bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Creep Crack Growth on Life of Elevated Temperature
Stainless Steel Components
Authors: Becht C. , Buchheim G. M. 
Published: March 2013

Abstract
The traditional approach to high temperature design of process equipment has been directed towards prevention of creep rupture in nominally defect free structures. However, experience has shown that many failures are by the growth of cracks that may have been introduced during fabrication, repairs, or operation. This growth is via a localized creep mechanism termed creep crack growth. Both load-controlled, primary stress and deformation-controlled (e.g. thermal), secondary stress can contribute to this crack growth. Simplified methods were used to predict creep crack growth due to primary and secondary stress. This required development of a solution for crack growth due to secondary stress that considered simultaneous crack growth and load relaxation. Closed-form solutions were developed based on the C* integral that yielded crack advance as a function of time and initial load. The predictions compared very well with the results of a deformation-controlled compact tension creep crack growth experiment. Parametric evaluations showed that only very shallow cracklike defects can be tolerated in highly stressed areas. Cracks can advance very quickly due to both high primary or high secondary stresses. With primary stresses at the ASME Boiler and Pressure Vessel Code Section VIII, Div. 1 limits, cracks as shallow as 1.3 mm (0.05 in.) can reduce average life to less than 100,000 hr. Where cyclic secondary stresses exceed shakedown limits, life may be limited to a relatively small number of start-up/shutdown cycles.
Sensitivity of the Dynamic Behavior of Structures to System Parameter
Changes
Authors: Nordmann R. , Eckey H. , Kaas P. , Steinwarz M. 
Published: March 2013

Abstract
A new calculation procedure has been developed to evaluate the influence of parameter changes to the dynamic behavior of structures. By this sensitivity analysis the variations of natural frequencies and natural modes can be expressed, generated by specific parameter alterations. Combined with modal methods, for example the response spectrum modal analysis, the changed dynamic response (displacements, internal forces) can also be found. The algorithm is suitable in connection with standard finite element routines, to investigate the effect of parameter modifications in relation to the dynamic characteristics of an original system. For a large vessel piping system, the influence of a spring stiffness variation to the natural frequencies and internal forces is demonstrated.
A Test and Analysis of the Multiple Support Piping
Systems
Authors: Chiba T. , Koyanagi R. , Ogawa N. , Minowa C. 
Published: March 2013

Abstract
One of the current topics in the seismic design of piping systems is the overall reliability of them in earthquake events. Actual piping systems are generally supported by independent structures such as vessels and steel structures. So, it is very important to clarify the behavior of actual piping systems during the seismic events. For this purpose, the analytical method of multiple excitation problems is a preferable approach to not only evaluate the actual behavior of the piping systems, but also improve the reliability of piping systems. To clarify the dynamic characteristics of the piping systems and to assess the computational methods in the linear system subjected to multiple support excitations, an experimental study using a realistic large-scale piping model has been conducted. The equations for the multiple excitation problem have been validated and the adequacy of the multiple response spectra method has been confirmed by the comparison of the test results with the analytical one. This paper reports the results focusing on the analytical methods of the multiple support piping system. It is noted that the multiple response spectrum method is efficient for the multiple excitation problems.
Large Deformation Analysis of an Elastic-Plastic Cantilevered
Beam
Authors: Nicholson D. W. 
Published: March 2013

Abstract
This study concerns the analysis of the deflection of an elastic-plastic cantilevered beam. Three regions of solution are treated: (i) purely elastic response at low loads; (ii) elastic-plastic response without a hinge, for intermediate loads; and (iii) elastic-plastic response with a hinge for loads corresponding to the fully plastic bending moment at the built-in end. Most existing solutions for this type of problem involve various approximations avoided here, for example, ignoring the elastic part of the strain or using upper bounds based on limit analysis. By avoiding such approximations, the solution given here may be useful as a benchmark for validating finite element codes in the large deformation elastic-plastic regime. Several aspects of the solution are analyzed: (i) the load-deflection relation; (ii) the growth of the elastic-plastic zone; (iii) limiting cases; (iv) the residual configuration; (v) the small bending configuration. A numerical procedure based on Runge-Kutta methods is used, leading to the load-deflection relation in graphical form.
Equivalent Damping in Piping Due to Local Yielding
Authors: Lazzeri L. , Scala M. 
Published: March 2013

Abstract
A method is presented to 1) account for ductility effects in the response of one degree of freedom systems by means of evaluating the frequency shift and additional damping; 2) evaluate the energy dissipation which takes place in piping due to local yielding in elbows.
Turbulence-Induced Vibration of Tube Bundle in Cross and Parallel Jet
Mixed Flow
Authors: Kawamura K. , Yasuo A. 
Published: March 2013

Abstract
In the multi-tube type of heat exchanger, baffle plates are located at appropriate intervals to support the heat transfer tubes. Depending on the baffle plate type employed, the flow field in the tube bundle will consist of a mixture of the cross flow (the fluid flows at right angles to the tube bundle along the baffle plate surfaces) and the parallel jet flow (the fluid streams through channels such as the flow holes of the baffle plates in the form of jets and flows in parallel with the tube bundle). Vibrations induced by the flow can cause fretting wear and fatigue of the heat transfer tubes. Therefore, it it essential to establish a method of evaluating heat transfer tube vibrations induced by the mixed flow for the purpose of evaluating the integrity of heat exchanger tubes. In this paper, three different flows, that is, cross, parallel jet and mixed flows, were simulated in order to clarify the relationships between the flow conditions and vibration of the tube bundle, and to study a method for evaluating tube bundle vibrations induced by turbulence in the mixed flow field by using the vibration characteristics in the cross flow field and the parallel jet flow field.
Dynamic Forcing Function for Flow-Acoustic-Induced
Vibration
Authors: Wang T. 
Published: March 2013

Abstract
Vibration problems in piping systems can manifest themselves in two forms: excessive noise generated from wall flexural vibrations, that in combination with jet noise itself may exceed OSHA limits, and piping system vibration, which could lead to fatigue failure at stress risers. Thus, a comprehensive dynamic forcing function for flow-acoustic-induced vibration on piping system needs to consider both the flexural and system excitation sources. Jet column instabilities and acoustic standing waves are utilized to identify the vibration sources in a large-capacity steam piping system. Initial noise generation originates from approximately six jet diameters downstream of a control valve. It consists of two sharply defined high-frequency sources, the shock cells and the large-scale axisymmetric coherent turbulent structure generated from the nonlinear shear layer instability. These sources effectively excite wall flexural vibrations because of their nonzero net dynamic forcing on pipe “shells.” The compact shock and instability wave noise sources further excite the low-frequency acoustic standing wave in the acoustic duct formed by the discharge piping. The low-frequency acoustic standing wave excites the piping system vibration axially. The piping system was also excited transversely by a more potent vibration source incurred by the spiral mode provoked by a piping elbow. Field observation and measurement of the vibration problem of a large-diameter piping system confirm the prediction.
Simulation of Tube-to-Support Dynamic Interaction in Heat Exchange
Equipment
Authors: Fisher N. J. , Olesen M. J. , Rogers R. J. , Ko P. L. 
Published: March 2013

Abstract
Tubes within tube and shell heat exchange components are supported at intermediate points by support plates. Flow-induced vibration of a tube can cause it to impact or rub against a support plate or against adjacent tubes and can result in tube fretting-wear. The tube-to-support dynamic interaction is used to relate experimental wear data from test rigs to real multi-span heat exchanger configurations. Analytical techniques are required to estimate this interaction in real heat exchangers. Simulation results from the VIBIC code are in good agreement with three examples from the open literature and are in reasonable agreement with measurements from the CRNL single-span room temperature fretting-wear rigs. Therefore, the VIBIC code is a good analytical tool for estimating tube-to-support dynamic interaction in real heat exchangers.
Measurement of Tube-to-Support Dynamic Forces in Fretting-Wear
Rigs
Authors: Fisher N. J. , Ingham B. 
Published: March 2013

Abstract
Tubes within tube and shell heat exchangers are supported at intermediate points by plates. Flow-induced vibration can cause tubes to impact and rub against these supports, or other tubes, and can result in tube fretting-wear. The tube-to-support dynamic interaction, which consists of dynamic contact forces and tube motion, is used to relate single-span wear data to real heat exchanger configurations consisting of multi-span tube bundles. This paper describes the technique used to measure tube-to-support dynamic forces in the Chalk River Nuclear Laboratories impact fretting-wear test facility and reports test results that validate the technique. The force measurement technique is shown to provide a reasonable measure of dynamic contact forces.
Vibration of Tube Bundles in Two-Phase Cross-Flow: Part
3—Turbulence-Induced Excitation
Authors: Taylor C. E. , Currie I. G. , Pettigrew M. J. , Kim B. S. 
Published: March 2013

Abstract
An extensive experimental program was carried out to study the vibration behavior of tube bundles subjected to two-phase cross-flow. Turbulence-induced excitation is discussed in Part 3 of this series of three papers. Random vibration response to turbulence-induced excitation is a significant vibration mechanism in heat exchanger tube bundles subjected to two-phase cross-flow. The vibration responses of centrally located tubes in four tube bundle configurations subjected to air-water cross-flow was measured. The results are presented in the form of a normalized forced-excitation spectrum which can be used as a design guideline over a void fraction range from 25 percent to 99 percent and over a practical range of flow rates. The data are further analyzed to determine the dependence of the vibration response on Reynolds number, void fraction and frequency. Measurements taken on a single tube, a row of tubes and on tubes having varying end conditions were used to assist in interpreting the bundle data.
Flow-Induced Vibration Analysis of an Integral Economizer
Once-Through Steam Generator
Authors: Au-Yang M. K. , Brenneman B. 
Published: March 2013

Abstract
The integral economizer once-through steam generator is a second-generation steam generator used in B&W's 205-fuel assembly nuclear power plants. Besides having an integral economizer, this steam generator differs from the first generation units, sixteen of which have been operating with B&W's 177 fuel assembly nuclear power plants for more than ten years, in having a much higher flow rate. This higher flow rate induces a correspondingly higher fluid-dynamic load on all of the steam generator internal components, particularly the tube bundle. This paper describes the flow-induced vibration design analysis of this second-generation nuclear steam generator. The three most commonly known flow-induced vibration phenomena were considered: fluid-elastic instability, turbulence-induced vibration and vortex-induced vibration. To minimize uncertainties in the many experimentally determined input parameters such as damping ratios, Connors’ constant and the dynamic pressure power spectral densities, a parallel analysis was carried out on the operating first-generation steam generator, and the results compared. The analytical results were verified by the recent start-up of B&W's first 205-fuel assembly nuclear plant. No vibration problems were encountered during either the pre-operational test or in several months of full power operations.
Automated chest wall line detection for whole‐breast segmentation in sagittal breast MR images
Authors: Wu Shandong , Weinstein Susan P. , Conant Emily F. , Schnall Mitchell D. , Kontos Despina 
Published: March 2013

Purpose:Breast magnetic resonance imaging (MRI) plays an important role in the clinical management of breast cancer. Computerized analysis is increasingly used to quantify breast MRI features in applications such as computer‐aided lesion detection and fibroglandular tissue estimation for breast cancer risk assessment. Automated segmentation of the whole‐breast as an organ from the other parts imaged is an important step in aiding lesion localization and fibroglandular tissue quantification. For this task, identifying the chest wall line (CWL) is most challenging due to image contrast variations, intensity discontinuity, and bias field.Methods:In this work, the authors develop and validate a fully automated image processing algorithm for accurate delineation of the CWL in sagittal breast MRI. The CWL detection is based on an integrated scheme of edge extraction and CWL candidate evaluation. The edge extraction consists of applying edge‐enhancing filters and an edge linking algorithm. Increased accuracy is achieved by the synergistic use of multiple image inputs for edge extraction, where multiple CWL candidates are evaluated by the dynamic time warping algorithm coupled with the construction of a CWL reference. Their method is quantitatively validated by a dataset of 60 3D bilateral sagittal breast MRI scans (in total 3360 2D MR slices) that span the full American College of Radiology Breast Imaging Reporting and Data System (BI‐RADS) breast density range. Agreement with manual segmentation obtained by an experienced breast imaging radiologist is assessed by both volumetric and boundary‐based metrics, including four quantitative measures.Results:In terms of breast volume agreement with manual segmentation, the overlay percentage expressed by the Dice's similarity coefficient is 95.0% and the difference percentage is 10.1%. More specifically, for the segmentation accuracy of the CWL boundary, the CWL overlay percentage is 92.7% and averaged deviation distance is 2.3 mm. Their method requires ∼4.5 min for segmenting each 3D breast MRI scan (56 slices) in comparison to ∼35 min required for manual segmentation. Further analysis indicates that the segmentation performance of their method is relatively stable across the different BI‐RADS density categories and breast volume, and also robust with respect to a varying range of the major parameters of the algorithm.Conclusions:Their fully automated method achieves high segmentation accuracy in a time‐efficient manner. It could support large scale quantitative breast MRI analysis and holds the potential to become integrated into the clinical workflow for breast cancer clinical applications in the future.
Complete Genome Sequence of the Sugar Beet Endophyte Pseudomonas poae RE*1-1-14, a Disease-Suppressive Bacterium
Authors: Müller Henry , Zachow Christin , Alavi Mohammadali , Tilcher Ralf , Krempl Peter Mauritius , Thallinger Gerhard Günther , Berg Gabriele 
Published: March 2013

ABSTRACT

The endophytic bacterium
Pseudomonas poae
RE*1-1-14 shows broad antagonistic activity and is applied to seeds as a biocontrol agent to suppress late root rot in the sugar beet. The completely sequenced 5.5-Mb genome reveals genes that putatively contribute to this antagonistic activity and the intimate plant-microbe interaction.
Genome Sequence of the Butanol Hyperproducer Clostridium saccharoperbutylacetonicum N1-4
Authors: del Cerro Carlos , Felpeto-Santero Carmen , Rojas Antonia , Tortajada Marta , Ramón Daniel , García José L. 
Published: March 2013

ABSTRACT

Clostridium saccharoperbutylacetonicum
is one of the most important acetone-butanol-ethanol (ABE)-generating industrial microorganisms and one of the few bacteria containing choline in its cell wall. Here, we report the draft genome sequence of
C. saccharoperbutylacetonicum
strain N1-4 (6.6 Mbp; G+C content, 29.4%) and the findings obtained from the annotation of the genome.
Genome Sequence of Avirulent Riemerella anatipestifer Strain RA-SG
Authors: Yuan Jianfeng , Li Linlin , Sun Minhua , Dong Jiawen , Hu Qilin 
Published: March 2013

ABSTRACT

Riemerella anatipestifer
is a pathogenic bacterium that has spread all over the world and is associated with epizootic infections in waterfowl and other avian species.
R. anatipestifer
RA-SG is an avirulent strain, isolated from an infected duck in Guangdong province, China. The genome sequence of this species is presented herein.
The varying role of the GP in the pathway between colonoscopy and surgery for colorectal cancer: a retrospective cohort study
Authors: Goldsbury David , Harris Mark , Pascoe Shane , Barton Michael , Olver Ian , Spigelman Allan , Beilby Justin , Veitch Craig , Weller David , O'Connell Dianne L 
Published: March 2013

ObjectivesTo describe general practitioner (GP) involvement in the treatment referral pathway for colorectal cancer (CRC) patients.DesignA retrospective cohort analysis of linked data.SettingA population-based sample of CRC patients diagnosed from August 2004 to December 2007 in New South Wales, Australia, using the 45 and Up Study, cancer registry diagnosis records, inpatient hospital records and Medicare claims records.Participants407 CRC patients who had a colonoscopy followed by surgery.Primary outcome measuresPatterns of GP consultations between colonoscopy and surgery (ie, between diagnosis and treatment). We investigated whether consulting a GP presurgery was associated with time to surgery, postsurgical GP consultations or rectal cancer cases having surgery in a centre with radiotherapy facilities.ResultsOf the 407 patients, 43% (n=175) had at least one GP consultation between colonoscopy and surgery. The median time from colonoscopy to surgery was 27 days for those with an intervening GP consultation and 15 days for those without the consultation. 55% (n=223) had a GP consultation up to 30 days postsurgery; it was more common in cases of patients who consulted a GP presurgery than for those who did not (65% and 47%, respectively, adjusted OR 2.71, 95% CI 1.50 to 4.89, p=0.001). Of the 142 rectal cancer cases, 23% (n=33) had their surgery in a centre with radiotherapy facilities, with no difference between those who did and did not consult a GP presurgery (21% and 25% respectively, adjusted OR 0.84, 95% CI 0.27 to 2.63, p=0.76).ConclusionsConsulting a GP between colonoscopy and surgery was associated with a longer interval between diagnosis and treatment, and with further GP consultations postsurgery, but for rectal cancer cases it was not associated with treatment in a centre with radiotherapy facilities. GPs might require a more defined and systematic approach to CRC management.
Comparison of CPR outcome predictors between rhythmic abdominal compression and continuous chest compression CPR techniques
Authors: Kammeyer Ryan M , Pargett Michael S , Rundell Ann E 
Published: March 2013

ObjectiveBystander cardiopulmonary resuscitation (CPR) provides treatment for out-of-hospital cardiac arrest since perfusion of vital organs is critical to resuscitation. Alternatives to standard CPR are evaluated for effectiveness based upon outcome predictive metrics and survival studies. This study focuses on evaluating the performance of rhythmic-only abdominal compression CPR (OAC-CPR) relative to chest compression (CC-CPR) using a complementary suite of mechanistically based CPR outcome predictors. Combined, these predictors provide insight on the transduction of compression-induced pressures into flow perfusing vital organs.MethodsIntrasubject comparisons between the CPR techniques were made during multiple 2-min intervals of induced fibrillation in 17 porcine subjects. Arterial pO2, cardiac output, carotid blood flow, coronary perfusion pressure (CPP), minute alveolar ventilation (MAV), end-tidal CO2, and time from defibrillation to the return of spontaneous circulation (ROSC) were recorded. Organ damage was assessed by necropsy.ResultsCompared with CC-CPR, OAC-CPR had higher pressure and ventilation metrics with increased relative CPP (+16 mm Hg), MAV (+75/ml/min/kg) and a lower reduction in arterial pO2(−22% baseline), but suffered from lower carotid flows (−9.3 ml/min). No significant difference was found comparing cardiac outputs. Furthermore, resuscitation was qualitatively more difficult after OAC-CPR, with a longer time to ROSC (+70 s). No abdominal damage was observed over short periods of OAC-CPR.ConclusionsAlthough OAC-CPR appeared superior to CC-CPR by pressure and ventilation metrics, lower carotid flow and longer delay until ROSC raise concerns about overall performance. These paradoxical observations suggest that the evaluation of efficacious alternative CPR techniques may require more direct measurements of vital organ perfusion.
Roux-en-Y gastric bypass for morbid obesity: what are the preoperative predictors of weight loss?
Authors: Adams Simon T , Salhab Mohammed , Hussain Zeiad I , Miller Glenn V , Leveson Stephen H 
Published: March 2013

Abstract
Obesity has become an increasingly important health problem over the past 30 years. Presently around a quarter of the UK adult population are obese and this figure is set to increase further in the coming decades. The health consequences of obesity on multiple body systems have been well established as has the financial cost of the condition to both the individuals affected as well as to society as a whole. Bariatric surgery has been shown to be the only long term effective solution in terms of sustained weight loss and comorbidity resolution. The commonest bariatric procedure in the UK is the Roux-en-y gastric bypass which consistently results in the loss of 70%-80% of excess bodyweight. Results however are variable and in order to optimise resource allocation and avoid exposing patients unlikely to benefit from surgery to its inherent risks, much research has been done to try to identify those patients most likely to obtain a good result. The only factor which has been subjected to meta-analysis is that of preoperative weight loss which shows a positive association with postoperative weight loss following bypass surgery. Although the remaining data are not based on level 1 evidence those other preoperatively identifiable factors which are associated with an improved outcome include Caucasian or Hispanic ethnicity, higher educational status, non-shift-work working patterns, female gender and divorced or single marital status. Similarly increased levels of preoperative physical activity and an absence of binge eating behaviour are consistent with a favourable result whereas increased age, smoking and other socioeconomic factors have not been shown to have a significant impact. Conversely diabetes mellitus seems to have a slight negative correlation with postoperative weight loss; however, a history of sexual abuse or psychiatric illness has not been shown to have a lasting influence.