bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental Study on Seismic Responses of Piping Systems With
Friction—Part 1: Large-Scale Shaking Table Vibration Test
Authors: Suzuki K. , Watanabe T. , Mitsumori T. , Shimizu N. , Kobayashi H. , Ogawa N. 
Published: February 2008

Abstract
This report deals with the experimental study of seismic response behavior of piping systems in industrial facilities such as petrochemical, oil refinery, and nuclear plants. Special attention is focused on the nonlinear dynamic response of piping systems due to frictional vibration appearing in piping and supporting devices. A three-dimensional mock-up piping and supporting structure model wherein piping is of 30-m length and 200-mm diameter is excited by a large-scale (15 m × 15 m) shaking table belonging to the National Research Institute for Earth Science and Disaster Prevention in Tsukuba, Ibaraki. Power spectra of the response vibration and the loading-response relationship in the form of a hysteresis loop under several loading conditions are obtained. The response reduction effect caused by frictional vibration is evaluated and demonstrated in terms of “response reduction factor.”
Collinear Internal Cracks and Edge Crack in a Semi-Infinite Sheet
Subjected to Arbitrary Tractions
Authors: Nishimura T. 
Published: February 2008

Abstract
The stress intensity factors are calculated for collinear internal cracks and an edge crack in a semi-infinite sheet subjected to arbitrary tractions. Analysis is conducted by formulating the integral equations of tractions along the plate edge and crack surfaces. The accuracy is checked with known results in the literature. Then, the numerical analysis is used to establish the stress intensity factors for various sizes of the edge crack and internal cracks in tension. Also, the stress intensity factors are calculated for the edge crack and internal crack subjected to typical distributed loadings, and the effects of mutual interaction between the cracks are presented.
Constraint in the Failure Assessment Diagram Approach for Fracture
Assessment
Authors: Ainsworth R. A. , O’Dowd N. P. 
Published: February 2008

Abstract
This paper presents a framework for including constraint effects in the failure assessment diagram approach for fracture assessment. As parameters for describing constraint are still the subject of development, the framework is illustrated using both the elastic T-stress and the hydrostatic Q-stress. It is shown that constraint effects can be treated by modifying the shape of the failure assessment curve. In their simplest form, the modifications involve only two parameters: one quantifying the magnitude of structural constraint which depends on geometry and crack size; and the second quantifying the influence of constraint on fracture toughness.
Sloshing Analysis Method Using Existing FEM Structural Analysis
Code
Authors: Tokuda N. , Sakurai T. , Teraoku T. 
Published: February 2008

Abstract
A fluid analysis method using an analogy relating the pressure wave equation of fluid to elasticity equations is applied to sloshing analysis, where existing FEM structural analysis codes are available. It is seen from theoretical consideration that the present method is equivalent to the classical FEM formulation of linear sloshing analysis. The numerical analyses of liquid sloshing in a rigid cubic tank and of vibration of tubulous fluid under gravitational force are performed by using the present method. The results are shown to be in excellent agreement with the theoretical values.
Enhancement of Pressurizer Safety Valve Operability by Seating Design
Improvement
Authors: Moisidis N. T. , Ratiu M. D. 
Published: February 2008

Abstract
Operating conditions specific to pressurizer safety valves (PSVs) have led to numerous problems and have caused industry and NRC concerns regarding the adequacy of spring-loaded self-actuated safety valves for reactor coolant system (RCS) overpressure protection. Specific concerns are: setpoint drift, spurious actuations, and leakage. Based on testing and valve construction analysis of a Crosby model 6M6 PSV (Moisidis and Ratiu, 1992), it was established that the primary contributor to the valve problems is a susceptibility to weak seating. To eliminate spring instability, a new spring washer was designed, which guides the spring and precludes its rotation from the “reference” installed position (Figs. 6 and 7). Results of tests performed on a prototype PSV equipped with the modified upper spring washer has shown significant improvements in valve operability and a consistent setpoint reproducibility to less than ±1 percent of the PSV setpoint (testing of baseline, unmodified valve, resulted in a setpoint drift of ±2 percent). Enhanced valve operability will result in a significant decrease in operating and maintenance costs associated with valve maintenance and testing. In addition, the enhanced setpoint reproducibility will allow the development of a nitrogen to steam correlation for future in-house PSV testing which will result in further reductions in costs associated with valve testing.
Peak Stress and Fatigue Assessment at the Saddle Support of a
Cylindrical Vessel
Authors: Ong L. S. 
Published: February 2008

Abstract
The maximum stress in a saddle-supported cylindrical storage vessel is often the circumferential stress developed at the tips (or horns) of the saddle support. Although the peak stress at the support is not immediately detrimental to the integrity of a vessel, it would have a long-term effect on the fatigue life of the vessel. This article provides a parametric equation to determine the peak circumferential stress at the support. To assist calculations, a worksheet procedure has been proposed. The parametric equation is accompanied by four graphs, each graph provides values for a geometric variation of the problem. An example has been shown on the application of the parametric equation. A fatigue assessment is also made on the example vessel and comparison is made between ASME and British design codes. The parametric curves can be also used as a set of design curves for specifying support dimensions.
Vibration of a Tube Bundle in Two-Phase Freon
Cross-Flow
Authors: Pettigrew M. J. , Taylor C. E. , Jong J. H. , Currie I. G. 
Published: February 2008

Abstract
Two-phase cross-flow exists in many shell-and-tube heat exchangers. The U-bend region of nuclear steam generators is a prime example. Testing in two-phase flow simulated by air-water provides useful results inexpensively. However, two-phase flow parameters, in particular surface tension and density ratio, are considerably different in air-water than in steam-water. A reasonable compromise is testing in liquid-vapor Freon, which is much closer to steam-water while much simpler experimentally. This paper presents the first results of a series of tests on the vibration behavior of tube bundles subjected to two-phase Freon cross-flow. A rotated triangular tube bundle of tube-to-diameter ratio of 1.5 was tested over a broad range of void fractions and mass fluxes. Fluidelastic instability, random turbulence excitation, and damping were investigated. Well-defined fluidelastic instabilities were observed in continuous two-phase flow regimes. However, intermittent two-phase flow regimes had a dramatic effect on fluidelastic instability. Generally, random turbulence excitation forces are much lower in Freon than in air-water. Damping is very dependent on void fraction, as expected.
A Crack Arrest Test Using a Toughness Gradient Steel
Plate
Authors: Okamura H. , Yagawa G. , Hidaka T. , Urabe Y. , Satoh M. , Sano J. 
Published: February 2008

Abstract
A crack arrest test was carried out using a toughness gradient steel plate with three layers to study the concept of crack arrest toughness. Four-point bending load with thermal shock was applied to the large flat plate specimen with a surface crack. Five crack initiations and arrests were observed during the test and the propagated crack bifurcated. Finally, cracks were arrested at the boundary of the first and the second layer, except for a small segment of the crack. The first crack initiation took place slightly higher than the lower bound of KIc data obtained by ITCT specimens. That is, the KIC concept for brittle crack initiation was verified for heavy section steel plates. The first crack arrest took place within the scatter band of KIa and KId data for the first layer. That is, the KIa concept appears applicable for crack arrest of a short crack jump.
A New Constitutive Model in the Theory of Plasticity—Part I:
Theory
Authors: Jiang W. 
Published: February 2008

Abstract
By proposing two rules to regulate the movement of the yield surface, this paper develops a new kinematic hardening model in the theory of plasticity. A closed-form general solution is obtained in the case of linear stress paths, material response under cyclic loadings is discussed, and various tube problems are solved to demonstrate the model.
A New Constitutive Model in the Theory of Plasticity—Part II:
Examples
Authors: Jiang W. 
Published: February 2008

Abstract
This part of the paper presents several examples to further demonstrate the hardening model proposed in the first part of the paper. Closed-form solutions are achieved for a thin-walled tube subjected to linear, rectangular, and circular loading paths, and the corresponding yield center loci and plastic strain trajectories are illustrated. The features of this model are further discussed.
Weight Functions and Stress Intensity Factors for Longitudinal
Semi-Elliptical Cracks in Thick-Wall Cylinders
Authors: Zheng X. J. , Glinka G. 
Published: February 2008

Abstract
Weight functions for the surface and the deepest point of an internal longitudinal semi-elliptical crack in a thick-wall cylinder (Ri/t = 1) were derived from a general weight function and two reference stress intensity factors. For several linear and nonlinear crack face stress, fields, the weight functions were validated against finite element data. Stress intensity factors were also calculated for the Lame´ through the thickness stress distribution induced by internal pressure. The weight functions appear to be particularly suitable for fatigue and fracture analysis of surface semi-elliptical cracks in complex stress fields. All stress intensity factor expressions given in the paper are valid for cylinders with the inner-radius-to-wall-thickness ratio, Ri/t = 1.
New Post-Yield Fracture Toughness Parameters for Engineering
Materials
Authors: Wang T.-J. , Kuang Z.-B. 
Published: February 2008

Abstract
Micromechanics approach is employed to investigate the constraint effect on post-yield fracture toughness. Relationships between the conventional post-yield fracture toughness values, J1c and δc, and crack tip constraint characterized by the crack tip stress triaxiality are derived on the basis of an improved micromechanics criterion for ductile fracture. Then, new crack tip parameters Jmc and δmc (and associated new criteria for ductile fracture) are proposed, in which the effects of crack tip deformation and constraint are taken into account. Experiments show that both Jmc and δmc are material constant independent of stress state or specimen geometry. They can serve as new post-yield fracture toughness parameters to differentiate the fracture toughness of engineering materials, which provide new approaches for fracture assessments of engineering structures.
Cumulative Detection Probability as a Basis for Pressure Vessel
Inspection Intervals
Authors: Garic G. 
Published: February 2008

Abstract
This work discusses use of the cumulative flaw detection probability as the basis for establishing pressure vessel inspection intervals. The method is based on the accumulated probability of detecting a flaw over several inspections. It explicitly incorporates a user decision as to the acceptable level of failure risk. A four-step approach is outlined including fracture mechanics flaw growth calculations with probabilistic treatment of detection probability. It is concluded that (a) inspection intervals based on the cumulative probability of detection provide significant advantages over traditional cycle-based methods, (b) pressure vessel recertification inspections should rely on high percentage inspections conducted on a relatively infrequent basis.
A Reduced Order Modeling Technique for Mistuned Bladed
Disks
Authors: Castanier M. P. , Óttarsson G. , Pierre C. 
Published: February 2008

Abstract
The analysis of the response statistics of mistuned turbomachinery rotors requires an expensive Monte Carlo simulation approach. Simple lumped parameter models capture basic localization effects but do not represent well actual engineering structures without a difficult parameter identification. Current component mode analysis techniques generally require a minimum number of degrees of freedom which is too large for running Monte Carlo simulations at a reasonable cost. In the present work, an order reduction method is introduced which is capable of generating reasonably accurate, very low order models of tuned or mistuned bladed disks. This technique is based on component modes of vibration found from a finite element analysis of a single disk-blade sector. It is shown that the phenomenon of mode localization is well captured by the reduced order modeling technique.
Cyclin E low molecular weight isoforms occur commonly in early-onset gastric cancer and independently predict survival
Authors: Milne A N A , Carvalho R , Jansen M , Kranenbarg E K , van de Velde C J H , Morsink F M , Musler A R , Weterman M A J , Offerhaus G J A 
Published: February 2008

Background:Post-translational cleavage of full-length cyclin E from the N-terminus can produce low molecular weight (LMW) isoforms of cyclin E containing the C-terminus only.Aim:To assess their presence in early-onset gastric cancer (EOGC), stump cancers and conventional gastric cancers and ascertain how they influence survival in EOGC.Methods:The expression of full-length and LMW isoforms of cyclin E in 330 gastric cancers, including early-onset gastric cancer (EOGC), stump cancer and conventional gastric cancer (>45 years old) was compared using antibodies targeted to the N- and C-terminals.Results:LMW isoforms were found in 35% of EOGCs, compared to 8% of conventional gastric cancers and 4% of stump cancers; their presence was visualised in cell lines using western blot analysis. In addition, C-terminal staining was a positive predictor of survival in EOGC. In contrast, no correlation with survival was found with the N-terminal antibody which detects only full-length cyclin E.Conclusion:EOGCs have a unique molecular phenotype and LMW isoforms of cyclin E may independently influence survival in EOGC.
The clinical significance of antinucleolar antibodies
Authors: Khan S , Alvi A , Holding S , Kemp M L , Raine D , Doré P C , Sewell W A C 
Published: February 2008

Background:The importance of antinucleolar antibodies seen by indirect immunofluorescence on HEp-2 cells, although associated with systemic sclerosis (SSc), in unselected patients is unknown.Aims:To determine the true clinical significance of antinucleolar antibodies in an unselected patient population.Methods:Antinucleolar antibody (ANoA) positive samples were identified in the immunology laboratory during routine autoimmune screening tests; case notes were reviewed using a standard proforma.Results:104 patients with ANoA were identified and ANoA+samples were subclassified into homogeneous, clumpy and speckled antinucleolar types. SSc was evident in only two (1.8%) patients. Other connective tissue diseases were identified in 33 patients (32%); 22 patients (21%) had evidence of various malignancies. Both disordered liver function and anaemia were seen in 22 patients and were the commonest laboratory abnormalities.Conclusions:Neither the presence nor subtype of ANoA is specific for systemic sclerosis. Laboratory comments appended to results should reflect this fact.
Event-related Potential Correlates of Negation in a Sentence–Picture Verification Paradigm
Authors: Lüdtke Jana , Friedrich Claudia K. , De Filippis Mónica , Kaup Barbara 
Published: February 2008

Abstract
In a sentence–picture verification paradigm, participants were presented in a rapid-serial-visual-presentation paradigm with affirmative or negative sentences (e.g., “In the front of the tower there is a/no ghost”) followed by a matching or mismatching picture. Response latencies and event-related potentials (ERPs) were measured during reading and verification. An enhanced negative shift in the ERPs for the subject noun (i.e., “ghost”) in negative, compared to affirmative sentences, was found during reading. We relate this ERP deflection to enhanced processing demands required by the negative particle no. Although this effect suggests a direct impact of negation on language processing, results for picture processing reveal that negation is not immediately integrated into sentence meaning. When the delay of picture presentation was short (250 msec), verification latencies and ERPs evoked by the picture showed a priming effect independent of whether the sentence contained a negation. Unprimed pictures (foreground object not mentioned in the sentence) led to longer latencies and higher N400 amplitudes than primed pictures (foreground object mentioned in the sentence). Main effects of negation showed up only in a late positive-going ERP effect. In contrast, when the delay was long (1500 msec), we observed main effects of truth value and negation in addition to the priming effect already in the N400 time window, that is, negation is fully integrated into sentence meaning only at a later point in the comprehension process. When negation has not yet been integrated, verification decisions appear to be modulated by additional time-consuming reanalysis processes.
When a Thought Equals a Look: Refreshing Enhances Perceptual Memory
Authors: Yi Do-Joon , Turk-Browne Nicholas B. , Chun Marvin M. , Johnson Marcia K. 
Published: February 2008

Abstract
Cognition constantly involves retrieving and maintaining information that is not perceptually available in the current environment. Studies on visual imagery and working memory suggest that such high-level cognition might, in part, be mediated by the revival of perceptual representations in the inferior temporal cortex. Here, we provide new support for this hypothesis, showing that reflectively accessed information can have similar consequences for subsequent perception as actual perceptual input. Participants were presented with pairs of frames in which a scene could appear, and were required to make a category judgment on the second frame. In the critical condition, a scene was presented in the first frame, but the second frame was blank. Thus, it was necessary to refresh the scene from the first frame in order to make the category judgment. Scenes were then repeated in subsequent trials to measure the effect of refreshing on functional magnetic resonance imaging repetition attenuation—a neural index of memory—in a scene-selective region of the visual cortex. Surprisingly, the refreshed scenes produced equal attenuation as scenes that had been presented twice during encoding, and more attenuation than scenes that had been presented once during encoding, but that were not refreshed. Thus, the top-down revival of a percept had a similar effect on memory as actually seeing the stimulus again. These findings indicate that high-level cognition can activate stimulus-specific representations in the ventral visual cortex, and that such top-down activation, like that from sensory stimulation, produces memorial changes that affect perceptual processing during a later encounter with the stimulus.
Noninvasive Brain Stimulation Improves Language Learning
Authors: Flöel Agnes , Rösser Nina , Michka Olesya , Knecht Stefan , Breitenstein Caterina 
Published: February 2008

AbstractAnodal transcranial direct current stimulation (tDCS) is a reliable technique to improve motor learning. We here wanted to test its potential to enhance associative verbal learning, a skill crucial for both acquiring new languages in healthy individuals and for language reacquisition after stroke-induced aphasia. We applied tDCS (20 min, 1 mA) over the posterior part of the left peri-sylvian area of 19 young right-handed individuals while subjects acquired a miniature lexicon of 30 novel object names. Every subject participated in one session of anodal tDCS, one session of cathodal tDCS, and one sham session in a randomized and double-blinded design with three parallel versions of the miniature lexicon. Outcome measures were learning speed and learning success at the end of each session, and the transfer to the subjects' native language after the respective stimulation. With anodal stimulation, subjects showed faster and better associative learning as compared to sham stimulation. Mood ratings, reaction times, and response styles were comparable between stimulation conditions. Our results demonstrate that anodal tDCS is a promising technique to enhance language learning in healthy adults and may also have the potential to improve language reacquisition after stroke.
Involuntary Attentional Capture is Determined by Task Set: Evidence from Event-related Brain Potentials
Authors: Eimer Martin , Kiss Monika 
Published: February 2008

Abstract
To find out whether attentional capture by irrelevant but salient visual objects is an exogenous bottom–up phenomenon, or can be modulated by current task set, two experiments were conducted where the N2pc component was measured as an electrophysiological marker of attentional selection in response to spatially uninformative color singleton cues that preceded target arrays. When observers had to report the orientation of a uniquely colored target bar among distractor bars (color task), behavioral spatial cueing effects were accompanied by an early cue-induced N2pc, indicative of rapid attentional capture by color singleton cues. In contrast, when they reported the orientation of target bars presented without distractors (onset task), no behavioral cueing effects were found and no early N2pc was triggered to physically identical cue arrays. Experiment 2 ruled out an alternative interpretation of these N2pc differences in terms of distractor inhibition. These results do not support previous claims that attentional capture is initially unaffected by top–down intention, and demonstrate the central role of task set in involuntary attentional orienting.
Time-course of Posterior Parietal and Occipital Cortex Contribution to Sound Localization
Authors: Collignon Olivier , Davare Marco , De Volder Anne G. , Poirier Colline , Olivier Etienne , Veraart Claude 
Published: February 2008

Abstract
It has been suggested that both the posterior parietal cortex (PPC) and the extrastriate occipital cortex (OC) participate in the spatial processing of sounds. However, the precise time-course of their contribution remains unknown, which is of particular interest, considering that it could give new insights into the mechanisms underlying auditory space perception. To address this issue, we have used event-related transcranial magnetic stimulation (TMS) to induce virtual lesions of either the right PPC or right OC at different delays in subjects performing a sound lateralization task. Our results confirmed that these two areas participate in the spatial processing of sounds. More precisely, we found that TMS applied over the right OC 50 msec after the stimulus onset significantly impaired the localization of sounds presented either to the right or to the left side. Moreover, right PPC virtual lesions induced 100 and 150 msec after sound presentation led to a rightward bias for stimuli delivered on the center and on the left side, reproducing transiently the deficits commonly observed in hemineglect patients. The finding that the right OC is involved in sound processing before the right PPC suggests that the OC exerts a feedforward influence on the PPC during auditory spatial processing.