIGN OF RESIDENTIAL STEEL ROOF SYSTEMS B. Mobasher1 , S-Y.Chen2 , C-5306 Abstract A comprehensive system for the design of residential steel roof truss systems is presented automatically design a roof truss given minimal input and using the design curves as the performance constraints

  14. Monitoring Thermal Fatigue Damage In Nuclear Power Plant Materials Using Acoustic Emission

    SciTech Connect (OSTI)

    Meyer, Ryan M.; Ramuhalli, Pradeep; Watson, Bruce E.; Pitman, Stan G.; Roosendaal, Timothy J.; Bond, Leonard J.

    2012-04-26T23:59:59.000Z

    Proactive aging management of nuclear power plant passive components requires technologies to enable monitoring and accurate quantification of material condition at early stages of degradation (i.e., pre-macrocrack). Acoustic emission (AE) is well-suited to continuous monitoring of component degradation and is proposed as a method to monitor degradation during accelerated thermal fatigue tests. A key consideration is the ability to separate degradation responses from external sources such as water spray induced during thermal fatigue testing. Water spray provides a significant background of acoustic signals, which can overwhelm AE signals caused by degradation. Analysis of AE signal frequency and energy is proposed in this work as a means for separating degradation signals from background sources. Encouraging results were obtained by applying both frequency and energy filters to preliminary data. The analysis of signals filtered using frequency and energy provides signatures exhibiting several characteristics that are consistent with degradation accumulation in materials. Future work is planned to enable verification of the efficacy of AE for thermal fatigue crack initiation detection. While the emphasis has been placed on the use of AE for crack initiation detection during accelerated aging tests, this work also has implications with respect to the use of AE as a primary tool for early degradation monitoring in nuclear power plant materials. The development of NDE tools for characterization of aging in materials can also benefit from the use of a technology such as AE which can continuously monitor and detect crack initiation during accelerated aging tests.

  15. A generalized fitting technique for the LIFE2 fatigue analysis code

    SciTech Connect (OSTI)

    Sutherland, H.J. [Sandia National Labs., Albuquerque, NM (United States). Wind Energy Research Dept.; Wilson, T. [Univ. of New Mexico, Albuquerque, NM (United States). New Mexico Engineering Research Inst.

    1996-08-01T23:59:59.000Z

    The analysis of component fatigue lifetime for a wind energy conversion system (WECS) requires that the component load spectrum be formulated in terms of stress cycles. Typically, these stress cycles are obtained from time series data using a cycle identification scheme. As discussed by many authors, the matrix or matrices of cycle counts that describe the stresses on a turbine are constructed from relatively short, representative samples of time series data. The ability to correctly represent the long-term behavior of the distribution of stress cycles from these representative samples is critical to the analysis of service lifetimes. Several techniques are currently used to convert representative samples to the lifetime cyclic loads on the turbine. There has been recently developed a set of fitting algorithms that is particularly useful for matching the body of the distribution of fatigue stress cycles on a turbine component. Fitting techniques are now incorporated into the LIFE2 fatigue/fracture analysis code for wind turbines. In this paper, the authors provide an overview of the fitting algorithms and describe the pre- and post-count algorithms developed to permit their use in the LIFE2 code. Typical case studies are used to illustrate the use of the technique.

  16. Regulatory Design for RES-E Support Mechanisms: Learning Curves, Market Structure, and Burden-Sharing

    E-Print Network [OSTI]

    Batlle, Carlos

    Drawing from relevant experiences in power systems around the world, this paper offers a critical review of existing policy support mechanisms for RES-E (renewable energy sources for electricity), with a detailed analysis ...

  17. Evaluation of design and operating speeds for crest vertical curves with limited sight distance

    E-Print Network [OSTI]

    Russell, Charles William

    1994-01-01T23:59:59.000Z

    The Puerto Colon field is located in the Putumayo basin in southern Colombia, South America, and is operated by Empresa Colombiana de petroleos (ECOPETROL), which is the national oil company. The field produces from the Cretaceous sandstones...

  18. The Impact of Thermal Fatigue and Carbidisation on the W Coatings Deposited on CFC tiles for the ITER-like Wall Project at JET

    E-Print Network [OSTI]

    The Impact of Thermal Fatigue and Carbidisation on the W Coatings Deposited on CFC tiles for the ITER-like Wall Project at JET

  19. PREDICTION OF LOW-CYCLE FATIGUE-LIFE BY ACOUSTIC EMISSION. PART 1: 2024-T3 ALUMINUM ALLOY PART 2: ALCLAD 7075-T6/ ALUMINUM ALLOY

    E-Print Network [OSTI]

    Baram, J.

    2013-01-01T23:59:59.000Z

    low-cycle fatigue life of Aluminum sheet alloys by acoustictoughness of structural aluminum alloys. Fracture . Fracturetoughness of structural aluminum alloys, Eng. Fracture Mech.

  20. Design and optimization of polymer electrolyte membrane (PEM) fuel cells

    E-Print Network [OSTI]

    Grujicic, Mica

    Design and optimization of polymer electrolyte membrane (PEM) fuel cells M. Grujicic* , K optimization algorithm to determine an optimum design of the fuel cell with respect to the operation difference has the largest effect on the predicted polarization curve of the fuel cell. However, the optimal

  1. Graphene based tunable fractal Hilbert curve array broadband radar absorbing screen for radar cross section reduction

    SciTech Connect (OSTI)

    Huang, Xianjun, E-mail: xianjun.huang@manchester.ac.uk [School of Electrical and Electronic Engineering, University of Manchester, Manchester M13 9PL (United Kingdom); College of Electronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China); Hu, Zhirun [School of Electrical and Electronic Engineering, University of Manchester, Manchester M13 9PL (United Kingdom); Liu, Peiguo [College of Electronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

    2014-11-15T23:59:59.000Z

    This paper proposes a new type of graphene based tunable radar absorbing screen. The absorbing screen consists of Hilbert curve metal strip array and chemical vapour deposition (CVD) graphene sheet. The graphene based screen is not only tunable when the chemical potential of the graphene changes, but also has broadband effective absorption. The absorption bandwidth is from 8.9GHz to 18.1GHz, ie., relative bandwidth of more than 68%, at chemical potential of 0eV, which is significantly wider than that if the graphene sheet had not been employed. As the chemical potential varies from 0 to 0.4eV, the central frequency of the screen can be tuned from 13.5GHz to 19.0GHz. In the proposed structure, Hilbert curve metal strip array was designed to provide multiple narrow band resonances, whereas the graphene sheet directly underneath the metal strip array provides tunability and averagely required surface resistance so to significantly extend the screen operation bandwidth by providing broadband impedance matching and absorption. In addition, the thickness of the screen has been optimized to achieve nearly the minimum thickness limitation for a nonmagnetic absorber. The working principle of this absorbing screen is studied in details, and performance under various incident angles is presented. This work extends applications of graphene into tunable microwave radar cross section (RCS) reduction applications.

  2. Driven Around the Bend: Novel Use of a Curved Steerable Needle

    SciTech Connect (OSTI)

    Murphy, Darra T., E-mail: darra.murphy@vch.ca; Korzan, Jeffrey R.; Ouellette, Hugue A.; Liu, David M. [Vancouver General Hospital, Department of Radiology (Canada)] [Vancouver General Hospital, Department of Radiology (Canada); Clarkson, Paul W. [Vancouver General Hospital, Department of Orthopedic Surgery (Canada)] [Vancouver General Hospital, Department of Orthopedic Surgery (Canada); Munk, Peter L. [Vancouver General Hospital, Department of Radiology (Canada)] [Vancouver General Hospital, Department of Radiology (Canada)

    2013-04-15T23:59:59.000Z

    This technical note describes the novel use of a curved, steerable needle to access symptomatic osseous lesions in the pelvis and sacrum for palliative percutaneous treatment that would otherwise be difficult to treat using conventional straight needles. Seven patients with lytic bone lesions were treated. One patient had multiple myeloma; the remaining had metastatic disease: breast carcinoma (n = 2), colorectal carcinoma (n = 1), renal cell carcinoma (n = 1), squamous cell carcinoma (n = 1), and leiomyosarcoma (n = 1). Five of the seven patients had lesions in the posterior acetabulum, and the two other patients had lesions in the sacrum. Four of the seven patients received radiofrequency ablation followed by cementoplasty; three patients received cementation alone. We used a novel needle designed for vertebroplasty, which has an articulating tip allowing it to be guided into lytic bone lesions located in difficult-to-access regions of the pelvis and sacrum. All patients were successfully treated with cementoplasty either with or without thermal ablation. No serious adverse events were reported. The needle was difficult to withdraw in two patients. Steerable curved needles can be successfully used to treat lytic osseous metastases with cementoplasty when lesions are located in sites that may be difficult to reach using conventional straight needles.

  3. Curve fitting methods for solar radiation data modeling

    SciTech Connect (OSTI)

    Karim, Samsul Ariffin Abdul, E-mail: samsul-ariffin@petronas.com.my, E-mail: balbir@petronas.com.my; Singh, Balbir Singh Mahinder, E-mail: samsul-ariffin@petronas.com.my, E-mail: balbir@petronas.com.my [Department of Fundamental and Applied Sciences, Faculty of Sciences and Information Technology, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak Darul Ridzuan (Malaysia)

    2014-10-24T23:59:59.000Z

    This paper studies the use of several type of curve fitting method to smooth the global solar radiation data. After the data have been fitted by using curve fitting method, the mathematical model of global solar radiation will be developed. The error measurement was calculated by using goodness-fit statistics such as root mean square error (RMSE) and the value of R{sup 2}. The best fitting methods will be used as a starting point for the construction of mathematical modeling of solar radiation received in Universiti Teknologi PETRONAS (UTP) Malaysia. Numerical results indicated that Gaussian fitting and sine fitting (both with two terms) gives better results as compare with the other fitting methods.

  4. Replicating the benefits of closed timelike curves without breaking causality

    E-Print Network [OSTI]

    Xiao Yuan; Syed M. Assad; Jayne Thompson; Jing Yan Haw; Vlatko Vedral; Timothy C. Ralph; Ping Koy Lam; Christian Weedbrook; Mile Gu

    2014-12-17T23:59:59.000Z

    In general relativity, closed timelike curves can break causality with remarkable and unsettling consequences. At the classical level, they induce causal paradoxes disturbing enough to motivate conjectures that explicitly prevent their existence. At the quantum level, resolving such paradoxes induce radical benefits - from cloning unknown quantum states to solving problems intractable to quantum computers. Instinctively, one expects these benefits to vanish if causality is respected. Here we show that in harnessing entanglement, we can efficiently solve NP-complete problems and clone arbitrary quantum states - even when all time-travelling systems are completely isolated from the past. Thus, the many defining benefits of closed timelike curves can still be harnessed, even when causality is preserved. Our results unveil the subtle interplay between entanglement and general relativity, and significantly improve the potential of probing the radical effects that may exist at the interface between relativity and quantum theory.

  5. Using the Hubbert curve to forecast oil production trends worldwide

    E-Print Network [OSTI]

    Almulla, Jassim M.

    2007-09-17T23:59:59.000Z

    .093 1272.377 0.95 0.0337 152.453 2069 Egypt 11338.65 2025 30.417 0.119 371.776 0.98 0.04298 336.504 2075 F.S.U. 172721.94 1968 74.370 0.098 2321.460 0.94 1.07557 4244.327 2047 Former Czechoslovakia 14611.80 1975 0.084 0.031 173041.972 0.67 0.0011849 111.... 2 0 1 2 3 4 5 6 7 8 9 10 1900 1920 1940 1960 1980 2000 2020 2040 2060 Year Pr od uc tio n R ate , M MS TB /D ay Actual Estimated Fig. 1.1 A Basic Hubbert Bell-Shaped Curve The highest point in the curve represents the production peak. After...

  6. Dissipative dark matter and the rotation curves of dwarf galaxies

    E-Print Network [OSTI]

    Foot, R

    2015-01-01T23:59:59.000Z

    There is ample evidence from rotation curves that dark matter halo's around disk galaxies have nontrivial dynamics. Of particular significance are: a) the cored dark matter profile of disk galaxies, b) correlations of the shape of rotation curves with baryonic properties, and c) the Tully-Fisher relation. Dark matter halo's around disk galaxies may have nontrivial dynamics if dark matter is strongly self interacting and dissipative. Multicomponent hidden sector dark matter featuring a massless `dark photon' (from an unbroken dark $U(1)$ gauge interaction) which kinetically mixes with the ordinary photon provides a concrete example of such dark matter. The kinetic mixing interaction facilitates halo heating by enabling ordinary supernovae to be a source of these `dark photons'. Dark matter halo's can expand and contract in response to the heating and cooling processes, but for a sufficiently isolated halo should have evolved to a steady state or `equilibrium' configuration where heating and cooling rates local...

  7. On calculation of microlensing light curve by gravitational lens caustic

    E-Print Network [OSTI]

    M. B. Bogdanov

    2001-02-02T23:59:59.000Z

    For an analysis of microlensing observational data in case of binary gravitational lenses as well as for an interpretation of observations of high magnification events in multiple images of a lensed quasar it is necessary to calculate for a given source the microlensing light curve by a fold caustic. This problem comes to the numerical calculation of a singular integral. We formulated the sufficient condition of a convergence of the integral sum for this singular integral. The strictly approach to the problem of a comparison of model results with the unequally sampled observational data consists in calculation of the model light curve in equidistant points of the canonical dissection of the integration segment and a following interpolation of its values at the moments of observations.

  8. Shading curves: vector-based drawing with explicit gradient control

    E-Print Network [OSTI]

    Lieng, Henrik; Tasse, Flora; Kosinka, Ji?í; Dodgson, Neil A.

    2015-01-01T23:59:59.000Z

    gradient. We resolve this problem by using subdivision surfaces that are constructed from shading curves and their shading profiles. Categories and Subject Descriptors (according to ACM CCS): I.3.3 [Computer Graphics]: Picture/Image Gene- ration... potential sources of visual artefacts in Illustrator’s tool: the rendering procedure, the deformation procedure, and blending with underlying layers. Figure 18 shows images coloured with Illustrator’s tool, where arte- facts are visible. In comparison, our...

  9. A dispersion curve study of dredged spoil basin inlets

    E-Print Network [OSTI]

    Male, Robert

    1974-01-01T23:59:59.000Z

    13 19 IV. PROCEDURES AND TECHNIOUHS Test Procenures. Interpretation of Dispersion Curves. Data Analysis, 26 26 28 37 V. EXPERIMENTAL RESULTS. VI. DISCUSSION. The Model as a Settling Tank Relationship to Dredging Practice. 58 58 70 VII... all the spoil must be confined. The additional costs to be incurred in that region over ten years vary from $2. 62 million to $12. 87 million according to the confinement scheme. In the USA, most of the dredging projects are under the con- trol...

  10. Generation of Closed Timelike Curves with Rotating Superconductors

    E-Print Network [OSTI]

    Clovis Jacinto de Matos

    2007-01-19T23:59:59.000Z

    The spacetime metric around a rotating SuperConductive Ring (SCR) is deduced from the gravitomagnetic London moment in rotating superconductors. It is shown that theoretically it is possible to generate Closed Timelike Curves (CTC) with rotating SCRs. The possibility to use these CTC's to travel in time as initially idealized by G\\"{o}del is investigated. It is shown however, that from a technology and experimental point of view these ideas are impossible to implement in the present context.

  11. Discontinuous quantum evolutions in the presence of closed timelike curves

    E-Print Network [OSTI]

    Richard DeJonghe; Kimberly Frey; Tom Imbo

    2010-05-06T23:59:59.000Z

    We consider Deutsch's computational model of a quantum system evolving in a spacetime containing closed timelike curves. Although it is known that this model predicts non-linear and non-unitary evolutions of the system, we demonstrate that it also gives rise to evolutions which are a discontinuous function of the input state. These discontinuities persist for the most natural modifications of Deutsch's approach.

  12. Discussions on the Cancellation Effect on a Curved Orbit

    SciTech Connect (OSTI)

    Rui Li; Ya. S. Derbenev

    2005-05-16T23:59:59.000Z

    The canonical formulation and the cancellation effect for bunch dynamics under collective interaction on a curved orbit were presented in Ref. [*]. Some possible controversial representations of the cancellation effect were later addressed by Geloni et al.** In this study, we discuss all the points raised in Ref. [**] based on our canonical treatment, and show how these points can be perceived from the view point of the cancellation picture.

  13. Characterization of micro-contact resistance between a gold nanocrystalline line and a tungsten electrode probe in interconnect fatigue testing

    SciTech Connect (OSTI)

    Ling, Xue; Wang, Yusheng [Department of Engineering Mechanics, AML, Tsinghua University, Beijing 100084 (China); Li, Xide, E-mail: lixide@tsinghua.edu.cn [Department of Engineering Mechanics, AML, Tsinghua University, Beijing 100084 (China); Center for Nano and Micro Mechanics, Tsinghua University, Beijing 100084 (China)

    2014-10-15T23:59:59.000Z

    An electromechanically-coupled micro-contact resistance measurement system is built to mimic the contact process during fatigue testing of nanoscale-thickness interconnects using multiple probe methods. The design combines an optical microscope, high-resolution electronic balance, and micromanipulator-controlled electric probe, and is coupled with electrical measurements to investigate microscale contact physics. Experimental measurements are performed to characterize the contact resistance response of the gold nanocrystalline pad of a 35-nm-thick interconnect under mechanical force applied by a tungsten electrode probe. Location of a stable region for the contact resistance and the critical contact force provides better understanding of micro-contact behavior relative to the effects of the contact force and the nature of the contact surface. Increasing contact temperature leads to reduced contact resistance, softens the pad material, and modifies the contact surface. The stability of both contact resistance and interconnect resistance is studied under increasing contact force. Major fluctuations emerge when the contact force is less than the critical contact force, which shows that temporal contact resistance will affect interconnect resistance measurement accuracy, even when using the four-wire method. This performance is demonstrated experimentally by heating the Au line locally with a laser beam. Finally, the contact resistances are calculated using the LET (Li–Etsion–Talke) model together with combined Holm and Sharvin theory under various contact forces. Good agreement between the results is obtained. This research provides a way to measure change in interconnect line resistance directly under a stable contact resistance regime with a two-wire method that will greatly reduce the experimental costs.

  14. Theory of a quantum noncanonical field in curved spacetimes

    SciTech Connect (OSTI)

    Indurain, Javier; Liberati, Stefano [Departamento de Fisica Teorica, Universidad de Zaragoza, Zaragoza 50009 (Spain); SISSA, Via Beirut 2-4, 34151 Trieste (Italy) and INFN sezione di Trieste (Italy)

    2009-08-15T23:59:59.000Z

    Much attention has been recently devoted to the possibility that quantum gravity effects could lead to departures from special relativity in the form of a deformed Poincare algebra. These proposals go generically under the name of doubly or deformed special relativity (DSR). In this article we further explore a recently proposed class of quantum field theories, involving noncanonically commuting complex scalar fields, which have been shown to entail a DSR-like symmetry. An open issue for such theories is whether the DSR-like symmetry has to be taken as a physically relevant symmetry, or if in fact the 'true' symmetries of the theory are just rotations and translations while boost invariance has to be considered broken. Here we analyze this issue by extending the known results to curved spacetime under both of the previous assumptions. We show that if the symmetry of the free theory is taken to be a DSR-like realization of the Poincare symmetry, then it is not possible to render such a symmetry a gauge symmetry of the curved physical spacetime. However, it is possible to introduce an auxiliary spacetime which allows one to describe the theory as a standard quantum field theory in curved spacetime. Alternatively, taking the point of view that the noncanonical commutation of the fields actually implies a breakdown of boost invariance, the physical spacetime manifold has to be foliated in surfaces of simultaneity, and the field theory can be coupled to gravity by making use of the Arnowitt-Deser-Misner prescription.

  15. Can CCM law properly represent all extinction curves?

    E-Print Network [OSTI]

    Geminale, A; Geminale, Anna; Popowski, Piotr

    2005-01-01T23:59:59.000Z

    We present the analysis of a large sample of lines of sight with extinction curves covering wavelength range from near-infrared (NIR) to ultraviolet (UV). We derive total to selective extinction ratios based on the Cardelli, Clayton and Mathis (1989, CCM) law, which is typically used to fit the extinction data both for diffuse and dense interstellar medium. We conclude that the CCM law is able to fit most of the extinction curves in our sample. We divide the remaining lines of sight with peculiar extinction into two groups according to two main behaviors: a) the optical/IR or/and UV wavelength region cannot be reproduced by the CCM formula; b) the optical/NIR and UV extinction data are best fit by the CCM law with different values of R_V. We present examples of such curves. The study of both types of peculiar cases can help us to learn about the physical processes that affect dust in the interstellar medium, e.g., formation of mantles on the surface of grains, evaporation, growing or shattering.

  16. Can CCM law properly represent all extinction curves?

    E-Print Network [OSTI]

    Anna Geminale; Piotr Popowski

    2005-02-23T23:59:59.000Z

    We present the analysis of a large sample of lines of sight with extinction curves covering wavelength range from near-infrared (NIR) to ultraviolet (UV). We derive total to selective extinction ratios based on the Cardelli, Clayton and Mathis (1989, CCM) law, which is typically used to fit the extinction data both for diffuse and dense interstellar medium. We conclude that the CCM law is able to fit most of the extinction curves in our sample. We divide the remaining lines of sight with peculiar extinction into two groups according to two main behaviors: a) the optical/IR or/and UV wavelength region cannot be reproduced by the CCM formula; b) the optical/NIR and UV extinction data are best fit by the CCM law with different values of R_V. We present examples of such curves. The study of both types of peculiar cases can help us to learn about the physical processes that affect dust in the interstellar medium, e.g., formation of mantles on the surface of grains, evaporation, growing or shattering.

  17. Method of non-destructively inspecting a curved wall portion

    DOE Patents [OSTI]

    Fong, James T. (Bethel Park, PA)

    1996-01-01T23:59:59.000Z

    A method of non-destructively inspecting a curved wall portion of a large and thick walled vessel for a defect by computed tomography is provided. A collimated source of radiation is placed adjacent one side of the wall portion and an array of detectors for the radiation is placed on the other side adjacent the source. The radiation from the source passing through the wall portion is then detected with the detectors over a limited angle, dependent upon the curvature of the wall of the vessel, to obtain a dataset. The source and array are then coordinately moved relative to the wall portion in steps and a further dataset is obtained at each step. The plurality of datasets obtained over the limited angle is then processed to produce a tomogram of the wall portion to determine the presence of a defect therein. In a preferred embodiment, the curved wall portion has a center of curvature so that the source and the array are positioned at each step along a respective arc curved about the center. If desired, the detector array and source can be reoriented relative to a new wall portion and an inspection of the new wall portion can be easily obtained. Further, the source and detector array can be indexed in a direction perpendicular to a plane including the limited angle in a plurality of steps so that by repeating the detecting and moving steps at each index step, a three dimensional image can be created of the wall portion.

  18. Experimental study of curved guide tubes for pellet injection

    SciTech Connect (OSTI)

    Combs, S.K.; Baylor, L.R.; Foust, C.R.; Gouge, M.J.; Jernigan, T.C.; Milora, S.L.

    1997-12-01T23:59:59.000Z

    The use of curved guide tubes for transporting frozen hydrogen pellets offers great flexibility for pellet injection into plasma devices. While this technique has been previously employed, an increased interest in its applicability has been generated with the recent ASDEX Upgrade experimental data for magnetic high-field side (HFS) pellet injection. In these innovative experiments, the pellet penetration appeared to be significantly deeper than for the standard magnetic low-field side injection scheme, along with corresponding greater fueling efficiencies. Thus, some of the major experimental fusion devices are planning experiments with HFS pellet injection. Because of the complex geometries of experimental fusion devices, installations with multiple curved guide tube sections will be required for HFS pellet injection. To more thoroughly understand and document the capability of curved guide tubes, an experimental study is under way at the Oak Ridge National Laboratory (ORNL). In particular, configurations and pellet parameters applicable for the DIII-D tokamak and the International Thermonuclear Experimental Reactor (ITER) were simulated in laboratory experiments. Initial test results with nominal 2.7- and 10-mm-diam deuterium pellets are presented and discussed.

  19. A method of evaluating Sulphlex mix designs based on the indirect tension test

    E-Print Network [OSTI]

    Richey, Barry Lee

    1982-01-01T23:59:59.000Z

    approach to characteriz1ng fatigue life. A procedure for optimizing a mix design was outlined. Design charts for permanent deformation, thermal cracking and fat1gue cracking were presented for Sulphiex binders CR-1 and CR-2 and an asphalt cement (AC-10... in a warm climate. 65 37 Calculated permament deformations for a thin CR-1 pavement in a warm climate. 66 38 Permament deformation design chart for a thick CR-1 p~vement in a warm climate for 106, 10 and 10 standard wheel loads . 68 39 Controlled...

  20. Structural Safety and Reliability, Corotis et al. (eds), 2001 Swets & Zeitlinger, ISBN 90 5809 197 X Moment-based fatigue load models for wind energy systems

    E-Print Network [OSTI]

    Manuel, Lance

    197 X 1 Moment-based fatigue load models for wind energy systems Steven R. Winterstein & LeRoy M. Veers Sandia National Laboratories, Wind Energy Technology Department, Albuquerque, NM 87185-0708 Keywords: load models, fatigue loads, wind energy, non-Gaussian, moment-based models, long- term, short

  1. Fatigue analysis of single-span and two-span solid-sawn, creosote-treated southern pine railroad bridge stringers

    E-Print Network [OSTI]

    Comardo, Angelique France

    2000-01-01T23:59:59.000Z

    be the preferred method of construction and rehabilitation of timber bridges. To properly assess the fatigue resistance of timber bridge stringers, it was necessary to conduct full-scale fatigue tests on stringer specimens. As part of the Timber Bridge Life...

  2. Two-dimensional finite element simulation of fracture and fatigue behaviours of alumina microstructures for hip prosthesis

    E-Print Network [OSTI]

    Kim, Kyungmok; Géringer, Jean; 10.1177/0954411911422843

    2012-01-01T23:59:59.000Z

    This paper describes a two-dimensional (2D) finite element simulation for fracture and fatigue behaviours of pure alumina microstructures such as those found at hip prostheses. Finite element models are developed using actual Al2O3 microstructures and a bilinear cohesive zone law. Simulation conditions are similar to those found at a slip zone in a dry contact between a femoral head and an acetabular cup of hip prosthesis. Contact stresses are imposed to generate cracks in the models. Magnitudes of imposed stresses are higher than those found at the microscopic scale. Effects of microstructures and contact stresses are investigated in terms of crack formation. In addition, fatigue behaviour of the microstructure is determined by performing simulations under cyclic loading conditions. It is shown that crack density observed in a microstructure increases with increasing magnitude of applied contact stress. Moreover, crack density increases linearly with respect to the number of fatigue cycles within a given con...

  3. Fatigue damage estimate comparisons for northern European and U.S. wind farm loading environments

    SciTech Connect (OSTI)

    Sutherland, H.J. [Sandia National Labs., Albuquerque, NM (United States). Wind Energy Technology Dept.; Kelley, N.D. [National Renewable Energy Lab., Golden, CO (United States). Wind Technology Div.

    1995-05-01T23:59:59.000Z

    Typical loading histories associated with wind turbine service environments in northern Europe and within a large wind farm in the continental US were recently compared by Kelley (1995) using the WISPER [Ten Have, 1992] loading standard and its development protocol. In this study, an equivalent load spectrum for a US wind farm was developed by applying the WISPER development protocol to representative service load histories collected from two adjacent turbines operating within a large wind farm in San Gorgonio Pass, California. The results of this study showed that turbines operating in the California wind farm experience many more loading cycles with larger peak-to-peak values for the same mean wind speed classification than their European counterparts. In this paper, the impact of the two WISPER-protocol fatigue-load spectra on service lifetime predictions are used to compare and contrast the impact of the two loading environments with one another. The service lifetime predictions are made using the LIFE2 Fatigue Analysis Code [Sutherland and Schluter, 1989] with the fatigue properties of typical fiber glass composite blade materials. Additional analyses, based on rainflow counted time histories from the San Gorgonio turbines, are also used in the comparisons. In general, these results indicate that the WISPER load spectrum from northern European sites significantly underestimates the WISPER protocol load spectrum from a US wind farm site; i.e., the WISPER load spectrum significantly underestimates the number and magnitude of the loads observed at a US wind farm site. The authors conclude that there are fundamental differences in the two service environments.

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

    SciTech Connect (OSTI)

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

    2002-08-01T23:59:59.000Z

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

  5. Technology Innovations and Experience Curves for Nitrogen Oxides Control Technologies

    E-Print Network [OSTI]

    Yeh, Sonia; Rubin, Edward S.; Taylor, Margaret R.

    2007-01-01T23:59:59.000Z

    design parameters to a consistent basis, with all of the results adjusted to $2000 using the chemical engineering

  6. Historical overview on Vacuum suitable Welding and fatigue resistance in Research Devices

    E-Print Network [OSTI]

    Wolf, Martin

    2015-01-01T23:59:59.000Z

    New inventions change the approach of vacuum suitable welding for research purpose. With orbital welding, laser welding and robot welding the possibilities increase to fabricate larger vessels more accurately. Despite this development there is still no perfect understanding on how to avoid virtual leaks and how to make such joints suitable for dynamic stress. By recalling its historical development, it is apparent how welding mistakes began occurring systematically and how to avoid them. With ASDEX-Upgrade as an example, it is shown how the attempt to conduct vacuum suitable welding has decreased the fatigue strength. ITER could repeat the mistakes of ASDEX-Upgrade even for unwanted welding (accidental fusing of joints).

  7. Cancer cachexia decreases specific force and accelerates fatigue in limb muscle

    SciTech Connect (OSTI)

    Roberts, B.M. [1225 Center Drive, HPNP Building Room 1142, Department of Physical Therapy, University of Florida, Gainesville, FL 32610 (United States)] [1225 Center Drive, HPNP Building Room 1142, Department of Physical Therapy, University of Florida, Gainesville, FL 32610 (United States); Frye, G.S.; Ahn, B.; Ferreira, L.F. [1864 Stadium Road, Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL 32610 (United States)] [1864 Stadium Road, Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL 32610 (United States); Judge, A.R., E-mail: arjudge@phhp.ufl.edu [1225 Center Drive, HPNP Building Room 1142, Department of Physical Therapy, University of Florida, Gainesville, FL 32610 (United States)

    2013-06-07T23:59:59.000Z

    Highlights: •C-26 cancer cachexia causes a significant decrease in limb muscle absolute force. •C-26 cancer cachexia causes a significant decrease in limb muscle specific force. •C-26 cancer cachexia decreases fatigue resistance in the soleus muscle. •C-26 cancer cachexia prolongs time to peak twitch tension in limb muscle. •C-26 cancer cachexia prolongs one half twitch relaxation time in limb muscle. -- Abstract: Cancer cachexia is a complex metabolic syndrome that is characterized by the loss of skeletal muscle mass and weakness, which compromises physical function, reduces quality of life, and ultimately can lead to mortality. Experimental models of cancer cachexia have recapitulated this skeletal muscle atrophy and consequent decline in muscle force generating capacity. However, more recently, we provided evidence that during severe cancer cachexia muscle weakness in the diaphragm muscle cannot be entirely accounted for by the muscle atrophy. This indicates that muscle weakness is not just a consequence of muscle atrophy but that there is also significant contractile dysfunction. The current study aimed to determine whether contractile dysfunction is also present in limb muscles during severe Colon-26 (C26) carcinoma cachexia by studying the glycolytic extensor digitorum longus (EDL) muscle and the oxidative soleus muscle, which has an activity pattern that more closely resembles the diaphragm. Severe C-26 cancer cachexia caused significant muscle fiber atrophy and a reduction in maximum absolute force in both the EDL and soleus muscles. However, normalization to muscle cross sectional area further demonstrated a 13% decrease in maximum isometric specific force in the EDL and an even greater decrease (17%) in maximum isometric specific force in the soleus. Time to peak tension and half relaxation time were also significantly slowed in both the EDL and the solei from C-26 mice compared to controls. Since, in addition to postural control, the oxidative soleus is also important for normal locomotion, we further performed a fatigue trial in the soleus and found that the decrease in relative force was greater and more rapid in solei from C-26 mice compared to controls. These data demonstrate that severe cancer cachexia causes profound muscle weakness that is not entirely explained by the muscle atrophy. In addition, cancer cachexia decreases the fatigue resistance of the soleus muscle, a postural muscle typically resistant to fatigue. Thus, specifically targeting contractile dysfunction represents an additional means to counter muscle weakness in cancer cachexia, in addition to targeting the prevention of muscle atrophy.

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

    SciTech Connect (OSTI)

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

    1997-02-01T23:59:59.000Z

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

  9. Optimization of fracture treatment designs

    E-Print Network [OSTI]

    Rueda, Jose Ignacio

    1992-01-01T23:59:59.000Z

    using the type curves published by Holditch et al2O. n f H r lic Fracture Pro a ation imula or In 1955, the first model to simulate the propagation of a vertical hydraulic fracture was developed by Khristianovitch and Zheltov O (K-Z model). This two... . . . . 93 97 LIST OF TABLES Table Page 5. I Reservoir and well data for base case example 54 5. 2 Fracture design data for base case example . 54 5. 3 Economic data for base case example . . 54 5. 4 Comparison of the methods used in STIMOP and LPOP...

  10. New Reliability Assessment Method for Solder Joints in BGA Package by Considering the Interaction between Design Factors

    E-Print Network [OSTI]

    Satoshi Kondo; Qiang Yu; T. Shibutani; M. Shiratori

    2008-01-07T23:59:59.000Z

    As the integration and the miniaturization of electronics devices, design space become narrower and interactions between design factors affect their reliability. This paper presents a methodology of quantifying the interaction of each design factor in electronics devices. Thermal fatigue reliability of BGA assembly was assessed with the consideration of the interaction between design factors. Sensitivity analysis shows the influence of each design factor to inelastic strain range of a solder joint characterizing the thermal fatigue life if no interaction occurs. However, there is the interaction in BGA assembly since inelastic strain range depends on not only a mismatch in CTE but also a warpage of components. Clustering can help engineers to clarify the relation between design factors. The variation in the influence was taken to quantify the interaction of each design factor. Based on the interaction, simple evaluating approach of inelastic strain range for the BGA assembly was also developed. BGA package was simplified into a homogeneous component and equivalent CTE wascalculated from the warpage of BGA and PCB. The estimated equation was derived by using the response surface method as a function of design factors. Based upon these analytical results, design engineers can rate each factor's effect on reliability and assess the reliability of their basic design plan at the concept design stage.

  11. HTP over Algebraic Extensions of Q: Normforms vs. Elliptic Curves HTP over Algebraic Extensions of Q

    E-Print Network [OSTI]

    Shlapentokh, Alexandra

    HTP over Algebraic Extensions of Q: Normforms vs. Elliptic Curves HTP over Algebraic Extensions and Computability, ICMS, June 2007 #12;HTP over Algebraic Extensions of Q: Normforms vs. Elliptic Curves A Talk in Two Rounds Round I: Normforms Today Round II: Elliptic Curves Later #12;HTP over Algebraic Extensions

  12. HTP over Algebraic Extensions of Q: Normforms vs. Elliptic Curves HTP over Algebraic Extensions of Q

    E-Print Network [OSTI]

    Shlapentokh, Alexandra

    HTP over Algebraic Extensions of Q: Normforms vs. Elliptic Curves HTP over Algebraic Extensions and Computability, ICMS, June 2007 #12;HTP over Algebraic Extensions of Q: Normforms vs. Elliptic Curves A Talk in Two Rounds Round II: Elliptic Curves Today #12;HTP over Algebraic Extensions of Q: Normforms vs

  13. The Geometric Invariants of Null Cartan Curves Under The Similarity Transformations

    E-Print Network [OSTI]

    Hakan Simsek; Mustafa Özdemir

    2015-04-07T23:59:59.000Z

    In this paper, we study the differential geometry of null Cartan curves under the similarity transformations in the Minkowski space-time. Besides, we extend the fundamental theorem for a null Cartan curve according to a similarity motion. We find the equations of all self-similar null curves which is given its shape Cartan curvatures.

  14. Recursive tilings and space-filling curves with little fragmentation Herman Haverkort, TU Eindhoven

    E-Print Network [OSTI]

    Haverkort, Herman

    Recursive tilings and space-filling curves with little fragmentation Herman Haverkort, TU Eindhoven-filling curves with little fragmentation Herman Haverkort, TU Eindhoven Circular range query: report all points;Recursive tilings and space-filling curves with little fragmentation Herman Haverkort, TU Eindhoven Circular

  15. Kolstad: EKC Dec 2005 Interpreting Estimated Environmental Kuznets Curves for Greenhouse Gases

    E-Print Network [OSTI]

    Kolstad, Charles

    Kolstad: EKC Dec 2005 Interpreting Estimated Environmental Kuznets Curves for Greenhouse Gases to interpret a relationship between income and carbon emissions in a country (the environmental Kuznets curve), it was primarily concerned with Environmental Kuznets Curves (EKC) for greenhouse gas emissions. The EKC literature

  16. WORKING PAPER N 2007 -12 Education inequalities and the Kuznets curves

    E-Print Network [OSTI]

    Boyer, Edmond

    WORKING PAPER N° 2007 - 12 Education inequalities and the Kuznets curves: a global perspective, human capital, economic history, Kuznets curve. PARIS-JOURDAN SCIENCES ECONOMIQUES LABORATOIRE D2011 #12;Education Inequalities and the Kuznets Curves: A Global Perspective Since 1870 Christian

  17. Green's Conjecture for curves on arbitrary K3 Marian Aprodu and Gavril Farkas

    E-Print Network [OSTI]

    Farkas, Gavril

    Green's Conjecture for curves on arbitrary K3 surfaces Marian Aprodu and Gavril Farkas Abstract Green's Conjecture predicts than one can read off special linear series on an algebraic curve-Ramanan, provides a complete solution to Green's Conjecture for smooth curves on arbitrary K3 surfaces. 1

  18. THE GREEN CONJECTURE FOR EXCEPTIONAL CURVES ON A K3 SURFACE

    E-Print Network [OSTI]

    Pacienza, Gianluca

    THE GREEN CONJECTURE FOR EXCEPTIONAL CURVES ON A K3 SURFACE to prove the Green conjecture f* *or exceptional curves on K3 surfaces. Such curves count among made in the eighties by Green, and Green-Lazarsfeld, pointed * *out to some deep links between

  19. Elliptic curves with large torsion and positive rank over number fields of small degree and ECM

    E-Print Network [OSTI]

    Dujella, Andrej

    Elliptic curves with large torsion and positive rank over number fields of small degree and ECM for construction of elliptic curves with large torsion group and positive rank over number fields of small degree). Keywords: Torsion group, rank, elliptic curves, number fields Mathematics Subject Classification (2010): 11

  20. HIGH RANK ELLIPTIC CURVES WITH PRESCRIBED TORSION GROUP OVER QUADRATIC FIELDS

    E-Print Network [OSTI]

    Dujella, Andrej

    HIGH RANK ELLIPTIC CURVES WITH PRESCRIBED TORSION GROUP OVER QUADRATIC FIELDS JULIÁN AGUIRRE for the torsion group of elliptic curves dened over quadratic number elds. We present examples of high rank elliptic curves with given torsion group which give the current records for most of the torsion groups

  1. IEEE TRANSACTIONS ON POWER SYSTEMS, CHEN, DENG AND HUO. 1 Electricity Price Curve Modeling by Manifold

    E-Print Network [OSTI]

    markets. Index Terms-- Electricity spot price, locational marginal price, electricity forward curveIEEE TRANSACTIONS ON POWER SYSTEMS, CHEN, DENG AND HUO. 1 Electricity Price Curve Modeling and prediction of electricity price curves by applying the manifold learning methodology. Cluster analysis based

  2. IEEE TRANSACTIONS ON POWER SYSTEMS, VOL. 23, NO. 3, AUGUST 2008 877 Electricity Price Curve Modeling

    E-Print Network [OSTI]

    Huo, Xiaoming

    --Electricity forward curve, electricity spot price, forecasting, locational marginal price, manifold learning. IIEEE TRANSACTIONS ON POWER SYSTEMS, VOL. 23, NO. 3, AUGUST 2008 877 Electricity Price Curve approach for the modeling and analysis of electricity price curves by ap- plying the manifold learning

  3. CSC6870 Computer Graphics II B-Spline Curves and NURBS

    E-Print Network [OSTI]

    Hua, Jing

    CSC6870 Computer Graphics II B-Spline Curves and NURBS CSC6870 Computer Graphics II Motivation continuity CSC6870 Computer Graphics II B-spline Curve CSC6870 Computer Graphics II B-Splines · Curve CSC6870 Computer Graphics II B-Splines Basis Functions: Cox- deBoor recursion · The basis function

  4. An Appliance-driven Approach to Detection of Corrupted Load Curve Data

    E-Print Network [OSTI]

    Pei, Jian

    An Appliance-driven Approach to Detection of Corrupted Load Curve Data Guoming Tang1,3 , Kui Wu1@sfu.ca, jiuyang_tang@nudt.edu.cn, jshlei@shiep.edu.cn ABSTRACT Load curve data in power systems refers to users discov- ered in the data. Load curve data, however, usually suffers from corruptions caused by various

  5. Spacefilling curves for 2simplicial meshes created with bisections and reflections

    E-Print Network [OSTI]

    Eindhoven, Technische Universiteit

    computational 2­meshes which can be very e#ciently load­balanced with the use of a space­filling curve. Keywords: Grid generation, space filling curve, load balancing Mathematics Subject Classification 2000: 65M the elements in curve­traversal order, and the required load­balance redistribution amounts to a possible

  6. Indexing Moving Objects by Space Filling Curves in the Dual Space

    E-Print Network [OSTI]

    Kaiserslautern, Universität

    The Bdual ­ tree: Indexing Moving Objects by Space Filling Curves in the Dual Space By Man Lung Yiu Objects by Space Filling Curves in the Dual Space Introduction Related work Problem definition: Indexing Moving Objects by Space Filling Curves in the Dual Space Introduction Related work Problem

  7. Ris-R-Report Multi-MW wind turbine power curve

    E-Print Network [OSTI]

    Risø-R-Report Multi-MW wind turbine power curve measurements using remote sensing instruments Wagner, Michael Courtney Title: Multi-MW wind turbine power curve measurements using remote sensing (max. 2000 char.): Power curve measurement for large wind turbines requires taking into account more

  8. High temperature fracture and fatigue of ceramics. Annual technical progress report No. 6, August 15, 1994--August 14, 1995

    SciTech Connect (OSTI)

    Cox, B.

    1996-04-01T23:59:59.000Z

    This report covers work done in the first year of our new contract {open_quotes}High Temperature Fracture and Fatigue of Ceramics,{close_quotes} which commenced in August, 1995 as a follow-on from our prior contract {open_quotes}Mechanisms of Mechanical Fatigue in Ceramics.{close_quotes} Our activities have consisted mainly of studies of the failure of fibrous ceramic matrix composites (CMCs) at high temperature; with a little fundamental work on the role of stress redistribution in the statistics of fracture and cracking in the presence of viscous fluids.

  9. Average Soil Water Retention Curves Measured by Neutron Radiography

    SciTech Connect (OSTI)

    Cheng, Chu-Lin [ORNL; Perfect, Edmund [University of Tennessee, Knoxville (UTK); Kang, Misun [ORNL; Voisin, Sophie [ORNL; Bilheux, Hassina Z [ORNL; Horita, Juske [Texas Tech University (TTU); Hussey, Dan [NIST Center for Neutron Research (NCRN), Gaithersburg, MD

    2011-01-01T23:59:59.000Z

    Water retention curves are essential for understanding the hydrologic behavior of partially-saturated porous media and modeling flow transport processes within the vadose zone. In this paper we report direct measurements of the main drying and wetting branches of the average water retention function obtained using 2-dimensional neutron radiography. Flint sand columns were saturated with water and then drained under quasi-equilibrium conditions using a hanging water column setup. Digital images (2048 x 2048 pixels) of the transmitted flux of neutrons were acquired at each imposed matric potential (~10-15 matric potential values per experiment) at the NCNR BT-2 neutron imaging beam line. Volumetric water contents were calculated on a pixel by pixel basis using Beer-Lambert s law after taking into account beam hardening and geometric corrections. To remove scattering effects at high water contents the volumetric water contents were normalized (to give relative saturations) by dividing the drying and wetting sequences of images by the images obtained at saturation and satiation, respectively. The resulting pixel values were then averaged and combined with information on the imposed basal matric potentials to give average water retention curves. The average relative saturations obtained by neutron radiography showed an approximate one-to-one relationship with the average values measured volumetrically using the hanging water column setup. There were no significant differences (at p < 0.05) between the parameters of the van Genuchten equation fitted to the average neutron radiography data and those estimated from replicated hanging water column data. Our results indicate that neutron imaging is a very effective tool for quantifying the average water retention curve.

  10. Optimal Monetary Policy with a Convex Phillips Curve

    E-Print Network [OSTI]

    Tambakis, Demosthenes N

    that inflation’s response to demand pressure is nonlinear and built this into estimation using the inverse unemployment rate. 9 Equation (6) holds regardless of the value of k. Because UN > ?, it requires that ?t > ?? for Ut to not diverge. Note... supply shocks, such as those of the 1970s. The convex Phillips curve functional form in this paper follows Debelle and Laxton (1997) and Laxton, Rose and Tambakis (1999). 6 At the aggregate level, convexity can be traced to the traditional Keynesian...

  11. Multigroup Radiation Transport in Supernova Light Curve Calculations |

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn AprilAElectronicCurves | SciTechLagrangeEnergy, Office of ScientificUS DeptUS

  12. chemical engineering research and design 8 6 ( 2 0 0 8 ) 892903 available at www.sciencedirect.com

    E-Print Network [OSTI]

    Lucia, Angelo

    the state of the art as it relates to finding minimum energy designs for distillation columns. They give.sciencedirect.com journal homepage: www.elsevier.com/locate/cherd Non-pinched, minimum energy distillation designs Amit S: Distillation design Non-pinched solutions Minimum energy designs Pinch point curves Looping structure Ancillary

  13. Fatigue crack growth of titanium rotor alloys in vacuum and air

    SciTech Connect (OSTI)

    McClung, R.C.; Lawless, B.H.; Gorelik, M.; Date, C.; Gill, Y.; Piascik, R.S.

    1999-07-01T23:59:59.000Z

    An enhanced life management system for aircraft turbine engine rotors based on probabilistic damage tolerance methods is currently under development by the engine industry and the FAA, with an initial focus on fatigue cracking at hard alpha (HA) defects in titanium. Since HA defects are usually subsurface, any resulting cracks are embedded and hence isolated from the atmosphere (i.e., vacuum-like) for at least some of their life. Fatigue crack growth (GCG) tests have been conducted in vacuum at various temperatures and stress ratios for Ti-6Al-4V and Ti-6Al-2Sn-4Zr-2Mo+Si rotor alloys. A brief study of vacuum levels suggests that pressures of 10{sup {minus}6} Torr are adequate to capture full vacuum effects on FCG rates. Vacuum FCG results are compared with available air data. The vacuum data demonstrate temperature and stress ratio effects comparable to air data. The vacuum and air data exhibit the same growth rates in the upper Paris regime, but apparent thresholds are significantly higher in vacuum than in air.

  14. Broadband turbulent spectra in gamma-ray burst light curves

    SciTech Connect (OSTI)

    Van Putten, Maurice H. P. M. [Astronomy and Space Science, Sejong University, 98 Gunja-Dong Gwangin-gu, Seoul 143-747 (Korea, Republic of); Guidorzi, Cristiano; Frontera, Filippo, E-mail: mvp@sejong.ac.kr [Department of Physics and Earth Sciences, University of Ferrara, Via Saragat 1, I-44122 Ferrara (Italy)

    2014-05-10T23:59:59.000Z

    Broadband power density spectra offer a window to understanding turbulent behavior in the emission mechanism and, at the highest frequencies, in the putative inner engines powering long gamma-ray bursts (GRBs). We describe a chirp search method alongside Fourier analysis for signal detection in the Poisson noise-dominated, 2 kHz sampled, BeppoSAX light curves. An efficient numerical implementation is described in O(Nnlog n) operations, where N is the number of chirp templates and n is the length of the light-curve time series, suited for embarrassingly parallel processing. For the detection of individual chirps over a 1 s duration, the method is one order of magnitude more sensitive in signal-to-noise ratio than Fourier analysis. The Fourier-chirp spectra of GRB 010408 and GRB 970816 show a continuation of the spectral slope with up to 1 kHz of turbulence identified in low-frequency Fourier analysis. The same continuation is observed in an average spectrum of 42 bright, long GRBs. An outlook on a similar analysis of upcoming gravitational wave data is included.

  15. Light curves from supernova shock breakout through an extended wind

    SciTech Connect (OSTI)

    Ginzburg, Sivan; Balberg, Shmuel [Racah Institute of Physics, The Hebrew University, Jerusalem 91904 (Israel)

    2014-01-01T23:59:59.000Z

    Recent observations suggest that some supernovae may be the result of an explosion into an optically thick circumstellar material, the product of pre-explosion mass loss (wind) by the progenitor star. This scenario has been studied previously both analytically and numerically. However, many previous studies base their analysis on the diffusion approximation for radiation transfer, which is inappropriate in the optically thin outer layers of the wind. Here we study the deviations from diffusion and calculate light curves more accurately using a Monte Carlo approach to photon transfer. We distinguish between 'compact' winds, for which the diffusion approximation is appropriate, and 'extended' winds, which require a more delicate treatment of the radiation. We show that this effect is more significant than that of the light-travel time difference to a distant observer, which has a secondary influence on the light curves of extended-wind systems. We also comment on the applicability of the widely used flux-limited diffusion approximation in this context: we find that it generally does not reproduce the Monte Carlo results. The flux-limited diffusion approximation leads to results that are not only quantitatively but also qualitatively wrong in the extended-wind regime.

  16. Magnetar Driven Shock Breakout and Double Peaked Supernova Light Curves

    E-Print Network [OSTI]

    Kasen, Daniel; Bildsten, Lars

    2015-01-01T23:59:59.000Z

    The light curves of some luminous supernovae are suspected to be powered by the spindown energy of a rapidly rotating magnetar. Here we describe a possible signature of the central engine: a burst of shock breakout emission occurring several days after the supernova explosion. The energy input from the magnetar inflates a high-pressure bubble that drives a shock through the pre-exploded supernova ejecta. If the magnetar is powerful enough, that shock will near the ejecta surface and become radiative. At the time of shock breakout, the ejecta will have expanded to a large radius (~10^{14} cm) so that the radiation released is at optical/ultraviolet wavelengths (T ~ 20,000 K) and lasts for several days. The luminosity and timescale of this magnetar driven shock breakout are similar to the first peak observed recently in the double-peaked light curve of SN-LSQ14BDQ. However, for a large region of model parameter space, the breakout emission is predicted to be dimmer than the diffusive luminosity from direct magn...

  17. On the Nuclear Rotation Curve of M31

    E-Print Network [OSTI]

    Thomas S. Statler

    1999-05-08T23:59:59.000Z

    The nuclear rotation curve of M31, as observed by the Hubble Space Telescope Faint Object Camera Spectrograph, shows a significant disturbance coinciding with the off-center brightness peak, P1. This +/- 60 km/s feature is distinguished by a local velocity maximum centered on P1 and a local minimum approxmately 0.08" closer to P2. If the M31 double nucleus is an eccentric disk with an off-center density concentration, as suggested by Tremaine, then the self-gravity of the disk can produce just such a disturbance. The expected kinematic signature is calculated approximately by examining sequences of closed periodic orbits in a Kepler potential perturbed by a model disk potential that precesses at constant frequency. The perturbation forces a steep negative eccentricity gradient in the sequence of closed orbits through the densest part of the disk, which reverses the arrangement of periapsis and apoapsis with respect to the central mass. Stars making up the inner part of the density concentration are at apoapsis, while stars making up the outer part are at periapsis, producing a steep local velocity gradient. This result is independent of the details of the mass distribution. The projected rotation curve of the model is shown to closely resemble that of M31, giving strong support to the eccentric disk picture.

  18. OBSERVATIONS OF DOPPLER BOOSTING IN KEPLER LIGHT CURVES

    SciTech Connect (OSTI)

    Van Kerkwijk, Marten H.; Breton, Rene P.; Justham, Stephen [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing (China); Rappaport, Saul A. [37-602B, MIT Department of Physics and Kavli Institute for Astrophysics and Space Research, 70 Vassar St., Cambridge, MA 02139 (United States); Podsiadlowski, Philipp [Sub-department of Astrophysics, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); Han, Zhanwen, E-mail: mhvk@astro.utoronto.ed [National Astronomical Observatories/Yunnan Observatory and Key Laboratory of the Structure and Evolution of Celestial Objects, Chinese Academy of Sciences, Kunming 650011 (China)

    2010-05-20T23:59:59.000Z

    Among the initial results from Kepler were two striking light curves, for KOI 74 and KOI 81, in which the relative depths of the primary and secondary eclipses showed that the more compact, less luminous object was hotter than its stellar host. That result became particularly intriguing because a substellar mass had been derived for the secondary in KOI 74, which would make the high temperature challenging to explain; in KOI 81, the mass range for the companion was also reported to be consistent with a substellar object. We re-analyze the Kepler data and demonstrate that both companions are likely to be white dwarfs. We also find that the photometric data for KOI 74 show a modulation in brightness as the more luminous star orbits, due to Doppler boosting. The magnitude of the effect is sufficiently large that we can use it to infer a radial velocity amplitude accurate to 1 km s{sup -1}. As far as we are aware, this is the first time a radial-velocity curve has been measured photometrically. Combining our velocity amplitude with the inclination and primary mass derived from the eclipses and primary spectral type, we infer a secondary mass of 0.22 {+-} 0.03 M{sub sun}. We use our estimates to consider the likely evolutionary paths and mass-transfer episodes of these binary systems.

  19. Adsorption of annealed branched polymers on curved surfaces

    E-Print Network [OSTI]

    Wagner, Jef; Zandi, Roya

    2015-01-01T23:59:59.000Z

    The behavior of annealed branched polymers near adsorbing surfaces plays a fundamental role in many biological and industrial processes. Most importantly single stranded RNA in solution tends to fold up and self-bind to form a highly branched structure. Using a mean field theory, we both perturbatively and numerically examine the adsorption of branched polymers on surfaces of several different geometries in a good solvent. Independent of the geometry of the wall, we observe that as branching density increases, surface tension decreases. However, we find a coupling between the branching density and curvature in that a further lowering of surface tension occurs when the wall curves towards the polymer, but the amount of lowering of surface tension decreases when the wall curves away from the polymer. We find that for branched polymers confined into spherical cavities, most of branch-points are located in the vicinity of the interior wall and the surface tension is minimized for a critical cavity radius. For bra...

  20. Incorporation of learning curve costs in acquisition strategy optimization

    SciTech Connect (OSTI)

    Loerch, A.

    1994-12-31T23:59:59.000Z

    Each year, the United States Army procures billions of dollars worth of weapons and equipment so that it can accomplish its worldwide mission of deterrence. The process of deciding what to buy, in what quantities, and when to best respond to the threat posed by potential adversaries, is extremely complex, requiring extensive analysis. Two techniques commonly used in this analysis are mathematical programming and cost estimation. Although they are related through constraints on available procurement funds, the use of nonlinear cost learning curves, which more accurately represent system costs as a function of quantity produced, have not been incorporated into mathematical programming formulations that compute the quantities of items to be procured. As a result, the solutions obtained could be either suboptimal, or even infeasible with respect to budgetary limitations. We present a mixed integer programming formulation that uses a piecewise linear approximation of the learning curve costs for a more accurate portrayal of budgetary constraints. In addition, implementation issues are discussed, and performance results are given.

  1. Int. Symposium on Mechanics and Materials, May 9-14, 2010, Greece Fatigue Investigation of Ultrasonic Impact Treatment

    E-Print Network [OSTI]

    Aristomenis, Antoniadis

    . A calculation procedure according to the IIW guideline is brought into discussion to assess the fatigue was issued [5] and a guideline was created [6]. In the last two decades UIT has been further developed is generated by ultrasonic transducer vibrations at the rear end of a freely axially moving needle indenter

  2. Methodology for predicting torsional fatigue life of turbine generator shafts using crack initiation plus propagation. Final report

    SciTech Connect (OSTI)

    Anderson, A.F.; Williams, R.A.; Wilkening, W.W.; LeFort, P.N.

    1985-11-01T23:59:59.000Z

    An overall methodology now exists that addresses both crack initiation and propagation in predicting the fatigue life of large turbine generator shafts. It can estimate previous torsional transient damage and predict residual life. In short, this improved methodology allows utilities to determine the availability of turbogenerators with greater confidence.

  3. FATIGUE RESISTANT FIBERGLASS LAMINATES FOR WIND TURBINE BLADES (published for Wind Energy 1996, ASME, pp. 46-51)

    E-Print Network [OSTI]

    FATIGUE RESISTANT FIBERGLASS LAMINATES FOR WIND TURBINE BLADES (published for Wind Energy 1996/MSU database to lifetime prediction as described in Ref. [1]. INTRODUCTION Most U.S. fiberglass wind turbine of unidirectional (0E) and ±45 stranded fabric layers, typical blade materials, vary significantly in tensile

  4. Analytical investigation of the applicability of simplified ratchetting and creep-fatigue rules to a nozzle-to-sphere geometry

    SciTech Connect (OSTI)

    Gwaltney, R.C.

    1982-01-01T23:59:59.000Z

    This paper presents an analysis of a nozzle-to-spherical-shell attachment and explores the applicability of simplified ratchetting and creep-fatigue rules to this attachment. A five-cycle inelastic analysis and creep-fatigue damage evaluation was carried out on this component. An elastic analysis also was done to provide input parameters required to apply the various rules and procedures of simplified analysis methods. Ten lines, or critical sections, were chosen for postprocessing to determine the ratchetting strain and creep-fatigue damage at both the inside and outside surfaces. At many of the 20 surface points analyzed, the inelastic analysis results did not develop a constant or decreasing pattern for the incremental strain or damage even after 5 cycles were analyzed. Failure to develop a constant or decreasing pattern was especially prevalent for creep damage. The results of the detailed inelastic analyses at the ten critical sections are compared with the results of elastic evaluations of ratchetting and creep-fatigue damage calculated according to American Society of Mechanical Engineers Boiler and Pressure Vessel Code Case N-47-13.

  5. Enhanced fatigue and aging resistance using reactive powders in the optical fiber buffer coating V. V. Rondinella

    E-Print Network [OSTI]

    Matthewson, M. John

    Enhanced fatigue and aging resistance using reactive powders in the optical fiber buffer coating V. V. Rondinella M. J. Matthewson P. R. Foy Fiber Optic Materials Research Program, Department of small quantities of colloidal silica to the UV- curable polymer coating of fused silica optical fiber

  6. Effect of Loading Mode and Coating on Dynamic Fatigue of Optical Fiber in Two-Point Bending

    E-Print Network [OSTI]

    Matthewson, M. John

    Effect of Loading Mode and Coating on Dynamic Fatigue of Optical Fiber in Two-Point Bending Vincenzo V Rondinella*and M. John Matthewson* Fiber Optic Materials Research Program, Department of Ceramic is a useful method for investigating the mechanical properties of optical fiber and has several advantages

  7. Two-dimensional finite element simulation of fracture and fatigue behaviours of alumina microstructures for hip prosthesis

    E-Print Network [OSTI]

    Boyer, Edmond

    microstructures for hip prosthesis Kyungmok Kim¹, Bernard Forest¹, Jean Geringer¹* ¹Ecole Nationale Supérieure des and fatigue behaviours of pure alumina microstructures found at hip prosthesis. Finite element models are similar to those found at a slip zone between a femoral head and an acetabular cup of hip prosthesis

  8. Fast evaluation of the fatigue lifetime of rubber-like materials based on a heat build-up protocol and

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Fast evaluation of the fatigue lifetime of rubber-like materials based on a heat build-up protocol Cedex, France Abstract The temperature of rubber-like materials increases under cyclic loadings, due results. Key words: rubber-like materials, heat build-up, infrared thermography, X-ray micro

  9. 10.1111/j.1460-2695.2007.01143.x Fatigue crack growth of filled rubber under constant and variable

    E-Print Network [OSTI]

    Fatemi, Ali

    10.1111/j.1460-2695.2007.01143.x Fatigue crack growth of filled rubber under constant and variable Assistant at The University of Toledo, Currently at Goodyear Tire and Rubber Company, 2Professor, Mechanical Toledo, Ohio 43606, USA, 3Lead Engineer, Research Department, Cooper Tire and Rubber Company, 701 Lima

  10. F A T I G U E 2 0 0 2 HIGH-CYCLE FATIGUE OF BETA TITANIUM ALLOYS

    E-Print Network [OSTI]

    Ritchie, Robert

    F A T I G U E 2 0 0 2 HIGH-CYCLE FATIGUE OF BETA TITANIUM ALLOYS J. O. Peters*+ , G. Lütjering*, R) properties of the high-strength titanium alloys -Cez and Ti-6246 (in two distinctly different + processed and processed conditions) with the conventional + titanium alloy Ti-6Al-4V (in a + processed condition

  11. Static and Fatigue Analysis of Wind Turbine Blades Subject to Cold Weather Conditions Using Finite Element Analysis

    E-Print Network [OSTI]

    Victoria, University of

    Static and Fatigue Analysis of Wind Turbine Blades Subject to Cold Weather Conditions Using Finite Turbine Blades Subject to Cold Weather Conditions Using Finite Element Analysis by Patricio Andres Lillo experienced in candi- date Canadian wind turbine deployment locations. The thesis then narrows its focus

  12. Micromechanisms of short fatigue crack growth in an Al-Si piston alloy. T.O. Mbuya1

    E-Print Network [OSTI]

    behaviour of a model cast aluminium piston alloy has been investigated. This has been achieved using1 Micromechanisms of short fatigue crack growth in an Al-Si piston alloy. T.O. Mbuya1 , and P frequently observed. These results have been compared with the long crack growth behaviour of the alloy

  13. A Table of Areas Under Disease Progress Curves.

    E-Print Network [OSTI]

    Johnson, Dennis A.; Wilcoxson, Roy D.

    1980-01-01T23:59:59.000Z

    o n s d a r i n g t h e development o f t h e ep idemic . The v a l u e s f o r AUDPC a r e l i s t e d under t h e days between t h e o b s e r v a t i o n s o f d i s e a s e . Thus , from d i s e a s e s e v e r i t i e s t a... a i d o f t h e m o d i f i e d c o b b Scale (12). The rus t sever i tyda tawere converted Fig. 2 Disease Progress Curves of Three Winter Wheat Cultivars Infected with Puccinia recondita f. sp. tritici. - TAM W-101 - - - I 1 A 0 ~ i m e...

  14. Relativistic scaling laws for the light curve in supernovae

    E-Print Network [OSTI]

    Zaninetti, L

    2015-01-01T23:59:59.000Z

    In order to explain light curve (LC) for Supernova (SN) we derive a classical formula for the conversion of the flux of kinetic energy into radiation. We then introduce a correction for the absorption adopting an optical depth as function of the time. The developed framework allows to fit the LC of type Ia SN 2005cf ( B and V ) and type IIp SN 2004A (B,V,I and R ). A relativistic formula for the flux of kinetic energy is also derived in terms of a Taylor expansion and the application is done to the LC of GRB 050814. The decay of the radioactive isotopes as a driver the LC for SNs is also reviewed and a new formulation is introduced. The Arnett's formula for bolometric luminosity is corrected for the optical depth and applied to SN 2001ay.

  15. Periodic relativity: deflection of light, acceleration, rotation curves

    E-Print Network [OSTI]

    Vikram H. Zaveri

    2014-12-08T23:59:59.000Z

    Vectorial analysis relating to derivation of deflection of light is presented. Curvilinear acceleration is distinguished from the Newtonian polar conic acceleration. The difference between the two is due to the curvature term. Lorentz invariant expression for acceleration is derived. A physical theory of rotation curves of galaxies based on second solution to Einstein's field equation is presented. Theory is applied to Milky Way, M31, NGC3198 and Solar system. Modified Kepler's third law yields correct orbital periods of stars in a galaxy. Deviation factor in the line element of the theory happens to be the ratio of the Newtonian gravitational acceleration to the measured acceleration of the star in the galaxy. Therefore this deviation factor can replace the MOND function.

  16. Enhanced carbon-oxygen log interpretations using supplemental log curves

    SciTech Connect (OSTI)

    Wyatt, D.F. Jr.; Jacobson, L.A.; Fox, P.

    1994-12-31T23:59:59.000Z

    Supplemental measurements from induced nuclear spectrometry tools are examined to demonstrate what additional information they provide about the well and reservoir conditions. Logs in shut-in wells from Indonesia provide examples of oxygen activation measurements showing cross-flow from one reservoir to another via open perforations. Leaking squeezed perforations were also observed. An example from Alaska shows radioactive scale build-up in the casing which spectral analysis identifies as a mixture of uranium and thorium salts. Another log, where the casing fluid was replaced with crude oil, demonstrates a technique for identifying cement channels. Logs from Nigeria comparing oil saturation estimates before and after a squeeze operation illustrate the effect of casing fluid flushing of the formation through open perforations. Understanding the diagnostic character of these curves leads to higher confidence in the overall log interpretation process.

  17. Photon Green Functions in Curved Space-Time

    E-Print Network [OSTI]

    Giuseppe Bimonte; Enrico Calloni; Luciano Di Fiore; Giampiero Esposito; Leopoldo Milano; Luigi Rosa

    2005-11-23T23:59:59.000Z

    Quantization of electrodynamics in curved space-time in the Lorenz gauge and with arbitrary gauge parameter makes it necessary to study Green functions of non-minimal operators with variable coefficients. Starting from the integral representation of photon Green functions, we link them to the evaluation of integrals involving Gamma-functions. Eventually, the full asymptotic expansion of the Feynman photon Green function at small values of the world function, as well as its explicit dependence on the gauge parameter, are obtained without adding by hand a mass term to the Faddeev-Popov Lagrangian. Coincidence limits of second covariant derivatives of the associated Hadamard function are also evaluated, as a first step towards the energy-momentum tensor in the non-minimal case.

  18. Graphene: QFT in curved spacetimes close to experiments

    E-Print Network [OSTI]

    Alfredo Iorio

    2013-04-09T23:59:59.000Z

    A recently proposed step-by-step procedure, to merge the low-energy physics of the $\\pi$-bonds electrons of graphene, and quantum field theory on curved spacetimes, is recalled. The last step there is the proposal of an experiment to test a Hawking-Unruh effect, emerging from the model, that manifests itself as an exact (within the model) prediction for the electronic local density of states, in the ideal case of the graphene membrane shaped as a Beltrami pseudosphere. A discussion about one particular attempt to experimentally test the model on molecular graphene is presented, and it is taken as an excuse to solve some basic issues that will help future experiments. In particular, it is stated that the effect should be visible on generic surfaces of constant negative Gaussian curvature, that are infinite in number.

  19. Dirac Equation on a Curved 2+1 Dimensional Hypersurface

    E-Print Network [OSTI]

    Mehmet Ali Olpak

    2011-12-22T23:59:59.000Z

    Interest on 2 + 1 dimensional electron systems has increased considerably after the realization of novel properties of graphene sheets, in which the behaviour of electrons is effectively described by relativistic equations. Having this fact in mind, the following problem is studied in this work: when a spin 1/2 particle is constrained to move on a curved surface, is it possible to describe this particle without giving reference to the dimensions external to the surface? As a special case of this, a relativistic spin 1/2 particle which is constrained to move on a 2 + 1 dimensional hypersurface of the 3 + 1 dimensional Minkowskian spacetime is considered, and an effective Dirac equation for this particle is derived using the so-called thin layer method. Some of the results are compared with those obtained in a previous work by M. Burgess and B. Jensen.

  20. Fields and fluids on curved non-relativistic spacetimes

    E-Print Network [OSTI]

    Geracie, Michael; Roberts, Matthew M

    2015-01-01T23:59:59.000Z

    We consider non-relativistic curved geometries and argue that the background structure should be generalized from that considered in previous works. In this approach the derivative operator is defined by a Galilean spin connection valued in the Lie algebra of the Galilean group. This includes the usual spin connection plus an additional "boost connection" which parameterizes the freedom in the derivative operator not fixed by torsion or metric compatibility. As an example of this approach we develop the theory of non-relativistic dissipative fluids and find significant differences in both equations of motion and allowed transport coefficients from those found previously. Our approach also immediately generalizes to systems with independent mass and charge currents as would arise in multicomponent fluids. Along the way we also discuss how to write general locally Galilean invariant non-relativistic actions for multiple particle species at any order in derivatives. A detailed review of the geometry and its rela...