bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of Ductile Fracture Behavior Using GTN Model
Authors: Takazawa Hidekazu , Iwamatsu Fuminori , Miyazaki Katsumasa
Published: November 2014

Ductile fracture behavior using GTN (Gurson-Tvergaard-Needleman) model in commercial FEA code was evaluated. The material properties of the GTN model for Type 304 SS were experimentally identified. Smooth-bar and notched-bar specimens were subjected to monotonic loading by tensile test, and load-displacement curves were measured. Then, the tensile test was simulated. Material properties of the GTN model were calculated from measured and simulated load-displacement curves with inverse analysis based on Bayes’ theorem. Simulated load-displacement curves using the GTN model of different curvature notched-specimens agreed well with the measured results. To verify the evaluation of ductile fracture behavior using the GTN model, flat-plate specimen with a single surface flaw and specimen with multiple through flaws were subjected to monotonic loading. Ductile fracture of the flat-plate specimen was simulated by FEA using the GTN model using the calculated material properties. The simulated load was less than the measured load at the same displacement. The analysis using the GTN model can estimate the load on the safe side and the GTN model can conservatively simulate ductile fracture behavior.
Comparison of Peak Stress-Based and Flaw Tolerance-Based Fatigue Analysis of a Cylinder With Variable Stress Concentrations
Authors: Reinhardt Wolf , Stevens Gary L.
Published: November 2014

To show the implications of using crack growth analysis to evaluate fatigue life, the case of a cylinder with an internal notch with a varying root radius is examined. The notch radius controls the stress gradient, where a steeper stress gradient is expected to result in slower crack growth and longer fatigue life. The notch root stress is made the same between specimens of different notch radius by scaling the applied load. As a result, the conventional fatigue analysis that calculates a fatigue usage factor from a fatigue curve based on stress at a point gives identical results for all specimens. A crack growth analysis, on the other hand, gives significantly different fatigue lives for the specimens because of the different stress gradients.

On this basis of allowable fatigue life, the traditional fatigue curve-based approach is compared with the crack growth-based flaw tolerance approach. The relative conservatism of the two approaches as a function of various parameters, including stress gradient, is discussed.
Application of the Non-Cyclic Method of Shakedown Analysis to Problems With Cyclically Moving Thermal Stress
Authors: Reinhardt Wolf , Adibi-Asl Reza
Published: November 2014

The non-cyclic method of shakedown analysis allows the entire ratchet boundary to be determined for a given set of monotonic and cyclic loads on a component. The method is based on an extension of the lower bound shakedown theorem. Typically, the loading of interest to shakedown consists of cyclic thermal loading acting in conjunction with cyclic and monotonic (mean) primary loads, such as pressure.

To date, a certain class of spatially moving cyclic thermal loads could not be analyzed with numerical implementations of the non-cyclic method. In these cases, the mean thermal load cannot be balanced by a self-equilibrating stress state, and the component can ratchet under a purely thermal load. This paper examines why the restriction on the non-cyclic method and similar other approaches to shakedown analysis exists, and proposes an extension with the help of which an analysis of this class of problems becomes feasible. The method is demonstrated on a number of simple examples.
Ductile Fracture Simulation of CRIEPI STPT 410 Pipe With Circumferential Crack
Authors: Nam Hyun-Suk , Oh Young-Ryun , Han Jae-Jun , Oh Chang-Young , Kim Yun-Jae , Miura Naoki
Published: November 2014

This paper provides simulation of ductile crack growth in full-scale cracked pipe tests using an element-size dependent damage model. This method is based on the stress-modified fracture strain damage model. The stress-modified fracture strain model is determined to be incremental damage in terms of stress triaxiality and fracture strain for dimple fracture from tensile test result with FE analyses technique. To validate the proposed method, this research analyses STPT 410 cracked pipes test at 300°C taken from CRIEPI (Central Research Institute of Electric Power Industry). In order to calibrate the stress-modified fractures strain model, tensile tests and fracture toughness tests were compared with simulated results using element-size dependent damage model. Tensile specimen and fracture toughness specimen were extracted from STPT 410 steel pipe. The calibrated damage model predicts ductile crack growth in 5 type circumferential cracked pipes bending test. And these results were compared with the experimental results. The results show that the proposed method can simulate ductile crack growth in full-scale cracked pipe tests.
An Overview of Numerical Method for Fluid-Structure Interaction
Authors: Jeong J.-H. , Kim M. , Hughes P.
Published: November 2014

Fluid-structure interaction (FSI) is the interaction of some movable or deformable structure with an internal or surrounding fluid flow. Therefore, fluid-structure interaction problems are too complex to solve analytically and so they have to be analysed by means of experiments or numerical simulation.

This paper provides an overview of numerical methods for fluid-structure interaction evaluation in an draft IAEA technical guideline: large eddy simulation (LES), direct numerical simulation (DNS), Lattice-Boltzmann method (LBM), finite element method (FEM) and computational fluid dynamics (CFD) method. In addition to providing general applications of numerical methods for fluid-structure interaction evaluation, the paper also describes some cases applied for problems associated with single-phase flow and two-phase flow in nuclear power plants.
The Effect of Area on the EN13555 Stress Relaxation (PQR) Properties of an Advanced ePTFE Gasket Tape
Authors: Bissett Daniel C. , Jones Charlene
Published: November 2014

The effect of the effective area of an advanced ePTFE gasket on the EN13555[ 1 ] stress retention (PQR) properties was investigated. It was found that larger areas gave higher PQR values but the systems actually lost more force and gave lower final thickness values. This effect of higher PQR with higher force lost is explained mathematically, and the reason behind the thinner final gaskets is also explained. Further analysis shows that the force loss is linked to the ratio of effective area and stiffness, and this effect can be used to better estimate the PQR values of larger area gaskets.
Writing and Reviewing FEA Reports Supporting ASME Section VIII, Division 1 and 2 Designs: Practical Considerations and Recommended Good Practice
Authors: Seipp Trevor , Stonehouse Mark
Published: November 2014

Finite element analysis (FEA) is used, with increasing frequency, to supplement or justify the design of an ASME Section VIII, Division 1 or 2 pressure vessel. When this occurs, good engineering practice indicates that a competent engineer should review the finite element analysis report. In some jurisdictions, it is required that a Professional Engineer review and certify the report.

This paper discusses some of the practical aspects of both writing and reviewing a good quality FEA report — both in the context of the technical perspective and in the context of Code compliance. This paper will serve as a practical assistant to an engineer reviewing an FEA report, as well as a guide to an engineer preparing an FEA report. Aspects such as properly following Code requirements, following appropriate Design By Analysis methodologies, and applying good design practices will be discussed.
Application of Gurson Model to Different Constraint Specimens
Authors: Watanabe Daigo , Hojo Kiminobu
Published: November 2014

This paper introduces the application of Gurson model to simulate the ultimate ductile failure of three types of specimens with different constraints. Fracture tests were conducted using three kinds of notched round bar tensile specimens with different notch radii, a flat plate tensile specimen with a centered semielliptical surface flaw and a 1/2TCT specimen. Using the test results of the notched round bar tensile specimens, the Gurson model parameters were determined from the literatures, fracture observation and experimental design calculations. After fixing the Gurson parameters, they were applied to the flat plate tensile specimen and the 1/2TCT specimen model. As a. result Gurson model could simulate the fracture behavior of the flat plate with good accuracy, on the other hand there was a large difference with the test result of the CT specimen. In order to determine the Gurson model parameters universally and quickly, the blind optimization calculations were performed without arbitrariness. Three of five parameters were in the same order of the parameters by the 1st consideration and the others were in the different order. However the blind optimization parameters could show the similar simulation results of the fracture behaviors of the flat plate and 1TCT specimen as the 1st consideration parameters. The further investigation suggested the reason of the different behavior of the CT specimen model may be the different stress distribution, bending component dominant in the cracked ligament of the CT specimen from those of the other models. Additionally the accuracy of the local strain criteria according to ASME Sec. VIII Division 2 was confirmed.
Prediction on Initiation of Hydrogen-Induced Delayed Cracking in High-Strength Steel Based on Cohesive Zone Modeling
Authors: Wang Yanfei , Gong Jianming , Geng Luyang , Jiang Yong
Published: November 2014

This study presents prediction on initiation of hydrogen-induced delayed cracking (HIDC) in hydrogen pre-charged high-strength steel notched bars under a constant load based on hydrogen influenced cohesive zone modeling (CZM). The prediction is implemented by using a three-step sequential coupling finite element procedure including elastic-plastic stress analysis, stress-assisted hydrogen diffusion analysis and cohesive stress analysis with cohesive elements embedded along the potential crack path. Hydrogen influenced linear traction separation law is applied to the cohesive elements. The predicted initiation time of HIDC gives a good agreement with the experimental fracture time reported in a literature. The prediction reproduces the experimental trend that the critical hydrogen concentration for crack initiation is independent of the initial hydrogen concentration, while decreases with increasing load or stress concentration factor of the notch. CZM has a potential to predict HIDC of high-strength steel.
Pressure Measurements Comparison Using Transducers During Vertical Slamming Test
Authors: El Malki Alaoui Aboulghit , Nême Alain
Published: November 2014

During slamming, the ship that hits water surface may be severely damaged due to high local water impact reaction. Such an event can produce extremely large impulsive pressures in local structure areas followed by submitting the entire hull structures to whipping forces. Slamming events typically have a short duration. This paper reports a series of impact test results and investigates the slamming loads and pressures acting on a square based pyramid. In this study, slamming tests were conducted at constant impact velocity. The three selected rigid pyramid velocities are: 10, 13 and 15 m s−1. Time-histories of pressures, accelerations and slamming loads were measured. Two sensors were used to measure the pressure distribution on the pyramid surface: piezoelectric pressure sensor (PCB) and Tekscan pressure sensor. A sufficient frequency of 100 KHz was used to measure pressure peaks during slamming. Indeed the pressure sensor size and acquisition frequency affect pressure measures especially their maximal values.
Detection of Incipient SCC Damage in Primary Loop Piping Using Fiber Optic Strain Gages
Authors: Jackson Benjamin K. , Bosko David A. , Cronin Michael T. , Warwick Jonnathan L. W. , Wall James J.
Published: November 2014

Current nondestructive examination (NDE) technology detection capabilities limit our ability to detect stress corrosion cracking (SCC) damage until it has progressed significantly. This work describes the continued development of an in-situ monitoring technique to detect and characterize mechanical damage caused by SCC, allowing the detection of the incipient stages of damage to components/piping. The application of this study is to prevent failures in the primary cooling loop piping in nuclear plants. The main benefit to the industry will be improved safety and component lifetime assessment with fewer inspections.

The technique utilizes high resolution fiber optic strain gages mounted on the pipe outside diameter (OD). This technique has successfully detected changes in the residual stress profile caused by a crack propagating from the pipe inside diameter (ID). The gages have a resolution of less than 1 με. It has been shown experimentally for different crack geometries that the gages can readily detect the changes of approximately 10 to 60 με caused on the OD of the pipe due to crack initiation on the ID.

This paper focuses on the latest in the development of the technology. Details of the previous work in this effort may be found in [1–3]. A short summary is provided in this paper. The main recent development was the full scale accelerated SCC cracking in boiling magnesium chloride (MgCl2) experiment. In conjunction with experimentation, both 2D and 3D finite element (FEA) models with thermal and mechanical analyses have been developed to simulate the changes in residual stresses in a welded pipe section as a SCC crack progresses.
Analysis and Testing of a Ring-Joint Flange
Authors: Hay Clifford A. , Brown Warren
Published: November 2014

This paper presents results from analysis and testing of an NPS 20 CL600 ring-joint (RTJ) flange through assembly and a thermal cycle. Using a mock-up assembly, multiple gasket materials and types including conversion gaskets were tested to evaluate relative performance based on amount of bolt preload loss as measured through the use of load-indicating studs. To simulate field geometry, most tests included a spacer in the flange pair, which necessitated use of two (2) gaskets in the joint. ASME PCC-1-2010 [1] Appendix O calculations and finite element analysis (FEA) were also performed for comparison with the test results and for evaluation of options to improve flanged joint performance. Testing and analysis results are discussed, and learnings are documented.
Evaluation of Strength Design Criteria and Plastic Flow Criteria for Pressure Vessels
Authors: Zhu Xian-Kui
Published: November 2014

The present paper evaluates the traditional strength design criteria and recently developed plastic flow criteria used in the structural design and integrity assessment for pressure vessels. This includes (1) a brief review of the traditional strength criteria used in ASME Boiler and Pressure Vessel (B&PV) Code, (2) a discussion of the shortcoming of existing strength criteria when used to predict the burst pressure of pressure vessels, (3) an analysis of challenges, technical gaps and basic needs to improve the traditional strength design criteria, (4) a comparison of strength theory and flow theory for ductile pressure vessels, (5) an evaluation of available flow criteria and their shortcoming in prediction of failure pressure of pressure vessels, (6) an introduction of newly developed multi-axial flow criterion and its application to pressure vessels, and (7) a demonstration of experimental validations of the new flow criterion when used to predict the burst pressure of pressure vessels. On this basis, several recommendations are made for further study to improve the existing strength design and integrity assessment methods of pressure vessels.
Multi-Feeder Stress Analysis With Interlinked Spacers for a CANDU Reactor
Authors: Li Bing , Neill Dan , Vijay D. K.
Published: November 2014

In one Ontario CANDU reactor unit, the horizontal feeders are interlinked with feeder spacer rods, which are installed to prevent the contact between adjacent feeders. In the normal operating conditions, spaces do not carry any loads. Therefore, the individual feeder model is used without spacers for the horizontal feeders. This reactor unit is under extensive fuel channel shifting in order to extend the life time. The axial shifting of channels is expected to put additional loads on spacers and may constrain feeder movement. In order to determine how the spacer affects the feeder stress and feeder movement due to the extensive fuel channel shifting, multifeeder models that include spacers are created for stress analysis. Multi-feeder modelling capability is not readily available in AUTOPIPE. A novel approach of inter connecting feeders with structural elements is developed for AUTOPIPE. A significant increase in feeder stress under the extensive fuel channel shift loading condition is found when the feeder spacers are included in the model. However, the feeder stresses for Design, Level A&B loading under fuel channel shift configuration meet the ASME B&PV Code NB-3600 stress limit requirements. The feeder spacer assessment results also show that the structural integrity of feeder spacers is not affected by the fuel channel shifting. In addition, this study confirmed that it is unnecessary to release the feeder spacers to prevent spacer break or feeder overstress during the post fuel channel sifting operation, thus saving significant outage time to achieve shifting configuration.
A Framework to Develop Flaw Acceptance Criteria for Structural Integrity Assessment of Multipurpose Canisters for Extended Storage of Used Nuclear Fuel
Authors: Lam Poh-Sang , Sindelar Robert L. , Duncan Andrew J. , Adams Thad M.
Published: November 2014

A multipurpose canister (MPC) made of austenitic stainless steel is loaded with used nuclear fuel assemblies and is part of the transfer cask system to move the fuel from the spent fuel pool to prepare for storage, and is part of the storage cask system for on-site dry storage. This weld-sealed canister is also expected to be part of the transportation package following storage. The canister may be subject to service-induced degradation especially if exposed to aggressive environments during possible very long-term storage period if the permanent repository is yet to be identified and readied. Stress corrosion cracking may be initiated on the canister surface in the welds or in the heat affected zone because the construction of MPC does not require heat treatment for stress relief. An acceptance criteria methodology is being developed for flaw disposition should the crack-like defects be detected by periodic Inservice Inspection. The external loading cases include thermal accident scenarios and cask drop conditions with the contribution from the welding residual stresses. The determination of acceptable flaw size is based on the procedure to evaluate flaw stability provided by American Petroleum Institute (API) 579 Fitness-for-Service (Second Edition). The material mechanical and fracture properties for base and weld metals and the stress analysis results are obtained from the open literature such as NUREG-1864. Subcritical crack growth from stress corrosion cracking (SCC), and its impact on inspection intervals and acceptance criteria, is not addressed.
Two Axisymmetric Models Application for Fast and Conservative Analysis of Cold Plumes in RPV at PTS Condition
Authors: Batura Anatolii , Bogdan Andrii , Orynyak Igor , Radchenko Sergii
Published: November 2014

To determine reactor pressure vessel (RPV) residual lifetime as well as its brittle failure probability at pressurized thermal shock (PTS) conditions the original “indirect” solution method for the nonstationary temperature problem in axisymmetric formulation with the method of further stress calculation is developed. Both methods are based on transfer matrix approach and use exact analytical expressions for the thick-walled cylinders.

The automatic timestep determination method is implemented, which provides maximum calculation speed, but without the loss of the critical timepoints of scenarios under consideration. Also the accuracy of the model is improved by separate temperature calculations for “cold” plume and “hot” rest of the reactor, according to IEAE recommendations. At that axial strain of the “hot” part is used to load “cold” one.

The comparison of the methods with well-known theoretical results as well as with numerical tests demonstrates very high accuracy. It is proved by the methods of shell theory that possible difference with full 3D model of cylinder can’t be essential. Obtained fields of the temperature and stresses can be used for further estimation of the allowable value of the ductile-to-brittle transition temperature.
Study on Seismic Safety Improvement of Mechanical Structure in Long Duration Earthquake
Authors: Yoshida Kazuhiro , Furuya Osamu
Published: November 2014

In the Great East Japan Earthquake (GEJE), the lot of seismic damage in hanging type mechanical structure with low damping occurred by a long duration earthquake. Therefore, the industrial function stopped at many facilities. Moreover, the fall from a ceiling of a mechanical structure and the falling off of some elements in a mechanical structure were connected for outbreak of the secondary damage such as a cut of an evacuation route. This study has been carried the seismic safety improvement of mechanical structure in long duration earthquake from an analytical and experimental approach. In this paper, the fundamental experimental results of falling mechanism of hanging type mechanical structure from a ceiling is shown, and analytical results using nonlinear model with hysteresis damping is described.
Effects of Metal Thickness on Bonding Strength in Bonded Dissimilar Materials
Authors: Tateno Masayoshi , Miura Takahiro
Published: November 2014

This study provides effects of metal thickness on bonding tensile strength of ceramic to metal joint based on numerical and experimental analyses. Thermal elastoplastic FEA was carried out to clarify effects of the metal side thickness on the stress distribution near the edge of the interface on ceramic side by changing metal side thickness each bonded silicon nitride to nickel joint system. It was confirmed the stress distribution on the ceramic of the joint system depends on the metal side thickness based on the FEM results. Decreasing of metal thickness reduces the intensity of the stress near the edge of the interface on ceramics side. It can be effective for reduction of the residual stress near the edge of the interface to use thin metal layer in the ceramic to metal joint.

Reduction effects on the residual stress were confirmed by using two stages of bonding processing. This process used in this experiment consists of two stages, first bonding process as the ceramic are bonded to thin layer metal at high temperature, and secondary process as thick metal are bonded to the thin metal layer of the joint specimen at lower temperature than first stage. The bonding tensile strength of the joint specimens manufactured from the two stages bonding processe was evaluated experimentally. It appears that setting a ratio of metal thickness to length of the interface to approximate tm/W=0.08 achieves maximum bonding tensile strength. Effects of metal thickness on bonding tensile strength of ceramic to metal joint are confirmed based on numerical and experimental results.
The Effect of Flat Bar Supports on Streamwise Fluidelastic Instability in Heat Exchanger Tube Arrays
Authors: Hassan Marwan , Weaver David S.
Published: November 2014

Flow-induced vibration is an important criterion for the design of heat exchangers in nuclear, fossil and chemical plant. Of the several known vibration excitation mechanisms, fluidelastic instability (FEI) is the most serious because it can cause tube failures in a relatively short period of time. Traditionally, FEI has been observed to occur in the direction transverse to the flow and anti-vibration bars (AVB) have been used to stiffen the tubes against this motion. More recently, interest has increased in the possibility of FEI occurring in the streamwise direction, parallel to the flow. This is the subject of the present paper. Numerical simulations have been carried out to study the effects of tube-to-support clearance, tube sliding friction, tube-to-support preload, and ambient turbulence levels on the FEI threshold in the streamwise direction. As one would expect, increasing friction and tube preload against the support both tend to stabilize the tube against streamwise FEI. Importantly, the results also show that decreasing tube-support clearances destabilizes streamwise FEI while having little effect on transverse FEI. Increasing ambient turbulence levels also has the effect of destabilizing streamwise FEI.
Fatigue Damage Estimation in a Three-Dimensional Piping System Under Seismic Loadings
Authors: Shibutani Tadahiro , Nakamura Izumi , Otani Akihito
Published: November 2014

This study introduces an approach by which to estimate fatigue damage in a three-dimensional piping system under seismic loadings. A hybrid piping system simulator consisting of detailed elbow/tee models and piping line elements was constructed in order to estimate fatigue damage in the piping system. A dynamic non-linear finite element analysis with modified seismic wave inputs was carried out in order to calculate the entire strain profile of the piping system. Fatigue damage due to seismic loading was calculated by Miner’s rule since seismic wave contains several amplitudes of total strain ranges. Several tests reported in previous papers were used in order to verify the validity of the proposed approach for fatigue damage estimation.
Repair of Through-Wall Piping Defects Using Carbon Fiber Composite Repair System
Authors: Mally Timothy S. , Hawkins Amanda P. , Walker Roger H. , Keller Michael W.
Published: November 2014

Uninhibited internal corrosion can create several different types of through-wall defects in pipelines. Circular holes, axial slots, and circumferential slots are three potential leaking situations that can develop as corrosion occurs internally on different piping systems. Theoretically, each defect can be repaired by a composite repair system in accordance with design equations given in the ASME PCC-2 Article 4.1 and ISO 24817 nonmetallic repair standards, however, empirical analyses for these types of through-wall defects do not always hold true in test environments. In this work, design equations were analyzed according to ASME PCC-2 Article 4.1 and ISO 24817 for a specific carbon fiber composite repair system on specific defect sizes and configurations. Test spools of different geometries were fabricated with circular holes, axial slots, and circumferential slots of pre-determined dimensions. A carbon fiber reinforced epoxy composite system was installed and hydro-tested over the three different defect types and the results are compared to the standard design equations. It was determined that although the ASME and ISO equations were conservative enough to predict significantly lower failure pressures for these repairs, the current models can almost be considered overly conservative and not accurately modeling the actual failure mechanism occurring in these types defects repaired with composite repairs.
Advancement of Lining Inspection Technology Inside Seawater Piping
Authors: Kono Yusuke , Okimura Koji , Minamiyama Akio , Noda Masaki
Published: November 2014

Seawater piping employed for cooling of emergency diesel generator and various components at Nuclear power plant, are internally lined for protection against seawater corrosion. (Fig. 1)

However, the lining materials such as rubber or polyethylene tend to incur peel-off or crack due to aged deterioration occurred by the operation, resulting in corrosion of the piping. (Fig. 2)

Internal piping integrity of seawater piping is usually performed by periodic visual inspection. But, for the 4B to 20B pipes it has been a challenge to detect the initial degradation because the inspector cannot get into the pipes.

Pinhole detection technology that enables detection of microscopic damages and cracks is available to use as means to detect its initial state of degradation, which seems effective as preventive maintenance of the lining.

Such being the case, we are developing Seawater Piping Inside Inspection Equipment applicable to the 4B to 20B sizes of pipes by evolving the conventional pinhole detection technology.
Potential Impact of Interfacial Bonding Efficiency on Used Nuclear Fuel Vibration Integrity During Normal Transportation
Authors: Jiang Hao , Wang Jy-An John , Wang Hong
Published: November 2014

Finite element analysis (FEA) was used to investigate the impacts of interfacial bonding efficiency at pellet–pellet and pellet–clad interfaces on surrogate of used nuclear fuel (UNF) vibration integrity. The FEA simulation results were also validated and benchmarked with reversible bending fatigue test results on surrogate rods consisting of stainless steel (SS) tubes with alumina-pellet inserts. Bending moments (M) are applied to the FEA models to evaluate the system responses of the surrogate rods. From the induced curvature, κ, the flexural rigidity EI can be estimated as EI=M/κ. The impacts of interfacial bonding efficiency include the moment carrying capacity distribution between pellets and clad and cohesion influence on the flexural rigidity of the surrogate rod system. The result also indicates that the immediate consequences of interfacial de-bonding are a load carrying capacity shift from the fuel pellets to the clad and a reduction of the composite rod flexural rigidity. Therefore, the flexural rigidity of the surrogate rod and the bending moment bearing capacity between the clad and fuel pellets are strongly dependent on the efficiency of interfacial bonding at the pellet–pellet and pellet–clad interfaces. FEA models will be further used to study UNF vibration integrity.
Detection and Characterization of Corrosion Under Coatings
Authors: Stakenborghs Robert J. , Goitia Ryan M.
Published: November 2014

The annual cost of corrosion to industry exceeded the trillion dollar mark in the US for the first time. This huge cost has led to the need for new developments in corrosion detection. Early detection of corrosion can lead to substantial savings if the corrosion can be abated once detected. Until recently, coatings have hindered the detection of corrosion. This paper describes a microwave method for detecting corrosion under coatings. The paper describes the detection method and provides examples of detection sensitivities and limits.
Analysis of Crack Front Length Effect Applicable to the Evaluation of Fracture Toughness of Base Metal for PWR Pressure Vessel Steel
Authors: Joly Pierre , Benhamou Claude , Andrieu Antoine , Churier-Bossenec Henriette , Parrot Aurore
Published: November 2014

The objective of the present paper is to review the crack front length effect (also called “specimen size effect”) on Fracture Toughness of PWR Reactor Pressure Vessel Steel base metal.

The analysis of the reality and amplitude of this effect is conducted in a first step on a database (the so called “GKSS database”) including fracture toughness test results on a single representative material using specimens of different thicknesses, tested in the same temperature range. A realistic analytical form for describing the size effect observed in this data set is thus derived from statistical analyses and proposed for engineering application.

In a second step, this size effect formulation is then applied to a large number of fracture toughness data, obtained in Irradiation Surveillance Programs, and also to the numerous data used for the definition of the ASME (and RCC-M) fracture toughness reference curves.

This analysis allows normalizing all the available fracture toughness data with a single specimen width of 100 mm and defining the fracture toughness reference curve as the lower bound of this normalized set of data points. It is thus demonstrated that the fracture toughness reference curve is associated with a reference crack length of 100 mm, and can be used in RPV integrity analyses for other crack front length in association with the crack front length correction formula defined in the first step.
Microstructure and Creep Property of Long-Term Serviced Mod.9Cr-1Mo Steels After Repair Welding
Authors: Kubushiro Keiji , Saito Noriko , Nakagawa Hirokatsu , Sawada Kota , Kimura Kazuhiro
Published: November 2014

The microstructure and creep properties of the Mod.9Cr-1Mo steel of repair welds after long-term service for about 80,000 hours at around 600°C were investigated. Two types of heat affected zone (HAZ) were formed after repair welding performed at the interface between base metal and original weld metal. The first type was a HAZ formed in an ex-service original weld metal and another type was formed in an ex-service base metal. Creep rupture life of HAZ formed in an ex-service original weld metal was extremely short and it was about one fourth of that of HAZ formed in an ex-service base metal. From microstructural observation, many fine ferrite grains surrounded by carbides were present on grain boundaries and, therefore, duplex structure of ferrite and martensite was observed in the fine grain HAZ region formed in an ex-service original weld metal. These fine ferrite grains were considered to be formed by diffusion transformation of gamma phase to alpha phase instead of martensitic transformation during cooling of thermal history due to repair welding. It has been concluded that the creep strength of an ex-service weld metal is remarkably reduced by the formation of many fine ferrite grains due to repair welding.
Syringomyelia and the Fluid-Structure Interactions of a Cerebrospinal Waveguide
Authors: Elliott Novak S. J. , Lucey Anthony D. , Lockerby Duncan A. , Brodbelt Andrew R.
Published: November 2014

In the disease syringomyelia, fluid-filled cavities, called syrinxes, form in the spinal cord. The expansion of these pathological pressure vessels compresses the surrounding nerve fibers and blood supply, which is associated with neurological damage. We investigate the spinal wave-propagation characteristics, principally to serve as a reference for more anatomically-detailed models. The spinal cord is modeled as an elastic cylinder, which becomes an annulus containing inviscid fluid when a syrinx is included. This is surrounded by an annulus of inviscid fluid, representing the cerebrospinal fluid occupying the subarachnoid space, with an outer rigid boundary approximating the dura mater. The axisymmetric harmonic motion is solved as an eigenvalue problem. We present dispersion diagrams and describe the physical mechanism of each wave mode. We identify potentially damaging syrinx fluid motions and tissue stress concentrations from the eigenvectors. Finally, we determine the dependence of each wave mode on syrinx radius and cord tissue compressibility.
Reversible Bending Fatigue Testing System Design Concepts for Spent Fuel Vibration Integrity Study
Authors: Jiang Hao , Wang Jy-An John , Wang Hong
Published: November 2014

The dynamic analyses of a reversible bending fatigue testing system designed for the spent nuclear fuel (SNF) vibration integrity study was presented in this paper. Different design concepts were evaluated to assist the U-frame tester development. A finite element analysis (FEA) based on the vertical test setup was established to simulate the U-frame test system dynamic performances. The FEA results provided general guideline on predicting the dynamic behaviors of U-frame bending fatigue system for testing SNF. The initial vertical test setup design concepts were investigated in detail and the associated deficiencies were also discussed in the paper. The horizontal test setup was also evaluated using FEA. Based on dynamic analysis results, the horizontal test setup with symmetric loading profile was recommended for developing a reversible U-frame bending fatigue testing system.
Against the Odds: Community Access Radio Broadcasting during the Canterbury Earthquakes: Some reflections on Plains FM 96.9
Authors: Pauling Brian , Reece Nicki
Published: November 2014

Plains FM is a community access radio station in Christchurch, New Zealand. Access radio is a particular form of community radio that provides an alternative outlet for organisations, groups and individuals for whom traditional media outlets are difficult to access. For twenty-five years PlainsFM has provided a voice for hundreds of programme-makers, broadcasting in many different languages, offering a diversity of content that permits the public expression of a wide range of ideas, opinions and beliefs. Editorial control lies with the programme-makers, not the station management. Plains FM is the source of many interesting, often compelling, stories. In the hours after the September 2010 earthquake Plains FM was the only local radio station actually on air. This paper draws on the memories of staff, volunteers and broadcasters to consider the unique role of the station as a media outlet during and immediately after the traumatic events of September 2010 and February 2011. It also attempts to locate those stories within the concepts of civic engagement, social utility and media theory.
www.useless.com: Crisis Communications on Shaky Ground
Authors: Vavasour Kris
Published: November 2014

After the magnitude 6.3 earthquake that struck the city of Christchurch on February 22, 2011, the physical and communications infrastructure that many city dwellers rely on suddenly ceased to function. For many, this disruption to physical and virtual networks resulted in access to media, information, assistance and family being cut off or restricted in a number of different ways. Survey results show residents of the less-damaged suburbs made more use of television, websites and social media than those in badly damaged areas, who relied more on radio, word-of-mouth, and print material.Social media and new technologies are now an established part of the crisis communications discourse; however, the infrastructure they rely on is not as solid and reliable as it may appear. After exploring the concept of blackboxing, the failures and weaknesses of previously backgrounded objects exposed by the earthquakes provide examples of its undoing (un-blackboxing). Quantitative and qualitative survey data is used to show how variations in location and disruption impacted on the information-seeking of residents, and how the un-blackboxing of infrastructure and socio-technical networks left residents out of the loop. This research also challenges perceptions of how widely used, accessible and/or useful technologies like Twitter are to those in the middle of a disaster.
Introduction
Authors: Joyce Zita , Goode Luke
Published: November 2014

The last issue of New Zealand Journal of Media Studies, prior to its renaming as Media Studies Journal of Aotearoa New Zealand, focused on the national turbulence of 2011 and included reflection on the media and the earthquakes, with analysis of the immediate coverage of the 22 February disaster as a news event (Beatty 2012), and the eye-witness documentary When a City Falls (Fisher 2012, Austrin and Farnsworth 2012). By mid-2013 the earthquakes, recovery and rebuild still dominated local media in Christchurch and maintained a constant presence in national news, particularly through the advocacy journalism of Campbell Live. We felt that a journal issue dedicated to the mediation of Christchurch’s earthquakes would emphasise the extent to which the disasters still resonate, and the fact that for most New Zealanders, even many in Christchurch, the quakes and aftermath remain a primarily mediated experience.
Fabrication of antireflection structure film by roll-to-roll ultraviolet nanoimprint lithography
Authors: Moro Masatoshi , Taniguchi Jun , Hiwasa Shin
Published: November 2014

Antireflection (AR) films are useful in preventing the reflection of light from the displays of mobile phones and tablet computers. In particular, films with an AR structure known as the moth-eye structure show excellent performance in preventing light reflection. In a previous study, the authors reported the fabrication of an AR structure by oxygen ion-beam irradiation of glassy carbon (GC). The fabricated pattern consisted of a series of self-assembled conical structures and it had a low-reflection surface. In this study, the authors transferred this AR structure onto a polymer film by roll-to-roll ultraviolet nanoimprint lithography using a replica mold produced from a GC master mold with the AR structure. As a result, the authors were able to produce high-performance AR film at a feed rate of 1.8 m/min. The reflectivity of the film was about 0.1% and its transmittance was about 95% at visible wavelengths.
In situ photoluminescence system for studying surface passivation in silicon heterojunction solar cells
Authors: Abolmasov Sergey N. , Cabarrocas Pere Roca i
Published: November 2014

An in situ photoluminescence (PL) system for studying the influence of process parameters on surface passivation of crystalline Si wafers during the PECVD growth of a-Si:H and its alloys is described. By monitoring the intensity of silicon interband PL, information on surface passivation can be correlated directly with processing conditions. The sensitivity of in situ PL in assessing of surface passivation is compared to that of lifetime measurements taken by a Sinton WCT-100 tester. This work demonstrates that in situ PL is a promising approach for obtaining fundamental information on surface passivation processes that have technological importance for the development of silicon heterojunction solar cells.
Ureter tracking and segmentation in CT urography (CTU) using COMPASS
Authors: Hadjiiski Lubomir , Zick David , Chan Heang‐Ping , Cohan Richard H. , Caoili Elaine M. , Cha Kenny , Zhou Chuan , Wei Jun
Published: November 2014

Purpose:

The authors are developing a computerized system for automated segmentation of ureters in CTU, referred to as combined model‐guided path‐finding analysis and segmentation system (COMPASS). Ureter segmentation is a critical component for computer‐aided diagnosis of ureter cancer.

Methods:

COMPASS consists of three stages: (1) rule‐based adaptive thresholding and region growing, (2) path‐finding and propagation, and (3) edge profile extraction and feature analysis. With institutional review board approval, 79 CTU scans performed with intravenous (IV) contrast material enhancement were collected retrospectively from 79 patient files. One hundred twenty‐four ureters were selected from the 79 CTU volumes. On average, the ureters spanned 283 computed tomography slices (range: 116–399, median: 301). More than half of the ureters contained malignant or benign lesions and some had ureter wall thickening due to malignancy. A starting point for each of the 124 ureters was identified manually to initialize the tracking by COMPASS. In addition, the centerline of each ureter was manually marked and used as reference standard for evaluation of tracking performance. The performance of COMPASS was quantitatively assessed by estimating the percentage of the length that was successfully tracked and segmented for each ureter and by estimating the average distance and the average maximum distance between the computer and the manually tracked centerlines.

Results:

Of the 124 ureters, 120 (97%) were segmented completely (100%), 121 (98%) were segmented through at least 70%, and 123 (99%) were segmented through at least 50% of its length. In comparison, using our previous method, 85 (69%) ureters were segmented completely (100%), 100 (81%) were segmented through at least 70%, and 107 (86%) were segmented at least 50% of its length. With COMPASS, the average distance between the computer and the manually generated centerlines is 0.54 mm, and the average maximum distance is 2.02 mm. With our previous method, the average distance between the centerlines was 0.80 mm, and the average maximum distance was 3.38 mm. The improvements in the ureteral tracking length and both distance measures were statistically significant (p < 0.0001).

Conclusions:

COMPASS improved significantly the ureter tracking, including regions across ureter lesions, wall thickening, and the narrowing of the lumen.
Neuromuscular and Perceptual Fatigue Responses to Consecutive Tag Football Matches
Authors: Hogarth Luke W. , Burkett Brendan J. , McKean Mark R.
Published: November 2014

Purpose:

To examine the neuromuscular and perceptual fatigue responses to consecutive tag football matches played on the same day and determine the relationship between fatigue and match running performance.

Methods:

Neuromuscular and perceptual fatigue responses of 15 national tag football players were assessed before and during the 2014 State of Origin tournament. Global positioning systems (GPS) provided data on players’ match running performance, and a vertical-jump test and subjective questionnaire were used to assess players’ neuromuscular and perceptual fatigue, respectively.

Results:

There were small to moderate reductions in the majority of match-running-performance variables over consecutive matches, including distance (ES = −0.81), high-speed-running (HSR) distance (ES = −0.51), HSR efforts (ES = −0.64), and maximal accelerations (ES = −0.76). Prematch vertical jump was initially below baseline values before the first match (ES = 0.68−0.88). There were no substantial reductions in vertical-jump performance from baseline values over consecutive matches, although there was a small decline from after match 2 to after match 3 (3.3%; ES = −0.45 ± 0.62). There were progressive reductions in perceived well-being scores after matches 1 (ES = −0.38), 2 (ES = −0.70), and 3 (ES = −1.14). There were small to moderate associations between changes in fatigue measures and match running performance.

Conclusions:

Perceptual fatigue accumulates over consecutive tag football matches, although there were only marginal increases in neuromuscular fatigue. However, both neuromuscular and perceptual fatigue measures were found to contribute to reduced match running performance in the final match.
Combined inhibition of PI3Kβ and PI3Kγ reduces fat mass by enhancing α-MSH–dependent sympathetic drive
Authors: Perino Alessia , Beretta Martina , Kilić Ana , Ghigo Alessandra , Carnevale Daniela , Repetto Ivan Enrico , Braccini Laura , Longo Dario , Liebig-Gonglach Michaela , Zaglia Tania , Iacobucci Roberta , Mongillo Marco , Wetzker Reinhard , Bauer Michael , Aime Silvio , Vercelli Alessandro , Lembo Giuseppe , Pfeifer Alexander , Hirsch Emilio
Published: November 2014

Blocking the activity of two PI3K isoforms in the brain may be a strategy for treating obesity.
In Vivo
Selection of Plasmodium falciparum
Pfcrt
and
Pfmdr1
Variants by Artemether-Lumefantrine and Dihydroartemisinin-Piperaquine in Burkina Faso
Authors: Baraka Vito , Tinto Halidou , Valea Innocent , Fitzhenry Robert , Delgado-Ratto Christopher , Mbonye Martin K. , Van Overmeir Chantal , Rosanas-Urgell Anna , Van geertruyden Jean-Pierre , D'Alessandro Umberto , Erhart Annette
Published: November 2014

Plasmodium falciparum
Pfcrt
-76 and
Pfmdr
1-86 gene polymorphisms were determined during a clinical trial in Burkina Faso comparing the efficacies of dihydroartemisinin-piperaquine (DHA-PPQ) and artemether-lumefantrine (AL). Significant selection of
Pfcrt
-K76 was observed after exposure to AL and DHA-PPQ, as well as selection of
Pfmdr
1-N86 after AL but not DHA-PPQ treatment, suggesting reverse selection on the
Pfcrt
gene by PPQ. These results support the rational use of DHA-PPQ in settings where chloroquine (CQ) resistance is high.