bluuebunny/crossref_metadata_2025 huggingface dataset:
Differential attraction of parasitoids in relation to specificity of kairomones from herbivores and their by‐products
Authors: Afsheen Sumera , Wang Xia , Li Ran , Zhu Chuan‐Shu , Lou Yong‐Gen
Published: October 2008

Infochemicals are used by foraging parasitoids in the host selection process from habitat preference until host recognition. Kairomones from the herbivore host plays a vital role in the attraction of parasitoids, particularly in the micro‐habitat. Parasitoids are specifically attracted to their respective herbivore species even when different herbivores are present on the same plant. Chemicals emitted from different stages of host (eggs, larvae, pupae, adult), host by‐products (e.g., frass, exuviae, mandibular gland secretions, defense secretions etc.), or intra‐specific infochemicals (pheromones) can be main signals for the parasitoids. Parasitoids can differentiate between host and non‐host, between different hosts and host stages by perceiving specific volatile and contact kairomones from the host itself, host along with its by‐product, by‐products alone or intra‐specific infochemicals; of which frass (by‐product) and intra‐specific infochemicals are the most reported ones. Adult and larval parasitoids have been reported to be attracted to kairomones of their target stage or byproduct of their host. Pupal parasitoids have been found to utilize kairomones from the preceding host stage while egg parasitoids are known to exploit a variety of host infochemicals, for example, either from eggs themselves or other non‐target host stages, especially adults and adult‐related by‐products. The kairomonal chemicals identified so far include various groups, but mainly hydrocarbons. A high degree of host specificity and host acceptance is important for the parasitoids as any mistake may result in the loss of fitness.
Reference genes identified in the silkworm Bombyx mori during metamorphism based on oligonucleotide microarray and confirmed by qRT‐PCR
Authors: Wang Gen‐Hong , Xia Qing‐You , Cheng Dao‐Jun , Duan Jun , Zhao Ping , Chen Jie , Zhu Li
Published: October 2008

Gene expression quantification at mRNA level is very important for post‐genomic studies, as gene expression level is the reflection of the special biological function of the target gene. Methods used for gene expression quantification, such as microarray or quantitative real‐time polymerase chain reaction (qRT‐PCR), require stable expressed reference genes. Thus, finding suitable control genes is essential for gene quantification. In this study, a genome‐wide survey of reference genes during metamorphism was performed on silkworm Bombyx mori. Twelve genes were chosen as putative reference genes based on a whole genome oligonucleotide microarray normalized by external controls. Then, qRT‐PCR was employed for further validation and selection of potential reference gene candidates. The results were analyzed, and stable genes were selected using geNorm 3.4 and NormFinder software. Finally, considering factors from every aspect, translation initiation factor 4A, translation initiation factor 3 subunit 4, and translation initiation factor 3 subunit 5 (represented by sw22934, swl4876, and swl3956) were selected as reliable internal controls across the examined developmental stages, while cytoplasmic actin (sw22671), the commonly used reference gene in a previous study was shown to vary drastically throughout the examined developmental stages. For future research, we recommend the use of the geometric mean of those three stable reference genes as an accurate normalization factor for data normalization of different developmental stages during metamorphism.
How to Break the Deadlock Preventing a Fair and Rational Use of Biodiversity
Authors: Straus Joseph
Published: October 2008

Sixteen years after the adoption of the Convention on Biological Diversity (CBD), the hopes in successful exploitation of genetic resources for the benefit of biodiversity‐rich host countries, as well as of humanity at large, have not materialized. Instead of aiming all efforts at achieving “the conservation of biological diversity, the sustainable use of its components and the fair and equitable sharing of the benefits arising out of the utilization of genetic resources”, the defined objectives of the CBD, based on the logical pattern that benefit sharing presupposes a generation of benefits, which in turn presupposes successful utilization of genetic resources, the international debate is captured by more or less politicized and fruitless debates as to how to anchor internationally in patent law a requirement of indication of origin of biological material.

Here some reflections on the recent negotiations within the World Trade Organization and the World Intellectual Property Organization are offered. However, the main focus is on national access and benefit‐sharing legislation of some biodiversity‐rich countries, which although is the key for achieving the CBD objectives, has not been paid the attention it necessitates. Based on a catalogue of questions of high practical importance, laws of Brazil, India, Peru, the Philippines, South Africa and some other countries are examined and suggestions made as to how to overcome the overall detrimental existing deadlock.
What are the implications of the new UK age discrimination legislation for research and practice?
Authors: Coupland Christine , Tempest Sue , Barnatt Christopher
Published: October 2008

Forthcoming changing demographics and the introduction of the relatively recent UK age discrimination legislation make it timely to consider some of the debates around the relevance of age to work. Issues surrounding ageing have been considered from within a number of disciplines and research perspectives which have led to some questioning of the dominant economic model that pivots on chronological age as a convenient, bureaucratic, measure that proxies for ability. The role of the HR practitioner in being able to redefine expectations throughout the lifespan of employees is considered while constraints to managing for the longer term are acknowledged. It is proposed that although the legislation will affect some age‐related practices positively, there are likely to be unintended consequences that single out particular age groups as special cases and therefore make age more relevant to the work relationship.
Workplace bullying and intention to leave: the moderating effect of perceived organisational support
Authors: Djurkovic Nikola , McCormack Darcy , Casimir Gian
Published: October 2008

This study examined whether perceived organisational support (POS) moderates the relationship between workplace bullying and victims’ intention to leave. Based on data from 335 schoolteachers, a hierarchical regression analysis using the product term revealed that POS moderates the effects of bullying on intention to leave. Furthermore, a series of univariate regression analyses revealed that the effects of bullying on intention to leave were significant with lower levels of POS but were non‐significant with higher levels of POS. Several implications for future research and policy are drawn from the findings.
Effects of Calcium Channel Blockers on Proteinuria in Patients With Diabetic Nephropathy
Authors: Toto Robert D. , Tian Min , Fakouhi Kaffa , Champion Annette , Bacher Peter
Published: October 2008

Diabetic nephropathy management should include the use of an angiotensin‐converting enzyme inhibitor (ACEI) or an angiotensin receptor blocker with additional antihypertensive medications to reduce proteinuria and cardiovascular events. Some studies suggest that adding a nondihydropyridine rather than a dihydropyridine calcium channel blocker (CCB) may more effectively lower proteinuria. We hypothesized that a trandolapril/verapamil SR (T/V) fixed‐dose combination (FDC) was superior to a benazepril/amlodipine (B/A) FDC for reducing albuminuria in 304 hypertensive diabetic nephropathy patients when treated for 36 weeks. No statistically significant differences were observed between groups in the primary end point; adjusted percentage change in urinary albumin/creatinine ratio (UACR), which increased (mean T/V, 29.29%; mean B/A, 8.49%; difference, 20.80%; P=.34); or in change in absolute UACR, which decreased (mean [g/g] T/V, −0.11; mean [g/g] B/A, −0.08; difference −0.03; P=.78). There were significant reductions in log UACR (mean change in T/V, −0.28; P<.01; mean change in B/A, −0.31; P<.001) and diastolic blood pressure in both groups and in systolic blood pressure in the B/A group. T/V was not superior to B/A for reducing UACR. Both ACEI/CCB FDCs may reduce albuminuria; in the case of T/V, this appears to be independent of systolic blood pressure reduction in patients who had previously been treated and had baseline blood pressure levels of 142/77 mm Hg.
Efficacy, Safety, and Pharmacokinetics of Candesartan Cilexetil in Hypertensive Children Aged 6 to 17 Years
Authors: Trachtman Howard , Hainer James W. , Sugg Jennifer , Teng Renli , Sorof Jonathan M. , Radcliffe Jerilynn ,   Candesartan in Children with Hypertension (CINCH) Investigators
Published: October 2008

This 4‐week randomized, double blind, placebo‐controlled study (N=240), 1‐year open label trial (N=233), and single‐dose pharmacokinetic study (N=22) evaluated candesartan cilexetil (3 doses) in hypertensive children aged 6 to 17 years. Seventy‐one percent were 12 years of age or older, 71% were male, and 47% were black. Systolic (SBP)/diastolic (DBP) blood pressure declined 8.6/4.8–11.2/8.0 mm Hg with candesartan and 3.7/1.8 mm Hg with placebo (P<.01 compared to placebo for SBP and for the mid and high doses for DBP; placebo‐corrected 4.9/3.0–7.5/6.2 mm Hg). The slopes for dose were not, however, different from zero (P>.05). The response rate (SBP and DBP <95th percentile) after 1 year was 53%. The pharmacokinetic profiles in 6‐ to 12‐ and 12‐ to 17‐year‐olds were similar and were comparable to adults. Eight candesartan patients discontinued treatment because of an adverse event. Candesartan is an effective, well‐tolerated antihypertensive agent for children aged 6 to 17 years and has a pharmacokinetic profile that is similar to that in adults.
New Common Design Rules for U-Tube Heat Exchangers in ASME, CODAP and UPV Codes
Authors: Osweiller F.
Published: October 2008

In year 2000, ASME Code (Section VIII – Div. 1), CODAP (French Code) and UPV (European Code for Unfired Pressure Vessels) have adopted the same rules for the design of U-tube tubesheet heat exchangers. Three different rules are proposed, based on different technical basis, to cover: • Tubesheet gasketed with shell and channel. • Tubesheet integral with shell and channel. • Tubesheet integral with shell and gasketed with channel or the reverse. At the initiative of the author, a more refined technical approach has been developed, to cover all tubesheet configurations. The paper explains the rationale for this new design rule which is being incorporated in ASME, CODAP and UPV in 2002. This is substantiated with comparisons to TEMA Standards and a benchmark of numerical comparisons.
Finite Element Analysis and Design of a Horizontal Tank on Saddle Supports
Authors: Birhane Afewerki H. , Hari Yogeshwar
Published: October 2008

The objective of this paper is to design and analyze a horizontal tank on saddle supports. The horizontal vessel is to store various chemicals used in today’s industry. The over all dimensions of the horizontal vessel are determined from the capacity of the stored chemicals. These dimensions are first determined. The design function is performed using the ASME Code Sec VIII Div 1. The horizontal tank design is broken up into (a) shell design, (b) two elliptical heads and (c) two saddle supports. The designed dimensions are used to recalculate the stresses for the horizontal vessel. The dimensioned horizontal vessel with saddle supports and the saddle support structure is modeled using STAAD III finite element software. The stresses from the finite element software are compared with the stresses obtained from calculated stresses by ASME Code Sec VIII Div 1 and L. P. Zick’s analysis printed in 1951. The difference in the stress value is explained. This paper’s main objective is to compare the code design to the finite element analysis. The design is found to be safe for the specific configuration considered.
Limit Load Analysis of API 620 Tank Roof-Shell Junction
Authors: Rana Mahendra D. , Bergsten Victor E. , Hari Yogeshwar
Published: October 2008

The compression ring at a tank’s roof-shell junction has been designed using the API 620 [1] rules. The geometrical configuration of the ring is non-conventional compared to the typical shapes recommended in API 620. In order to verify the structural integrity of the roof-shell junction, a plastic FEA was conducted to establish the maximum allowable working pressure (MAWP) using a limit load analysis procedure. The FEA results indicated that the tank’s roof-shell junction’s MAWP is 18.7 psi which exceeds the calculated MAWP of 15 psi using the API 620 rules. This paper presents the comparisons of the MAWPs calculated using the API 620 rules and the plastic FEA.
Identification and Resolution of Piping Analysis Activities for Extended Power Uprates at Nuclear Plants
Authors: Bhavnani Dilip
Published: October 2008

Recent experience has shown that many utilities have installed new feedwater flow measurement instrumentation, which is designed with new, proven technology that more accurately monitors feedwater flow and therefore, allows for improved thermal power level calculations. As a result of this new approach, many utilities have been able to extend limited power upgrades to the tune of 1.4%, and yet with no noticeable additional environmental impact. These electric power increases are generally attributable to the large design margins included in the original nuclear power plant designs and in addition, to the technological advances that have been made to the nuclear industry. Power increases are now carried out by several nuclear utilities in the United States with the NRC’s concurrence. Current nuclear power plants are providing cheap, reliable and affordable electricity to help meet current energy growing demands. As a result of this, power uprate increases are encouraged. Current economic conditions strongly favor power uprates and plant life extensions. In the early 1990s, a limited power uprate program was initiated, but due to complex design reviews, this was not steadfastedly recommended during this time period. Nuclear Steam Supply Systems (NSSS) vendors performed a key role in this nuclear power uprate program. This paper discusses structural and piping qualification review required to achieve these power uprate programs, currently being performed by nuclear utilities in the United States.
Technical Basis for the Incorporation of a Fatigue Crack Growth Threshold Limit Into Appendix A to Section XI
Authors: Friedman Edward , Cipolla Russell C. , Bloom Joseph M.
Published: October 2008

A recent revision to A-4300 of Appendix A to Section XI of the ASME Boiler and Pressure Vessel Code specifies a limiting threshold value of the stress intensity factor range below which crack propagation under cyclic loading can be neglected. The threshold value decreases with increasing R ratio, where R is defined as the ratio of the minimum to the maximum stress intensity factor. This paper reviews the crack closure phenomenon that is the underlying reason for this effect, summarizes the low-alloy pressure vessel steel test data upon which the threshold limit is based, and proposes an empirical equation for the threshold stress intensity factor range that is a reasonably conservative limit. The threshold equation incorporated into Appendix A will also replace the more restrictive threshold formula currently in Code Case N-643.
Simulation of Excessive Deformation of Piping Due to Seismic and Weight Loads
Authors: Fujiwaka Tatsuya , Kobayashi Hiroe , Asada Yasuhide , Shitara Chikashi
Published: October 2008

The ASME Code for seismic design of piping system was revised in 1994 based on evaluation of pipe component test results submitted by the Piping and Fitting Dynamic Reliability Program (PFDRP). PFDRP indicated piping component failure to result in most cases from fatigue with ratchet. Excessive progressive deformation was noted by this program to ultimately occur in test #37, #39 and #40 piping models. This mode of failure was considered due to superposition of bending moment arising from vertical load produced by weight and horizontal seismic inertia force. To clarify the conditions leading to such failure, elastic-plastic dynamic analysis using the general-purpose FEM Code was carried out on the test#37 piping model of PFDRP. The analytical model and method were verified as effective means of study by comparison of analytical results with those obtained experimentally. The parameter determinations were made under condition of variation in dead weight stress and excitation and its dominant frequency. 1994 ASME seismic stress limits were shown effective for preventing excessive progressive deformation in tests #37, #39 and #40.
Margins for ASME Code Fatigue Design Curve: Effects of Surface Finish and Material Variability
Authors: Chopra O. K. , Shack W. J.
Published: October 2008

The ASME Boiler and Pressure Vessel Code provides rules for the construction of nuclear power plant components. This Code specifies fatigue design curves for structural materials. However, the effects of light water reactor (LWR) coolant environments are not explicitly addressed by the Code design curves. Existing fatigue strain-vs.-life (ε-N) data illustrate potentially significant effects of LWR coolant environments on the fatigue resistance of pressure vessel and piping steels. This report provides an overview of the existing fatigue ε-N data for carbon and low-alloy steels and wrought and cast austenitic SSs to define the effects of key material, loading, and environmental parameters on the fatigue lives of the steels. Experimental data are presented on the effects of surface roughness on the fatigue life of these steels in air and LWR environments. Statistical models are presented for estimating the fatigue ε-N curves as a function of the material, loading, and environmental parameters. Two methods for incorporating environmental effects into the ASME Code fatigue evaluations are discussed. Data available in the literature have been reviewed to evaluate the conservatism in the existing ASME Code fatigue evaluations. A critical review of the margins for the ASME Code fatigue design curve is presented.
Status and Future of NDE in Section XI
Authors: Spanner Jack
Published: October 2008

This paper discusses the current status of NDE requirements in Section XI and future directions. The Code is well on its way migrating towards performance-based requirements in contrast to the traditional prescriptive requirements. The requirements for ultrasonic examination performance demonstration are contained in Appendix VIII and this has had a significant impact on the nuclear industry. The question arises as to the necessity and value of imposing performance demonstration requirements on the less technically demanding surface examination methods such as magnetic particle and liquid Penetrant examination methods. The impact of risk informed inspection and license renewal on NDE should be evaluated in the near future. Finally, the trend towards developing performance based NDE personnel certification requirements will be described.
Section XI: Responding to Inservice Inspection Findings
Authors: Bamford Warren
Published: October 2008

As plants continue to age, modes of degradation are found that had not been anticipated as part of the design process. One of the most important modes of degradation found recently has been stress corrosion cracking. This presentation will deal with three examples of such cracking for which acceptance criteria and evaluation methodology are being developed for Section XI. These three include: • Class 1 piping; • Reactor Vessel Head Penetration Cracking (PWR only); • Low Energy Piping, Vessels and Tanks.
Significant Changes in the ASME Section XI Requirements for Repair/Replacement Activities
Authors: Swayne Richard W.
Published: October 2008

In the last ten years, there have been a lot of changes in the Section XI requirements for Repair/Replacement Activities. This paper will discuss the most significant of those changes, as well as of the changes currently being discussed in the Subgroup on Repair/Replacement Activities of the Subcommittee on Nuclear Inservice Inspection.
Terrorism Risk Models: The Need for Common Measures
Authors: Feigel Richard E.
Published: October 2008

From the hot dog vendor located near a national monument to a multinational corporation with operations and significant assets around the world, we are all faced with decisions about addressing terrorism. Since the events of 9/11, enormous amounts of financial and intellectual capital have been invested to develop security responses to potential terrorism threats. Beyond specific, focused initiatives — most visibly increased airport security — a plethora of risk models have been (or are being) developed. Ostensibly, these models attempt to address the basic risk proposition: Risk = Frequency * Severity.
Pump Start Transients in Closed Loop System Solved With Restriction Orifices
Authors: Van Duyne Daniel A. , Semprucci Lenin B. , Jaycox Nathan
Published: October 2008

Pressure spikes following pump start in a closed loop system at Millstone Unit 2, caused thermal relief valve lifting, and two remained partially open, draining 40 gpm (2.5 L/s). Entrapped air following maintenance activities caused these pressure spikes. Proposed solutions included changing pump impellers, removing all thermal relief valves, and vacuum filling the system. Altran proposed installing orifice plates as flow restrictors in the 8” (203 mm) lines from the surge tank. These flow restrictors reduced the collapse rate of the captive gas pockets and thus reduced the associated pressure spikes following pump start which was confirmed by tests performed in March, 2002.
An Unsteady Analysis on Thermal Stratification in the SCS Piping Branched Off the RCS Piping
Authors: Kim Kwang-Chu , Park Man-Heung , Youm Hag-Ki , Lee Sun-Ki , Kim Tae-Ryong , Yoon Jun-Kyu
Published: October 2008

A numerical study is performed to estimate on an unsteady thermal stratification phenomenon in the Shutdown Cooling System (SCS) piping branched off the Reactor Coolant System (RCS) piping of Nuclear Power Plant. In the results, turbulent penetration reaches to the 1st isolation valve. At 500sec, the maximum temperature difference between top and bottom inner wall in piping is observed at the starting point of horizontal piping passing elbow. The temperature of coolant in the rear side of the 1st isolation valve disk is very slowly increased and the inflection point in temperature difference curve for time is observed at 2700sec. At the beginning of turbulent penetration from RCS piping, the fast inflow generates the higher temperature for the inner wall than the outer wall in the SCS piping. In the case the hot-leg injection piping and the drain piping are connected to the SCS piping, the effect of thermal stratification in the SCS piping is decreased due to an increase of heat loss compared with no connection case. The hot-leg injection piping affected by turbulent penetration from the SCS piping has a severe temperature difference that exceeds criterion temperature stated in reference. But the drain piping located in the rear compared with the hot-leg injection piping shows a tiny temperature difference. In a viewpoint of designer, for the purpose of decreasing the thermal stratification effect, it is necessary to increase the length of vertical piping in the SCS piping, and to move the position of the hot-leg injection piping backward.
A Boundary Element Method for the Conjugate Heat Transfer Problem of Thermally Developing Laminar Flow in a Pipe
Authors: Choi Chang-Yong , Jo Jong Chull , Kim Hho Jung
Published: October 2008

This paper presents a sole application of boundary element method to the conjugate heat transfer problem of thermally developing laminar flow in a thick walled pipe when the fluid velocities are fully developed. Due to the coupled mechanism of heat conduction in the solid region and heat convection in the fluid region, two separate solutions in the solid and fluid regions are sought to match the solid-fluid interface continuity condition. In this method, the dual reciprocity boundary element method (DRBEM) with the axial direction marching scheme is used to solve the heat convection problem and the conventional boundary element method (BEM) of axisymmetric model is applied to solve the heat conduction problem. An iterative and numerically stable BEM solution algorithm is presented, which uses the coupled interface conditions instead of the uncoupled ones. Both the local convective heat transfer coefficient at solid-fluid interface and the local mean fluid temperature are initially guessed and updated as the unknown interface thermal conditions in the iterative solution procedure. Two examples imposing uniform temperature and heat flux boundary conditions are tested and compared with analytic solutions where available. The benchmark test results are shown to be in good agreement with the analytic solutions for both examples with different boundary conditions.
Response of AISC Steel Column Sections to Blast Loading
Authors: Lawver Darell , Daddazio Raymond , Vaughan David , Stanley Michael , Levine Howard
Published: October 2008

One dozen American Institute of Steel Construction (AISC) W14 steel columns were tested at the Energetic Materials Research and Testing Center (EMRTC), New Mexico Institute of Mining and Technology in Socorro, New Mexico with loading from typical size vehicle bomb threats at very close to moderately close standoffs. Pretest predictions of structural response were performed using standard SDOF methods and the Weidlinger Associates, Inc. (WAI) FLEX finite element code. Loads acting on the columns were determined from the U. S. Army developed CONWEP code using the Kingery-Bulmash equations for the pretest predictions. Seven tests included individual columns with axial loading and blast loading applied simulataneously. One test included 5 columns built into a frame with moment connections at the top of the columns and base plate connections at the base of the columns. The columns were instrumented with accelerometers and pressure transducers. The tests were designed to produce various levels of damage from mild to severe. This paper will compare the pretest and posttest predictions using both the SDOF and FLEX finite element methods with the actual test results. The comparison between actual loading and CONWEP loading will also be discussed. Conclusions will be drawn with regard to the use of CONWEP loading for this type of threat at various standoffs. Also, the use of SDOF and FLEX finite element methods to predict the response of AISC W14 steel columns will be compared.
A Critical Examination of Sachs’ Material-Removal Method for Determination of Residual Stress
Authors: Parker Anthony P.
Published: October 2008

Sachs’ method is an experimental procedure used primarily in the determination of residual stresses in autofrettaged thick cylinders. In its usual form it involves fixing axial and hoop direction strain gauges to the OD of a tube; strain readings are then obtained after each incremental removal of material from the bore. Sachs’ analysis assumes that the remaining tube unloads in linear-elastic fashion throughout the process and that superposition may therefore be employed to quantify the residual stresses within the original tube. By numerical simulation of two complete Sachs’ experimental sequences with ‘open end’ conditions it is demonstrated that the assumption of elastic unloading is invalidated by the Bauschinger effect. Sachs’ method thereby overestimates compressive residual bore hoop stresses in a typical tube by between 24% and 43%. If used as the basis for cyclic pressurization fatigue lifetime predictions with pre-existing cracks, such discrepancies will cause overestimates in fatigue lifetime of an order of magnitude. Sachs’ experimental procedure is therefore not recommended as a reliable or conservative method for determination of residual stress.
Stress Intensity Correction Factors for Radial-Longitudinal Surface Cracks in Thick-Walled Cylinders
Authors: Kiciak A. , Burns D. J. , Glinka G.
Published: October 2008

Section XI and Appendix D of Section VIII, Div. 3 of the ASME Code include an influence coefficients method for calculating Mode I crack tip stress intensity factors, K1. When outlining the technical basis for this method, Cippola mentions that the fiee surface correction factors G0, G1, G2 and G3, that are tabulated for uniform, linear, quadratic and cubic stress variations, respectively, were derived using Shen and Glinka’s weight functions for surface cracks in plates. In the interim, the authors and colleagues have extended the validity range of their weight functions for cracks in plates and developed solutions for internal or external cracks in thin- or thick-walled vessels. This paper is a comprehensive comparison of correction factors, Gi, obtained from weight functions for an edge or surface semi-elliptic crack in a plate with those obtained for a radial-longitudinal edge or surface semi-elliptic crack in a cylinder. The differences, which in some cases are large, and the well know uncertainties when calculating K1 for the surface points of cracks are discussed.
Lessons Learned From a Vessel Explosion Caused by Human Error
Authors: Perez E. H. , Dixon R. D.
Published: October 2008

The object of this paper is to describe the details of a vessel explosion caused by human error, the incident investigation including engineering analysis of the explosion observations, and the recommended changes that were implemented to avoid a similar incident in the future. Fortunately, this incident did not cause any personal injuries. Stress analysis of the Breech Nut threads was performed to determine if the Breech Nut could be safely used after the incident. Released energy and missile analyses were performed to verify the assumptions made on the source of the explosion.
A New Approach to Reducing the Stress Concentration Factors of Cross-Bores in Blocks Under High Pressure
Authors: Sahney Mira K.
Published: October 2008

The fundamental design of high pressure joints such as crosses and tees has remained the same for many years. However, the introduction of commercially available high pressure equipment operating at 600 MPa and higher has demanded improved designs for these classic connections. This study presents a new design concept for reducing the stress concentration at intersecting crossbores. Both the finite element analysis and the fatigue test results from the standard high pressure design and the new design are compared. The new approach realizes a 17–25% reduction in the stress concentration factors and a 40% improvement in fatigue life test results when compared to the standard design.
Advanced Ultrasonic Techniques in Pipeline Girth Welds Examination
Authors: Cataldo Giuseppina , Legori Roberto
Published: October 2008

Installation of pipelines onboard a lay-barge requires rapid inspection and judgement of all girth welds prior to leaving the vessel. Furthermore, the new philosophy of Engineering Critical Assessment (ECA) based on the principles of fracture mechanics to assess the severity of a defect on its vertical extent requires the application of an inspection system able to accurately assess height, length and through thickness location of the defect in order to reducing the number of unnecessary repairs. Automated Ultrasonic Testing (AUT) is rapidly replacing radiography as standard method of inspecting pipeline girth welds, reducing pipeline costs through increased productivity and avoiding the radiation hazard and the chemical waste of the film processing. This paper describes SAIPEM experience with the new Phased Array AUT technology carried out on several projects, particularly with reference to the ultra-deep water Blue Stream Project, which required an extensive qualification of the AUT System in accordance to DNV Rules [1,2].
A Novel Technique With a Magnetostrictive Transducer for In Situ Length Monitoring of a Distant Specimen
Authors: Pedrick Michael , Heckman Michael , Tittmann B. R.
Published: October 2008

A Magnetostrictive sensor was used to generate sound waves in a specimen through thirty feet of wire. Many hardware aspects are discussed such as boundaries, materials, acoustic horn design, and sound propagation characteristics which facilitated the generation of sound energy in the specimen. Temperature effects on velocity and length were calculated and a model was developed to determine length from a time of flight measurement. The specimen was heated in an oven to various temperatures and times of flight were measured and compared to the model. Results show agreement between the measured values and the model as well as the ability for a high precision length measurement.
Longitudinal Wave Distribution in Fluid Saturated Granular Media
Authors: Tavossi H. M. , Tittmann B. R.
Published: October 2008

Ultrasonic wave transmission in a porous material as a function of frequency and incident direction was investigated, both theoretically and experimentally. The aim of this study was to determine the optimal frequency and incidence direction for the most penetrating ultrasonic radiation into sediment. The results can be applied towards the detection of underground objects, in particular, the detection of non-metallic objects such as mines currently undetectable with metal-detectors. Computer software was developed to determine the dispersion characteristics of ultrasonic waves in fluid saturated media of packed spherical grains in the 50μm to 3000μm size range. The wave frequency range was from 0.1 MHz to 10 MHz. The results showed that Biot’s theory could not be used to explain the observations without significant modification. Good agreement between theory and experiment could finally be obtained with the modified theoretical approach.
What Is The Meaning of Tight?
Authors: Bartonicek J. , Roos E. , Kockelmann H. , Schoeckle F.
Published: October 2008

Generally, sealed joints are not absolutely tight. Only a certain (finite) tightness can be reached. In this connection the following aspects are of importance: • the tightness requirement (depending on the medium to be sealed), • the suitability of the design of the joint for the intended application, • the gasket characteristics, • the strength and tightness proof, and • the required assembly bolt load. An optimized tightening capability of the gasket in a bolted flange connection is reached by means of adequate assembly bolt load and corresponding gasket deformation. The leakage channels in the body of the gasket as well as the leakage paths between gasket surface and the flanges sealing faces are closed. Depending on the required tightness and the type of medium a minimum gasket stress has to be applied during assembly. The higher the pre-deformation of the gasket during assembly the lower is the required gasket service stress for the intended tightness class. Both the required gasket stress for assembly and service condition are depending on the internal pressure and the medium to be sealed. These two gasket characteristics are to be determined by means of a leakage test. First of all, the required tightness class of a bolted flange connection has to be defined. Thereafter the flanges, bolts and the gasket are chosen (material, dimensions). On the basis of a calculation of the bolted flange connection the required assembly bolt or gasket load is determined and — if necessary — tightness and strength proof are carried out. Last but not least the defined assembly bolt load has to be applied with sufficient accuracy and limited scatter.
The Determination of Load Changes in Bolted Gasketed Joints Subjected to Elevated Temperature
Authors: Nechache Akli , Bouzid Abdel-Hakim
Published: October 2008

The tightness of bolted flanged joints subjected to elevated temperature is not properly addressed by flange design codes. The development of an analytical method based on the flexibility of the different joint components and their elastic interaction could serve as a powerful tool for elevated temperature flange designs. This paper addresses the effect of the internal fluid operating temperature on the variation of the bolt load and consequently on the gasket stress in bolted joints. The theoretical analysis used to predict the gasket load variation as a result of a temperature change is outlined. It details the analytical basis of the elastic interaction model and the thermally induced deflections that are used to evaluate the load changes. Two flange joint type configurations are treated; a joint with identical pair of flanges and a joint with a cover plate. The analytical models are validated and verified by comparison to finite element results.
Structural Integrity of Dissimilar Welds: ADIMEW Project Overview
Authors: Faidy Claude
Published: October 2008

The objective of the ADIMEW project, that follows BIMET program finished in 2000, is to contribute to the development and verification of analysis methods which describe the behaviour of an external circumferential defect at the surface of a Dissimilar Metal Weld (DMW). The complexity of the problem results from the prevailing mixed-mode loading conditions, the variation in material constitutive equations across the weld zone, and the presence of large residual stress field. Under these circumstances, classic fracture mechanics concepts are difficult to apply. Recently different cracks has been discovered in different US and European plants (VC SUMMER, RINGHALS, BIBLIS). The problem of integrity of aged (cracked) DMW’s remains an important safety issue. This paper presents the new on-going program ADIMEW, with similar organisation than BIMET and complementary objectives. Within the framework of this project, one large test has been successfully done on July 2003. The paper presents a general overview of the program and the major recommendations and conclusions.
Experimental Four Points Bending Test on a Real Size Bimetallic Welded Pipe: European Project ADIMEW
Authors: Martin Gre´goire , Me´nard Antoine
Published: October 2008

In July 2003 EDF-R&D performed a 4 points bending test on a real size bimetallic welded pipe. This test (following the BIMET program) is a major part of the European project ADIMEW (Assessment of aged piping DIssimilar MEtal Welds integrity). The mock-up was representative of an Expansion line of the Pressurizers of French N4 Power Plants: it was a 16” pipe including a ferritic part (SA508 Class 3), an austenitic one (316L) and a weld with buttering (309L) and weld metal (308L). An outer circumferential 1/3-thickness defect had been introduced in the first layer of the buttering, parallel to the buttering/ferritic interface (at a distance of 2mm). The test was conducted under displacement control and the partial unloading method was used to control the defect initiation and propagation. Crack initiation occurred at a relatively low bending moment but a long stable propagation was to observe. This proves the ability of such junctions with large defects to overcome very high bending loads without any unstable crack growth. This paper will provide more detailed information about the testing conditions, all important experimental results and a discussion around them.
Fracture Analysis of Surface-Breaking Shallow Flaw Behaviour in the NESC-IV Bend Beam Tests
Authors: Taylor N. , Sattari-Far I. , Siegele D. , Varfolomeyev I. , Stumpfrock L.
Published: October 2008

NESC-IV is an experimental/analytical program to develop validated analysis methods for transferring fracture toughness data generated on standard test specimens to shallow flaws in reactor pressure vessel welds subject to biaxial loading in the lower-transition temperature region. The testing program exploited material from a production-quality reactor pressure vessel. In Part A six clad cruciform specimens containing shallow surface-breaking flaws located in weld material were successfully tested. Post-test fracture mechanics analyses have been conducted by several organizations to determine fracture mechanics parameters such as K, J, Q and T at the flaws. These have been used to interpret the results with respect to the Master Curve, giving particular attention to constraint aspects.
Application of a Weibull Stress Model to Predict the Failure of Surface and Embedded Cracks in Large Scale Beams Made of Clad and Unclad RPV Steel
Authors: Yin Shengjun , Bass Richard , Williams Paul , Ludwig Michael , Keim Elisabeth
Published: October 2008

Within the European Network NESC, the project NESC IV deals with constraint effects of cracks in large scale beam specimens, loaded by uni- or biaxial bending moments and containing surface or embedded cracks. The specimens are fabricated from original US RPV material, being cladded or cladding is removed. All large scale tests have been conducted at ORNL outside the NESC IV project. The outcome and the analyses of these uncladded and cladded beams containing the surface or embedded cracks are shown. By means of the finite element method, local approach methods and the Weibull stress models the specimens are analysed at the test temperatures and the probability of failure is calculated, taking into account constraint effects. For the case of the embedded cracks it turned out that the failure moment of the uncladded beam is 5% lower than the one of the cladded beam. Both crack fronts of the embedded crack are supposed to fail at the same failure moment. The results of the analysis of the cladded beam showed that the upper crack front nearer to the surface fails prior to the lower crack front, which is located deeper in the specimen (the failure moment is 5% lower). The numerical results agree very well with the experiments. The experimental failure moments could be well predicted and the failure scenario (which crack front fails first) could be determined. A theoretical shift in the transition temperature T0 due to constraint effects could be defined for both crack fronts.
Crack Initiation and Arrest of Irradiated RPV-Steels: A National Project on German RPV Weld and Base Materials
Authors: Keim Elisabeth , Langer Reinhard , Schnabel Hilmar , Hein Hieronymus
Published: October 2008

In Germany the procedure which has to be applied for the safety assessment of the reactor pressure vessel is based on the RTNDT concept. The Master Curve concept (based on T0) has the advantage compared to the RTNDT concept that the basic tests are fracture toughness tests instead of Charpy impact energy or Pellini tests. By means of the recently initiated German project CARISMA (Crack Initiation and Arrest of Irradiated Steel Materials), a data base will be created on pre-irradiated original materials of the four generations of German nuclear pressurized water reactors, which allows to examine the consequences if the Master Curve instead of the RTNDT concept will be applied.
FEA Welding Residual Stress and Fracture Mechanics Model for Nozzles With J-Groove Attachment Welds: Methodology and Application
Authors: Broussard John E. , Hunt E. Stephen , White Glenn A.
Published: October 2008

Residual stresses due to welding in reactor pressure vessel (RPV) top head nozzle penetrations have been predicted using finite element analysis since the early 1990s. While the analyses were originally targeted at calculating nozzle stresses, the finite element methods have been extended to model a number of different aspects of RPV head penetrations. Both top and bottom head penetrations have been modeled, and the effects of J-groove butter weld deposition and subsequent thermal stress relief of the top head are now included in the analytical model. Development work has recently been completed to integrate a fracture mechanics model into the welding residual stress model. This has allowed for the prediction of crack tip stress intensity factors in the presence of welding residual stresses that include the effects of stress redistribution due to the presence of the crack. This paper presents some of the modeling techniques used in these recent analyses, and some key results obtained.
A Fracture Mechanics Evaluation of an Indication in an RPV Vertical Shell Weld Produced by the Upjohn Welding Technique
Authors: Mehta Hardayal S. , Miller Wade F. , Brooks M. A.
Published: October 2008

A reactor pressure vessel (RPV) manufacturer used the Upjohn welding technique to fabricate the longitudinal and meridional seam welds in a number of RPVs. The Upjohn welding process allowed fabrication of heavy plate sections without the use of positioning devices. With this welding technique, the major dimension of fabrication flaws extends through the weld thickness rather than parallel to the thickness as with other fabrication welding techniques. One vertical weld seam of a RPV fabricated using the Upjohn weld process was examined by ultrasonic techniques consistent with PDI requirements. Flaws were detected during the ASME Code required in-service inspection. After the application of the flaw proximity rules, one indication was characterized as a planar flaw 4.24 inches long (along the weld thickness direction) and 2-inches wide. One end of the indication was located 0.7 inch from the ID surface, which included a clad thickness of 5/16 inch. The use of Section XI flaw characterization and proximity rules would have required the characterization of this flaw as a large surface flaw. Therefore, a three-dimensional finite element model, including crack tip elements, was developed to determine the increase in the theoretical infinite plate K value due to the edge effect. The flaw evaluation was based on the guidelines of Appendix A of ASME Section XI. The allowable K values considered adjusted reference temperature (ART) based on cumulative fluence from operation to end of design life, which included a 20-year license renewal period. Because the calculated values of K were less than the allowable values of K, it was concluded that the indication is not expected to become a surface indication during future operation. Discussion on recommendations for RPVs with Upjohn welds, suggested changes to ASME Section XI Paragraph IWB-3610 and a comparison with the RPV flaw database is also provided.
Postirradiation Ductility Demonstration Tests of Weapons-Derived MOX Fuel Cladding
Authors: McAfee W. J. , Hendrich W. R. , McGreevy T. E. , Baldwin C. A. , Packan N. H.
Published: October 2008

The U.S. Department of Energy (DOE) Fissile Materials Disposition Program (FMDP) is pursuing reactor irradiation of mixed uranium-plutonium oxide (MOX) fuel for disposal of surplus weapons-usable plutonium. Since most of the MOX fuel utilization experience has been with reactor-grade plutonium, it is desired to demonstrate that the unique properties of the surplus weapons-derived or weapons-grade (WG) plutonium do not compromise the applicability of this MOX experience base. A related question to be addressed for weapons-derived MOX fuel is that of ductility loss of the cladding. While irradiation induced loss of ductility has long been known and quantified for many cladding materials, the potential synergistic effects of irradiation and the unique constituents (i.e., gallium) of weapons-derived MOX fuel are not known. As part of an extensive fuel qualification research program conducted by Oak Ridge National Laboratory (ORNL), a new test method was developed and validated to measure the room temperature ductility and hoop tensile properties of MOX fuel cladding. The cladding material is a zirconium alloy designated as Zr-4 manufactured by Sandvick Corporation. This paper is a summary of the test method developed and of demonstration test results obtained for MOX cladding irradiated to 21 GWd/MT [7 × 1020 n/cm2 (E > 1 MeV)].